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43 results on '"Sylvie Le Floch"'

1. Effect of High Pressure Spark Plasma Sintering on the Densification of a Nb-Doped TiO2 Nanopowder

Author: Alexandre Verchère, Sandrine Cottrino, Gilbert Fantozzi, Shashank Mishra, Thomas Gaudisson, Nicholas Blanchard, Stéphane Pailhès, Stéphane Daniele, and Sylvie Le Floch
Subjects: nanopowder TiO2, high-pressure spark plasma sintering, grain growth, densification rate, Technology, Chemical technology, TP1-1185
Abstract: Sintering under pressure by means of the spark plasma sintering (SPS) technique is a common route to reduce the sintering temperature and to achieve ceramics with a fine-grained microstructure. In this work, high-density bulk TiO2 was sintered by high pressure SPS. It is shown that by applying high pressure during the SPS process (76 to 400 MPa), densification and phase transition start at lower temperature and are accelerated. Thus, it is possible to dissociate the two densification steps (anatase then rutile) and the transition phase during the sintering cycle. Regardless of the applied pressure, grain growth occurs during the final stage of the sintering process. However, twinning of the grains induced by the phase transition is enhanced under high pressure resulting in a reduction in the crystallite size.
Published: 2020
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2. Relaxation study of pre-densified silica glasses under 2.5 MeV electron irradiation

Author: Nadège Ollier, Matthieu Lancry, Christine Martinet, Valérie Martinez, Sylvie Le Floch, and Daniel Neuville
Subjects: Medicine, Science
Abstract: Abstract We examined the “relaxation properties” of pre-densified synthetic fused silica glass under 2.5 MeV electron irradiation. The densification of the glass was either obtained by hot compression (5 GPa-350 °C and 5 GPa-1000 °C) or via a thermal treatment increasing its fictive temperature (Tf = 1050, 1250 and 1400 °C). Under irradiation, the pre-densified silica glasses exhibit a relaxation of their macroscopic density with increasing integrated dose. Density was reduced for hot compressed silica and increased for Tf samples with different relaxation rates but it is remarkable that all sample densities follow a trend towards the same equilibrium value around 2.26 for a dose larger than 10 GGy despite a different final topology. After irradiation of hot compressed silica, the Raman spectra display a significant increment of 4 and almost 3-membered rings whereas they exhibit a glass density reduction; demonstrating that a D2 band increase cannot be considered as an absolute marker of the glass compaction. The correlation between density and D2 intensity remains valid until silica density remains lower than 2.26. In contrast, the FWHM of the main band peaking at 440 cm−1 appears to remain correlated to the silica glass density for all investigated samples.
Published: 2019
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3. Extreme structural stability of Ti0.5Sn0.5O2 nanoparticles: synergistic effect in the cationic sublattice

Author: Denis Machon, Sylvie Le Floch, Shashank Mishra, Stéphane Daniele, Karine Masenelli-Varlot, Patrick Hermet, Patrice Mélinon, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Transport, Nanomagnétisme et Matériaux pour l'Énergie (ENERGIE), IRCELYON-C'Durable (CDURABLE), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), École Supérieure de Chimie Physique Électronique de Lyon (CPE), Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Consortium Lyon Saint-Etienne de Microscopie (CLYM), École normale supérieure de Lyon (ENS de Lyon)-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), and Université de Montpellier (UM)
Subjects: [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science
Abstract: International audience; Ti0.5Sn0.5O2 nanoparticles (∼5 nm and ∼10 nm) have been studied under high pressure by Raman spectroscopy. For particles with diameter ∼10 nm, a transformation has been observed at 20–25 GPa while for particles with ∼5 nm diameter no phase transition has been observed up to ∼30 GPa. The Ti0.5Sn0.5O2 solid solution shows an extended stability at the nanoscale, both of its cationic and anionic sublattices. This ultrastability originates from the contribution of Ti and Sn mixing: Sn stabilizes the cationic network at high pressure and Ti ensures a coupling between the cationic and anionic sublattices. This result questions a “traditional” crystallographic description based on polyhedra packing and this synergistic effect reported in this work is similar to the case of metamaterials but at the nanoscale.
Published: 2022
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4. Probing densified silica glass structure by molecular oxygen and E’ point defect formation under irradiation

Author: Nadège Ollier, Imène Reghioua, Olivier Cavani, Mahinour Mobasher, Antonino Alessi, Sylvie Le Floch, and Linards Skuja
Abstract: The aim of the paper was to learn more about the structure of densified silica, in particular about the metamict-like silica phase (density = 2.26g/cm3) by examining the radiation-induced formation of E’ point defects and interstitial molecular oxygen. The large amount of the molecular oxygen produced after 11 GGy integrated dose irradiation in the metamict-like phase is destroyed when this one is submitted to electron irradiation. It infers a particular behavior to this silica phase compared to the other densified silica where the amount of O2 is reduced compared to silica. The position and shape of the O2 emission line support the idea that the void configuration of metamict phase is close to silica. A strong correlation exists between the formation of 3-membered rings of Si-O bonds and E’-centers in the densification process between 2.20-and 2.26 density.
Published: 2023
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5. In situ X-ray diffraction study of a TiO2 nanopowder Spark Plasma Sintering under very high pressure

Author: Sandrine Cottrino, Thomas Gaudisson, Stéphane Pailhès, Emanuela Archina Ferrara, Shashank Mishra, Stéphane Daniele, Mohamed Mézouar, Alain Largeteau, Yann Le Godec, Sylvie Le Floch, Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut Lumière Matière [Villeurbanne] (ILM), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Transport, Nanomagnétisme et Matériaux pour l'Énergie (ENERGIE), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), IRCELYON-C'Durable (CDURABLE), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), École Supérieure de Chimie Physique Électronique de Lyon (CPE), European Synchroton Radiation Facility [Grenoble] (ESRF), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Programme de prématuration du CNRS
Subjects: In situ X-ray diffraction, Materials Chemistry, Ceramics and Composites, Activation energy, Nanopowder TiO2, [CHIM.MATE]Chemical Sciences/Material chemistry, High-pressure spark plasma sintering, Grain growth
Abstract: International audience; We investigated the effect of very high pressure on the sintering temperature, phase transition and the grain growth during Spark Plasma Sintering (SPS) of a 15 nm TiO2 nanopowder. Using in situ synchrotron X-ray diffraction during sintering at 1.5 and 3.5 GPa, we followed the evolution of the crystalline phases and the crystallite size as a function of temperature. In comparison, in the laboratory, SPS experiments were performed on two original facilities: A Paris-Edinburgh press and a high-pressure module adapted to standard SPS equipment. We studied the effect of the pressure on the sintering in the range 76 MPa to 3.5 GPa. We have shown that highly dense nanostructured ceramics can be prepared under very high pressure at low sintering temperatures. At 1 GPa, we limited the grain growth to an average size of 233 nm by heating at only 560 °C, and achieved a relative density of 98 %.
Published: 2023
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6. Effect of extreme mechanical densification on the electrical properties of carbon nanotube micro-yarns

Author: Cassandre Miralaei, Sylvie Le Floch, Regis Debord, Hung V Nguyen, Julio C Da Silva, Alfonso San-Miguel, Hélène Le Poche, Stephane Pailhès, Vittoria Pischedda, Transport, Nanomagnétisme et Matériaux pour l'Énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Matériaux, Rayonnements, Structure (NEEL - MRS), 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), European Synchrotron Radiation Facility (ESRF), Spectroscopies optiques des matériaux verres, amorphes et à nanoparticules (SOPRANO), Laboratoire des Composants pour la Récupération d'Énergies (LCRE), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: [PHYS]Physics [physics], [SPI]Engineering Sciences [physics], Mechanics of Materials, Mechanical Engineering, [CHIM]Chemical Sciences, General Materials Science, Bioengineering, General Chemistry, Electrical and Electronic Engineering
Abstract: We have explored the effect of high pressure post-treatment in optimizing the properties of carbon nanotube yarns and found that the application of dry hydrostatic pressure reduces porosity and enhances electrical properties. The CNT yarns were prepared by the dry-spinning method directly from CNT arrays made by the hot filament chemical vapour deposition (HF-CVD) process. Mechanical hydrostatic pressure up to 360 MPa induces a decrease in yarn resistivity between 3% and 35%, associated with the sample’s permanent densification, with CNT yarn diameter reduction of 10%–25%. However, when increasing the pressure in the 1–3 GPa domain in non-hydrostatic conditions, the recovered samples show lower electrical conductivity. This might be due to concomitant macroscopic effects such as increased twists and damage to the yarn shown by SEM imaging (caused by strong shear stresses and friction) or by the collapse of the CNTs indicated by in situ high pressure Raman spectroscopy data.
Published: 2022
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7. Recent Developments of High-Pressure Spark Plasma Sintering: An Overview of Current Applications, Challenges and Future Directions

Author: Yann Le Godec and Sylvie Le Floch
Subjects: General Materials Science
Abstract: Spark plasma sintering (SPS), also called pulsed electric current sintering (PECS) or field-assisted sintering technique (FAST) is a technique for sintering powder under moderate uniaxial pressure (max. 0.15 GPa) and high temperature (up to 2500 °C). It has been widely used over the last few years as it can achieve full densification of ceramic or metal powders with lower sintering temperature and shorter processing time compared to conventional processes, opening up new possibilities for nanomaterials densification. More recently, new frontiers of opportunities are emerging by coupling SPS with high pressure (up to ~10 GPa). A vast exciting field of academic research is now using high-pressure SPS (HP-SPS) in order to play with various parameters of sintering, like grain growth, structural stability and chemical reactivity, allowing the full densification of metastable or hard-to-sinter materials. This review summarizes the various benefits of HP-SPS for the sintering of many classes of advanced functional materials. It presents the latest research findings on various HP-SPS technologies with particular emphasis on their associated metrologies and their main outstanding results obtained. Finally, in the last section, this review lists some perspectives regarding the current challenges and future directions in which the HP-SPS field may have great breakthroughs in the coming years.
Published: 2023
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8. Raman spectroscopy to determine CO2 solubility in mafic silicate melts at high pressure: Haplobasaltic, haploandesitic and approach of basaltic compositions

Author: Nicolas Sator, Julien Amalberti, Philippe Sarda, Daniel R. Neuville, Charles Le Losq, Bertrand Guillot, Tahar Hammouda, Sylvie Le Floch, Eva Chamorro-Pérez, Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Théorique de la Matière Condensée (LPTMC), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-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 de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon
Subjects: 0106 biological sciences, Basalt, Andesite, Partial melting, Mineralogy, Geology, 010502 geochemistry & geophysics, Early Earth, 010603 evolutionary biology, 01 natural sciences, Silicate, chemistry.chemical_compound, CO2 content, chemistry, 13. Climate action, Geochemistry and Petrology, [SDU]Sciences of the Universe [physics], Carbonatite, Mafic, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: CO2 degassing of mafic silicate melts is an important part of the terrestrial carbon cycle, at mid-ocean ridges, oceanic hot spots, or in the middle of continents. Deeper CO2-bearing mafic magmas may also exist, such as those suspected in the D″ zone, and certainly existed in the magma ocean of the early Earth. Knowledge of the CO2 solubility in mafic melts at high pressure is therefore important but unknown at present. Results from molecular dynamics simulation (e.g., Guillot and Sator, 2011) predict that CO2 solubility in basalt may be much higher than previously thought at pressures and temperatures relevant to the upper mantle. But some recent models predict low solubility at high pressure (e.g., Eguchi and Dasgupta, 2018). The present study thus experimentally investigates the solubility of CO2 in basalt and andesite in the pressure range 1.5–8.5 GPa at 1820–2130 K in oxidizing conditions. Up to 4 GPa, the quenched samples are essentially vitreous and CO2-saturated. Their CO2 contents are measured using confocal micro-Raman spectroscopy, where we establish an internal calibration line relating CO2 content to the area of the Raman band assigned to the ν1 stretching vibration of carbonate groups. This calibration appears independent from the spectrometer, sample or experimentalist, thus enhancing confidence in this method. At 5 and 8.5 GPa, some of the quenched samples are found partially crystallized. Their CO2 abundance is estimated at micro-scale from Raman mapping, and at large scale from image analysis and presence/absence of vesicles. Over the 1.5–8.5 GPa pressure range, obtained CO2 concentrations vary between 1.8 and > 13.6 wt%. At 5 GPa and 1873 K, the CO2 content in basalt and andesite are similar. These findings experimentally confirm the ability of mafic melts to accommodate large amounts of CO2 at conditions prevailing in the deep Earth. A consequence is that magmas issued from partial melting of carbonate-bearing silicate rocks may ascend with significant quantities of CO2 of several wt% and more: when reaching shallower depths, they may degas large quantities of CO2. Present estimates of the global carbon flux to the atmosphere may thus be underestimated, and implications to early magma ocean degassing may be considered. Other consequences may concern the genesis of kimberlites and carbonatites. We finally speculate that, if silicate melts exist in the D″ zone, significant amounts of carbon may be stored there, and consequences may arise as to carbon sequestration in the core.
Published: 2021
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9. Optimum in the thermoelectric efficiency of nanostructured Nb-doped TiO2 ceramics: from polarons to Nb–Nb dimers

Author: Alexandre Verchère, Stéphane Daniele, Gilbert Fantozzi, Sylvie Le Floch, Shashank Mishra, Sandrine Cottrino, Shantanu Misra, Régis Debord, Christophe Candolfi, Stéphane Pailhès, Bertrand Lenoir, Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Centre National de la Recherche Scientifique (CNRS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC), IRCELYON-C'Durable (CDURABLE), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, and Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], Materials science, Condensed matter physics, General Physics and Astronomy, 02 engineering and technology, 021001 nanoscience & nanotechnology, Polaron, Thermal conduction, 01 natural sciences, [SPI]Engineering Sciences [physics], Thermal conductivity, Lattice constant, Electrical resistivity and conductivity, Rutile, Seebeck coefficient, 0103 physical sciences, Thermoelectric effect, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, 010306 general physics, 0210 nano-technology
Abstract: International audience; Rutile is the most common and stable polymorph form of titanium oxide TiO2 at all temperatures. The doping of rutile TiO2 with a small amount of niobium is reknown for being responsible for a large increase of the electrical conductivity by several orders of magnitude, broadening its technological interest towards new emerging fields such as the thermoelectric conversion of waste heat. The electronic conduction has been found to be of a polaronic nature with strongly localized charges around the Ti3+ centers while, on the other side, the relatively high value of the thermal conductivity implies the existence of lattice heat carriers, i.e. phonons, with large mean free paths which makes the nanostructuration relevant for optimizing the thermoelectric efficiency. Here, the use of a high-pressure and high-temperature sintering technique has allowed to vary the grain size in rutile TiO2 pellets from 300 to 170 nm, leading to a significant reduction of the lattice thermal conductivity. The thermoelectric properties (electrical conductivity, Seebeck coefficient and thermal conductivity) of Nb-doped rutile nanostructured ceramics, namely NbxTi1−xO2 with x varying from 1 to 5%, are reported from room temperature to ∼900 K. With the incorporation of Nb, an optimum in the thermoelectric properties together with an anomaly on the tetragonal lattice constant c are observed for a concentration of ∼2.85%, which might be the fingerprint of the formation of short Nb dimers.
Published: 2020
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10. Corrigendum to ‘Production and Characterization of Compacted Fe16N2 Permanent Magnets’ Acta Materialia 235 (2022) 118064

Author: N.G. Akdogan, O. Zirhli, S. Ozunlu, M. Gerin, Sylvie Le Floch, D. Le Roy, and O. Akdogan
Subjects: Polymers and Plastics, Metals and Alloys, Ceramics and Composites, Electronic, Optical and Magnetic Materials
Published: 2022
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11. TEM observation and in situ compression tests of transition alumina prepared by high pressure compaction at room temperature

Author: Lucile Joly-Pottuz, Karine Masenelli-Varlot, Sylvie Le Floch, Agnieszka Krawczyńska, Inas Issa, Denis Machon, and Vincent Garnier
Subjects: In situ, Materials science, Transmission electron microscopy, High pressure, Compaction, Plasticity, Composite material, Compression (physics)
Published: 2021
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12. Production and characterization of compacted Fe16N2 permanent magnets

Author: N.G. Akdogan, O. Zirhli, M. Gerin, Sylvie Le Floch, D. Le Roy, and O. Akdogan
Subjects: Polymers and Plastics, Metals and Alloys, Ceramics and Composites, Electronic, Optical and Magnetic Materials
Published: 2022
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13. Nanoscale Coal Deformation and Alteration of Porosity and Pore Orientation Under Uniaxial Compression: An In Situ SANS Study

Author: Rui Zhang, Shimin Liu, Alfonso San-Miguel, Ralf Schweins, Sylvie Le Floch, Vittoria Pischedda, Pennsylvania State University (Penn State), Penn State System, Spectroscopies optiques des matériaux verres, amorphes et à nanoparticules (SOPRANO), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, (nano)Matériaux pour l'énergie (ENERGIE), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon
Subjects: [PHYS]Physics [physics], Materials science, Macropore, Bedding, business.industry, 0211 other engineering and technologies, Geology, 02 engineering and technology, Neutron scattering, 010502 geochemistry & geophysics, Geotechnical Engineering and Engineering Geology, 01 natural sciences, Stress (mechanics), Nanopore, [SPI]Engineering Sciences [physics], [CHIM]Chemical Sciences, Coal, Deformation (engineering), Composite material, Porosity, business, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Civil and Structural Engineering
Abstract: International audience; Nanoscale coal deformation aﬀects thegeomechanics response of coal structure under external stress conditions. In this study, insitu small-angle neutron scattering (SANS) is used to characterize the evolution of nanopore structures under uni-axial compression on an Illinois coal specimen. Porod invariant mapping is used to estimate apparent porosities at diﬀerent azimuthal angles. Structure-free orientation factors, including the alignment factor and Hermans’ orientation factor, are used to characterize orientation degree in nanopores quantitatively. The nanoscale pore deformation and evolution with stress have not been directly measured before, and the insitu SANS technique oﬀers the unique capability to probe the nanoscale rock deformation. From the results, higher values of apparent porosities are shown near the coal bedding direction.At dif-ferent azimuthal angles, the apparent porosities increase with increasing uniaxial stress in the elastic deformation range (54–575bar) for the measured coal. The pore-scale degree of orientation is a size-dependent parameter, and pore orientation along the coal bedding generally increases as pore size increases. The degree of orientation in nanopores on average (in a size range between ~ 2 × 103Å and ~ 15Å) tends to increase ﬁrst and then decreases with increasing stress loading, although diﬀerent from that of macropores, indicating higher stresses on the nanopore edges along the bedding direction and then on the nanopore body along the normal direction. There is no distinct permanent change ofporosity within the measured stress range (0–575 bar)after the stress relief
Published: 2021
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14. Deuterium‑hydrogen inter-diffusion in chlorite

Author: Gilles Montagnac, Sylvie Le Floch, Hélène Pilorgé, Anne-Céline Ganzhorn, Hervé Cardon, Bruno Reynard, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Diffusion, Analytical chemistry, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Activation energy, 010502 geochemistry & geophysics, 01 natural sciences, chemistry.chemical_compound, symbols.namesake, Isotope fractionation, Geochemistry and Petrology, Chlorite, 0105 earth and related environmental sciences, Arrhenius equation, Lattice diffusion coefficient, Geology, Atmospheric temperature range, Silicate, Subduction zone, chemistry, [SDU]Sciences of the Universe [physics], symbols, [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Abstract: International audience; Interactions between aqueous fluids and rocks occur in a broad range of contexts ranging from hydrothermal alteration veins to regional metamorphism. Tracking these processes and understanding their reaction kinetics require a precise knowledge of the diffusion of water in rocks, and of isotope fractionation in major minerals, such as chlorite. Deuterium‑hydrogen exchange between Mg-rich chlorite and water (D2O) was experimentally investigated using a belt press over the temperature range of 315–650 °C at pressures of 1.5 GPa and 3 GPa. Both chloritite chip and chlorite powder were used. D/(D + H) ratios in chlorite grains were mapped using Raman spectroscopy. Deuterium‑hydrogen exchange proceeded by deuterium‑hydrogen inter-diffusion in chlorite (lattice diffusion). As chlorite is a phyllosilicate, i.e. an anisotropic mineral, diffusion coefficients were determined for crystallographic directions parallel and perpendicular to the silicate layers (perpendicular and parallel to the c* axis, respectively). Arrhenius relations for deuterium‑hydrogen inter-diffusion coefficients were derived from the new dataset. Activation energy (E) is comprised between 215 ± 21 (1σ) kJ/mol (perpendicular to the c* axis) and 194 ± 21 kJ/mol (parallel to the c* axis). Log10(D0) is −2.2 ± 1.3 m2/s for diffusion in the direction perpendicular to the c* axis and −4.5 ± 1.3 m2/s for diffusion parallel to it. The bulk diffusion law derived from a combination of our data with data from Graham et al. (1987) yields E = 176 ± 8 kJ/mol and log10(D0) = −5.1 ± 0.4 m2/s.
Published: 2018
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15. Unique silica polymorph obtained under electron irradiation

Author: Olivier Cavani, Daniel R. Neuville, Sylvie Le Floch, Imène Reghioua, Nadège Ollier, Matthieu Lancry, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Institut de Chimie du CNRS (INC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), 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), and 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)
Subjects: Materials science, Physics and Astronomy (miscellaneous), Analytical chemistry, chemistry.chemical_element, 02 engineering and technology, 01 natural sciences, Oxygen, symbols.namesake, Metamictization, [SPI]Engineering Sciences [physics], Phase (matter), 0103 physical sciences, Electron beam processing, [CHIM]Chemical Sciences, Irradiation, 010302 applied physics, [PHYS]Physics [physics], [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Crystallographic defect, chemistry, High pressure, symbols, 0210 nano-technology, Raman spectroscopy, [CHIM.RADIO]Chemical Sciences/Radiochemistry
Abstract: International audience; High purity synthetic silica glass (Suprasil F300) samples were densified by High Pressure/High Temperature (HP-HT) using three different pressure/temperature/duration values. Their relaxation process was studied by applying 2.5 MeV electron irradiation with doses varying from 1 MGy up to 11 GGy. At very high dose (11 GGy), all the densified silica samples exhibit the same density value (∼2.26 g/cm3) regardless of the densification conditions, referring to an equilibrium value known as an amorphous silica metamict phase. In detail, the HP-HT silica samples were progressively dedensified from 1 GGy irradiation dose until reaching this equilibrium. Whatever the initial topological disorder revealed through Raman spectra, all silica samples present identical Raman spectra at 11 GGy, with high intensities of D1 and D2 components, attesting they reach one unique silica polymorph. Regarding the irradiation at high temperature (600 MGy, 600 K), the results show that the thermal annealing during irradiation “accelerates” somehow the relaxation kinetics of both macroscopic density and vibrational signature. Furthermore, it seems that such high irradiation temperatures lead to increase the Non-Bridging Oxygen Hole Center point defects generation.The National Network EMIR was acknowledged for supporting the irradiation experiments in SIRIUS (No. 18-6129). The authors would like to thank l'Ecole Polytechnique for the junior postdoctoral grant. DEFI CNRS “Instrumentation aux Limites” was thanked for funding the Ultra-Bragg project.
Published: 2019
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16. Revisiting Pressure-Induced Transitions in Mesoporous Anatase TiO2

Author: Vittoria Pischedda, Denis Machon, Jérémie Margueritat, Laurence Bois, Quentin Martinet, Sylvie Le Floch, Alexis Forestier, Denis Morris, Lucien Saviot, Défi Jr.Jubgang Fandio, Laboratoire Nanotechnologies Nanosystèmes (LN2 ), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Sherbrooke (UdeS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS), Institut Interdisciplinaire d'Innovation Technologique [Sherbrooke] (3IT), Université de Sherbrooke (UdeS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Laboratoire des Multimatériaux et Interfaces (LMI), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Regroupement Québécois sur les Matériaux de Pointe (RQMP), École Polytechnique de Montréal (EPM)-Université de Sherbrooke (UdeS)-McGill University = Université McGill [Montréal, Canada]-Université de Montréal (UdeM)-Fonds Québécois de Recherche sur la Nature et les Technologies (FQRNT), Spectroscopies optiques des matériaux verres, amorphes et à nanoparticules (SOPRANO), Luminescence (LUMINESCENCE), Laboratoire Interdisciplinaire Carnot de Bourgogne (LICB), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Université de Sherbrooke (UdeS)-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
Subjects: Phase transition, Anatase, Materials science, Nanoparticle, Oxides, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, [SPI]Engineering Sciences [physics], General Energy, Chemical engineering, Chemical structure, Phase transitions, Phase (matter), Nanoparticles, Physical and Theoretical Chemistry, Mesoporous material, Porosity
Abstract: International audience; Mesoporous materials may be considered as the negative image of a collection of nanoparticles. In both cases, the large surface area induces an increase of the system energy. Pressure-induced phase transitions are used to study the differences between mesoporous TiO 2 and a collection of TiO 2 nanoparticles. The synthesis and characterization of mesoporous TiO 2 with a nanosponge-like structure are presented and the inputs of different spectroscopic techniques (Terahertz, Brillouin and Raman) are highlighted. The results show that the phase stability of mesoporous TiO 2 under pressure is very similar to that observed in nanoparticles. 2
Published: 2019
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17. Porosity evolution of expanded vermiculite under pressure: the effect of pre-compaction

Author: A.N. Nguyen, Alfonso San-Miguel, Annie Brûlet, Sylvie Le Floch, Laurent Duclaux, Félix Balima, Laurence Reinert, Isabelle Daniel, Laurent Gremillard, Vittoria Pischedda, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Spectroscopies optiques des matériaux verres, amorphes et à nanoparticules (SOPRANO), Laboratoire LCME / Equipe Chimie Verte (LCME_CV), Laboratoire de Chimie Moléculaire et Environnement (LCME), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), University of Sciences [Ho Chi Minh City] (HCMC), Ho Chi Minh City University of Science (HCMUS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), LLB - Matière molle et biophysique (MMB), Laboratoire Léon Brillouin (LLB - UMR 12), 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), Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), ANR-08-MAPR-0011,CELAJOAS,ComposÉs LAmellaires pour les JOints en Applications Sévères(2008), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon
Subjects: Materials science, General Chemical Engineering, General Engineering, Compaction, General Physics and Astronomy, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, Vermiculite, 021001 nanoscience & nanotechnology, 01 natural sciences, Fractal dimension, 010305 fluids & plasmas, Stress (mechanics), 0103 physical sciences, General Earth and Planetary Sciences, General Materials Science, Lamellar structure, Texture (crystalline), Composite material, 0210 nano-technology, Anisotropy, Porosity, General Environmental Science
Abstract: International audience; The evolution of the pore structure of compressed expanded vermiculite was investigated in situ under uniaxial stress up to 3200 bar using small-angle neutron and X-ray scattering. The studied samples have a lamellar texture in which the presence of oriented oblate pores was revealed by the anisotropic small-angle scattering patterns. The initial pore size distribution and the mechanical behaviour of the pellets at working pressure conditions are strongly related to the applied initial stresses used to pre-compact the vermiculite powder. Our study shows that the porous structure of the pellets was not modified under compression up to the pre-compaction pressure. Higher densification is associated with increasing anisotropy of the pore–matrix interface structure. The pore–matrix interface could be described with fractal geometry. The stress dependence of the system fractal dimension, apparent specific surface area and total porosity was determined and related to the meso- and macropore evolution under uniaxial stress.
Published: 2019
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18. Correction to: Nanoscale Coal Deformation and Alteration of Porosity and Pore Orientation Under Uniaxial Compression: An In Situ SANS Study

Author: Rui Zhang, Shimin Liu, Sylvie Le Floch, Ralf Schweins, Vittoria Pischedda, and Alfonso San-Miguel
Subjects: In situ, Materials science, business.industry, Uniaxial compression, Geology, Orientation (graph theory), Deformation (meteorology), Geotechnical Engineering and Engineering Geology, Coal, Composite material, Porosity, business, Nanoscopic scale, Civil and Structural Engineering
Published: 2021
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19. Perspective: High pressure transformations in nanomaterials and opportunities in material design

Author: Vittoria Pischedda, Denis Machon, Sylvie Le Floch, Alfonso San-Miguel, Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Institut Interdisciplinaire d'Innovation Technologique [Sherbrooke] (3IT), Université de Sherbrooke (UdeS), Laboratoire Nanotechnologies et Nanosystèmes [Sherbrooke] (LN2), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-École Centrale de Lyon (ECL), and Université de Lyon-Université de Sherbrooke (UdeS)
Subjects: Phase transition, Materials science, General Physics and Astronomy, Nanotechnology, 02 engineering and technology, Carbon nanotube, 01 natural sciences, law.invention, Nanomaterials, law, 0103 physical sciences, [CHIM]Chemical Sciences, 010306 general physics, Phase diagram, [PHYS]Physics [physics], High pressure instruments, Nanotubes, Nanoporous, Graphene, Material Design, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Nanocrystals, Nanocrystal, Phase transitions, Complex solids, Fullerenes, 0210 nano-technology
Abstract: International audience; Pressure and temperature phase transitions of nanomaterials often differ significantly from those of their bulk parents, offering novel approaches for the engineering of original materials. The importance or even the dominance of surface atoms in the nanoworld enhances the effects of environment, geometry, and intercalation. In the present article, we explore the current knowledge of these effects, as evidenced in the high pressure phase diagrams of nanomaterials such as nanocrystals, carbon nanotubes, fullerites, graphene, and other 2D systems, as well as nanoporous structures like clathrates or zeolites. Recent advances and future challenges in the use of extreme thermodynamic conditions to develop new functional nanomaterials, composites, or devices will be reviewed, along with the specificities of the experimental environment required for these investigations.
Published: 2018
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20. Relaxation study of pre-densified silica glasses under 2.5 MeV electron irradiation

Author: Nadège Ollier, Matthieu Lancry, Christine Martinet, Valérie Martinez, Sylvie Le Floch, Daniel Neuville, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Institut de Physique du Globe de Paris (IPGP), 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), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
Subjects: Science, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Medicine, [CHIM.RADIO]Chemical Sciences/Radiochemistry, Article
Abstract: International audience; We examined the “relaxation properties” of pre-densified synthetic fused silica glass under 2.5 MeV electron irradiation. The densification of the glass was either obtained by hot compression (5 GPa-350 °C and 5 GPa-1000 °C) or via a thermal treatment increasing its fictive temperature (Tf = 1050, 1250 and 1400 °C). Under irradiation, the pre-densified silica glasses exhibit a relaxation of their macroscopic density with increasing integrated dose. Density was reduced for hot compressed silica and increased for Tf samples with different relaxation rates but it is remarkable that all sample densities follow a trend towards the same equilibrium value around 2.26 for a dose larger than 10 GGy despite a different final topology. After irradiation of hot compressed silica, the Raman spectra display a significant increment of 4 and almost 3-membered rings whereas they exhibit a glass density reduction; demonstrating that a D2 band increase cannot be considered as an absolute marker of the glass compaction. The correlation between density and D2 intensity remains valid until silica density remains lower than 2.26. In contrast, the FWHM of the main band peaking at 440 cm−1 appears to remain correlated to the silica glass density for all investigated samples.
Published: 2018
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21. Anti-Aging in ultrastable metallic glasses

Author: Martin Lüttich, Y. Luo, Sylvie Le Floch, Beatrice Ruta, Konrad Samwer, Federico Zontone, Eloi Pineda, Valentina M. Giordano, Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. GCM - Grup de Caracterització de Materials, I. Physikalisches Institut [Göttingen], Georg-August-University [Göttingen], European Synchrotron Radiation Facility (ESRF), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), and Universitat Politècnica de Catalunya [Barcelona] (UPC)
Subjects: Materials science, General Physics and Astronomy, Collective dynamics, Física::Termodinàmica [Àrees temàtiques de la UPC], 02 engineering and technology, 01 natural sciences, Annealing (glass), Potential energy landscape, [SPI]Engineering Sciences [physics], Dynamic light scattering, 0103 physical sciences, Thermal, Metal crystals, Coherent X-ray scattering, [CHIM]Chemical Sciences, Physics::Atomic Physics, 010306 general physics, Metallic glasses, [PHYS]Physics [physics], Amorphous metal, Física [Àrees temàtiques de la UPC], Glasses, Relaxation process, 021001 nanoscience & nanotechnology, Vidres metàl·lics, Chemical physics, Relaxation (physics), 0210 nano-technology, Cristalls metàl·lics
Abstract: This is the author final draft version of article https://doi.org/10.1103/PhysRevLett.120.135504 As ultrastable metallic glasses (UMGs) are promising candidates to solve the stability issues of conventional metallic glasses, their study is of exceptional interest. By means of x -ray photon correlation spectroscopy, we have investigated the stability of UMGs at the atomic level. We find a clear signature of ultrastability at the atomic level that results in slower relaxation dynamics of UMGs with respect to conventional (rapidly quenched) metallic glasses, and in a peculiar acceleration of the dynamics by near T g annealing. This surprising phenomenon, called here anti-aging, can be understood in the framework of the potential energy landscape. For all samples, the structural relaxation process can be described with a highly compressed shape of the density fluctuations, unaffected by thermal treatments and regardless of the ultrastability of the glass.
Published: 2018
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22. D/H diffusion in serpentine

Author: Hervé Cardon, Sylvie Le Floch, Hélène Pilorgé, Bruno Reynard, Laurent Remusat, Gilles Montagnac, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Sciences de la Terre (LST), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Arrhenius equation, 010504 meteorology & atmospheric sciences, Diffusion, Analytical chemistry, Mineralogy, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, 01 natural sciences, Hydrothermal circulation, Grain size, Silicate, symbols.namesake, chemistry.chemical_compound, Isotope fractionation, chemistry, 13. Climate action, Geochemistry and Petrology, Chondrite, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, symbols, Closure temperature, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Abstract: Interactions between aqueous fluids and ultrabasic rocks are essential processes in a broad range of contexts including hydrothermal alteration on the parent body of carbonaceous chondrites, at mid-oceanic ridge, and in subduction zones. Tracking these processes and understanding reaction kinetics require knowledge of the diffusion of water in rocks, and of isotope fractionation in major minerals forming under hydrous conditions, such as serpentines. We present a study of D/H inter-diffusion in antigorite, a common variety of serpentine. Experiments were performed in a belt apparatus at 315 °C, 450 °C and 540 °C and at 3.0 GPa on natural antigorite powders saturated with interstitial D2O. An experiment was performed in a diamond anvil cell at 350 °C and 2.5 GPa on an antigorite single-crystal loaded with pure D2O. D/(D + H) ratios were mapped using Raman spectroscopy for the experiments at 315 °C, 450 °C and 540 °C and by NanoSIMS for the experiment at 350 °C. As antigorite is a phyllosilicate, diffusion coefficients were obtained for crystallographic directions parallel and perpendicular to the silicate layers (perpendicular and parallel to the c∗-axis, respectively). Arrhenius relations for D/H inter-diffusion coefficients were determined to be DD/H (m2/s) = 4.71 × 10−2 × exp(−207(−33/+58) (kJ/mol)/RT) and DD/H (m2/s) = 1.61 × 10−4 × exp(−192(−34/+93) (kJ/mol)/RT) perpendicular and parallel to the c∗-axis, respectively, and DD/H (m2/s) = 7.09 × 10−3 × exp(−202(−33/+70) (kJ/mol)/RT) for the bulk diffusivity. Assuming D/H inter-diffusion coefficients for antigorite are the same for all serpentine species, closure temperature and diffusion durations are applied to hydrothermal alteration in the oceanic lithosphere, and in CI, CM and CR chondrites. Closure temperatures lie below 300 °C for terrestrial hydrothermal alteration and depend on serpentine variety because they have different typical grain sizes. Closure temperatures lie below 160 °C for carbonaceous chondrites, indicating that D/H isotopic exchange may have persisted down to very low temperatures in their parent bodies. Local D/H isotopic compositions may be associated with grain size heterogeneities in carbonaceous chondrites due to protracted alteration of fine-grained material with the lowest closure temperatures (ca 80 °C).
Published: 2017
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23. Anomalous Compressibility and Amorphization in AlPO4-17, the Oxide with the Highest Negative Thermal Expansion

Author: Frederico G. Alabarse, Olivier Cambon, Gilles Silly, Sylvie Le Floch, Claire Levelut, Julien Haines, Abel Haidoux, Pascale Roy, Jean-Blaise Brubach, Shinji Kohara, Jean-Louis Bantignies, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), European Synchrotron Radiation Facility (ESRF), Laboratoire Charles Coulomb (L2C), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Japan Synchrotron Radiation Research Institute [Hyogo] (JASRI), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
Subjects: Diffraction, Equation of state, Bulk modulus, Materials science, Oxide, Thermodynamics, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Crystallography, chemistry.chemical_compound, General Energy, chemistry, Negative thermal expansion, Compressibility, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Physical and Theoretical Chemistry, 0210 nano-technology, Spectroscopy, Softening
Abstract: AlPO4-17, known as the oxide with the highest negative thermal expansion (NTE), was studied under high pressure by angle-dispersive X-ray diffraction (XRD), mid- and far-infrared (IR) spectroscopy. Upon increasing pressure, the closure of the (P–O–Al) angle destabilizes the porous AlPO4-17 structure, which drives the amorphization process. On the basis of the decrease in intensity of the XRD lines and broadening of the IR modes, the material was found to begin to amorphize near 1 GPa. XRD, mid- and far-IR analysis evidenced pressure-induced framework softening and complete irreversible amorphization near 2.5 GPa corresponding to the collapse of the pores. The bulk modulus and its first pressure derivative (B0 = 31.2(5) GPa and B′0 = −10.1(3)) at ambient temperature were determined by fitting a third order Birch–Murnaghan equation of state (EOS) to the pressure–volume data. The material is extremely compressible and exhibits an elastic instability. Anomalous (negative) values of B′0 are very rare and have been observed previously for cyanides and metal–organic frameworks. Such an instability appears to be characteristic of materials, which exhibit strong NTE behavior and indicates a link between NTE and anomalous compressibility behavior. Mid-IR, far-IR, nuclear magnetic resonance, and pair distribution function analysis of the new amorphous form allow an amorphization mechanism to be proposed corresponding to a collapse of the structure around its pores retaining the columns built up of cancrinite cages and hexagonal prisms, based on alternating AlO4 and PO4 tetrahedra. An increase in coordination number of 10% of the Al atoms was observed. The pressure-induced amorphization in the strong NTE material AlPO4-17 opens the door to the development of new technological applications as crystal–amorphous nanocomposites with zero or specifically selected thermal expansion coefficients.
Published: 2017
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24. Amorphization in Nanoparticles

Author: Thibaut Cornier, Stéphane Daniele, Sylvie Le Floch, Denis Machon, Lucas Piot, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), MATERIAUX (MATERIAUX), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)
Subjects: Work (thermodynamics), Argon, Materials science, chemistry.chemical_element, Nanoparticle, [CHIM.CATA]Chemical Sciences/Catalysis, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, [SDE.ES]Environmental Sciences/Environmental and Society, 01 natural sciences, Surface energy, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Amorphous solid, General Energy, chemistry, Chemical physics, Surface modification, Special care, Physical and Theoretical Chemistry, 0210 nano-technology
Abstract: MATERIAUX+TCO:SDA; Nanoparticles have more propensities for amorphization than their bulk counterparts, opening the opportunity to achieve the amorphous states in well-known poor glass-former compounds. Classical size effects are often invoked to explain such phenomenon. However, this argument is not sufficient to cover all experimental results such as functionalization effect. In this work, Y2O3 nanoparticles of 7 nm diameter are investigated under pressure. Special care is taken on the surface state of the particles by comparing the pressure-induced transformation of nanoparticles stored under different conditions (atmospheric vs argon environment). A clear difference is reported as one batch shows a transformation to an amorphous state, whereas the second undergoes a crystal-to-crystal transition. These results are discussed in terms of interface energy taking into account not only the usual surface energy but also the surface state contribution. The link between different types of amorphization (pressure-, mechanical-, and radiation-induced amorphization) in nanoparticles is underlined as a critical defect density is required to achieve the crystal-to-amorphous transformation. Defect creation may arise from multiple sources: irradiation, functionalization, and reconstructive transition.
Published: 2013
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25. Oxide Thermoelectrics Nanostructured by Spinodal Decomposition

Author: Verchere, A., Mishra, S., Sylvie Le Floch, Gilbert Fantozzi, Daniele, S., Pailhès, S., IRCELYON, ProductionsScientifiques, IRCELYON-C'Durable (CDURABLE), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), IRCELYON-Chimie durable: du fondamental à l'application ( CDFA ), Institut de recherches sur la catalyse et l'environnement de Lyon ( IRCELYON ), Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique ( CNRS ) -Université Claude Bernard Lyon 1 ( UCBL ), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique ( CNRS )
Subjects: [ CHIM.CATA ] Chemical Sciences/Catalysis, [CHIM.CATA] Chemical Sciences/Catalysis, [CHIM.CATA]Chemical Sciences/Catalysis, [SDE.ES] Environmental Sciences/Environmental and Society, [SDE.ES]Environmental Sciences/Environmental and Society, [ SDE.ES ] Environmental Sciences/Environmental and Society
Abstract: SSCI-VIDE+CDFA+AVC:SMR:SDA; International audience; High-efficiency thermoelectric (TE) materials are important for power-generation devices that are designed to convert waste heat into electrical energy or to use in solid-state refrigeration. These applications require innovative materials which not only possess high conversion efficiency (related to high dimensionless number called figure of merit, "ZT" which is a combination of three material properties: Seebeck coefficient, electrical conductivity and thermal conductivity , but should also be no toxic and have high chemical stability in air, over a wide temperature range such as oxide materials. From last decade, a major breakthrough in the field of TE came by designing nanostructures that scatter phonons more effectively than electrons, so that the thermal conductivity is reduced more than the electrical conductivity. Herein we present a cheap and thermodynamically driven process to produce intra-granular nanostructures in bulk materials: the spinodal decomposition in the Nb5+-doped SnO2-TiO2 system via an innovative molecular approach. Such in-situ partitioning takes advantage to produce nanostructuration with coherent interfaces. While classical approach based on SnO2 (nano)powders mixing faces trouble to sinter dense ceramics, our bottom-up approach, trough synthesis of mixed TixSn1-xO2 (x = 0.25; 0.5; 0.75) rutile nanoparticles, suppress pure SnO2 grains and allow full densification at low temperature by SPS process. Impact of the pressure, heating rate and soaking time of SPS process onto the densification, the nano-structuration and the dopant distribution will be addressed towards the thermoelectric properties.
Published: 2017

26. An Individual Carbon Nanotube Transistor Tuned by High Pressure

Author: Jean-Michel Benoit, Alfonso San Miguel, Jean-Louis Sauvajol, Vincent Gouttenoire, Stephen T. Purcell, Anthony Ayari, Matthieu Picher, Christophe Caillier, Sylvie Le Floch, Vincent Jourdain, Matthieu Paillet, Laboratoire de Physique de la Matière Condensée et Nanostructures (LPMCN), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Laboratoire des colloïdes, verres et nanomatériaux (LCVN), and Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Nanotube, Materials science, Schottky barrier, FABRICATION, TRANSITIONS, Nanotechnology, 02 engineering and technology, Carbon nanotube, 01 natural sciences, law.invention, Biomaterials, Condensed Matter::Materials Science, Potential applications of carbon nanotubes, law, 0103 physical sciences, Electrochemistry, 010306 general physics, business.industry, Transistor, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Carbon nanotube field-effect transistor, ELECTRONIC-PROPERTIES, Carbon nanotube quantum dot, HYDROSTATIC-PRESSURE, SIZE, SINGLE, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Optoelectronics, SHAPE, Field-effect transistor, FIELD-EFFECT TRANSISTORS, 0210 nano-technology, business
Abstract: A transistor based on an individual multiwalled carbon nanotube is studied under high-pressure up to 1 GPa. Dramatic effects are observed, such as the lowering of the Schottky barrier at the gold-nanotube contacts, the enhancement of the intertube conductance, including a discontinuity related to a structural transition, and the decrease of the gate hysteresis of the device.
Published: 2010
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27. Laser-induced transformation of Li4C60 and Na4C60 polymers into metallic monomeric fulleride phases

Author: Thomas Wågberg, Sylvie Le Floch, Vittoria Pischedda, Alfonso San Miguel, Bertil Sundqvist, and Mingguang Yao
Subjects: chemistry.chemical_classification, Materials science, Condensed matter physics, General Physics and Astronomy, Insulator (electricity), Polymer, Laser, Transformation (music), law.invention, Metal, chemistry.chemical_compound, symbols.namesake, Monomer, chemistry, Chemical physics, law, visual_art, visual_art.visual_art_medium, symbols, Irradiation, Physical and Theoretical Chemistry, Raman spectroscopy
Abstract: We demonstrate that laser irradiation on the narrow-gap insulator Li4C60 and Na4C60 polymers results in metallic monomeric structures, having the same Raman features as metallic fcc K3C60 and Rb3C6 ...
Published: 2010
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28. Melamine-derived carbon sponges for oil-water separation

Author: Dominique Baillis, Sylvie Le Floch, Nicholas Blanchard, Philippe Chaudet, Yasushi Soneda, Alfonso San-Miguel, Laurence Reinert, Laurent Duclaux, Stella M. M. Ramos, Aude Stolz, J. Tuaillon-Combes, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie Moléculaire et Environnement (LCME), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), National Institute of Advanced Industrial Science and Technology (AIST), Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne] (LaMCoS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Thermogravimetric analysis, Materials science, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, chemistry.chemical_compound, [CHIM]Chemical Sciences, General Materials Science, Fourier transform infrared spectroscopy, Composite material, Porosity, Melamine foam, ComputingMilieux_MISCELLANEOUS, Carbonization, General Chemistry, 021001 nanoscience & nanotechnology, 6. Clean water, 0104 chemical sciences, Chemical engineering, chemistry, [SDE]Environmental Sciences, 0210 nano-technology, Melamine, Pyrolysis, Carbon
Abstract: The elaboration and characterization of hydrophobic melamine-based sponges are presented. Sponges were obtained by single-step carbonization of commercial melamine foam having a 3D interconnected network. We show that optimized sponges can be elaborated from a simple pyrolysis treatment with rather low temperatures of 500–600 °C. These materials exhibited excellent absorption capacities (they absorbed 90 to 200 times their own weight), a very high porosity of 99.5%, a low density around 7 mg/cm3 and water contact angles ranging from 120° to 140° close to superhydrophobicity. The relationship between hydrophobicity and physicochemical evolution on heat treatment (carbonization process, diffusion of additives, porosity evolution) was studied in detail. The as-prepared carbon sponges are compressible up to 80% with a Young’s modulus ranging from 0.58 kPa to 0.80 kPa, and keep part of their elastic properties after a hundred compression-decompression cycles. The carbonized sponges were characterized by thermogravimetric analysis (TGA), infra-red spectroscopy (FTIR), Raman spectroscopy, elemental analysis (EA), X-ray photoelectron spectroscopy (XPS) and scanning electronic microscopy (SEM). These characteristics make these materials promising absorbents for water depollution: oil-spill clean-ups or removal of oils and organic solvents from water, especially for the recovering of the pollutant by simple squeezing of the absorbent.
Published: 2016
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29. Radial collapse of carbon nanotubes for conductivity optimized polymer composites

Author: Raul Arenal, Alfonso San-Miguel, Silvana Botti, Tiago F. T. Cerqueira, Nicholas Blanchard, Christophe Adessi, Sylvie Le Floch, Miguel A. L. Marques, Annie Brûlet, Félix Balima, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), University of Zaragoza - Universidad de Zaragoza [Zaragoza], Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], Nanotube, Materials science, Carbon nanotube actuators, Mechanical properties of carbon nanotubes, 02 engineering and technology, General Chemistry, Carbon nanotube, Conductivity, 021001 nanoscience & nanotechnology, 01 natural sciences, Small-angle neutron scattering, law.invention, Optical properties of carbon nanotubes, Carbon nanotube metal matrix composites, Condensed Matter::Materials Science, law, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Composite material, 010306 general physics, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract: The optimization of the electronic conduction of carbon nanotube polymer composites is studied by tuning the radial geometry of the carbon nanotubes in a compression cycle. We have investigated the structural evolution of multi-walled carbon nanotubes in a polyamide matrix as a function of applied high pressure. Combining high resolution electron microscopy and small angle neutron scattering experiments, we conclude that the nanotube radial cross-section is irreversibly deformed following applied pressures up to 5 GPa. Studying highly percolated composites we observe that the sample resistivity drastically decreases with pressure up to about 2 GPa with no further change up to the maximum 5 GPa applied pressure. An important hysteresis is observed upon decompression which leads to an enhanced electrical conductivity of the composite in all the studied compression cycles with maximum pressures ranging from 1 to 5 GPa. Modelling the radial collapse of single-walled carbon nanotubes shows that the modified radial geometry can considerably improve the electronic transport properties in contacted carbon nanotube junctions. Our results open opportunities for engineering nanotube composites by controlling the radial collapse.
Published: 2016
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30. Effect of the temperature on the structural and textural properties of a compressed K-vermiculite

Author: Alfonso San-Miguel, Félix Balima, An-Ngoc Nguyen, Sylvie Le Floch, Vittoria Pischedda, Laurence Reinert, Laurent Duclaux, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie Moléculaire et Environnement (LCME), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Laboratoire LCME / Equipe Chimie Verte (LCME_CV), and Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])
Subjects: Thermogravimetric analysis, Materials science, Scanning electron microscope, Annealing (metallurgy), Applied Mathematics, General Chemical Engineering, Pellets, Compaction, Mineralogy, General Chemistry, Vermiculite, Small-angle neutron scattering, Industrial and Manufacturing Engineering, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, [SDE]Environmental Sciences, Composite material, Porosity, ComputingMilieux_MISCELLANEOUS
Abstract: K-vermiculite pellets were obtained by compression (80 MPa, 25 °C or 200 °C) of submicrometer size vermiculite particles. The evolution of the structural and textural properties of the compressed materials was studied as a function of the annealing temperature in the 400–1000 °C range. Small Angle Neutron Scattering patterns of the pressed samples suggest a preferential orientation of the vermiculite particles for which the basal planes were arranged perpendicular to the compaction axis. Thermogravimetric analyses, Scanning Electron Micrographs, density and porosity measurements show that the most significant changes occurred for annealing temperatures higher than 800 °C. When heated above 800 °C, the pressed vermiculite samples undergo a simultaneous increase in density and decrease in porosity concomitant to a structural evolution, leading to a more three dimensional-based structure.
Published: 2015
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31. A convenient and quantitative route to Sn(IV)-M [M = Ti(IV), Nb(V), Ta(V)] heterobimetallic precursors for dense mixed-metal oxide ceramics

Author: Sylvie Le Floch, Gilbert Fantozzi, Stéphane Pailhès, Erwann Jeanneau, Shashank Mishra, G. Bonnefont, Mahboubeh Poor Kalhor, Stéphane Daniele, Stéphane Mangematin, Henry Chermette, IRCELYON-C'Durable (CDURABLE), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université de Lyon, Chemometrics and Theoretical Chemistry - Chimiométrie et chimie théorique, Institut des Sciences Analytiques (ISA), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut Lumière Matière [Villeurbanne] (ILM), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), and The authors acknowledge the PEPS-INSIS of the CNRS for financial support (project GREAT) and the GENCI/CINES for HPC resources/computer time (Project cpt2130). They also thank M. Aouine (TEM), Y. Aizac and F. Bosselet (PXRD) of IRCELYON and E. Leroux (pellet's photographs) of UCBL.
Subjects: Materials science, Spinodal decomposition, Inorganic chemistry, HETEROMETALLIC ALKOXIDE COMPLEXES, Sintering, Spark plasma sintering, Nanoparticle, ENHANCED PHOTOCATALYTIC ACTIVITY, 02 engineering and technology, Thermal treatment, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Inorganic Chemistry, THIN-FILMS, LOW-TEMPERATURE, Molecule, Reactivity (chemistry), RAY CRYSTAL-STRUCTURES, X-ray, TERT-BUTOXIDE, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, [SDE.ES]Environmental Sciences/Environmental and Society, 0104 chemical sciences, HIGH-TECH OXIDES, SINGLE-SOURCE PRECURSORS, X-RAY, Physical chemistry, 0210 nano-technology, MOLECULAR-STRUCTURE
Abstract: SSCI-VIDE+CDFA+SMR:SMA:HCH:SDA; International audience; The strategy of reacting SnCl4 with M(OR)(x) provided a convenient and quantitative approach to new heterobimetallics with a simple addition formula, [SnCl4M(OR)(x)(HOR)(y)] (M = Ti, Nb, Ta; R = Et, Pr-i, x = 4, 5; y = 0-2) or sometimes an oxo complex [SnCl3(O)Ti-2(OPri)(7)(HOPri)(2)]. The alcoholysis reactions of these heterometallics afforded mixed alkoxo complexes [SnCl4(mu-OEt)(2)M((PrO)-O-i)(x)((PrOH)-O-i)(y)] [M = Ti (x = y = 2), Nb, Ta (x = 3, y = 1)] under mild conditions, or a planar rectangular oxo product [SnCl3(mu-OEt)(2)Nb-(OEt)(2)(EtOH)(mu-O)](2) at refluxing/extended stirring time. DFT calculations shed light on the stability and reactivity of these complexes. The use of these thoroughly characterized heterometallics as sol-gel precursors suppresses the formation of the undesired SnO2 grains, which are difficult to be sintered to a high density. The combined approach of using bottom-up synthesis of mixed Ti0.5Sn0.5O2 nanoparticles and Spark Plasma Sintering allowed the successful densification of chloride-free mixed-metal oxide ceramics. The influence of thermal treatment before sintering on the density and spinodal decomposition of the TiO2-SnO2 pellets is reported.
Published: 2015
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32. Eponges de carbone pour la dépollution par absorption de solvants et d’hydrocarbures

Author: Aude Stolz, Reinert, L., Sylvie Le Floch, Ramos-Canut, S., Chaudet, P., Baillis-Doermann, D., Duclaux, L., San-Miguel, A., Oumedjbeur, Abdelkrim, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire LCME / Equipe Chimie Verte (LCME_CV), Laboratoire de Chimie Moléculaire et Environnement (LCME), and Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])
Subjects: [SDE] Environmental Sciences, [SDE]Environmental Sciences, [CHIM] Chemical Sciences, [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract: National audience
Published: 2015

33. Shear effects on expanded graphite under uniaxial pressure: An in situ small angle neutron scattering study

Author: Laurent Duclaux, Alfonso San-Miguel, Vittoria Pischedda, Annie Brûlet, Félix Balima, Sylvie Le Floch, Peter Lindner, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Laboratoire de Chimie Moléculaire et Environnement (LCME), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, [SDE.IE]Environmental Sciences/Environmental Engineering, Mineralogy, General Chemistry, Neutron scattering, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, Small-angle neutron scattering, Fractal dimension, Shear (geology), [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Shear stress, General Materials Science, Graphite, Composite material, Porosity, Anisotropy
Abstract: International audience; In a previous work [1] we elucidated the in situ evolution of the porosity of out-of-plane com- pressed flexible graphite under uniaxial pressure up to 1000 bar using small-angle neutron scattering (SANS) technique. In order to understand the influence of shear effect on the properties of flexible graphite we study, in the present paper, the in situ behaviour of in-plane compressed flexible graphite under a uniaxial pressure. The sample had a pleated layered structure in which anisotropic SANS patterns revealed a distribution of differently oriented ellipsoid pores. Uniaxial compression generates important shear effects in this kind of sample.We have determined the evolution of the system fractal dimension, pore size distribu- tion and apparent specific surface area with applied pressure which together allow us to describe the meso and macro pore structure evolution. Under pressure, the irreversible col- lapse and splitting of larger pores into smaller size ones which is characteristic of out-of- plane uniaxial compression [1], is accompanied, in the presence of shear stress compo- nents, by an in-plane slipping mechanism giving rise to cracks and consequently to inter- face formation.
Published: 2014
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34. An in situ small angle neutron scattering study of expanded graphite under a uniaxial stress

Author: Annie Brûlet, Laurent Duclaux, Sylvie Le Floch, Félix Balima, Alfonso San-Miguel, Peter Lindner, Vittoria Pischedda, Institut de Chimie de la Matière Condensée de Bordeaux ( ICMCB ), Université de Bordeaux ( UB ) -Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique ( CNRS ), Institut Lumière Matière [Villeurbanne] ( ILM ), Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Léon Brillouin ( LLB - UMR 12 ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Banca d'Italia, Laboratoire de Chimie Moléculaire et Environnement ( LCME ), Université Grenoble Alpes [Saint Martin d'Hères]-Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ), Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Institut Laue-Langevin (ILL), ILL, Laboratoire de Chimie Moléculaire et Environnement (LCME), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Mineralogy, 02 engineering and technology, Neutron scattering, 010402 general chemistry, 01 natural sciences, Fractal dimension, [ CHIM ] Chemical Sciences, Stress (mechanics), [ SDE ] Environmental Sciences, Electrical resistivity and conductivity, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, [CHIM]Chemical Sciences, General Materials Science, Graphite, Composite material, Anisotropy, Porosity, ComputingMilieux_MISCELLANEOUS, General Chemistry, 021001 nanoscience & nanotechnology, Small-angle neutron scattering, 0104 chemical sciences, [SDE]Environmental Sciences, [ CHIM.ANAL ] Chemical Sciences/Analytical chemistry, 0210 nano-technology
Abstract: International audience; The present article studies the in situ evolution of the pore structure of compressed expanded graphite under a uniaxial stress up to 1000 bar using small-angle neutron scattering (SANS). The uniaxial stress was applied in the direction of the average c-axis of the graphite crystallites composing the sample. Ex situ characterization by electrical resistivity and mercury intrusion porosimetry was performed on the compressed samples. The anisotropic SANS pattern indicates the presence of spheroidal pores in the 4–100 nm detectable range. The stress dependence of the different extractable parameters (fractal dimension, apparent specific surface area and apparent porosity) was related to the meso and macro pore structure evolution. In particular, the fractal dimension increases irreversibly with the applied stress. We propose a model of evolution under uniaxial load in which the irreversible collapse and splitting of larger pores into smaller size ones provides a coherent description of the experimental observations.
Published: 2013
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35. Infrared reflectivity study of the metastable solid solution Y2O3Al2O3 on both sides of the yttrium aluminium garnet Y3Al5O12 composition

Author: Sylvie Le Floch, François Gervais, and Monique Gervais
Subjects: Aluminium oxides, Materials science, Mechanical Engineering, Analytical chemistry, chemistry.chemical_element, Infrared spectroscopy, Yttrium, Condensed Matter Physics, chemistry.chemical_compound, chemistry, Mechanics of Materials, Yttrium aluminium garnet, Aluminium, Aluminium oxide, General Materials Science, Single crystal, Solid solution
Abstract: Infrared reflection spectra of compacted powdered samples of yttrium aluminium garnet are shown to provide essentially the same information as the more conventional measurements performed upon the surface of a single crystal. The method is applied to the infrared study of the metastable solid solution Y 2 O 3 Al 2 O 3 on both sides of the Y 3 Al 5 O 12 composition with a molar percentage of Y 2 O 3 varying from 28.5% to 46.4%. The structure is shown to remain cubic Ia3d over the whole composition range since the 17 modes allowed by group symmetry analysis are observed for all compositions. No local mode is observed, and the increase of intensities of low frequency modes in yttrium-rich compositions is found to be consistent with the substitution of heavy yttrium onto octahedral aluminium sites.
Published: 1995
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36. Interface Energy Impact on Phase Transitions: The Case of TiO2 Nanoparticles

Author: Patrice Mélinon, Pierre Bouvier, Stéphane Daniele, Sylvie Le Floch, Vittoria Pischedda, Denis Machon, Marlene Daniel, Laboratoire de Physique de la Matière Condensée et Nanostructures (LPMCN), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des matériaux et du génie physique (LMGP ), Institut National Polytechnique de Grenoble (INPG)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and European Synchrotron Radiation Facility (ESRF)
Subjects: Phase transition, Materials science, Nanoparticle, Nanotechnology, 02 engineering and technology, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, 01 natural sciences, [SDE.ES]Environmental Sciences/Environmental and Society, Surface energy, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Amorphous solid, Nanomaterials, Condensed Matter::Materials Science, General Energy, Phase (matter), 0103 physical sciences, Surface modification, Physical and Theoretical Chemistry, 010306 general physics, 0210 nano-technology, Phase diagram
Abstract: MATERIAUX+SDA; We investigate the interface energy impact on phase stability using the shining example of TiO2 nanoparticles under pressure. We revisit the previously reported phase diagram of this system and propose a new mechanism allowing the control of pressure-induced amorphization of TiO2 ultrafine particles. We demonstrate that the size effect is necessary for stabilizing the amorphous state but is not sufficient in the sense that surface chemical functionalization of nanoparticles is determinant. This discovery opens the possibility to select the high-pressure phase in nanomaterials and, consequently, the recovered structure under ambient conditions.
Published: 2011
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37. High pressure stability of Cs6C60

Author: Poloni, R., Machon, D., Fernandez-Serra, M. V., Sylvie Le Floch, Pascarelli, S., Gilles Montagnac, Hervé Cardon, San Miguel, A., Secrétariat, Sylvie, Laboratoire de Sciences de la Terre (LST), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2008

38. High-pressure behavior of CsC8 graphite intercalation compound: Lattice structures and phase-transition mechanism

Author: Rey, N., Pierre Toulemonde, Machon, D., Duclaux, L., Sylvie Le Floch, Pischedda, V., Itié, J. P., Flank, A. M., Lagarde, P., Crichton, W. A., Mezouar, M., Th Strässle, Sheptyakov, D., Gilles Montagnac, San Miguel, A., Laboratoire de Sciences de la Terre (LST), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Matériaux, Rayonnements, Structure (MRS), Institut Néel (NEEL), and 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)
Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2008

39. Small angle scattering methods to study porous materials under high uniaxial strain

Author: Vittoria Pischedda, Sylvie Le Floch, Félix Balima, Franck Legrand, Alfonso San-Miguel, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], 010302 applied physics, Materials science, business.industry, Neutron diffraction, 02 engineering and technology, Neutron scattering, 021001 nanoscience & nanotechnology, 01 natural sciences, Diamond anvil cell, [SPI]Engineering Sciences [physics], Optics, 0103 physical sciences, Perpendicular, [CHIM]Chemical Sciences, Neutron, Small-angle scattering, Composite material, 0210 nano-technology, business, Porosity, Porous medium, Instrumentation, ComputingMilieux_MISCELLANEOUS
Abstract: We developed a high pressure cell for the in situ study of the porosity of solids under high uniaxial strain using neutron small angle scattering. The cell comprises a hydraulically actioned piston and a main body equipped with two single-crystal sapphire windows allowing for the neutron scattering of the sample. The sample cavity is designed to allow for a large volume variation as expected when compressing highly porous materials. We also implemented a loading protocol to adapt an existing diamond anvil cell for the study of porous materials by X-ray small angle scattering under high pressure. The two techniques are complementary as the radiation beam and the applied pressure are in one case perpendicular to each other (neutron cell) and in the other case parallel (X-ray cell). We will illustrate the use of these two techniques in the study of lamellar porous systems up to a maximum pressure of 0.1 GPa and 0.3 GPa for the neutron and X-ray cells, respectively. These devices allow obtaining information on the evolution of porosity with pressure in the pore dimension subdomain defined by the wave-numbers explored in the scattering process. The evolution with the applied load of such parameters as the fractal dimension of the pore-matrix interface or the apparent specific surface in expanded graphite and in expanded vermiculite is used to illustrate the use of the high pressure cells.
Published: 2015
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40. Effect of the Melt Temperature on the Solidification Process of Liquid Garnets Ln3Al5O12 (Ln = Dy, Y, and Lu)

Author: Monique Gervais, Jean Pierre Coutures, Sylvie Le Floch, J.P. Coutures, and Jean Claude Rifflet
Subjects: chemistry.chemical_classification, Materials science, Inorganic chemistry, Analytical chemistry, Crystal growth, law.invention, chemistry, law, Excited state, Phase (matter), Differential thermal analysis, Materials Chemistry, Ceramics and Composites, Crystallization, Inorganic compound, Phase diagram, Perovskite (structure)
Abstract: This paper reports on the solidification process of liquid garnets Ln[sub 3]Al[sub 5]O[sub 12] (Ln = Dy, Y, Lu) that was probed by differential thermal analysis. A critical temperature T[sub clg] was evidence in the liquid. Cooling from temperatures under T[sub clg] leads to the crystallization of the single garnet phase. Cooling from temperatures above T[sub clg] leads to the solidification of a mixture of perovskite LnAlO[sub 3] and aluminum oxide [alpha]-Al[sub 2]O[sub 3]. For Ln = Y, the results are in agreement with stable and metastable phase diagrams previously proposed. The YAlO[sub 3] melt was shown to display a critical temperature T[sub clp] also. Its metastable solidification from temperatures above T[sub clp] leads to the formation of the perovskite at around 1550[degrees]C.
Published: 1992
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41. Pressure-induced homothetic volume collapse in Si and Ge clathrates

Author: Vittoria Pischedda, Denis Machon, Colin Bousige, Sylvie Le Floch, Pierre Toulemonde, Alfonso San Miguel, Régis Debord, and Jean-Christophe Blancon
Subjects: Materials science, Volume (thermodynamics), Structural Biology, Collapse (topology), Thermodynamics, Homothetic transformation
Published: 2009
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42. Effect of Sr substitution on superconductivity in Hg2(Ba1-ySry)2YCu2O8-d (part2): bond valence sum approach of the hole distribution

Author: Pierre Toulemonde, Odier, P., Pierre Bordet, Sylvie Le Floch, Suard, E., Arxiv, Import, Laboratoire de Cristallographie, Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), and ILL
Subjects: [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Superconductivity (cond-mat.supr-con), Condensed Matter - Superconductivity, FOS: Physical sciences, [PHYS.COND.CM-S] Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con]
Abstract: The effects of Sr substitution on superconductivity, and more particulary the changes induced in the hole doping mechanism, were investigated in Hg2(Ba1-ySry)2YCu2O8-d by a "bond valence sum" analysis with Sr content from y = 0.0 to y = 1.0. A comparison with CuBa2YCu2O7-d and Cu2Ba2YCu2O8 systems suggests a possible explanation of the Tc enhancement from 0 K for y = 0.0 to 42 K for y = 1.0. The charge distribution among atoms of the unit cell was determined from the refined structure, for y = 0.0 to 1.0. It shows a charge transfer to the superconducting CuO2 plane via two doping channels pi(1) and pi(2), i.e. through O2(apical)-Cu and Ba/Sr-O1 bonds respectively., Comment: 13 pages, 5 figures, accepted for publication in Journal of Physics: Condensed Matter

43. Development of High-Pressure Device, based on Paris-Edinburgh Press, Applied on SPS Process

Author: Thomas Gaudisson, Sandrine Cottrino, Pascal Munsch, Marion Vandenhende, Rémy Boulesteix, Alexandre Maitre, Stéphane Pailhès, Yann Le Godec, Sylvie Le Floch, and DERORY, BEATRICE
Subjects: [CHIM.MATE] Chemical Sciences/Material chemistry, [SPI.MAT] Engineering Sciences [physics]/Materials

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