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1. Correlation Between Perpendicular Anisotropy and Magnetoresistance in Magnetic Tunnel Junctions

Author

Bernard Dieny, C. Portemont, I Lucian Prejbeanu, Clarisse Ducruet, Bernard Rodmacq, and Lavinia Elena Nistor

Subjects
Materials science, Magnetoresistance, Condensed matter physics, Perpendicular magnetic anisotropy, chemistry.chemical_element, Electronic, Optical and Magnetic Materials, Magnetization, Tunnel magnetoresistance, Magnetic anisotropy, chemistry, Electrode, Electrical and Electronic Engineering, Platinum, Cobalt
Abstract

The perpendicular magnetic anisotropy (PMA) of Pt/CoFe(B)/MgO bottom electrodes and the tunnel magnetoresistance (TMR) of CoFeB-based magnetic tunnel junctions (MTJ) have been analyzed as a function of Mg thickness for naturally oxidized barriers. Low PMA and TMR values are found for over-oxidized (small MgO thickness) and under-oxidized (large MgO thickness) barriers. When CoFe is used as bottom electrode, a strong correlation is observed between TMR and PMA variation as a function of MgO thickness with maxima in both quantities occurring for an MgO thickness around 1.2 nm. On the contrary, for CoFeB bottom electrodes, the sensitivity of PMA to MgO thickness is completely lost, as a probable consequence of boron diffusion towards the MgO interface.

Published
2010
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2. Steady State and Dynamics of Joule Heating in Magnetic Tunnel Junctions Observed via the Temperature Dependence of RKKY Coupling

Author

C. Portemont, I. L. Prejbeanu, Antoine Chavent, Ricardo C. Sousa, Clarisse Ducruet, Laurent Vila, Jérémy Alvarez-Hérault, 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, and ANR-13-NANO-0010,EXCALYB,Cellules MRAM sub-20nm et intégration CMOS de circuits hybrides(2013)

Subjects
Coupling, Magnetoresistive random-access memory, Condensed Matter - Materials Science, Materials science, Steady state, Condensed matter physics, Magnetic moment, Spintronics, General Physics and Astronomy, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, 02 engineering and technology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, 01 natural sciences, 3. Good health, Tunnel magnetoresistance, 0103 physical sciences, Torque, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, 0210 nano-technology, Joule heating, ComputingMilieux_MISCELLANEOUS
Abstract

Understanding quantitatively the heating dynamics in magnetic tunnel junctions (MTJ) submitted to current pulses is very important in the context of spin-transfer-torque magnetic random access memory development. Here we provide a method to probe the heating of MTJ using the RKKY coupling of a synthetic ferrimagnetic storage layer as a thermal sensor. The temperature increase versus applied bias voltage is measured thanks to the decrease of the spin-flop field with temperature. This method allows distinguishing spin transfer torque (STT) effects from the influence of temperature on the switching field. The heating dynamics is then studied in real-time by probing the conductance variation due to spin-flop rotation during heating. This approach provides a new method for measuring fast heating in spintronic devices, particularly magnetic random access memory (MRAM) using thermally assisted or spin transfer torque writing., Comment: 6 pages, 9 figures

Published
2016
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3. Effects of the Heating Current Polarity on the Writing of Thermally Assisted Switching-MRAM

Author

Ken Mackay, Julien Vidal, I. L. Prejbeanu, Claire Creuzet, C. Portemont, Jérémy Alvarez-Hérault, Antoine Chavent, Bernard Dieny, Ricardo Sousa, Jeremy Pereira, 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
Magnetoresistive random-access memory, Materials science, Nuclear magnetic resonance, business.industry, Polarity (physics), Optoelectronics, Electrical and Electronic Engineering, Current (fluid), [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], business, ComputingMilieux_MISCELLANEOUS, Electronic, Optical and Magnetic Materials
Abstract

International audience

Published
2014
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4. Self-referenced multi-bit thermally assisted magnetic random access memories

Author

C. Creuzet, R. C. Sousa, C. Portemont, D. Lee, Sébastien Bandiera, B. Dieny, Quentin Stainer, K. Mackay, Lucien Lombard, 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, Coupling, Materials science, Physics and Astronomy (miscellaneous), Field (physics), Condensed matter physics, Reading (computer), Phase (waves), 02 engineering and technology, 021001 nanoscience & nanotechnology, Rotation, 01 natural sciences, Magnetization, Tunnel magnetoresistance, Ferromagnetism, Condensed Matter::Superconductivity, 0103 physical sciences, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, 0210 nano-technology
Abstract

International audience; The feasibility of 3-bits per cell storage in self-referenced thermally assisted magnetic random access memories is demonstrated both by macrospin simulations and experiments. The memory dot consists of a storage layer where CoFe/CoFeB magnetization direction is pinned by an IrMn layer using the ferromagnet/antiferromagnet interfacial exchange coupling, separated by an MgO tunnel barrier from a CoFeB sense layer whose magnetization direction is free to rotate. Writing is performed by heating the antiferromagnet above its blocking temperature by sending a current pulse through the magnetic tunnel junction, with the application of an in-plane field during the subsequent cooling phase, thus setting the new storage layer pinning direction. This pinning direction actually carries the information stored in the storage layer. Reading is performed by applying a rotating field, inducing a coherent rotation of the sense layer, and subsequently locating the field angle associated with the minimum measured resistance. This angle corresponds to the parallel magnetic configuration of the magnetic tunnel junction and therefore allows determining the pinning direction established during the write operation. The number of distinguishable pinning angles defines the total number of bits that can be stored in a single dot. V C 2014 AIP Publishing LLC.

Published
2014
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5. Mixing antiferromagnets to tune NiFe-[IrMn/FeMn] interfacial spin-glasses, grains thermal stability, and related exchange bias properties

Author

K. Akmaldinov, I. Joumard, I. L. Prejbeanu, B. Dieny, C. Portemont, Clarisse Ducruet, Vincent Baltz, 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
Materials science, Spin glass, Spintronics, Condensed matter physics, Magnetism, General Physics and Astronomy, 02 engineering and technology, 021001 nanoscience & nanotechnology, Microstructure, 01 natural sciences, Exchange bias, Ferromagnetism, 0103 physical sciences, Antiferromagnetism, Thermal stability, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, 0210 nano-technology
Abstract

International audience; Spintronics devices and in particular thermally assisted magnetic random access memories require a wide range of ferromagnetic/antiferromagnetic (F/AF) exchange bias (EB) properties and subsequently of AF materials to fulfil diverse functionality requirements for the reference and storage. For the reference layer, large EB energies and high blocking temperature (T B) are required. In contrast, for the storage layer, mostly moderate T B are needed. One of the present issues is to find a storage layer with properties intermediate between those of IrMn and FeMn and in particular: (i) with a T B larger than FeMn for better stability at rest-T but lower than IrMn to reduce power consumption at write-T and (ii) with improved magnetic interfacial quality, i.e., with reduced interfacial glassy character for lower properties dispersions. To address this issue, the EB properties of F/AF based stacks were studied for various mixed [IrMn/FeMn] AFs. In addition to EB loop shifts, the F/AF magnetic interfacial qualities and the AF grains thermal stability are probed via measurements of the low-and high-temperature contributions to the T B distributions, respectively. A tuning of the above three parameters is observed when evolving from IrMn to FeMn via [IrMn/FeMn] repetitions.

Published
2014
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6. FeMn Exchange Biased Storage Layer for Thermally Assisted MRAM

Author

Ricardo Sousa, Clarisse Ducruet, Marie Therese Delaye, C. Portemont, Christian Papusoi, Bernard Dieny, Jeremy Herault, Jean-Pierre Nozieres, Ken Mackay, Erwan Gapihan, and I Lucien Prejbeanu

Subjects
Magnetoresistive random-access memory, Materials science, Diffusion barrier, Condensed matter physics, Annealing (metallurgy), Electrical and Electronic Engineering, Pulsed power, Coercivity, Magnetic hysteresis, Current density, Electronic, Optical and Magnetic Materials, Power density
Abstract

Thermally assisted MRAM cells with FeMn exchange biased storage layers were successfully written using 50 ns current pulses with write power densities below 10 mW/?m2 and current densities below 1.3 ×10 6 A/cm2. These low power density values were achieved without using thermal barriers to confine the heat in the cell. Introducing thermal barriers would even further lower the write power density by increasing the heating efficiency. The storage layer coercivity increased upon anneal at 340 C. This could be related to manganese diffusion or to a texture incompatibility between the CoFe and the FeMn antiferromagnetic layer, a problem which can be fixed by insertion of appropriate diffusion barrier or texture control layer. Successful writing was observed for repeated write attempts with heating pulse power densities in the 7-12.5 mW/?m2 range.

Published
2010
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7. Spin Pumping and Inverse Spin Hall Effect in Germanium

Author

M. Cubukcu, A. Jain, Serge Gambarelli, J.-M. George, Henri Jaffrès, Emmanuel Augendre, Clarisse Ducruet, Matthieu Jamet, Jean-Philippe Attané, C. Portemont, G. Desfonds, C. Vergnaud, Alain Marty, A. Barski, Juan-Carlos Rojas-Sánchez, and Laurent Vila

Subjects
Spin pumping, Condensed Matter - Materials Science, Materials science, Magnetoresistance, Condensed matter physics, Electromotive force, Condensed Matter - Mesoscale and Nanoscale Physics, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Condensed Matter Physics, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Ferromagnetic resonance, Electronic, Optical and Magnetic Materials, Tunnel magnetoresistance, Condensed Matter::Materials Science, Hall effect, Condensed Matter::Superconductivity, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Spin Hall effect, Quantum tunnelling
Abstract

We have measured the inverse spin Hall effect (ISHE) in \textit{n}-Ge at room temperature. The spin current in germanium was generated by spin pumping from a CoFeB/MgO magnetic tunnel junction in order to prevent the impedance mismatch issue. A clear electromotive force was measured in Ge at the ferromagnetic resonance of CoFeB. The same study was then carried out on several test samples, in particular we have investigated the influence of the MgO tunnel barrier and sample annealing on the ISHE signal. First, the reference CoFeB/MgO bilayer grown on SiO$_{2}$ exhibits a clear electromotive force due to anisotropic magnetoresistance and anomalous Hall effect which is dominated by an asymmetric contribution with respect to the resonance field. We also found that the MgO tunnel barrier is essential to observe ISHE in Ge and that sample annealing systematically lead to an increase of the signal. We propose a theoretical model based on the presence of localized states at the interface between the MgO tunnel barrier and Ge to account for these observations. Finally, all of our results are fully consistent with the observation of ISHE in heavily doped $n$-Ge and we could estimate the spin Hall angle at room temperature to be $\approx$0.001., Comment: 34 pages, 14 figures

Published
2013
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8. 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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9. 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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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. Electrical and thermal spin accumulation in germanium

Author

A. Jain, A. Barski, Matthieu Jamet, Vincent Baltz, Emmanuel Augendre, J. C. Le Breton, L. Louahadj, Pascale Bayle-Guillemaud, Henri Jaffrès, Céline Vergnaud, Clarisse Ducruet, J.-M. George, Eric Prestat, Jean-Philippe Attané, C. Portemont, Laurent Vila, Alain Marty, J. Peiro, 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), 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]), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES-Centre National de la Recherche Scientifique (CNRS), 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)), 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
Materials science, Physics and Astronomy (miscellaneous), FOS: Physical sciences, chemistry.chemical_element, Germanium, 02 engineering and technology, 01 natural sciences, Signal, Spin wave, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Thermoelectric effect, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, Spin-½, Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed matter physics, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, Temperature gradient, chemistry, Ferromagnetism, Spin diffusion, Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology
Abstract

In this letter, we first show electrical spin injection in the germanium conduction band at room temperature and modulate the spin signal by applying a gate voltage to the channel. The corresponding signal modulation agrees well with the predictions of spin diffusion models. Then by setting a temperature gradient between germanium and the ferromagnet, we create a thermal spin accumulation in germanium without any tunnel charge current. We show that temperature gradients yield larger spin accumulations than pure electrical spin injection but, due to competing microscopic effects, the thermal spin accumulation in germanium remains surprisingly almost unchanged under the application of a gate voltage to the channel., 7 pages, 3 figures

Published
2012
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13. 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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