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82 results on '"Olivier Bourgeois"'

1. Inducing micromechanical motion by optical excitation of a single quantum dot

Author

Alexia Auffèves, Pierre Verlot, Pierre-Louis de Assis, Benjamin Besga, Benjamin Pigeau, Jean-Michel Gérard, Jan Kettler, Laure Mercier de Lépinay, Jean-Philippe Poizat, Nitika Vaish, Maxime Richard, Julien Claudon, Olivier Arcizet, Olivier Bourgeois, Nanophysique et Semiconducteurs (NEEL - NPSC), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Nano-Optique et Forces (NEEL - NOF), Laboratoire de Physique de l'ENS Lyon (Phys-ENS), École normale supérieure de Lyon (ENS de Lyon)-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Universidade Estadual de Campinas = University of Campinas (UNICAMP), Thermodynamique et biophysique des petits systèmes (NEEL - TPS), Nanophysique et Semiconducteurs (NPSC), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), University of Nottingham, UK (UON), ANR-16-CE09-0010,QDOT,Transducteurs optomécaniques à base de boites quantiques(2016), ANR-16-CE30-0021,QFL,Fluides Quantiques de Lumière(2016), Nano-Optique et Forces (NOF), École normale supérieure - Lyon (ENS Lyon)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, University of Campinas [Campinas] (UNICAMP), Thermodynamique et biophysique des petits systèmes (TPS), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Université Grenoble Alpes (UGA)

Subjects
Orders of magnitude (temperature), Exciton, Biomedical Engineering, FOS: Physical sciences, Bioengineering, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, law.invention, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], law, Quantum state, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), General Materials Science, Electrical and Electronic Engineering, Quantum, ComputingMilieux_MISCELLANEOUS, [PHYS]Physics [physics], Physics, Quantum Physics, Condensed Matter - Mesoscale and Nanoscale Physics, business.industry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Laser, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, Radiation pressure, Quantum dot, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Optoelectronics, Quantum Physics (quant-ph), 0210 nano-technology, business, Excitation
Abstract

Hybrid quantum optomechanical systems offer an interface between a single two-level system and a macroscopical mechanical degree of freedom. In this work, we build a hybrid system made of a vibrating microwire coupled to a single semiconductor quantum dot (QD) via material strain. It was shown a few years ago, that the QD excitonic transition energy can thus be modulated by the microwire motion. We demonstrate here the reverse effect, whereby the wire is set in motion by the resonant drive of a single QD exciton with a laser modulated at the mechanical frequency. The resulting driving force is found to be almost 3 orders of magnitude larger than radiation pressure. From a fundamental aspect, this state dependent force offers a convenient strategy to map the QD quantum state onto a mechanical degree of freedom., Comment: 16 pages, 12 figures

Published
2020

2. Niobium Nitride Thin Films for Very Low Temperature Resistive Thermometry

Author

Benjamin A. Piot, Mathieu Gibert, Adib Tavakoli, Eddy Collin, Aki Ruhtinas, Rahul Swami, Pablo Garcia-Campos, Jeremy Gradel, Sébastien Triqueneaux, Klaus Hasselbach, Olivier Bourgeois, Aviad Frydman, Tuyen Nguyen, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Cryogénie (Cryo), Magnétisme et Supraconductivité (MagSup ), Bar-Ilan University [Israël], Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G ), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Hélium : du fondamental aux applications (HELFA), and Ultra-basses températures (UBT)

Subjects
Niobium nitride, Materials science, FOS: Physical sciences, Applied Physics (physics.app-ph), 02 engineering and technology, 7. Clean energy, 01 natural sciences, chemistry.chemical_compound, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, General Materials Science, Thin film, 010306 general physics, Nanoscopic scale, Electrical impedance, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Resistive touchscreen, Condensed Matter - Mesoscale and Nanoscale Physics, business.industry, Physics - Applied Physics, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, Magnetic field, chemistry, Thermometer, Optoelectronics, 0210 nano-technology, business, Temperature coefficient
Abstract

We investigate thin film resistive thermometry based on metal-to-insulator-transition (niobium nitride) materials down to very low temperature. The variation of the NbN thermometer resistance have been calibrated versus temperature and magnetic field. High sensitivity in tempertaure variation detection is demonstrated through efficient temperature coefficient of resistance. The nitrogen content of the niobium nitride thin films can be tuned to adjust the optimal working temperature range. In the present experiment, we show the versatility of the NbN thin film technology through applications in very different low temperature use-cases. We demonstrate that thin film resistive thermometry can be extended to temperatures below 30 mK with low electrical impedance., Comment: Article accepted for publication in JLTP

Published
2019

3. Tectonics of Enceladus’ South Pole: Block Rotation of the Tiger Stripes

Author

Paola Cianfarra, Francesco Salvini, Gabriel Tobie, Olivier Bourgeois, Costanza Rossi, Università degli Studi Roma Tre, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Rossi, C., Cianfarra, P., Salvini, F., Bourgeois, O., and Tobie, G.

Subjects
strike-slip, 010504 meteorology & atmospheric sciences, Lineament, lineaments, Block rotation, Enceladus, lineaments, strike-slip, tectonics, Rotation, Block rotation, 01 natural sciences, Enceladus, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Geochemistry and Petrology, Block (telecommunications), 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), tectonics, 14. Life underwater, lineament, 010303 astronomy & astrophysics, strike‐ slip, 0105 earth and related environmental sciences, Geodesy, Strike-slip tectonics, Tectonics, Geophysics, Space and Planetary Science, Enceladu, Geology
Abstract

The South Polar Terrain (SPT) of Enceladus is a site with eruptions of gas and water ice particle plumes, which indicate internal geodynamic activity. These eruptions are located along a series of tectonic structures, that is, the Tiger Stripe Fractures (TSF), which are composed of regularly spaced, linear depressions. The SPT is surrounded by sinuous chains of ridges and troughs (the Marginal Zone). To unravel the tectonics that affect the region and its evolution, we performed specific structural mapping and quantitative analyses of brittle features from remotely sensed images. The results are consistent with a block rotation model, in which several tectonic regimes coexist. The TSF are left-lateral strike-slip faults that bound rigid elongated blocks. The blocks rotate clockwise and are enclosed in a regional scale right-lateral kinematic framework expressed in the Marginal Zone. These two opposite and complementary kinematic regimes induce transtensional and transpressional regimes within the SPT. An evolutionary tectonic model is proposed for the past and future evolution of the SPT. This model confirms the role of tectonic-related kinematics in icy satellites and contributes to preparations for future missions.

Published
2020

4. Thermal Exchange of Glass Micro-Fibers Measured by the 3ω Technique

Author

T. D. Nguyen, J. Doumouro, Olivier Bourgeois, Jacques Richard, Y. De Wilde, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Laboratoire de Modélisation et Simulation Multi Echelle (MSME), Université Paris-Est Marne-la-Vallée (UPEM)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, Institut Langevin - Ondes et Images (UMR7587) (IL), Sorbonne Université (SU)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Paris (UP)-Centre National de la Recherche Scientifique (CNRS), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)

Subjects
010302 applied physics, Convection, Materials science, Mechanical Engineering, Glass fiber, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Mechanics of Materials, 0103 physical sciences, Thermal, General Materials Science, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Composite material, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall]
Abstract

In this work, we propose an experimental setup to measure the thermal conductivity and specific heat of a single suspended glass fiber, as well as the thermal contact resistance between two glass fibers. By using optical lithography, wet and dry etching and thin film deposition, we prepared suspended glass fibers that are coated by niobium nitride (NbN) thin film used as room temperature thermal transducer. By using the 3ω technique, the thermal conductivity of glass fiber was measured to be 1.1 W m−1 K–1 and specific heat 0.79 J g−1 K–1 around 300 K under vacuum conditions. By introducing exchange gas into the measurement chamber, influence of the gas on the heat transfer was studied, and the convection coefficient h for all the measurement ranges from a pressure of 0.01 hPa to 1000 hPa, over more than five orders of magnitude, has been obtained. By adding a bridging glass fiber on top of two other suspended glass fibers, it was possible to estimate the thermal contact resistance between two glass fibers Rc in the range of 107–108 K W–1.

Published
2020

5. Investigation of specific heat in ultrathin two-dimensional superconducting Pb

Author

T. D. Nguyen, Olivier Bourgeois, Aviad Frydman, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), and Bar-Ilan University [Israël]

Subjects
[PHYS]Physics [physics], Condensed Matter::Quantum Gases, Physics, Superconducting coherence length, Superconductivity, Work (thermodynamics), Condensed matter physics, Transition temperature, 02 engineering and technology, Function (mathematics), BCS theory, 021001 nanoscience & nanotechnology, 01 natural sciences, Measure (mathematics), Singularity, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], Condensed Matter::Superconductivity, 0103 physical sciences, 010306 general physics, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall]
Abstract

Superconductivity in two dimensions is nontrivial. One way to achieve global superconductivity is via the Berezinskii-Kosterlitz-Thouless (BKT) transition due to proliferation of vortex-antivortex pairs. This transition is expected to have a clear signature on the specific heat. The singularity at the transition temperature ${T}_{\mathrm{BKT}}$ is predicted to be immeasurable, and a broad nonuniversal peak is expected at $Tg{T}_{\mathrm{BKT}}$. Up to date, this has not been observed in two-dimensional superconductors; this work is then dedicated to investigate ${c}_{p}$ signatures in the limit of ultrathin 2d superconductors. We use a unique highly sensitive technique to measure the specific heat of quench condensed ultrathin Pb films. We find that thick films exhibit a specific heat jump at ${T}_{C}$ that is consistent with BCS theory. As the film thickness is reduced below the superconducting coherence length and the systems enter the 2D limit, the specific heat reveals BKT-like behavior in what can appear as to be a continuous BCS-BKT crossover as a function of film thickness. However, a number of problems arise with this interpretation. We discuss the experimental results and the possible significance of various scenarios involving BKT physics.

Published
2020

6. Sublimation waves: Geomorphic markers of interactions between icy planetary surfaces and winds

Author

Olivier Bourgeois, S. Douté, M. Bordiec, Clémence Herny, Philippe Claudin, S. Carpy, Marion Massé, Stéphane Pochat, Laurent Perret, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de recherche en Hydrodynamique, Énergétique et Environnement Atmosphérique (LHEEA), École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS), Physique et mécanique des milieux hétérogenes (UMR 7636) (PMMH), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)

Subjects
Bedform, 010504 meteorology & atmospheric sciences, Sublimation, Blue ice, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, 01 natural sciences, Wind speed, Physics::Geophysics, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Planet, Astrophysics::Solar and Stellar Astrophysics, Planetary surfaces, [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Martian, geography, geography.geographical_feature_category, Scaling laws, Instability, Geophysics, Wavelength, Physics::Space Physics, General Earth and Planetary Sciences, Sublimation (phase transition), Astrophysics::Earth and Planetary Astrophysics, Ice sheet, WindIce sheets, Bedforms, Geology
Abstract

International audience; Sublimation waves are periodic, linear and transverse bedforms that grow by sublimation of icy substrates under turbulent winds. They occur in different environments of the Earth and other planets, where the climate is favorable to sublimation. Their morphological and kinematic characteristics (wavelength, migration velocity, characteristic time of formation) depend on the environmental conditions in which they develop (atmosphere viscosity, wind speed, sublimation rate). To highlight these relations, we designed a theoretical model for their formation, based on models previously designed for dissolution bedforms. From a linear stability analysis of the model, we derived a dispersion relation and three scaling laws. These are validated by comparison with measurements available for two natural terrestrial examples (Blue Ice Areas of the Antarctic ice sheets and ice caves) and with new measurements in a laboratory experiment. They are applied to linear bedforms, of hitherto unknown origin, that we identified on the Martian North Polar Cap. We thus demonstrate that sublimation waves are convenient geomorphic markers to constrain surface compositions, atmospheric properties, climates, and winds on terrestrial ice sheets and other icy planetary surfaces.

Published
2020

7. On-chip Thermometry for Microwave Optomechanics Implemented in a Nuclear Demagnetization Cryostat

Author

R. R. Gazizulin, Olivier Maillet, Thierry Crozes, Eddy Collin, A. Luck, Andrew Fefferman, Olivier Bourgeois, J.-F. Motte, D. Cattiaux, Xin Zhou, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Nano and Microsystems - IEMN (NAM6 - IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Ultra-basses températures (UBT), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Nanofab (Nanofab ), Thermodynamique et biophysique des petits systèmes (TPS), Ultra-basses températures (NEEL - UBT), Nanofabrication (NEEL - Nanofab), Thermodynamique et biophysique des petits systèmes (NEEL - TPS), A C K N O W L E D G M E N T S :We acknowledge the use of the Néel facility Nanofab for the device fabrication, and the Néel Cryogenics facility with especially Anne Gerardin for realization of mechanical elements of the demagnetization cryostat. X.Z. and E.C. thank Olivier Arcizet and Benjamin Pigeau for help in room-temperature characterization of the NEMS devices using optics, E.C. also thanks O. Arcizet, M. Sillanpää,K. Lehnert, J. Teufel, S. Barzanjeh, K. Schwab, J. Parpia, and M. Dykman for very useful discussions. We acknowledge support from the ERC CoG Grant ULT-NEMS No. 647917, StG Grant UNIGLASS No. 714692, and theSTaRS-MOC project from Région Hauts-de-France. The research leading to these results has received funding fromthe European Union’s Horizon 2020 Research and Innovation Programme, under Grant Agreement No. 824109, theEuropean Microkelvin Platform (EMP). Note added.—Recently, a collaboration between Aalto University and Institut Néel has started with the aim of cooling down a drumhead Al device as low as possible on our adiabatic nuclear demagnetization platform. We have evidence that the same features as for beams are present, at a different level of expression. This shall be publishedelsewhere., European Project: 647917,H2020,ERC-2014-CoG,ULT-NEMS(2015), European Project: 714692,H2020,ERC-2016-STG,UNIGLASS(2017), and European Project: 824109,H2020,H2020-INFRAIA-2018-1,EMP(2019)

Subjects
Cryostat, Quantum decoherence, Materials science, Nuclear engineering, FOS: Physical sciences, General Physics and Astronomy, 02 engineering and technology, Mechanics, 7. Clean energy, 01 natural sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Thermal, 010306 general physics, Adiabatic process, Optomechanics, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Quantum Physics, Condensed Matter - Mesoscale and Nanoscale Physics, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 3. Good health, Active cooling, 0210 nano-technology, Ground state, Microwave
Abstract

We report on microwave optomechanics measurements performed on a nuclear adiabatic demagnetization cryostat, whose temperature is determined by accurate thermometry from below 500$~\mu$K to about 1$~$Kelvin. We describe a method for accessing the on-chip temperature, building on the blue-detuned parametric instability and a standard microwave setup. The capabilities and sensitivity of both the experimental arrangement and the developed technique are demonstrated with a very weakly coupled silicon-nitride doubly-clamped beam mode of about 4$~$MHz and a niobium on-chip cavity resonating around 6$~$GHz. We report on an unstable intrinsic driving force in the coupled microwave-mechanical system acting on the mechanics that appears below typically 100$~$mK. The origin of this phenomenon remains unknown, and deserves theoretical input. It prevents us from performing reliable experiments below typically 10-30$~$mK; however no evidence of thermal decoupling is observed, and we propose that the same features should be present in all devices sharing the microwave technology, at different levels of strengths. We further demonstrate empirically how most of the unstable feature can be annihilated, and speculate how the mechanism could be linked to atomic-scale two level systems. The described microwave/microkelvin facility is part of the EMP platform, and shall be used for further experiments within and below the millikelvin range., Comment: 14 pages with appendix; plus Erratum 17, 049901 (2022)

Published
2019

8. Measuring Frequency Fluctuations in Nonlinear Nanomechanical Resonators

Author

Rob Ilic, Eddy Collin, Xin Zhou, R. R. Gazizulin, Olivier Maillet, Olivier Bourgeois, Andrew Fefferman, Jeevak M. Parpia, Ultra-basses températures (UBT), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), National Institute of Standards and Technology [Gaithersburg] (NIST), Cornell University [New York], Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel ( NEEL ), Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes [Saint Martin d'Hères], UBT - Ultra-basses températures, Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes [Saint Martin d'Hères]-Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes [Saint Martin d'Hères], National Institute of Standards and Technology [Gaithersburg] ( NIST ), Cornell University, and TPS - Thermodynamique et biophysique des petits systèmes

Subjects
Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Bistability, Dephasing, General Engineering, FOS: Physical sciences, General Physics and Astronomy, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Noise (electronics), Computational physics, Nonlinear system, Resonator, [ PHYS.COND.CM-MSQHE ] Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Limit (music), General Materials Science, 010306 general physics, 0210 nano-technology, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Nanomechanics, Bifurcation
Abstract

Advances in nanomechanics within recent years have demonstrated an always expanding range of devices, from top-down structures to appealing bottom-up MoS$_2$ and graphene membranes, used for both sensing and component-oriented applications. One of the main concerns in all of these devices is frequency noise, which ultimately limits their applicability. This issue has attracted a lot of attention recently, and the origin of this noise remains elusive up to date. In this Letter we present a very simple technique to measure frequency noise in nonlinear mechanical devices, based on the presence of bistability. It is illustrated on silicon-nitride high-stress doubly-clamped beams, in a cryogenic environment. We report on the same $T/f$ dependence of the frequency noise power spectra as reported in the literature. But we also find unexpected {\it damping fluctuations}, amplified in the vicinity of the bifurcation points; this effect is clearly distinct from already reported nonlinear dephasing, and poses a fundamental limit on the measurement of bifurcation frequencies. The technique is further applied to the measurement of frequency noise as a function of mode number, within the same device. The relative frequency noise for the fundamental flexure $\delta f/f_0$ lies in the range $0.5 - 0.01~$ppm (consistent with literature for cryogenic MHz devices), and decreases with mode number in the range studied. The technique can be applied to {\it any types} of nano-mechanical structures, enabling progresses towards the understanding of intrinsic sources of noise in these devices., Comment: Published 7 may 2018

Published
2018

9. Effect of texture on the structural and transport properties of Sb-doped Mg2Si thin films

Author

Olivier Bourgeois, C. Prahoveanu, Laetitia Laversenne, C. De Vaulx, Yanqing Liu, Ana Lacoste, M. Salaun, Dimitri Tainoff, Kamel Azzouz, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS), Optique et Matériaux (OPTIMA ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Thermodynamique et biophysique des petits systèmes (TPS), Matériaux, Rayonnements, Structure (MRS), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
Materials science, Analytical chemistry, Microwave plasma-assisted co-sputtering, 02 engineering and technology, 7. Clean energy, 01 natural sciences, Thermal conductivity, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Electrical resistivity and conductivity, Seebeck coefficient, 0103 physical sciences, Thermoelectric effect, Materials Chemistry, Texture, Texture (crystalline), Thin film, Composite material, 010302 applied physics, Mechanical Engineering, Doping, Metals and Alloys, 021001 nanoscience & nanotechnology, Thermoelectric materials, Mechanics of Materials, Transport properties, Sb-doped Mg2Si thin films, 0210 nano-technology
Abstract

International audience; With the ever increasing energy demand, the need for miniaturized thermoelectric (TE) devices that minimize energy waste is becoming urgent. In this context, the use of thin film-based devices is a promising strategy provided that suitable materials with appropriate properties are developed. Here, for applications at temperatures ranging from 500 K to 850 K, the TE properties of the Mg2Si compound are investigated after its deposition as thin film by microwave plasma-assisted co-sputtering method. The effects of doping the Mg2Si films with different Sb contents and of the deposition temperature are assessed. Structural characterization shows that the films grown at room temperature exhibit a larger degree of texture and strains compared to those deposited at 463 K. Furthermore, the TE properties (electrical conductivity, Seebeck coefficient, thermal conductivity) are affected in a different way by the deposition temperature, resulting eventually in a higher power factor (based on in-plane characteristics) and higher thermal conductivity (measured out-of-plane) for RT depositions

Published
2016

10. Experimental modeling of pressurized subglacial water flow: Implications for tunnel valley formation

Author

Régis Mourgues, Stéphane Pochat, Olivier Bourgeois, Pierre Strzerzynski, Thomas Lelandais, and Edouard Ravier

Subjects
geography, geography.geographical_feature_category, Tunnel valley, 010504 meteorology & atmospheric sciences, Water flow, Landform, 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, Erosion, Drainage, Ice sheet, Meltwater, Geomorphology, Groundwater, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract

Tunnel valleys are elongated hollows commonly found in formerly glaciated areas and interpreted as resulting from subglacial meltwater erosion beneath ice sheets. Over the past two decades, the number of studies of terrestrial tunnel valleys has continuously increased and their existence has been hypothesized also on Mars, but their formation mechanisms remain poorly understood. We introduce here, an innovative experimental approach to examine erosion by circulation of pressurized meltwater within the substratum and at the silicon-substratum interface. We used a permeable substratum (sand) partially covered by a viscous, impermeable and transparent lid (silicon putty), below which we applied a central injection of pure water. Low water pressures led to groundwater circulation in the substratum only, while water pressures exceeding the sum of the glaciostatic and lithostatic pressures led to additional water circulation and formation of drainage landforms at the cap-substratum interface. The formation of these drainage landforms was monitored through time and their shapes were analyzed from digital elevation model obtained by stereo-photogrammetry. The experimental landforms include valleys that are similar to natural tunnel valleys in their spatial organization and in a number of diagnostic morphological criteria, such as undulating longitudinal profiles and “tunnel” shapes. These results are consistent with the hypothesis that overpressurized subglacial water circulation controls the formation of tunnel valleys.

Published
2016

11. A paraglacial rock-slope failure origin for cirques: a case study from Northern Iceland

Author

Denis Mercier, Julien Coquin, Olivier Bourgeois, Armelle Decaulne, Littoral, Environnement, Télédétection, Géomatique (LETG - Nantes), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN), Laboratoire de géographie physique : Environnements Quaternaires et Actuels (LGP), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN), Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université de Brest (UBO)-Université de Caen Normandie (UNICAEN), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010506 paleontology, erosion rates, gravitational spreading, 0507 social and economic geography, rock slope failure, deglaciation, cirques glaciaires, 01 natural sciences, Paraglacial, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Glacial period, Geomorphology, ComputingMilieux_MISCELLANEOUS, Holocene, rupture de versants rocheux, étalement gravitaire, 0105 earth and related environmental sciences, Earth-Surface Processes, déglaciation, geography, geography.geographical_feature_category, Plateau, 05 social sciences, Cirque, Glacier, 15. Life on land, Cirque glacier, glacial cirques, taux d’érosion, Quaternary, 050703 geography, Geology
Abstract

The contribution of paraglacial rock-slope failure (RSF) to the excavation of cirques in glacial landscapes is explored in the Tindastóll Mountain, Skagi peninsula, northern Iceland. We analyze 8 cirques that developed during the Quaternary and 13 paraglacial RSF cavities that developed during the Holocene in this paleo-plateau. From a reconstruction of the pre-Quaternary surface of the plateau, we calculate the excavated volumes of the cirques and RSF cavities and quantify the contribution of Holocene RSF to cirque growth. By extrapolating this contribution to the whole Quaternary, we find that paraglacial RSF is a first-order contributor to the development of cirques. This contribution is twofold: first, paraglacial RSF creates cavities along valley slopes, in which cirque glaciers can develop during subsequent glaciations; second, paraglacial RSF along pre-existing cirque walls promotes cirque widening and deepening. Our results also reveal that Quaternary glacial/paraglacial erosion rates range from 0.02 to 0.17 mm yr‑¹ in the studied cirques. We infer that glaciers are (i) efficient preparatory factors for the destabilization of slopes by paraglacial RSF, (ii) efficient conveyors to evacuate deposits produced by paraglacial RSF in cirques, but (iii) not necessarily predominant agents in the excavation of cirque bedrocks. La contribution des mouvements de masse rocheuse paraglaciaires au creusement de cirques dans des paysages glaciaires est explorée dans la montagne de Tindastóll, dans la péninsule de Skagi, dans le nord de l'Islande. Nous analysons 8 cirques qui se sont développés pendant le Pléistocène et 13 cavités de mouvements de masse rocheuse paraglaciaires qui se sont développées pendant l'Holocène dans ce paléo-plateau. À partir d'une reconstruction de la surface pré-quaternaire du plateau, nous calculons les volumes excavés des cirques et des cavités des mouvements de masse rocheuse et quantifions leur contribution au cours de l'Holocène à l’élargissement du cirque. En extrapolant cette contribution à l'ensemble du Quaternaire, nous constatons que les mouvements de masse rocheuse paraglaciaires sont des contributeurs de premier ordre au développement des cirques. Cette contribution est double : premièrement, les mouvements de masse rocheuse paraglaciaires créent des cavités le long des versants de la vallée, dans lesquels des glaciers de cirque peuvent se développer lors de glaciations ultérieures ; deuxièmement, les mouvements de masse rocheuse paraglaciaires le long des parois de cirque préexistants favorisent l’élargissement et l’approfondissement du cirque lui-même. Nos résultats révèlent également que les taux d’érosion glaciaire / paraglaciaire du Quaternaire varient de 0,02 à 0,17 mm par an dans les cirques étudiés. Nous en déduisons que les glaciers sont (i) des facteurs préparatoires efficaces pour la déstabilisation des pentes par les mouvements de masse rocheuse paraglaciaires, (ii) des convoyeurs efficaces pour évacuer les dépôts produits par les mouvements de masse rocheuse paraglaciaire dans les cirques, mais (iii) des agents non nécessairement prédominants dans l'excavation des planchers du cirque.

Published
2019

12. Nanowire forest of pnictogen–chalcogenide alloys for thermoelectricity

Author

Clivia M. Sotomayor-Torres, Juliana Jaramillo Fernandez, Daniel Bourgault, David Lacroix, Dhruv Singhal, Laurent Cagnon, Dimitri Tainoff, Olivier Bourgeois, Jacques Richard, Jessy Paterson, Emigdio Chavez-Angel, Meriam Ben-Khedim, Denis Buttard, Agencia Estatal de Investigación (España), Agence Nationale de la Recherche (France), Ministerio de Ciencia, Innovación y Universidades (España), Generalitat de Catalunya, Ministerio de Economía y Competitividad (España), European Commission, Singhal, Dhruv [0000-0003-3362-5990], Paterson, Jessy [0000-0003-0508-2191], Chávez, Emigdio [0000-0002-9783-0806], Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Silicon Nanoelectronics Photonics and Structures (SiNaps), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Micro et NanoMagnétisme (MNM ), Catalan Institute of Nanotechnology (ICN-CIN2), Universitat Autònoma de Barcelona (UAB), Institució Catalana de Recerca i Estudis Avançats (ICREA), Laboratoire Énergies et Mécanique Théorique et Appliquée (LEMTA ), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), IMPACT N4S, ANR-15-IDEX-0004,LUE,Isite LUE(2015), Singhal, Dhruv, Paterson, Jessy, Chávez, Emigdio, Thermodynamique et biophysique des petits systèmes (NEEL - TPS), Micro et NanoMagnétisme (NEEL - MNM), and ICN2 - Institut Catala de Nanociencia i Nanotecnologia (ICN2)

Subjects
Materials science, Boundary scattering, Chalcogenide, Nanowire, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, 7. Clean energy, chemistry.chemical_compound, Thermal conductivity, Electrical resistivity and conductivity, Seebeck coefficient, Thermoelectric effect, Electrical conductivity, Thermoelectric conversion, General Materials Science, Pnictogen, ComputingMilieux_MISCELLANEOUS, Chalcogenide compound, business.industry, Nanoporous, Thermoelectric figure of merit, 021001 nanoscience & nanotechnology, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, Potential building blocks, 0104 chemical sciences, chemistry, Temperature dependence, Measurement techniques, [SPI.MECA.THER]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph], Optoelectronics, 0210 nano-technology, business
Abstract

Pnictogen and chalcogenide compounds have been seen as high-potential materials for efficient thermoelectric conversion over the past few decades. It is also known that with nanostructuration, the physical properties of these pnictogen–chalcogenide compounds can be further enhanced towards a more efficient heat conversion. Here, we report the reduced thermal conductivity of a large ensemble of Bi2Te3 alloy nanowires (70 nm in diameter) with selenium for n-type and antimony for p-type (Bi2Te3−ySey and Bi2−xSbxTe3 respectively). The nanowire growth was carried out through electrodeposition in nanoporous aluminium oxide templates with high aspect ratios leading to a forest (109 per centimetre square) of nearly identical nanowires. The temperature dependence of thermal conductivity for the nanowire ensembles was acquired through a highly sensitive 3ω measurement technique. The change in the thermal conductivity of nanowires is largely affected by the roughness in addition to the size effect due to enhanced boundary scattering. The major factor that influences the thermal conductivity was found to be the ratio of the rms roughness to the correlation length of the nanowire. With a high Seebeck coefficient and electrical conductivity at room temperature, the overall thermoelectric figure of merit ZT allows the consideration of such forests of nanowires as efficient potential building blocks of future TE devices., The authors acknowledge funding and support from the ANR project MESOPHON, the Laboratoire dexcellence LANEF in Grenoble (No. ANR-10-LABX-51-01), and from the ANRT. ECA, JJF and CMST acknowledge support from the Severo Ochoa Program (MINECO, Grant SEV-2017-0706) and funding from the CERCA Programme/Generalitat de Catalunya. Funding from the Spanish Ministry MINECO/FEDER: FIS2015-70862-P PHENTOM is also acknowledged.

Published
2019

13. Network of thermoelectric nanogenerators for low power energy harvesting

Author

Sébastien Dufresnes, Anaïs Proudhom, Olivier Bourgeois, Sylvain Dumont, Céline Tur, Daniel Bourgault, Thierry Crozes, Dimitri Tainoff, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Nanofab (Nanofab ), and Electronique (ElecLab)

Subjects
Materials science, Airflow, FOS: Physical sciences, 02 engineering and technology, Applied Physics (physics.app-ph), 010402 general chemistry, 01 natural sciences, 7. Clean energy, Temperature measurement, Planar, Thermal insulation, Thermoelectric effect, General Materials Science, Electrical and Electronic Engineering, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Renewable Energy, Sustainability and the Environment, business.industry, Physics - Applied Physics, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Temperature gradient, Optoelectronics, 0210 nano-technology, business, Energy harvesting, Voltage
Abstract

International audience; We report the design, elaboration and measurements of an innovative planar thermoelectric (TE) devices made of a large array of small mechanically suspended nanogenerators (nanoTEG). The miniaturized TE generators based on SiN membranes are arranged in series and/or in parallel depending on the expected final resistance adapted to the one of the load. The microstructuration allows, at the same time, a high thermal insulation of the membrane from the silicon frame and high thermal coupling to its environment (surrounding air, radiations). We show a ratio of 60% between the measured effective temperature of the membrane, (and hence of the TE junctions), and the available temperature of the heat source (air). The thermal gradient generated across the TE junction reaches a value as high as 60 kelvin per mm. Energy harvesting with this planar TE module is demonstrated through the collected voltage on the TE junctions when a temperature gradient is applied, showing a harvested power on the order of 0.3 µWatt for a 1 cm 2 chip for an effective temperature gradient of 10 K. The optimization of nanoTEGs performances will increase the power harvested significantly and permit to send a signal by a regular communication protocol and feed basic functions like temperature measurement or airflow sensing.

Published
2019

14. Observational evidence for active dust storms on Titan at equinox

Author

Clément Narteau, Roger N. Clark, Benjamin Charnay, T. Appéré, S. Courrech du Pont, Jason M. Soderblom, Thomas Cornet, B. J. Buratti, J. Bow, G. Vixie, Jasper F. Kok, Jason W. Barnes, Ralf Jaumann, Philip D. Nicholson, Mathieu Hirtzig, Pascal Rannou, S. Le Mouélic, Olivier Bourgeois, Jani Radebaugh, L. Maltagliati, Ralph D. Lorenz, Kevin H. Baines, Sebastien Rodriguez, Robert H. Brown, Christophe Sotin, Antoine Lucas, S. Rafkin, Caitlin A. Griffith, Katrin Stephan, Athena Coustenis, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), College of Earth, Ocean and Atmospheric Sciences [Corvallis] (CEOAS), Oregon State University (OSU), Christ University, Bangalore, India, Department of Space Studies [Boulder], Southwest Research Institute [Boulder] (SwRI), University of Arizona, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Geological Sciences [BYU], Brigham Young University (BYU), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Groupe de spectrométrie moléculaire et atmosphérique (GSMA), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [Tucson] (LPL), Department of Planetary Sciences [Tucson], University of Idaho [Moscow, USA], Matière et Systèmes Complexes (MSC (UMR_7057)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), DLR Institute of Planetary Research, German Aerospace Center (DLR), Faculty of Sciences [Lebanese University], Lebanese University [Beirut] (LU), John Innes Centre [Norwich], Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), California Institute of Technology (CALTECH)-NASA, Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Southwest Research Institute [San Antonio] (SwRI), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Centre de physique moléculaire optique et hertzienne (CPMOH), Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1, Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Lebanese University [Beirut], Laboratoire d'Electronique et des Technologies de l'Information (CEA-LETI), Université Grenoble Alpes (UGA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Centre National de la Recherche Scientifique (CNRS), and Matière et Systèmes Complexes (MSC)

Subjects
Haze, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Equator, Equinox, 01 natural sciences, Methane, Astrobiology, chemistry.chemical_compound, symbols.namesake, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, dust storm, 0103 physical sciences, Radiative transfer, Meteorology & Atmospheric Sciences, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [MATH]Mathematics [math], [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Storm, Planetengeologie, chemistry, 13. Climate action, [SDU]Sciences of the Universe [physics], symbols, General Earth and Planetary Sciences, Aeolian processes, Cassini, Titan, Titan (rocket family)
Abstract

Saturn’s moon Titan has a dense nitrogen-rich atmosphere, with methane as its primary volatile. Titan’s atmosphere experiences an active chemistry that produces a haze of organic aerosols that settle to the surface and a dynamic climate in which hydrocarbons are cycled between clouds, rain and seas. Titan displays particularly energetic meteorology at equinox in equatorial regions, including sporadic and large methane storms. In 2009 and 2010, near Titan’s northern spring equinox, the Cassini spacecraft observed three distinctive and short-lived spectral brightenings close to the equator. Here, we show from analyses of Cassini spectral data, radiative transfer modelling and atmospheric simulations that the brightenings originate in the atmosphere and are consistent with formation from dust storms composed of micrometre-sized solid organic particles mobilized from underlying dune fields. Although the Huygens lander found evidence that dust can be kicked up locally from Titan’s surface, our findings suggest that dust can be suspended in Titan’s atmosphere at much larger spatial scale. Mobilization of dust and injection into the atmosphere would require dry conditions and unusually strong near-surface winds (about five times more than estimated ambient winds). Such strong winds are expected to occur in downbursts during rare equinoctial methane storms—consistent with the timing of the observed brightenings. Our findings imply that Titan—like Earth and Mars—has an active dust cycle, which suggests that Titan’s dune fields are actively evolving by aeolian processes. Saturn’s moon Titan may have an active dust cycle in equatorial regions driven by storm winds, Cassini observations consistent with dust suspension in Titan’s atmosphere suggest.

Published
2018

15. Enceladus's internal ocean and ice shell constrained from Cassini gravity, shape, and libration data

Author

Ondřej Čadek, A. Lefèvre, Giuseppe Mitri, Marion Massé, Gabriel Tobie, Tim Van Hoolst, Gaël Choblet, Marie Běhounková, Olivier Bourgeois, Anthony Trinh, and Rose-Marie Baland

Subjects
Gravity (chemistry), 010504 meteorology & atmospheric sciences, Shell (structure), Geophysics, Radius, 01 natural sciences, Plume, 13. Climate action, Lithosphere, 0103 physical sciences, Sea ice thickness, Libration, General Earth and Planetary Sciences, 14. Life underwater, Enceladus, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract

The intense plume activity at the South Pole of Enceladus together with the recent detection of libration hints at an internal water ocean underneath the outer ice shell. However, the interpretation of gravity, shape, and libration data leads to contradicting results regarding the depth of ocean/ice interface and the total volume of the ocean. Here we develop an interior structure model consisting of a rocky core, an internal ocean, and an ice shell, which satisfies simultaneously the gravity, shape, and libration data. We show that the data can be reconciled by considering isostatic compensation including the effect of a few hundred meter thick elastic lithosphere. Our model predicts that the core radius is 180–185 km, the ocean density is at least 1030 kg/m3, and the ice shell is 18–22 km thick on average. The ice thicknesses are reduced at poles decreasing to less than 5 km in the south polar region.

Published
2016

16. Thermal conductivity and thermal boundary resistance of amorphous Al2O3 thin films on germanium and sapphire

Author

Dhruv Singhal, Jacques Richard, Olivier Bourgeois, Dimitri Tainoff, Jessy Paterson, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)

Subjects
010302 applied physics, Materials science, Thermal resistance, Analytical chemistry, General Physics and Astronomy, chemistry.chemical_element, Germanium, 02 engineering and technology, Substrate (electronics), 021001 nanoscience & nanotechnology, 7. Clean energy, 01 natural sciences, Amorphous solid, Atomic layer deposition, Thermal conductivity, chemistry, 0103 physical sciences, Interfacial thermal resistance, Thin film, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall]
Abstract

Sub-nanometer thickness accuracy and excellent conformity make atomic layer deposited films prevalent in modern electronics, continuously shrinking in size. The thermal resistance of these films plays a major role in the overall energy efficiency of miniaturized devices. We report very sensitive thermal conductivity measurements of amorphous Al 2O 3 thin films grown using atomic layer deposition in the temperature range of 100–300 K. The 3 ω method is used to characterize these films ranging from 17.0 to 119.4 nm in thickness, using a series-resistor model to deconvolve the intrinsic thermal conductivity of the film from thermal boundary resistances inherently present in the multilayer system. The thermal conductivity of amorphous alumina films with a density of 2.77 ± 0.14 g cm − 3 is measured to be 1.73 ± 0.08 W m − 1 K − 1 at 300 K. Measurements were carried out on germanium and sapphire substrates, leading to no substrate dependence of the films’ thermal conductivity, within experimental accuracy. On the other hand, thermal boundary resistances of the systems Pt/Al 2O 3/substrate are observed to be strongly substrate-dependent, with values ranging from 2.1 × 10 − 8 m 2 K W − 1 to 3.7 × 10 − 8 m 2 K W − 1 at 300 K for films deposited on sapphire and germanium, respectively. These results provide further insights into the significance of interfaces in thermal transport across layered materials, in particular, for potential germanium-based devices.

Published
2020

17. Measurement of heat conduction in a ballistic 1D phonon waveguide: no quantization of the thermal conductance

Author

Eddy Collin, Olivier Bourgeois, Thierry Crozes, Kunal Lulla, and Adib Tavakoli

Subjects
Josephson effect, Materials science, Condensed matter physics, Phonon, Nanowire, 02 engineering and technology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Thermal conduction, 01 natural sciences, Quantum technology, Quantization (physics), Thermal conductivity, 0103 physical sciences, 010306 general physics, 0210 nano-technology, Quantum tunnelling
Abstract

with the emergence of quantum technologies mastering thermal management is required, especially at the nanoscale. It is now accepted that thermal metamaterials (phononic diodes, themo-crystals) based on phonon manipulation are made possible especially at sub-Kelvin temperatures. In these extreme limits of low temperature and low dimension, phonon heat conduction enters into a quantum regime where the phonon exchange obeys the Landauer formalism. In this regime, phonon transport is governed by the value of the transmission coefficients between the ballistic conductor and the thermal reservoirs. Here, we report an ultra-sensitive thermal experiments made on a ballistic 1D phonon conductor using a new micro-platform suspended sensor. We achieved the measurement of thermal conductance with a resolution of $\Delta \mathrm{K}=\mathrm{K}$ of 1.5% and an unprecedented power sensitivity of few attoWatts around 100 mK. We show that the ballistic thermal transport is dominated by non-ideal transmission coefficients and not by the quantized thermal conductance of the nanowire itself. The measurements reveal scattering mechanisms dominated by phonon diffusion in the reservoirs. Since amorphous silicon nitride are used in that experiment we suspect that scattering of phonons on tunneling two Level systems (TLS) may be at the origin of the reduction of thermal transport. Complementary specific heat experiments are confirming that hypothesis of significant phonon-TLS scattering. The demonstration of the breakdown of the thermal conductance quantization is a major result for the phonon physics, showing that optimized thermal coupling to reservoirs from a 1D structure might be difficult to obtain. This limitation of heat transport in the quantum regime may have significant impacts on the design of modern thermal circuits and nanoelectronics (Josephson junction, quantum solid state devices). This high resolution experimental achievement gives new insight of heat transport in the quantum regime, a scientific goal that has remained uncertain till now.

Published
2018

18. Landform assemblage in Isidis Planitia, Mars: Evidence for a 3 Ga old polythermal ice sheet

Author

Stéphane Pochat, Ondřej Souček, Olivier Bourgeois, Thomas Guidat, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Martian, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Landform, 15. Life on land, Structural basin, 01 natural sciences, Geophysics, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Geochemistry and Petrology, Moraine, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Hesperian, Glacial period, Ice sheet, Meltwater, 010303 astronomy & astrophysics, Geomorphology, ComputingMilieux_MISCELLANEOUS, Geology, 0105 earth and related environmental sciences
Abstract

The floor of Isidis Planitia, a giant impact basin located close to the martian equator, exhibits a landform assemblage, nicknamed Thumbprint Terrain, made of Arcuate Ridges, Aligned Cones, Isolated Cones, Cone Fields, associated with a peripheral network of Sinuous Ridges, Linear Depressions, and Mounds. From a new comprehensive mapping initiative of these landforms and from comparisons with terrestrial analogues (ribbed moraines, dirt cones, kettle holes, eskers, tunnel valleys and moraine plateaux), we demonstrate that this distinctive assemblage is a glacial landsystem inherited from the presence of a massive polythermal ice sheet over the basin during the Hesperian. The flow of the ice sheet was controlled by its basal thermal regime. Wet-based conditions led to the formation of Arcuate Ridges and Aligned Cones in most parts of the basin, while a negative geothermal anomaly due to impact-related crustal thinning was responsible for cold-based conditions in its central part, where only Isolated Cones and Cones Fields are present. Sinuous Ridges, Linear Depressions and Mounds at the basin margins are interpreted as relicts of a radial network of subglacial channels, which drained the glacial meltwater produced within the interior of the ice sheet across its cold-based periphery.

Published
2015

19. Universality of thermal transport in amorphous nanowires at low temperatures

Author

Hossein Ftouni, Christophe Blanc, Andrew Fefferman, Olivier Bourgeois, Adib Tavakoli, Eddy Collin, Kunal Lulla, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Ultra-basses températures (UBT)

Subjects
010302 applied physics, Materials science, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed matter physics, Phonon, Mean free path, Nanowire, FOS: Physical sciences, 02 engineering and technology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Thermal conduction, 01 natural sciences, Power law, Amorphous solid, Condensed Matter::Materials Science, Thermal conductivity, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, 0210 nano-technology, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Quantum tunnelling
Abstract

International audience; Thermal transport properties of amorphous materials at low temperatures are governed by the interaction between phonons and localized excitations referred to as tunneling two level systems (TLS). The temperature variation of the thermal conductivity of these amorphous materials is considered as universal and is characterized by a quadratic power law. This is well described by the phenomenological TLS model even though its microscopic explanation is still elusive. Here, by scaling down to the nanometer scale amorphous systems much below the bulk phonon-TLS mean free path, we probed the robustness of that model in restricted geometry systems. Using very sensitive thermal conductance measurements, we demonstrate that the temperature dependence of the thermal conductance of silicon nitride nanostructures remains mostly quadratic independently of the nanowire section. It is not following the cubic power law in temperature as expected in a Casimir-Ziman regime of boundary limited thermal transport. This shows a thermal transport counter intuitively dominated by phonon-TLS interactions and not by phonon-boundary scattering in the nanowires. This could be ascribed to an unexpected high density of TLS on the surfaces which still dominates the phonon diffusion processes at low temperatures and explains why the universal quadratic temperature dependence of thermal conductance still holds for amorphous nanowires.

Published
2017

20. Quantum criticality at the superconductor to insulator transition revealed by specific heat measurements

Author

T. Nguyen-Duc, Aviad Frydman, Olivier Bourgeois, Assa Auerbach, N. Dupuis, Shachaf Poran, Bar-Ilan University [Israël], Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Technion - Israel Institute of Technology [Haifa], Laboratoire de Physique Théorique de la Matière Condensée (LPTMC), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Thermodynamique et biophysique des petits systèmes (NEEL - TPS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Quantum phase transition, Science, General Physics and Astronomy, FOS: Physical sciences, 01 natural sciences, Article, General Biochemistry, Genetics and Molecular Biology, 010305 fluids & plasmas, Superconductivity (cond-mat.supr-con), Condensed Matter::Superconductivity, Quantum critical point, 0103 physical sciences, 010306 general physics, Quantum, Quantum fluctuation, [PHYS]Physics [physics], Physics, Multidisciplinary, Condensed matter physics, Condensed Matter - Superconductivity, General Chemistry, 3. Good health, Superconductor Insulator Transition, Mean field theory, Criticality, Cooper pair
Abstract

The superconductor-insulator transition (SIT) is considered an excellent example of a quantum phase transition which is driven by quantum fluctuations at zero temperature. The quantum critical point is characterized by a diverging correlation length and a vanishing energy scale. Low energy fluctuations near quantum criticality may be experimentally detected by specific heat, $c_{\rm p}$, measurements. Here, we use a unique highly sensitive experiment to measure $c_{\rm p}$ of two-dimensional granular Pb films through the SIT. The specific heat shows the usual jump at the mean field superconducting transition temperature $T_{\rm c}^{\rm {mf}}$ marking the onset of Cooper pairs formation. As the film thickness is tuned toward the SIT, $T_{\rm c}^{\rm {mf}}$ is relatively unchanged, while the magnitude of the jump and low temperature specific heat increase significantly. This behaviour is taken as the thermodynamic fingerprint of quantum criticality in the vicinity of a quantum phase transition., 9 pages, 5 figures, 1 table

Published
2017

21. Surface-induced near-field scaling in the Knudsen layer of a rarefied gas

Author

R. R. Gazizulin, Olivier Maillet, A. Maldonado Cid, Eddy Collin, Xin Zhou, Olivier Bourgeois, Ultra-basses températures (UBT), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Thermodynamique et biophysique des petits systèmes (TPS)

Subjects
Materials science, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed matter physics, Scattering, General Physics and Astronomy, Rarefaction, FOS: Physical sciences, 02 engineering and technology, Knudsen layer, 021001 nanoscience & nanotechnology, 01 natural sciences, Knudsen equation, Boundary layer, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Kinetic theory of gases, Knudsen number, 010306 general physics, 0210 nano-technology, Scaling, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall]
Abstract

We report on experiments performed within the Knudsen boundary layer of a low-pressure gas. The non-invasive probe we use is a suspended nano-electro-mechanical string (NEMS), which interacts with $^4$He gas at cryogenic temperatures. When the pressure $P$ is decreased, a reduction of the damping force below molecular friction $\propto P$ had been first reported in Phys. Rev. Lett. Vol 113, 136101 (2014) and never reproduced since. We demonstrate that this effect is independent of geometry, but dependent on temperature. Within the framework of kinetic theory, this reduction is interpreted as a rarefaction phenomenon, carried through the boundary layer by a deviation from the usual Maxwell-Boltzmann equilibrium distribution induced by surface scattering. Adsorbed atoms are shown to play a key role in the process, which explains why room temperature data fail to reproduce it., Comment: Article plus supplementary material

Published
2017
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22. Thermally anomalous features in the subsurface of Enceladus’s south polar terrain

Author

Alice Le Gall, Ralph D. Lorenz, C. Leyrat, Léa Bonnefoy, Flora Paganelli, Randolph L. Kirk, Aurélien Stolzenbach, Antoine Lucas, Michael A. Janssen, Christophe Sotin, A. H. Hayes, Gabriel Tobie, Olivier Bourgeois, Marion Massé, Carly Howett, Gaëlle Veyssière, Gaël Choblet, Richard D. West, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Southwest Research Institute [Boulder] (SwRI), Astrogeology Science Center [Flagstaff], United States Geological Survey [Reston] (USGS), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Center for Radiophysics and Space Research [Ithaca] (CRSR), Cornell University [New York], Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), American Public University System (APUS), IMPEC - LATMOS, Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), NASA-California Institute of Technology (CALTECH), Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Cornell University, Météo France-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy and Astrophysics, Terrain, Thermal emission, Geophysics, 01 natural sciences, law.invention, law, Saturn, 0103 physical sciences, Polar, Radar, Microwave radiometry, Enceladus, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Geology, Transport system, 0105 earth and related environmental sciences, Remote sensing
Abstract

International audience; Saturn’s moon Enceladus is an active world. In 2005, the Cassini spacecraft witnessed for the first time water-rich jets venting from four anomalously warm fractures (called sulci) near its south pole (1,2). Since then, several observations have provided evidence that the source of the material ejected from Enceladus is a large underground ocean, the depth of which is still debated (3,​4,​5,​6). Here, we report on the first and only opportunity that Cassini’s RADAR instrument (7,8) had to observe Enceladus’s south polar terrain closely, targeting an area a few tens of kilometres north of the active sulci. Detailed analysis of the microwave radiometry observations highlights the ongoing activity of the moon. The instrument recorded the microwave thermal emission, revealing a warm subsurface region with prominent thermal anomalies that had not been identified before. These anomalies coincide with large fractures, similar or structurally related to the sulci. The observations imply the presence of a broadly distributed heat production and transport system below the south polar terrain with ‘plate-like’ features and suggest that a liquid reservoir could exist at a depth of only a few kilometres under the ice shell at the south pole. The detection of a possible dormant sulcus further suggests episodic geological activity.

Published
2017

23. Nonlinear frequency transduction of nanomechanical Brownian motion

Author

R. R. Gazizulin, Olivier Maillet, Ana Maldonado Cid, Eddy Collin, Martial Defoort, Xin Zhou, Olivier Bourgeois, Ultra-basses températures (UBT), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Thermodynamique et biophysique des petits systèmes (TPS)

Subjects
Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Crossover, Mode (statistics), FOS: Physical sciences, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Nonlinear system, Resonator, Transduction (biophysics), Classical mechanics, Quantum mechanics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, 010306 general physics, 0210 nano-technology, Motional narrowing, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Brownian motion, Free parameter
Abstract

We report on experiments addressing the non-linear interaction between a nano-mechanical mode and position fluctuations. The Duffing non-linearity transduces the Brownian motion of the mode, and of other non-linearly coupled ones, into frequency noise. This mechanism, ubiquitous to all weakly-nonlinear resonators thermalized to a bath, results in a phase diffusion process altering the motion: two limit behaviors appear, analogous to motional narrowing and inhomogeneous broadening in NMR. Their crossover is found to depend non-trivially on the ratio of the frequency noise correlation time to its magnitude. Our measurements obtained over an unprecedented range covering the two limits match the theory of Y. Zhang and M. I. Dykman, Phys. Rev. B 92, 165419 (2015), with no free parameters. We finally discuss the fundamental bound on frequency resolution set by this mechanism, which is not marginal for bottom-up nanostructures., Article plus Supplementary Material

Published
2017
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24. Reduction of phonon mean free path: from low temperature physics to room temperature applications in thermoelectricity

Author

Adib Tavakoli, Christophe Blanc, M. Boukhari, A. Barski, Dimitri Tainoff, Olivier Bourgeois, Emmanuel Hadji, Yanqing Liu, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Silicon Nanoelectronics Photonics and Structures (SiNaps), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Service de Physique des Matériaux et Microstructures (SP2M - UMR 9002), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Thermodynamique et biophysique des petits systèmes (NEEL - TPS)

Subjects
Materials science, Mean free path, Phonon, inclusions, Nanowire, FOS: Physical sciences, Energy Engineering and Power Technology, 02 engineering and technology, Physics and Astronomy(all), 7. Clean energy, 01 natural sciences, thermoelectricity, thermoélectricité, Condensed Matter::Materials Science, Thermal conductivity, Condensed Matter::Superconductivity, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Thermoelectric effect, inclusions Mots-clés : phonon, Thin film, 010306 general physics, semiconducteur, phonon, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed matter physics, Phonon scattering, General Engineering, Materials Science (cond-mat.mtrl-sci), semiconductor, nanofil, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Thermoelectric materials, transport thermique, thermal transport, nanowire, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology
Abstract

International audience; It has been proposed for a long time now that the reduction of the thermal conductivity by reducing the phonon mean free path is one of the best way to improve the current performance of thermoelectrics. By measuring the thermal conductance and thermal conductivity of nanowires and thin films, we show different ways of increasing the phonon scattering from low temperature up to room temperature experiments. It is shown that playing with the geometry (constriction, periodic structures, nano-inclusions), from the ballistic to the diffusive limit, the phonon thermal transport can be severely altered in single crystalline semiconducting structures; the phonon mean free path being in consequence reduced. The diverse implications on thermoelectric properties will be eventually discussed.; Reduction du libre parcours moyen des phonons : de la physique des basses températures aux applications en thermoélectricitésthermoélectricitésà l'ambiante. Il a ´ eté proposé depuis longtemps maintenant que dimi-nuer la conductivité thermique en réduisant le libre parcours moyen des phonons est une des meilleures facons d'améliorer les performances actuelles des matériaux thermoélectriques. En mesurant la conductance thermique et la conductivité thermique de nanofils et de couches minces, nous montrons différentesmanì eres d'augmenter la diffusion des phonons des basses températures jusqu'` a température ambiante. Il est montré qu'en jouant sur la géométrie (constriction, structures périodiques, nano-inclusions), ` a partir de la limite balistique jusqu'` a la limite diffusive, le transport thermique phononique peutêtrepeutêtre de facon significative altéré dans des structures monocris-tallines semiconductrices ; le libre parcours moyen des phononsétantphononsétant réduit en conséquence. Enfin, les diverses implications sur les propriétés thermoélectriques seront discutées.

Published
2016

25. Very Sensitive Nanocalorimetry of Small Mass Systems and Glassy Materials

Author

Jacques Richard, T. Nguyen-Duc, Aviad Frydman, Mohcine Laarraj, Adib Tavakoli, Olivier Bourgeois, Jean-Luc Garden, Thermique Elaboration Matériaux Applications (ThEMA), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Thermodynamique et biophysique des petits systèmes (TPS), Université Hassan II [Casablanca] (UH2MC), and Janez Bonča, Sergei Kruchinin

Subjects
[PHYS]Physics [physics], Measurement method, Range (particle radiation), Materials science, Field (physics), Analytical chemistry, 7. Clean energy, 01 natural sciences, Heat capacity, 010305 fluids & plasmas, Chemical physics, 0103 physical sciences, Monolayer, Thermal, Nanometre, Thin film, 010306 general physics
Abstract

Nanocalorimetry is a technique that deals with any thermal measurement methods in which either the samples to be studied have a size in the range of the nanometer scale or the measured energies involved are of the order of the nanojoule or below Garden et al (Acta 492:16–28, 2009). In this paper, we show the results of two nanocalorimetric experiments. The first one is related to the measurement of specific heat on ultra-thin small systems (thin films) at low temperature. It is shown that such measurement can be sensitive to less than one monolayer of materials. The second one illustrates the efficiency of calorimetric studies sensitive at the nanoJoule on complex system (polymeric glass) at room temperature. We then discuss the potentiality of these experimental methods in the field of security: the measurement of either a very small mass or very small quantity of energy for the detection of tiny thermal events.

Published
2016

26. Is gravitational spreading a precursor for the Stífluhólar landslide (Skagafjörður, Northern Iceland)?

Author

Julien Coquin, Denis Mercier, Thierry Feuillet, Olivier Bourgeois, Armelle Decaulne, Littoral, Environnement, Télédétection, Géomatique (LETG - Nantes), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN), Espaces, Nature et Culture (ENeC), Université Paris-Sorbonne (UP4)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Dynamiques Sociales et Recomposition des Espaces (LADYSS), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris Nanterre (UPN)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université de Brest (UBO)-Université de Caen Normandie (UNICAEN), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Normandie Université (NU)-Normandie Université (NU)-École pratique des hautes études (EPHE)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement (IGARUN), Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université Paris Diderot - Paris 7 (UPD7)-Université Paris Nanterre (UPN)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Panthéon-Sorbonne (UP1)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Panthéon-Sorbonne (UP1)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris Nanterre (UPN)-Université Paris Diderot - Paris 7 (UPD7)

Subjects
landslide, 010504 meteorology & atmospheric sciences, Lava, Paraglacial, Iceland, deglaciation, 010502 geochemistry & geophysics, 01 natural sciences, DSGSD, Bed, Deglaciation, Geomorphology, déglaciation, 0105 earth and related environmental sciences, Earth-Surface Processes, paraglaciaire, geography, geography.geographical_feature_category, Holocene, Bedrock, glissement de terrain, Basal sliding, Landslide, [SHS.GEO]Humanities and Social Sciences/Geography, Palagonite, paraglacial, Islande, 13. Climate action, Holocène, Geology
Abstract

In Iceland, the Late Weichselian deglaciation led to paraglacial topographic readjustments in the form of extensive deep-seated gravitational slope deformation (DSGSD) and large rockslope failures (landslides and rock-avalanches). Here we provide age estimates for the Stífluhólar landslide (Tröllaskagi Peninsula, Northern Central Iceland), which indicate that this occurred between the end of the Late Weichselian deglaciation (15-13 ka cal. yr. BP) and 8200 ± 1400 cal. yr. BP. Our surface observations also suggest that the Stífluhólar landslide was probably initiated by propagation and connection of DSGSD failure planes. This observation suggests that the DSGSD can act as a precursor for landsliding in paraglacial settings. However, further investigations are still required to fully assess the role of DSGSD as a landslide precursor, both at the local and at a regional scale. Comparisons with other examples of paraglacial rock slope failures in Northern Iceland and in the world suggest that DSGSD is not the main or sufficient precondition for large landslides. The landslide of Stífluhólar occurred due to some combination of favorable preconditioning, predisposing and triggering controls. Predisposing controls include: the favourable dip of the bedding planes in the basaltic bedrock and the presence of intercalated poorly cohesive layers of palagonite between the lava layers, probably acting as basal sliding planes for the landslide. En Islande, la déglaciation du Weichselien tardif a conduit à d’importants réajustements topographiques paraglaciaires. Ces réajustements se déclinent sous la forme de processus de déformation du relief par étalement gravitaire (DSGSD) et de mouvements de masse (glissements de terrain et avalanches rocheuses). Dans cette étude, on apporte des éléments de datation au glissement de terrain de Stífluhólar, datations qui indiquent que celui-ci a été actif entre la fin de la déglaciation du Weichselien tardif (15-13 ka) et 8200 ± 1400 ans (âge calibré). Nos observations de surface suggèrent que les déformations par étalement gravitaire ont pu jouer un rôle dans le déclenchement des glissements de terrain. Des études plus approfondies sont néanmoins nécessaires pour confirmer pleinement le rôle de l’étalement gravitaire dans le développement des glissements de terrain, tant à l’échelle du site d’étude qu’à l’échelle régionale. Sur le plan de la discussion, la comparaison avec d’autres processus de réajustement paraglaciaire en Islande et dans le monde suggère néanmoins que les processus d’étalements gravitaires à eux seuls ne sont pas suffisamment efficaces pour déclencher des mouvements de masse. En effet, le glissement de terrain de Stífluhólar est le résultat d’une combinaison complexe de facteurs favorables à son déclenchement. Les paramètres structurels tels que le pendage des bancs de basaltes, conformes à la pente, ainsi que la présence entre ces bancs de couches peu cohérentes de palagonite ont joué un rôle déterminant dans son déclenchement.

Published
2016

27. Equatorial glaciations on Mars revealed by gravitational collapse of Valles Marineris wallslopes

Author

Olivier Bourgeois, Daniel Mège, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Martian, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Glacial landform, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Glacier, Mars Exploration Program, 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, Paraglacial, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Moraine, Ridge, Earth and Planetary Sciences (miscellaneous), Glacial period, Geomorphology, ComputingMilieux_MISCELLANEOUS, Geology, 0105 earth and related environmental sciences
Abstract

Martian global climate models that account for evidence of past glaciations reported in tropical to mid-latitude regions of Mars predict accumulation of water ice in Valles Marineris during past periods of high obliquity. Observational evidence for such glaciations is given here. Topographic basement ridges of tectonic origin are common in Valles Marineris, and display sackung features, an assemblage of tectonic patterns that are diagnostic of deep-seated gravitational slope deformation. This deformation is most easily explained by paraglacial ridge failure subsequent to ridge wall debuttressing and decohesion following the retreat of glaciers. This interpretation is supported by extensive bibliographic analysis of sackung triggers on Earth, by morphological evidence of subglacial erosion of the lower parts of Valles Marineris wallslopes, of periglacial erosion of their upper parts and by the presence of various types of glacial landforms on the floors of Valles Marineris troughs. The age of these equatorial glaciations is found to be older than 1.4 Gy and younger than 3.5 Gy.

Published
2011

28. Novel 'Vibrating Wire Like' NEMS and MEMS Structures for Low Temperature Physics

Author

Johannes Kofler, Yuriy M. Bunkov, Jean-Savin Heron, Eddy Collin, Olivier Bourgeois, Henri Godfrin, Ultra-basses températures (UBT), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), and Thermodynamique et biophysique des petits systèmes (TPS)

Subjects
Microelectromechanical systems, Physics, Quantum fluid, Nanoelectromechanical systems, Cantilever, Nanotechnology, Dissipation, Condensed Matter Physics, 01 natural sciences, Engineering physics, Atomic and Molecular Physics, and Optics, 010305 fluids & plasmas, 0103 physical sciences, General Materials Science, 010306 general physics, Vibrating wire, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Nanomechanics, Microfabrication
Abstract

Using microfabrication techniques, it has become possible to make mechanical devices with dimensions in the micro and even in the nano scale domain. Allied to low temperature techniques, these systems have opened a new path in physics with the ultimate goal of reaching the quantum nature of a macroscopic mechanical degree of freedom (LaHaye et al. in Science 304:74, 2004). Within this field, materials research plays a significant role. It ranges from the fundamental nature of the dissipation mechanisms at the lowest temperatures, to the non-linear behavior of mechanical oscillators. We present experimental results on cantilever structures mimicking the well known “vibrating wire” technique, which present many advantages as far as the mechanical studies are concerned: the measurement is phase-resolved, they can be magnetomotive and electrostatically driven, and support extremely large displacements. Moreover, these devices can be advantageously used to study quantum fluids, making the link with conventional low temperature physics.

Published
2009

29. Non-equilibrium heat capacity of polytetrafluoroethylene at room temperature

Author

Hervé Guillou, Jacques Richard, Jean-Luc Garden, Olivier Bourgeois, Thermique Elaboration Matériaux Applications (ThEMA), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Thermodynamique et biophysique des petits systèmes (TPS), and Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )

Subjects
Phase transition, ac-calorimetry, Thermodynamic equilibrium, FOS: Physical sciences, Thermodynamics, Non-equilibrium thermodynamics, 02 engineering and technology, Calorimetry, Condensed Matter - Soft Condensed Matter, 01 natural sciences, Heat capacity, Relaxation time constants, chemistry.chemical_compound, 020401 chemical engineering, 0103 physical sciences, Thermal, 0204 chemical engineering, Physical and Theoretical Chemistry, Polymer, 010306 general physics, Thermal analysis, Polytetrafluoroethylene, Instrumentation, Frequency dependent complex heat capacity, Chemistry, Condensed Matter Physics, Soft Condensed Matter (cond-mat.soft), [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

International audience; Polytetrafluoroethylene can be considered as a model for calorimetric studies of complex systems with thermodynamics transitions at ambient temperature. This polymer exhibits two phase transitions of different nature at 292 K and 303 K. We show that sensitive ac-calorimetry measurements allow us to study the thermodynamic behaviour of polytetrafluoroethylene when it is brought out of thermodynamic equilibrium. Thanks to the thermal modelisation of our calorimetric device, the frequency dependent complex heat capacity of this polymer is extracted. The temperature and frequency variations of the real and imaginary parts of the complex heat capacity are obtained when polytetrafluoroethylene undergoes its first-order structural phase transition at 292 K.

Published
2007

30. Noise measurements on NbN thin films with a negative temperature resistance coefficient deposited on sapphire and on SiO2

Author

L.K.J. Vandamme, J. Gest, Olivier Bourgeois, G. Leroy, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Integrated Circuits, and Electromagnetic compatibility

Subjects
010302 applied physics, Materials science, Silicon, business.industry, General Mathematics, Analytical chemistry, General Physics and Astronomy, chemistry.chemical_element, Substrate (electronics), 01 natural sciences, 010305 fluids & plasmas, law.invention, Semiconductor, chemistry, law, 0103 physical sciences, Sapphire, Negative temperature, Resistor, Thin film, business, Noise (radio), ComputingMilieux_MISCELLANEOUS, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall]
Abstract

We characterize granular NbN x thin cermet films deposited on either sapphire substrate or on SiO 2 and compare the 1/f noise at 300 K and 80 K. The films were characterized with an impedance analyzer from 20 Hz to 1 MHz and analyzed as a resistor R in parallel with a capacitor C. The calculated noise voltage spectral density SvTh of the sample is in agreement with the experimentally observed noise for unbiased samples. The noise measurements on biased samples show 1/f noise. We checked that contact noise does not contribute to our measurements. The 1/f noise was compared for the films deposited on the silicon substrate and on the sapphire. Finally a model is proposed to explain the observed trends in the temperature resistance coefficient (TRC < 0 for all samples) and the relative 1/f noise at 300 K and 80 K with the composition x = N/Nb of the layers.

Published
2007

31. Nonlinear parametric amplification in a tri-port nanoelectromechanical device

Author

Thomas Moutonet, Olivier Bourgeois, Henri Godfrin, Yurij-U. M. Bunkov, Eddy Collin, Jean-Savin Heron, Ultra-basses températures (UBT), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), and Thermodynamique et biophysique des petits systèmes (TPS)

Subjects
Physics, Nanoelectromechanical systems, Cantilever, Condensed Matter - Mesoscale and Nanoscale Physics, Capacitive sensing, FOS: Physical sciences, Nanotechnology, 02 engineering and technology, Elasticity (physics), 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, Computational physics, Nonlinear system, Control system, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Electronics, 010306 general physics, 0210 nano-technology, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Parametric statistics
Abstract

We report on measurements performed at low temperatures on a nanoelectromechanical system (NEMS) under (capacitive) parametric pumping. The excitations and detection schemes are purely electrical, and enable in the present experiment the straightforward measurement of forces down to about a femtonewton, for displacements of an Angstr\"om, using standard room temperature electronics. We demonstrate that a small (linear) force applied on the device can be amplified up to more than a 100 times, while the system is {\it truly moving}. We explore the dynamics up to about 50$~$nm deflections for cantilevers about 200$~$nm thick by 3$~$$\mu$m long oscillating at a frequency of 7$~$MHz. We present a generic modeling of nonlinear parametric amplification, and give analytic theoretical solutions enabling the fit of experimental results. We finally discuss the practical limits of the technique, with a particular application: the measurement of {\it anelastic damping} in the metallic coating of the device with an exceptional resolution of about 0.5$~$\%.

Published
2015
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32. Thermal conductivity of silicon nitride membranes is not sensitive to stress

Author

Martial Defoort, Jacques Richard, Eddy Collin, Christophe Blanc, Olivier Bourgeois, Andrew Fefferman, Hossein Ftouni, Kunal Lulla, Dimitri Tainoff, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), and Ultra-basses températures (UBT)

Subjects
[PHYS]Physics [physics], Materials science, Condensed Matter - Mesoscale and Nanoscale Physics, FOS: Physical sciences, Context (language use), 02 engineering and technology, Atmospheric temperature range, Dissipation, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, Amorphous solid, Stress (mechanics), chemistry.chemical_compound, Membrane, Thermal conductivity, Silicon nitride, chemistry, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Composite material, 010306 general physics, 0210 nano-technology
Abstract

We have measured the thermal properties of suspended membranes from 10 K to 300 K for two amplitudes of internal stress (about 0.1 GPa and 1 GPa) and for two different thicknesses (50 nm and 100 nm). The use of the original 3 \omega -Volklein method has allowed the extraction of both the specific heat and the thermal conductivity of each SiN membrane over a wide temperature range. The mechanical properties of the same substrates have been measured at helium temperatures using nanomechanical techniques. Our measurements show that the thermal transport in freestanding SiN membranes is not affected by the presence of internal stress. Consistently, mechanical dissipation is also unaffected even though Qs increase with increasing tensile stress. We thus demonstrate that the theory developed by Wu and Yu [Phys. Rev. B 84, 174109 (2011)] does not apply to this amorphous material in this stress range. On the other hand, our results can be viewed as a natural consequence of the "dissipation dilution" argument [Y. L. Huang and P. R. Saulson, Rev. Sci. Instrum. 69, 544 (1998)] which has been introduced in the context of mechanical damping., Comment: 15 pages, 6 figures. Submitted to PRB

Published
2015

33. Lithosphere strength controls oceanic transform zone structure: insights from analogue models

Author

Olivier Dauteuil, Thomas Mauduit, and Olivier Bourgeois

Subjects
geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Transform fault, Geometry, Geophysics, Fault (geology), Classification of discontinuities, 010502 geochemistry & geophysics, 01 natural sciences, Plate tectonics, Discontinuity (geotechnical engineering), Geochemistry and Petrology, Lithosphere, Analogue modelling, Hotspot (geology), Geology, 0105 earth and related environmental sciences
Abstract

SUMMARY Oceanic transform zones have often been regarded as plate boundaries. The origin of their structural variability is poorly constrained. A simple observation indicates that the transform zone is narrow and linear when the offset is large; while it is wide with a complex faulting pattern in the case of a small offset. On the other hand, for a given offset, large structural differences exist between transform zones located on the fast-spreading South-East Pacific Rise and on the slowspreading Mid-Atlantic ridge. In general, the transform zones in slow-spreading environments are linear with a simple fault pattern, while in fast-spreading systems they are wide with a complex pattern of deformation. We perform small-scale analogue modelling to constrain the influence of lithospheric strength on the development of deformation above a transform boundary. The models are made up of sand and silicone putty as analogues of the brittle layer and the viscous layer of the lithosphere, respectively. Two plastic sheets coming from shifted gashes form a set-up of two diverging discontinuities connected by a transform boundary. The rheological layering and strength of the model were modified using different shapes of the viscous layer placed on the transform boundary. Above the divergent discontinuities, the faulting pattern is always formed by parallel normal faults. When no viscous layer is placed on the transform boundary (strong discontinuity), the deformed zone is narrow and has few linear faults. By adding a narrow and thin viscous layer, the deformed zone becomes wider with a complex faulting pattern formed by oblique-slip faults on the limits and by pure strike-slip faults in the inner part. These latter strike-slip faults trend oblique to the transform boundary. When a viscous layer with a wide lateral extent overlays the transform discontinuity (weak strength), the faulting is dominated by obliquely normal faults extending over a wide zone, and the strike-slip is restricted to the inner part of the deformed zone. Therefore, the mechanical strength of the small scale-model controls the shape of the deformed zone and the deformation partitioning. These results were applied to 24 oceanic transforms zones: we point out that the spreading rate and the transform offset are the two dominant parameters controlling the deformation pattern. These two factors directly control the lithospheric strength at the transform boundary. However, the distance to the nearest hotspot, which may generate warmer thermal conditions even in slow-spreading environments, should modify this result.

Published
2002

34. Slippage and boundary layer probed in an almost ideal gas by a nanomechanical oscillator

Author

Martial Defoort, Kunal Lulla, Eddy Collin, Thierry Crozes, Olivier Bourgeois, Olivier Maillet, Ultra-basses températures (UBT), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Nanofab (Nanofab), and Thermodynamique et biophysique des petits systèmes (TPS)

Subjects
Monatomic gas, General Physics and Astronomy, FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, Physics::Fluid Dynamics, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 010306 general physics, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Laminar flow, Mechanics, nano-fluidics, Dissipation, 021001 nanoscience & nanotechnology, Ideal gas, nano-mechanics, Boundary layer, Classical mechanics, Orders of magnitude (time), Slippage, Knudsen number, 0210 nano-technology, low temperatures
Abstract

We have measured the interaction between $^4$He gas at 4.2$~$K and a high-quality nano-electro-mechanical string device for its first 3 symmetric modes (resonating at 2.2$~$MHz, 6.7$~$MHz and 11$~$MHz with quality factor $Q > 0.1$ million) over almost 6 orders of magnitude in pressure. This fluid can be viewed as the best experimental implementation of an almost-ideal monoatomic and inert gas which properties are tabulated. The experiment ranges from high pressure where the flow is of laminar Stokes-type presenting slippage, down to very low pressures where the flow is molecular. In the molecular regime, when the mean-free-path is of the order of the distance between the suspended nano-mechanical probe and the bottom of the trench we resolve for the first time the signature of the boundary (Knudsen) layer onto the measured dissipation. Our results are discussed in the framework of the most recent theories investigating boundary effects in fluids (both analytic approaches and Monte-Carlo DSMC simulations)., Editor's suggestion

Published
2014

35. Sedimentation waves on the Martian North Polar Cap: Analogy with megadunes in Antarctica

Author

Olivier Bourgeois, Sebastien Rodriguez, T. Appéré, C. Herny, Aymeric Spiga, Marion Massé, Isaac B. Smith, S. Carpy, S. Le Mouélic, Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)

Subjects
Martian, geography, Katabatic wind, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Glacier, Geophysics, Snow, 01 natural sciences, Wavelength, Space and Planetary Science, Geochemistry and Petrology, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Cryosphere, Sastrugi, [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology, Ice sheet, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract

International audience; Complex interactions between katabatic winds and the cryosphere may lead to the formation of sedimentation waves at the surface of ice sheets. These have been first described and named snow megadunes in Antarctica. Here we use topographic data, optical images, subsurface radar soundings and spectroscopic data acquired by Mars orbiters, to show that the surface of the Martian North Polar Cap displays two superimposed sets of sedimentation waves with differing wavelengths. These sedimentation waves have similarities with Antarctic snow megadunes regarding their surface morphology, texture, grain size asymmetry, and internal stratigraphic architecture. Both sets of Martian sedimentation waves present young ice and occasional sastrugi fields, indicative of net accumulation, on their shallow-dipping upwind sides, their tops and the intervening troughs. Old layers of dusty ice, indicative of net ablation, are exhumed on the steep-dipping downwind sides of the larger waves. Smooth surfaces of coarse-grained ice, indicative of reduced accumulation associated with sublimation metamorphism, cover the steep-dipping downwind sides of the smaller waves. These surface characteristics and the internal stratigraphy revealed by radar soundings are consistent with the interpretation that both sets of Martian sedimentation waves grow and migrate upwind in response to the development of periodic accumulation/ablation patterns controlled by katabatic winds. The recognition of these sedimentation waves provides the basis for the development of a common model of ice/wind interaction at the surface of Martian and terrestrial glaciers. Martian smaller waves, characterized by reduced net accumulation on their downwind sides, are analogous to Antarctic snow megadunes that have been described so far. A terrestrial equivalent remains to be discovered for the larger Martian waves, characterized by net ablation on their downwind sides. © 2014 Elsevier B.V.

Published
2014

36. Specific heat measurement of thin suspended SiN membrane from 8 K to 300 K using the 3ω-Völklein method

Author

Hossein Ftouni, Olivier Bourgeois, Eddy Collin, Jacques Richard, Dimitri Tainoff, Kunal Lulla, Jean Guidi, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Ultra-basses températures (UBT), and Informatique et Réseaux (InfoLab)

Subjects
Wheatstone bridge, Materials science, thin film, Analytical chemistry, 02 engineering and technology, 01 natural sciences, Heat capacity, law.invention, symbols.namesake, Thermal conductivity, law, 0103 physical sciences, thermal conductivity, 010306 general physics, Instrumentation, Debye model, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Condensed Matter - Mesoscale and Nanoscale Physics, Oscillation, 021001 nanoscience & nanotechnology, Heat flux, Thermometer, Heat transfer, symbols, specific heat, 0210 nano-technology
Abstract

We present a specific heat measurement technique adapted to thin or very thin suspended membranes from low temperature (8 K) to 300 K. The presented device allows the measurement of the heat capacity of a 70 ng silicon nitride membrane (50 or 100 nm thick), corresponding to a heat capacity of 1.4x10$^{-10}$ J/K at 8 K and 5.1x10$^{-8}$ J/K at 300 K. Measurements are performed using the 3$\omega$ method coupled to the V$\ddot{o}$lklein geometry. This configuration allows the measurement of both specific heat and thermal conductivity within the same experiment. A transducer (heater/thermometer) is used to create an oscillation of the heat flux on the membrane; the voltage oscillation appearing at the third harmonic which contains the thermal information is measured using a Wheatstone bridge set-up. The heat capacity measurement is performed by measuring the variation of the 3$\omega$ voltage over a wide frequency range and by fitting the experimental data using a thermal model adapted to the heat transfer across the membrane. The experimental data are compared to a regular Debye model; the specific heat exhibits features commonly seen for glasses at low temperature.

Published
2013

37. Phonon Heat Conduction in Corrugated Silicon Nanowires Below the Casimir Limit

Author

Olivier Bourgeois, Ali Rajabpour, Thierry Fournier, Sebastian Volz, Christophe Blanc, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Department of Mechanical Engineering, Imam Khomeini International University (IKIU), Laboratoire d'Énergétique Moléculaire et Macroscopique, Combustion (EM2C), Université Paris Saclay (COmUE)-Centre National de la Recherche Scientifique (CNRS)-CentraleSupélec, and Nanofab (Nanofab)

Subjects
Materials science, Physics and Astronomy (miscellaneous), Silicon, Mean free path, Phonon, Nanowire, chemistry.chemical_element, FOS: Physical sciences, Physics::Optics, 02 engineering and technology, 01 natural sciences, Monocrystalline silicon, Condensed Matter::Materials Science, Thermal conductivity, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 010306 general physics, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Condensed matter physics, Condensed Matter - Mesoscale and Nanoscale Physics, Scattering, 021001 nanoscience & nanotechnology, Thermal conduction, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, chemistry, 0210 nano-technology
Abstract

hh; The thermal conductance of straight and corrugated monocrystalline silicon nanowires has been measured between 0.3~K and 5~K. The difference in the thermal transport between corrugated nanowires and straight ones demonstrates a strong reduction in the mean free path of the phonons. This averaged mean free path is remarkably smaller than the smaller diameter of the nanowire, evidencing a phonon thermal transport reduced below the Casimir limit. Monte Carlo simulations highlight that this effect can be attributed to significant multiple scattering of ballistic phonons occuring on the corrugated surfaces. This result suggests an original approach to transforming a monocrystalline material into a phonon glass.

Published
2013

38. Modal 'self-coupling' as a sensitive probe for nanomechanical detection

Author

Christophe Blanc, Kunal Lulla, Eddy Collin, Andrew D. Armour, Martial Defoort, Olivier Bourgeois, Ultra-basses températures (UBT), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Thermodynamique et biophysique des petits systèmes (TPS), School of Physics and Astronomy [Nottingham], and University of Nottingham, UK (UON)

Subjects
Physics, Physics and Astronomy (miscellaneous), Condensed Matter - Mesoscale and Nanoscale Physics, business.industry, Local oscillator, Single-mode optical fiber, FOS: Physical sciences, Resonance, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Nonlinear system, Coupling (physics), Optics, Amplitude, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Phase noise, 010306 general physics, 0210 nano-technology, business, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Free parameter
Abstract

International audience; We present a high-sensitivity measurement technique for mechanical nanoresonators. Due to intrinsic nonlinear effects, different flexural modes of a nanobeam can be coupled while driving each of them on resonance. This mode-coupling scheme is dispersive and one mode resonance shifts with respect to the motional amplitude of the other. The same idea can be implemented on a single mode, exciting it with two slightly detuned signals. This two-tone scheme is used here to measure the resonance lineshape of one mode through a frequency shift in the response of the device. The method acts as an amplitude-to-frequency transduction which ultimately suffers only from phase noise of the local oscillator used and of the nanomechanical device itself. We also present a theory which reproduces the data without free parameters

Published
2013

39. Stressed silicon nitride nanomechanical resonators at helium temperatures

Author

Martial Defoort, Hossein Ftouni, Olivier Bourgeois, Eddy Collin, Kunal Lulla, Christophe Blanc, Ultra-basses températures (UBT), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), and Thermodynamique et biophysique des petits systèmes (TPS)

Subjects
Range (particle radiation), Materials science, business.industry, Dynamic range, chemistry.chemical_element, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Atomic and Molecular Physics, and Optics, Nonlinear system, chemistry.chemical_compound, Resonator, Quality (physics), Silicon nitride, chemistry, 0103 physical sciences, Optoelectronics, General Materials Science, Mechanical resonance, 010306 general physics, 0210 nano-technology, business, Helium, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall]
Abstract

International audience; We have characterized the mechanical resonance properties (both linear and nonlinear) of various doubly-clamped silicon nitride nanomechanical resonators, each with a different intrinsic tensile stress. The measurements were carried out at 4 K and the magnetomotive technique was used to drive and detect the motion of the beams. The resonant frequencies of the beams are in the megahertz range, with quality factors of the order of 104.We also measure the dynamic range of the beams and their nonlinear (Duffing) behaviour

Published
2013

40. Evidence for the role of normal-state electrons in nanoelectromechanical damping mechanisms at very low temperatures

Author

Martial Defoort, Kunal Lulla, Christophe Blanc, Eddy Collin, Olivier Bourgeois, Ultra-basses températures (UBT), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), and Thermodynamique et biophysique des petits systèmes (TPS)

Subjects
Superconductivity, Materials science, Silicon, Condensed matter physics, Condensed Matter - Mesoscale and Nanoscale Physics, FOS: Physical sciences, General Physics and Astronomy, chemistry.chemical_element, Nanotechnology, 02 engineering and technology, Electron, 021001 nanoscience & nanotechnology, 01 natural sciences, Vibration, Resonator, Quality (physics), chemistry, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Dissipative system, 010306 general physics, 0210 nano-technology, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Quantum tunnelling
Abstract

We report on experiments performed at low temperatures on aluminum covered silicon nanoelectromechanical resonators. The substantial difference observed between the mechanical dissipation in the normal and superconducting states measured within the same device unambiguously demonstrates the importance of normal-state electrons in the damping mechanism. The dissipative component becomes vanishingly small at very low temperatures in the superconducting state, leading to exceptional values for the quality factor of such small silicon structures. A critical discussion is given within the framework of the standard tunneling model., SI not provided

Published
2013

41. Searching for thermal signatures of persistent currents in normal metal rings

Author

Philippe Gandit, Jerome Mars, Olivier Bourgeois, Julien Huillery, Germain M. Souche, Sergey E. Skipetrov, Hugues Pothier, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), GIPSA - Signal Images Physique (GIPSA-SIGMAPHY), Département Images et Signal (GIPSA-DIS), Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Stendhal - Grenoble 3-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Stendhal - Grenoble 3-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Stendhal - Grenoble 3-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Stendhal - Grenoble 3-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Quantronics Group (QUANTRONICS), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Hélium : du fondamental aux applications (HELFA), Laboratoire de physique et modélisation des milieux condensés (LPM2C), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Thermodynamique et biophysique des petits systèmes (NEEL - TPS), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), and Hélium : du fondamental aux applications (NEEL - HELFA)

Subjects
Physics, Condensed matter physics, Period (periodic table), Condensed Matter - Mesoscale and Nanoscale Physics, FOS: Physical sciences, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Heat capacity, Electronic, Optical and Magnetic Materials, Magnetic field, Amplitude, Magnetic flux quantum, Phase (matter), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Thermal, Atomic physics, 010306 general physics, 0210 nano-technology, Order of magnitude, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall]
Abstract

We introduce a calorimetric approach to probe persistent currents in normal metal rings. The heat capacity of a large ensemble of silver rings is measured by nanocalorimetry under a varying magnetic field at different temperatures (60, 100, and 150 mK). Periodic oscillations versus magnetic field are detected in the phase signal of the temperature oscillations, though not in the amplitude (both of them directly linked to the heat capacity). The period of these oscillations (${\ensuremath{\Phi}}_{0}/2$, with ${\ensuremath{\Phi}}_{0}=h/e$ the magnetic flux quantum) and their evolution with temperature are in agreement with theoretical predictions. In contrast, the amplitude of the corresponding heat capacity oscillations (several ${k}_{\mathrm{B}}$) is two orders of magnitude larger than predicted by theory.

Published
2013

42. Post-breakup evolution and palaeotopography of the North Namibian Margin during the Meso-Cenozoic

Author

Olivier Dauteuil, François Guillocheau, Olivier Bourgeois, François Deschamps, Antoine Mocquet, Dynamique des Basins, Géosciences Rennes (GR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), and Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Elevated plateau, Trough (geology), [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, Fault scarp, Neogene, 01 natural sciences, Subsidence, Uplift, Paleontology, Passive margin, Vertical displacements, 14. Life underwater, Geomorphology, 0105 earth and related environmental sciences, Earth-Surface Processes, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Rift, Crust, Geophysics, Denudation, Sedimentary rock, Geology, Onshore-offshore connections
Abstract

International audience; Passive margins display various structural and morphological patterns resulting in a complex coupling between local effects.We performed an integrated analysis from the ocean to the continent at the crustal scale of the post-breakup evolution of the northern Namibian margin in terms of vertical displacements and palaeotopography. A main topographic scarp that disappears where the Palaeo-Proterozoic Damara belt crosses the coast separates the Namibian margin and the South African plateau.We analysed this transition using a synthetic crustal cross-section based on a compilation of published data as well as new field data. The thinned margin displays two domains separated by a deep sedimentary trough. This trough separates a proximal part with landward tilted blocks from the distal part with seaward tilted blocks. This structural pattern reveals a complex flowing pattern of the ductile crust controlled by magmatism. Onshore, the basalts and Cenozoic conglomerates recorded a progressive seaward tilting of the coastal zone. Post-breakup vertical motions were estimated with subsidence curves in the offshore domain and from isostatic adjustments induced by the variations of cover thickness (depth of magmatic intrusions and Apatite Fission Tracks) in onshore domain. Three domains are recognised: a subsiding offshore domain, a uplifting continental domain and a transitional domain, located on both sides of the current shoreline with successive phases of uplift and subsidence. The offshore subsidence displays variations along the margin controlled by the thinning crust generated by the continental breakup. The onshore palaeotopogaphy is approximately assessed since the end of rifting by integrating the isostatic adjustment induced by denudation: the mean elevation of the plateau has remained above 1000 m since continental breakup. No significant additional uplift was pointed out during the late Cretaceous or late Neogene. Therefore, we conclude that the South African plateau has been present in northern Namibia since 130 Ma, at least

Published
2013

43. Classical decoherence in a nanomechanical resonator

Author

Eddy Collin, Olivier Maillet, Olivier Bourgeois, F. Vavrek, Andrew Fefferman, Ultra-basses températures (UBT), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), P.J. Safarik University, and Thermodynamique et biophysique des petits systèmes (TPS)

Subjects
[PHYS]Physics [physics], Physics, Quantum decoherence, Condensed Matter - Mesoscale and Nanoscale Physics, Dephasing, FOS: Physical sciences, General Physics and Astronomy, Macroscopic quantum phenomena, 02 engineering and technology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, 01 natural sciences, Classical physics, Phase space, Quantum mechanics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Quantum information, 010306 general physics, 0210 nano-technology, Quantum, Coherence (physics)
Abstract

Decoherence is an essential mechanism that defines the boundary between classical and quantum behaviours, while imposing technological bounds for quantum devices. Little is known about quantum coherence of mechanical systems, as opposed to electromagnetic degrees of freedom. But decoherence can also be thought of in a purely classical context, as the loss of phase coherence in the classical phase space. Indeed the bridge between quantum and classical physics is under intense investigation, using in particular classical nanomechanical analogues of quantum phenomena. In the present work, by separating pure dephasing from dissipation, we quantitatively model the classical decoherence of a mechanical resonator: through the experimental control of frequency fluctuations, we engineer artificial dephasing. Building on the fruitful analogy introduced between spins/quantum bits and nanomechanical modes, we report on the methods available to define pure dephasing in these systems, while demonstrating the intrinsic almost-ideal properties of silicon-nitride beams. These experimental and theoretical results, at the boundary between classical nanomechanics and quantum information fields, are prerequisite in the understanding of decoherence processes in mechanical devices, both classical and quantum., Comment: SI not provided

Published
2016

44. Highly sensitive thermal conductivity measurements of suspended membranes (SiN and diamond) using a 3ω-Völklein method

Author

Clément Hébert, Franck Omnès, Hossein Ftouni, Olivier Bourgeois, Jacques Richard, David Eon, Aurélien Sikora, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), and Semi-conducteurs à large bande interdite (SC2G)

Subjects
Physics - Instrumentation and Detectors, Materials science, Wheatstone bridge, FOS: Physical sciences, 02 engineering and technology, engineering.material, 01 natural sciences, law.invention, Thermal conductivity measurement, chemistry.chemical_compound, Thermal conductivity, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Composite material, 010306 general physics, Instrumentation, ComputingMilieux_MISCELLANEOUS, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Materials Science (cond-mat.mtrl-sci), Diamond, Instrumentation and Detectors (physics.ins-det), 021001 nanoscience & nanotechnology, Membrane, Heat flux, Silicon nitride, chemistry, Thermometer, engineering, 0210 nano-technology
Abstract

A suspended system for measuring the thermal properties of membranes is presented. The sensitive thermal measurement is based on the 3$\omega$ dynamic method coupled to a V$\ddot{o}$lklein geometry. The device obtained using micro-machining processes allows the measurement of the in-plane thermal conductivity of a membrane with a sensitivity of less than 10nW/K (+/-$5x10^{-3}$Wm$^{-1}K^{-1}$ at room temperature) and a very high resolution ($\Delta K/K =10^{-3}$). A transducer (heater/thermometer) centered on the membrane is used to create an oscillation of the heat flux and to measure the temperature oscillation at the third harmonic using a Wheatstone bridge set-up. Power as low as 0.1nanoWatt has been measured at room temperature. The method has been applied to measure thermal properties of low stress silicon nitride and polycrystalline diamond membranes with thickness ranging from 100 nm to 400 nm. The thermal conductivity measured on the polycrystalline diamond membrane support a significant grain size effect on the thermal transport., Comment: 17 pages

Published
2012

45. In-situ comprehensive calibration of a tri-port nano-electro-mechanical device

Author

Yu. M. Bunkov, Kunal Lulla, Eddy Collin, Martial Defoort, Jean-Savin Heron, Thomas Moutonet, Olivier Bourgeois, Henri Godfrin, Ultra-basses températures (UBT), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), and Thermodynamique et biophysique des petits systèmes (TPS)

Subjects
Capacitive sensing, Acoustics, Electrical Equipment and Supplies, FOS: Physical sciences, Port (circuit theory), 02 engineering and technology, Electric Capacitance, 01 natural sciences, Capacitance, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Calibration, Nanotechnology, 010306 general physics, Instrumentation, Electrical impedance, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Mechanical Phenomena, Physics, Nanoelectromechanical systems, Condensed Matter - Mesoscale and Nanoscale Physics, Temperature, Models, Theoretical, 021001 nanoscience & nanotechnology, Thermometer, 0210 nano-technology, Joule heating
Abstract

International audience; We report on experiments performed in vacuum and at cryogenic temperatures on a tri-port nano-electro-mechanical (NEMS) device. One port is a very non-linear capacitive actuation, while the two others implement the magnetomotive scheme with a linear input force port and a (quasilinear) output velocity port. We present an experimental method enabling a full characterization of the nanomechanical device harmonic response: the non-linear capacitance function C(x) is derived, and the normal parameters k and m (spring constant and mass) of the mode under study are measured through a careful definition of the motion (in meters) and of the applied forces (in Newtons). These results are obtained with a series of purely electric measurements performed without disconnecting/reconnecting the device, and rely only on known DC properties of the circuit, making use of a thermometric property of the oscillator itself: we use the Young modulus of the coating metal as a thermometer, and the resistivity for Joule heating. The setup requires only three connecting lines without any particular matching, enabling the preservation of a high impedance NEMS environment even at MHz frequencies. The experimental data are fit to a detailed electrical and thermal model of the NEMS device, demonstrating a complete understanding of its dynamics. These methods are quite general and can be adapted (as a whole, or in parts) to a large variety of elecromechanical devices

Published
2012

46. Size dependence of exchange bias in Co/CoO nanostructures

Author

Eric Prestat, Dominique Givord, Olivier Bourgeois, Helge Haas, Sara Laureti, Sarah Y. Suck, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Nanofab (Nanofab), and Micro et NanoMagnétisme (MNM)

Subjects
010302 applied physics, Materials science, Nanostructure, Characteristic length, Condensed matter physics, Field (physics), General Physics and Astronomy, 02 engineering and technology, Coercivity, 021001 nanoscience & nanotechnology, 01 natural sciences, Exchange bias, 0103 physical sciences, Antiferromagnetism, Coupling (piping), 0210 nano-technology, Size dependence, ComputingMilieux_MISCELLANEOUS, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], exchange bias, size confinement
Abstract

In Co=CoO nanostructures, of dimensions l 3l, at small Co thickness ( 6; 10 nm), a strong increase in the bias field and the associated coercive field are found as the nanostructure size is reduced from l ¼ 120 nm to l ¼ 30 nm. This property indicates that the vharacteristic length DAF within the antiferromagnet which governs exchange-bias effects is the nanostructure size. By contrast, at larger Co thickness ( 23 nm), the exchange-bias field does not depend on the nanostructure size, implying that DAF is smaller than the nanostructure size. The results are discussed in the framework of the Malozemoff model, taking into account that the coupling between CoO grains is weak. Exchange bias is dominated either by coupling within the antiferromagnetic layer (6- and 10-nm-thick Co samples) or by ferromagnetic-antiferromagnetic interfacial coupling (23-nm-thick Co sample).

Published
2012

47. Geomorphological significance of Ontario Lacus on Titan: Integrated interpretation of Cassini VIMS, ISS and RADAR data and comparison with the Etosha Pan (Namibia)

Author

Philip D. Nicholson, Sebastien Rodriguez, Jason W. Barnes, Gabriel Tobie, S. Le Mouélic, Thomas Cornet, C. Fleurant, B. J. Buratti, Roger N. Clark, Christophe Sotin, T. Lopez Gonzalez, Olivier Bourgeois, Robert H. Brown, Kevin H. Baines, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etude de Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN), Department of Physics [Moscow,USA], University of Idaho [Moscow, USA], Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), US Geological Survey [Denver], United States Geological Survey [Reston] (USGS), California Institute of Technology (CALTECH), Department of Astronomy [Ithaca], Cornell University [New York], Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), and California Institute of Technology (CALTECH)-NASA

Subjects
Shore, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Evaporite, Landform, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy and Astrophysics, Structural basin, 01 natural sciences, Alluvial plain, symbols.namesake, 13. Climate action, Space and Planetary Science, Radar imaging, 0103 physical sciences, symbols, Titan (rocket family), 010303 astronomy & astrophysics, Geomorphology, Southern Hemisphere, Geology, 0105 earth and related environmental sciences, Remote sensing
Abstract

Ontario Lacus is the largest lake of the whole southern hemisphere of Titan, Saturn’s major moon. It has been imaged twice by each of the Cassini imaging systems (Imaging Science Subsystem (ISS) in 2004 and 2005, Visual and Infrared Mapping Spectrometer (VIMS) in 2007 and 2009 and RADAR in 2009 and 2010). We compile a geomorphological map and derive a “hydrogeological” interpretation of Ontario Lacus, based on a joint analysis of ISS, VIMS and RADAR SAR datasets, along with the T49 altimetric profile acquired in December 2008. The morphologies observed on Ontario Lacus are compared to landforms of a semi-arid terrestrial analog, which resembles Titan’s lakes: the Etosha Pan, located in the Owambo Basin (Namibia). The Etosha Pan is a flat-floored depression formed by dissolution, under semi-arid conditions, of a surface evaporitic layer (calcretes) controlled by groundwater vertical motions. We infer that Ontario Lacus is an extremely flat and shallow depression lying in an alluvial plain surrounded by small mountain ranges under climatic conditions similar to those of terrestrial semi-arid regions. Channels are seen in the southern part of Ontario Lacus in VIMS and RADAR data, acquired at a 2-years time interval. Their constancy in location with time implies that the southern portion of the depression is probably not fully covered by a liquid layer at the time of the observations, and that they most probably run on the floor of the depression. A shallow layer of surface liquids, corresponding to the darkest portions of the RADAR images, would thus cover about 53% of the surface area of the depression, of which almost 70% is located in its northern part. These liquid-covered parts of the depression, where liquid ethane was previously identified, are interpreted as topographic lows where the “alkanofer” raises above the depression floor. The rest of the depression, and mostly its southern part, is interpreted as a flat and smooth exposed floor, likely composed of a thick and liquid-saturated coating of photon-absorbing materials in the infrared. This hypothesis could explain its dark appearance both in the infrared and radar data and the persistence of channels seen on the depression floor over the time. Shorelines are observed on the border of Ontario Lacus suggesting past high-stand levels of the alkanofer table. The analogy with the Etosha Pan suggests that Ontario Lacus’ depression developed at the expense of a soluble layer covering the region. Dissolution of this layer would be controlled by vertical motions of the alkanofer table over the time. During flooding events, liquid hydrocarbons covering the depression floor would dissolve the surface layer, increasing progressively the diameter of the depression on geological timescales. During drought episodes, liquid hydrocarbons of the underground alkanofer would evaporate, leading to crystallization of “evaporites” in the pores and at the surface of the substratum, and to the formation of the regional soluble layer. The presence of specific landforms (lunette dunes or evaporites) is compatible with such evaporitic regional settings. Alternatively, but not exclusively, the surface soluble layer might have formed by accumulation on the ground of soluble compounds formed in the atmosphere.

Published
2012

48. Wide distribution and glacial origin of polar gypsum on Mars

Author

L. Le Deit, S. Le Mouélic, Charles Verpoorter, Marion Massé, Aymeric Spiga, Olivier Bourgeois, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Limnology [Norbyvägen], Department of Ecology and Genetics [Uppsala] (EBC), Uppsala University-Uppsala University, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), DLR Institute of Planetary Research, German Aerospace Center (DLR), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)

Subjects
Katabatic wind, 010504 meteorology & atmospheric sciences, Mars, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Weathering, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, 01 natural sciences, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Geochemistry and Petrology, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Glacial period, 010303 astronomy & astrophysics, Geomorphology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, sulfates, Mars Exploration Program, CRISM, polar caps, Geophysics, 13. Climate action, Space and Planetary Science, weathering, Polar, Martian polar ice caps, Sedimentary rock, Geology
Abstract

International audience; The North Polar Cap of Mars is associated with different kinds of superficial sediments, including the Circumpolar Dune Field, interior dune fields and sedimentary veneers scattered over the ice cap. In order to resolve the mineralogical composition and the regional distribution of these sediments, we processed OMEGA and CRISM hyperspectral data with an original method based on spectral derivation. We find that gypsum is present in all areas where undefined hydrated minerals had been previously detected, including superficial sedimentary veneers covering the North Polar Cap, interior dune fields and the whole Circumpolar Dune Field. Morphological and structural analyses reveal that these gypsum crystals derive directly from the interior of the ice cap. The source of superficial sedimentary veneers is the dust that was previously contained in the upper part of the ice cap, the ice-rich North Polar Layered Deposits (NPLD). This gypsum-bearing dust was released, on south-facing slopes of spiral troughs and arcuate scarps, by ice ablation controlled by katabatic winds. By the analysis of all associations of erosional scarps and dune fields over the North Polar Cap, we also demonstrate that the polar dunes are composed of sand-sized particles that were previously contained in the sediment-rich Basal Unit (BU), corresponding to the lower part of the ice cap. These particles contain gypsum and were released from the BU, by regressive ablation of ice at marginal scarps that border the North Polar Cap and by vertical ablation of ice on Olympia Planum. From a reconstruction of wind streamlines over and around the ice cap, we infer that katabatic winds descending from the polar high and rotating around the North Polar Cap control the release of these gypsum-bearing particles by ice ablation and the redistribution of these particles in the Circumpolar Dune Field. © 2011 Elsevier B.V.

Published
2012

49. Evidence of finite-size effect on the Néel temperature in ultrathin layers of CoO nanograins

Author

Aitor F. Lopeandía, Manel Molina-Ruiz, D. Givord, F. Pi, Javier Rodríguez-Viejo, Olivier Bourgeois, Thermodynamique et biophysique des petits systèmes (TPS), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), and Micro et NanoMagnétisme (MNM)

Subjects
Materials science, Specific heat, Condensed matter physics, Spins, Critical phenomena, Exchange interaction, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, Reduction (complexity), Condensed Matter::Materials Science, Condensed Matter::Superconductivity, 0103 physical sciences, Antiferromagnetism, Condensed Matter::Strongly Correlated Electrons, 010306 general physics, 0210 nano-technology, Néel temperature, ComputingMilieux_MISCELLANEOUS, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Strengthening mechanisms of materials
Abstract

A significant reduction in the N\'eel temperature of CoO ultrathin films is revealed by highly sensitive specific heat measurement. It is found that the films consist of weakly coupled antiferromagnetic (AF) grains. The ${T}_{N}$ reduction from large to small grain samples scales with the grain size reduction, according to the Binder theory of critical phenomena in systems of reduced dimensions. In these finite AF nanosystems, the intergrain exchange interaction is reduced by the presence of surface Co spins, weakly coupled to Co moments inside the grains.

Published
2011

50. A tunable hybrid electro-magnetomotive NEMS device for low temperature physics

Author

Eddy Collin, Thomas Moutonet, Jean-Savin Heron, Olivier Bourgeois, Henri Godfrin, Yurij-U. M. Bunkov, Ultra-basses températures (UBT), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), and Thermodynamique et biophysique des petits systèmes (TPS)

Subjects
Microelectromechanical systems, Nanoelectromechanical systems, Cantilever, Materials science, business.industry, Nanotechnology, 02 engineering and technology, Cryogenics, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 7. Clean energy, Atomic and Molecular Physics, and Optics, Magnetic field, 0103 physical sciences, Nano, Optoelectronics, General Materials Science, Electronics, 010306 general physics, 0210 nano-technology, business, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Microfabrication
Abstract

Microfabrication techniques have made possible the realization of mechanical devices with dimensions in the micro- and nano-scale domain. At low temperatures, one can operate and study these devices in well-controlled conditions, namely low electrical noise and cryogenic vacuum, with the ability to use high magnetic fields and superconducting coating metals (Collin et al. in J. Low Temp. Phys. 150(5–6):739, 2008). Moreover, the temperature turns out to be a control parameter in the experimental study of mechanical dissipation processes, with the cryogenic environment ensuring that only low energy states are thermally populated. Immersed in a quantum fluid, these MEMS and NEMS devices (micro and nano electro-mechanical systems) can probe the excitations of the liquid at a smaller scale, with higher frequencies and better resolution than “classical” techniques (Triqueneaux et al. in Physica B 284:2141, 2000). We present experimental results obtained in vacuum on cantilever NEMS structures which can be both magnetomotive and electrostatically driven. The device is extremely sensitive with resolved displacements down to 1 A using conventional room-temperature electronics. It is calibrated in situ, and frequency/non-linearity can be tuned electrostatically. The design should allow parametric amplification to be used.

Published
2011

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