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15 results on '"Clarisse Ducruet"'

1. Evaluation of a new MgO barrier based on CoFeB/MgO/CoFeB structure for advanced MRAM applications

Author

T. Sedoykina, A. Orlov, Jeremy Pereira, Jérémy Alvarez-Hérault, C. Portemont, Clarisse Ducruet, E. Danilkin, and E. Smirnov

Subjects
010302 applied physics, Magnetoresistive random-access memory, Materials science, Spintronics, Nanotechnology, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Engineering physics, Atomic and Molecular Physics, and Optics, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Amorphous solid, Non-volatile memory, Tunnel magnetoresistance, Sputtering, 0103 physical sciences, Static random-access memory, Electrical and Electronic Engineering, 0210 nano-technology, Dram
Abstract

MRAM technology offers the opportunity to provide all the advantages of the most popular types of memory, such as DRAM, SRAM and FLASH with none of its disadvantages. Magnetic tunnel junctions (MTJs) based on CoFeB/MgO/CoFeB structures are very promising for future spintronics, especially in MRAM memory operation due to its high tunnel magnetoresistance (TMR) and reasonable range of resistance area product (RA). The deposition process of MgO barrier in such structures is one of the most difficult challenges to achieve good parameters of MTJs and it strongly affects on the barrier roughness, especially on the low RA region because of insufficient crystallization of thin MgO on an amorphous CoFeB. Ordinary MgO barrier creation takes a long time due to obligatory steps of Mg oxidation in different module that makes process complicated and provides a risk of CoFeB oxidation through Mg. It is shown that the new approach of barrier formation using in-situ MgO RF sputtering with Mg insertions and higher Ar partial pressure has very promising ratio of TMR vs RA which can be used in MTJs required for low "read" and "write" currents having a big delta between Rmin and Rmax in the most advanced MRAM applications.

Published
2017
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2. Noise study of magnetic field sensors based on magnetic tunnel junctions

Author

Myckael Mouchel, C. Baraduc, Amandine Bocheux, Jérémy Alvarez-Hérault, Clarisse Ducruet, K. Mackay, Ph. Sabon, Y. Conraux, I. L. Prejbeanu, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CROCUS Technology, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES)

Subjects
010302 applied physics, Physics, History, Infrasound, Acoustics, Low frequency, 01 natural sciences, Noise (electronics), Computer Science Applications, Education, Magnetic field, Low noise, Amplitude, 0103 physical sciences, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Noise level, Sensitivity (electronics)
Abstract

International audience; Low frequency noise has been studied for two types of magnetic field sensors based on magnetic tunnel junctions (MTJ). The first structure, composed of a few large MTJs, is designed for low noise applications; the second one, composed of hundreds of small MTJs, is designed for general purposes. At low frequency, both structures exhibit 1/f noise, but with very different amplitudes. The sensors for general purposes show a much higher noise level compared to the low-noise sensors. However, the sensitivity of the low noise sensors is much smaller compared to the other ones. Thus, the limit of detection, defined as the ratio of noise and sensitivity, turns out to be roughly the same for both technologies. Using the advantages of each sensor could help to design a sensor with an improved limit of detection.

Published
2017
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3. Enhanced annealing stability and perpendicular magnetic anisotropy in perpendicular magnetic tunnel junctions using W layer

Author

N. Perrissin, Jyotirmoy Chatterjee, Stéphane Auffret, Ricardo C. Sousa, Clarisse Ducruet, Bernard Dieny, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CROCUS Technology, ANR-13-NANO-0010,EXCALYB,Cellules MRAM sub-20nm et intégration CMOS de circuits hybrides(2013), ANR-10-LABX-0055,MINOS Lab,Minatec Novel Devices Scaling Laboratory(2010), and European Project: 669204,H2020,ERC-2014-ADG,MAGICAL(2015)

Subjects
010302 applied physics, Materials science, Physics and Astronomy (miscellaneous), Condensed matter physics, Annealing (metallurgy), Perpendicular magnetic anisotropy, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Tunnel magnetoresistance, Nuclear magnetic resonance, 0103 physical sciences, Electrode, Thermal, Perpendicular, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Antiferromagnetism, 0210 nano-technology, Anisotropy
Abstract

International audience; The magnetic properties of the perpendicular storage electrode (buffer/MgO/FeCoB/Cap) were studied as a function of annealing temperature by replacing Ta with W and W/Ta cap layers with variable thicknesses. W in the cap boosts up the annealing stability and increases the effective perpendicular anisotropy by 30% compared to the Ta cap. Correspondingly, an increase in the FeCoB critical thickness characterizing the transition from perpendicular to in-plane anisotropy was observed. Thicker W layer in the W(t)/Ta 1 nm cap layer makes the storage electrode highly robust against annealing up to 570 °C. The stiffening of the overall stack resulting from the W insertion due to its very high melting temperature seems to be the key mechanism behind the extremely high thermal robustness. The Gilbert damping constant of FeCoB with the W/Ta cap was found to be lower when compared with the Ta cap and stable with annealing. The evolution of the magnetic properties of bottom pinned perpendicular magnetic tunnel junctions (p-MTJ) stack with the W2/Ta1 nm cap layer shows back-end-of-line compatibility with increasing tunnel magnetoresistance up to the annealing temperature of 425 °C. The pMTJ thermal budget is limited by the synthetic antiferromagnetic hard layer which is stable up to 425 °C annealing temperature while the storage layer is stable up to 455 °C.

Published
2017
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4. High sensitivity magnetic field sensor for spatial applications

Author

Myckael Mouchel, C. Baraduc, Ioan Lucian Prejbeanu, Claude Cavoit, Philippe Sabon, Clarisse Ducruet, Amandine Bocheux, Romain Fons, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), CROCUS Technology, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
010302 applied physics, Materials science, Magnetic energy, Electromagnet, business.industry, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Magnetic flux, law.invention, Magnetic circuit, Search coil, Magnetic core, Electromagnetic coil, law, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Optoelectronics, Magnetic pressure, 0210 nano-technology, business
Abstract

International audience; A high sensitivity 1D magnetic field sensor is developed for spatial applications, in order to replace the heavy search-coils currently used. This new sensor combines a flux concentrator, biasing coils for field modulation and magnetic tunnel junctions. These three elements are fabricated and independently characterized. Finally, the expected performance of a sensor combining these three elements can be estimated.

Published
2016
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5. Electrical spin injection in silicon and the role of defects

Author

F. Rortais, C. Vergnaud, Jean-Philippe Attané, Matthieu Jamet, Henri Jaffrès, Alain Marty, C. Beigné, Julie Widiez, Clarisse Ducruet, J.-M. George, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CROCUS Technology, Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES-Centre National de la Recherche Scientifique (CNRS), ANR-13-BS10-0002,SiGeSPIN,Spintronique dans le silicium et le germanium(2013), and THALES [France]-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Hanle effect, Materials science, Silicon, Condensed matter physics, Magnetoresistance, chemistry.chemical_element, Germanium, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Signal, chemistry, Ferromagnetism, 0103 physical sciences, Condensed Matter::Strongly Correlated Electrons, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 0210 nano-technology, Quantum tunnelling, Spin-½
Abstract

International audience; Three-terminal devices, where the same ferromagnetic electrode is used for electrical spin injection and detection, is a very easy and powerful tool to probe the spin properties in nonmagnetic materials. For instance, it has been intensively used to study spin injection and detection in silicon. However the interpretation of the magnetoresistance signals observed experimentally is still under debate. In particular, a controversy has been raised about the experimental spin signal which is orders of magnitude larger than the predicted value. Recently, Song et al. [Phys. Rev. Lett. 113, 047205 (2014)] proposed that the magnetoresistance signal measured using the Hanle effect in a three-terminal geometry is due to defects or impurities in the tunnel barrier separating the ferromagnetic electrode from the silicon channel. It has also been supported by the experimental work of Txoperena et al. [Phys. Rev. Lett. 113, 146601 (2014)]. In this study, we perform electrical spin injection/detection measurements using three-terminal devices in different silicon films and study the role of defects. For this purpose, we use the tunneling inelastic spectroscopy to measure the Hanle effect and control the presence of defects in the tunnel barrier. Contrary to previous reports, we demonstrate that defects have no significant contribution to the spin signal. From a comparison with capacitance-voltage measurements in n-doped germanium in which interface states contribute to the spin signal, we also conclude on the presence of interface states in silicon.

Published
2016
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6. Influence of a Ta spacer on the magnetic and transport properties of perpendicular magnetic tunnel junctions

Author

Bernard Dieny, Clarisse Ducruet, Léa Cuchet, Bernard Rodmacq, Stéphane Auffret, Ricardo C. Sousa, SPINtronique et TEchnologie des Composants (SPINTEC), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), ANR-10-NANO-0013,PATHOS,Matériaux à Anisotropie Perpendiculaire pour cellules Mémoire Magnétiques Non-volatiles Haute-densité(2010), European Project: 246942,EC:FP7:ERC,ERC-2009-AdG,HYMAGINE(2010), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
010302 applied physics, [PHYS]Physics [physics], Materials science, Physics and Astronomy (miscellaneous), Condensed matter physics, Tantalum, chemistry.chemical_element, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Magnetization, Magnetic anisotropy, Tunnel magnetoresistance, Condensed Matter::Materials Science, Nuclear magnetic resonance, chemistry, Condensed Matter::Superconductivity, 0103 physical sciences, Electrode, Perpendicular, Coupling (piping), 0210 nano-technology, Layer (electronics)
Abstract

International audience; Ultrathin Ta layers were inserted in the bottom hard (Co/Pt)/Ta/CoFeB/MgO magnetic electrode of perpendicular magnetic tunnel junctions. The magnetization of the top part of this electrode abruptly falls in-plane when the Ta thickness exceeds 0.45 nm. This results from the balance between the various energy terms acting on this layer (exchange-like coupling through Ta, demagnetizing energy, and perpendicular anisotropy at the CoFeB/MgO interface). For small Ta thicknesses, this insertion leads to a strong improvement of the tunnel magnetoresistance, as long as the magnetization of all layers remains perpendicular-to-plane.

Published
2013
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7. Crossover from spin accumulation into interface states to spin injection in the germanium conduction band

Author

J. Peiro, J. C. Le Breton, Matthieu Jamet, Emmanuel Augendre, Pascale Bayle-Guillemaud, A. Barski, Laurent Vila, Eric Prestat, Juan-Carlos Rojas-Sánchez, Vincent Baltz, M. Cubukcu, Henri Jaffrès, G. Desfonds, S. Gambarelli, Clarisse Ducruet, Jean-Philippe Attané, C. Portemont, J.-M. George, L. Louahadj, A. Jain, C. Vergnaud, Nanostructures et Magnétisme (NM), Service de Physique des Matériaux et Microstructures (SP2M - UMR 9002), Institut Nanosciences et Cryogénie (INAC), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut Nanosciences et Cryogénie (INAC), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), Centre National de la Recherche Scientifique (CNRS)-THALES, Laboratoire d'Etude des Matériaux par Microscopie Avancée (LEMMA ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), CROCUS Technology, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Magnetic Resonance (RM ), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), THALES [France]-Centre National de la Recherche Scientifique (CNRS), and Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG)

Subjects
010302 applied physics, Spin pumping, Condensed Matter - Materials Science, Materials science, Condensed matter physics, Spin polarization, Spintronics, Condensed Matter - Mesoscale and Nanoscale Physics, General Physics and Astronomy, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, 02 engineering and technology, Zero field splitting, 021001 nanoscience & nanotechnology, 01 natural sciences, Tunnel magnetoresistance, Spin wave, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Spin Hall effect, Spin diffusion, Condensed Matter::Strongly Correlated Electrons, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 0210 nano-technology
Abstract

Electrical spin injection into semiconductors paves the way for exploring new phenomena in the area of spin physics and new generations of spintronic devices. However the exact role of interface states in spin injection mechanism from a magnetic tunnel junction into a semiconductor is still under debate. In this letter, we demonstrate a clear transition from spin accumulation into interface states to spin injection in the conduction band of $n$-Ge. We observe spin signal amplification at low temperature due to spin accumulation into interface states followed by a clear transition towards spin injection in the conduction band from 200 K up to room temperature. In this regime, the spin signal is reduced down to a value compatible with spin diffusion model. More interestingly, we demonstrate in this regime a significant modulation of the spin signal by spin pumping generated by ferromagnetic resonance and also by applying a back-gate voltage which are clear manifestations of spin current and accumulation in the germanium conduction band., 5 pages, 4 figures

Published
2012
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8. Heating asymmetry induced by tunneling current flow in magnetic tunnel junctions

Author

Clarisse Ducruet, R. C. Sousa, B. Dieny, C. Portemont, Y. Dahmane, Laurent Vila, K. Mackay, J.-P. Nozieres, Erwan Gapihan, Ioan Lucian Prejbeanu, J. Herault, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Service de Physique des Matériaux et Microstructures (SP2M - UMR 9002), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), CROCUS Technology, ANR-07-NANO-052-02 Project, and European Project: 246942,EC:FP7:ERC,ERC-2009-AdG,HYMAGINE(2010)

Subjects
010302 applied physics, [PHYS]Physics [physics], Materials science, Physics and Astronomy (miscellaneous), Condensed matter physics, Fermi level, 02 engineering and technology, Dissipation, 021001 nanoscience & nanotechnology, 01 natural sciences, symbols.namesake, Tunnel magnetoresistance, Exchange bias, Ballistic conduction, 0103 physical sciences, symbols, Current (fluid), 0210 nano-technology, Joule heating, Quantum tunnelling
Abstract

International audience; In this work, exchange bias was used as a probe to characterise the temperature profile induced by the inelastic relaxation of electrons tunnelling across a MgO barrier. Thermally assisted magnetic random access memory (TA-MRAM) cells comprising a magnetic tunnel junction (MTJ) with a reference pinned layer and a FeMn exchange biased storage layer were used. The pinning direction of the ferromagnetic storage layer is reversed when heated above the blocking temperature of the antiferromagnetic layer (FeMn). The power density required to reach this blocking temperature in the FeMn layer depends on the current polarity, indicating that the heat source term associated with the current flowing through the barrier depends itself on the current direction in contrast to simple Joule heating. This effect is due to the mechanism of energy dissipation in tunnelling. The tunnelling itself is ballistic i.e., without dissipation. However, after tunnelling, the hot electrons very quickly relax to the Fermi energy thereby loosing their excess energy in the receiving electrode. Therefore, the heat is essentially generated on one side of the barrier so that the whole profile of temperature throughout the pillar depends on the current direction. Full 3D thermal simulations also confirmed the temperature profile asymmetry. The proper choice of heating current direction (i.e., voltage polarity applied to the MTJ) can yield a reduction of about 10% in the heating power density required to enable writing in thermally assisted MRAM cells.

Published
2012
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9. Extended scalability and functionalities of MRAM based on thermally-assisted writing

Author

Stéphane Auffret, C. Portemont, Ricardo Sousa, Bertrand Cambou, S. Bandiera, J.P. Nozieres, J. Herault, Bernard Dieny, Ioan Lucian Prejbeanu, Clarisse Ducruet, Bernard Rodmacq, K. Mackay, Erwan Gapihan, and M. Castro Souza

Subjects
010302 applied physics, Magnetoresistive random-access memory, Hardware_MEMORYSTRUCTURES, Memory hierarchy, business.industry, Computer science, Electrical engineering, 02 engineering and technology, Avionics, 021001 nanoscience & nanotechnology, 01 natural sciences, Microcontroller, Hardware_GENERAL, Embedded system, 0103 physical sciences, Scalability, Node (circuits), 0210 nano-technology, business, Dram, Electronic circuit
Abstract

MRAM are already used in low density applications such as microcontrollers or for spatial/avionics applications where they benefit from their radiation hardness. Thermally assisted writing allows extending the downsize scalability of both FIMS and STT-MRAM below the 20nm node. Within a few years, MRAM can play an important role in the memory hierarchy of electronic circuits. They may be first used as DRAM replacement below the 20nm node and in a second step even closer the logic units (Fig.10).

Published
2011
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10. Spin transfer torque switching assisted by thermally induced anisotropy reorientation in perpendicular magnetic tunnel junctions

Author

I. L. Prejbeanu, S. Auffret, M. Marins de Castro, S. Bandiera, R. C. Sousa, Clarisse Ducruet, Bernard Dieny, C. Portemont, B. Rodmacq, and Laurent Vila

Subjects
010302 applied physics, Magnetoresistive random-access memory, Materials science, Physics and Astronomy (miscellaneous), Spin polarization, Condensed matter physics, Spin-transfer torque, 02 engineering and technology, 021001 nanoscience & nanotechnology, 7. Clean energy, 01 natural sciences, Tunnel magnetoresistance, Magnetization, Magnetic anisotropy, Spin wave, 0103 physical sciences, Perpendicular, 0210 nano-technology
Abstract

A method to switch the magnetization of the free layer in magnetic tunnel junctions with perpendicular anisotropy is demonstrated. It consists in assisting the spin transfer switching of the magnetization by a thermally induced reorientation of the free layer magnetic anisotropy from out-of-plane to in-plane. The junction temperature increase is due to the Joule dissipation around the tunnel barrier produced by the same pulse of current which generates the spin transfer torque. This magnetic reorientation allows the spin transfer torque efficiency to be maximal since the spin polarization of the current is perpendicular to the magnetization of the free layer. Such a thermally assisted switching allows designing highly down-size scalable magnetoresistive random access memory cells with improved write efficiency.

Published
2011
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11. Comparison of Synthetic Antiferromagnets and Hard Ferromagnets as Reference Layer in Magnetic Tunnel Junctions With Perpendicular Magnetic Anisotropy

Author

B. Dieny, Vincent Baltz, C. Portemont, Stéphane Auffret, Sébastien Bandiera, Y. Dahmane, Ioan Lucian Prejbeanu, Clarisse Ducruet, R. C. Sousa, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and CROCUS Technology

Subjects
010302 applied physics, Materials science, Condensed matter physics, Perpendicular magnetic anisotropy, Nanostructured materials, media_common.quotation_subject, Magnetic tunnelling, 02 engineering and technology, 021001 nanoscience & nanotechnology, Magnetic hysteresis, 01 natural sciences, Asymmetry, Electronic, Optical and Magnetic Materials, Dipole, Ferromagnetism, 0103 physical sciences, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 0210 nano-technology, Layer (electronics), ComputingMilieux_MISCELLANEOUS, media_common
Abstract

In magnetic tunnel junctions (MTJ), synthetic antiferromagnets (SAF) are usually used as reference layer to minimize dipolar interactions induced between this layer and the free layer (FL). We show here that the use of SAF allows us to reduce the asymmetry of the FL reversal due to stray fields in nanosized MTJs with perpendicular magnetic anisotropy.

Published
2010
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12. Metallic Mg insertion in rf deposited MgO barrier

Author

R. C. Sousa, B. Dieny, M. M. C. Souza, S. Auffret, Clarisse Ducruet, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and ANR-07-NANO-052-02 project

Subjects
010302 applied physics, [PHYS]Physics [physics], Materials science, Magnetoresistance, Magnesium, Annealing (metallurgy), Significant difference, Analytical chemistry, General Physics and Astronomy, Magnetic tunnelling, chemistry.chemical_element, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, law.invention, Metal, Tunnel magnetoresistance, Nuclear magnetic resonance, chemistry, law, visual_art, 0103 physical sciences, visual_art.visual_art_medium, Crystallization, 0210 nano-technology
Abstract

International audience; Metallic Mg insertions in rf deposited MgO barrier of magnetic tunnel junctions structures were investigated in a resistance-area (RA) range from 1 to 1000 $\Omega$$\mu$m$^2$. For the first time, investigations on Mg insertions above the MgO barrier and simultaneously on both sides of the barrier are reported. It is shown that for RA larger than 5 $\Omega$$\mu$m$^2$, a bottom Mg insertion does not improve the tunnel magnetoresistance (TMR) ratio compared to a sample with no Mg insertion. Furthermore, a top Mg insertion yields a lower TMR ratio decreasing as the Mg thickness is increased. On the other side, for RA lower than 5 $\Omega$$\mu$m$^2$, there is no significant difference between top and bottom Mg insertions indicating that in this region, the MgO crystallization occurs mainly during the annealing process. In the RA range investigated, there is no significant difference in coupling field for different insertions. In very low RA regions between 1 and 10 $\Omega$$\mu$m$^2$, an increase in TMR is observed for 0.3 nm insertions simultaneously below an above the barrier.

Published
2010
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13. Investigation of polycrystalline Nd2Fe14B texturing by solidification in a magnetic field

Author

P. de Rango, C Paduani, Sophie Rivoirard, Robert Tournier, Clarisse Ducruet, Univ Fed Santa Catarina, Dept Fis, Univ Fed Santa Catarina, Consortium de Recherches pour l'Emergence des Technologies Avancées (CRETA), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire de Cristallographie, and Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Condensed matter physics, Magnetism, rare-earth, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Magnetocrystalline anisotropy, 01 natural sciences, transition metal, Electronic, Optical and Magnetic Materials, Magnetic field, Magnetization, Magnetic anisotropy, magnetocrystalline anisotropy, magnetism, 0103 physical sciences, Melting point, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Crystallite, 0210 nano-technology, Anisotropy
Abstract

International audience; A polycrystalline sample of Nd2Fe14B was prepared by induction melting and solidification in an intense applied magnetic field, to study the alignment due to residual magnetocrystalline anisotropy of this compound near the melting point. A well-defined direction of the thermal gradient perpendicular to the magnetic field was achieved by means of an appropriate experimental set-up. The results of measurements indicate that the sample is substantially textured, but not in parallel to the elaboration field. A numerical method is utilized for the determination of anisotropy parameters in Nd2Fe14B compound, involving the analysis of measured magnetization curves. The minimization of the free-energy density, expanded in terms of these constants, is performed to determine the sub-lattice terms which are necessary to calculate the polarization curves. A fitting of the measured magnetization curves obtained at room temperature is realized to obtain the anisotropy constants, texture parameters and saturation magnetization.

Published
2001
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14. Analysis of oxygen induced anisotropy crossover in Pt/Co/MOx trilayers

Author

G. Panaccione, V. Uhlíř, Clarisse Ducruet, Stefania Pizzini, Jan Vogel, Stéphane Auffret, B. Rodmacq, Aurelien Manchon, M. Hochstrasser, Lucien Lombard, and B. Dieny

Subjects
010302 applied physics, X-ray absorption spectroscopy, Materials science, Analytical chemistry, General Physics and Astronomy, chemistry.chemical_element, PERPENDICULAR ANISOTROPY, 02 engineering and technology, Electronic structure, Plasma, 021001 nanoscience & nanotechnology, 01 natural sciences, INTERFACE, Condensed Matter::Materials Science, Magnetic anisotropy, chemistry, X-ray photoelectron spectroscopy, AU MULTILAYERS, Hall effect, 0103 physical sciences, 0210 nano-technology, Spectroscopy, Cobalt, MAGNETOCRYSTALLINE ANISOTROPY, MAGNETIC TUNNEL-JUNCTIONS
Abstract

Extraordinary Hall effect and x-ray spectroscopy measurements have been performed on a series of Pt/Co/MOx trilayers (M=Al, Mg, Ta, etc.) in order to investigate the role of oxidation in the onset of perpendicular magnetic anisotropy at the Co/MOx interface. It is observed that varying the plasma oxidation time modifies the magnetic properties of the Co layer, inducing a magnetic anisotropy crossover from in plane to out of plane. We focused on the influence of plasma oxidation on Pt/Co/AlOx perpendicular magnetic anisotropy. The interfacial electronic structure is analyzed via x-ray photoelectron spectroscopy measurements. It is shown that the maximum of out-of-plane magnetic anisotropy corresponds to the appearance of a significant density of Co-O bondings at the Co/AlOx interface. (C) 2008 American Institute of Physics.

Published
2008
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15. Precessional spin-transfer switching in a magnetic tunnel junction with a synthetic antiferromagnetic perpendicular polarizer

Author

Sébastien Bandiera, B. Rodmacq, R. C. Sousa, Cristian Papusoi, M. Marins de Castro, B. Dieny, Clarisse Ducruet, C. Portemont, A. Chavent, Ursula Ebels, S. Auffret, Laurent Vila, Ioan Lucian Prejbeanu, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CROCUS Technology, Nanostructures et Magnétisme (NM), Service de Physique des Matériaux et Microstructures (SP2M - UMR 9002), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut Nanosciences et Cryogénie (INAC), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
010302 applied physics, Materials science, Condensed matter physics, General Physics and Astronomy, 02 engineering and technology, Polarizer, 021001 nanoscience & nanotechnology, 01 natural sciences, law.invention, Magnetization, Tunnel magnetoresistance, law, Tunnel junction, Condensed Matter::Superconductivity, 0103 physical sciences, Perpendicular, Precession, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 0210 nano-technology, Current density, Nanopillar
Abstract

International audience; This paper reports sub-nanosecond precessional spin-transfer switching in elliptical magnetic tunnel junction nanopillars. This result is obtained in samples integrating a synthetic antiferromagnetic perpendicular polarizer and a tunnel junction with in-plane magnetized electrodes. The out-of-plane precession of the free layer magnetization results in oscillations of the switching probability as a function of the pulse width. At 9.25 MA/cm2 current density, these oscillations have a period of 1 ns with a high degree of coherence.

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