1
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Merbouche H, Divinskiy B, Gouéré D, Lebrun R, El Kanj A, Cros V, Bortolotti P, Anane A, Demokritov SO, Demidov VE. True amplification of spin waves in magnonic nano-waveguides. Nat Commun 2024; 15:1560. [PMID: 38378662 PMCID: PMC10879122 DOI: 10.1038/s41467-024-45783-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 02/05/2024] [Indexed: 02/22/2024] Open
Abstract
Magnonic nano-devices exploit magnons - quanta of spin waves - to transmit and process information within a single integrated platform that has the potential to outperform traditional semiconductor-based electronics. The main missing cornerstone of this information nanotechnology is an efficient scheme for the amplification of propagating spin waves. The recent discovery of spin-orbit torque provided an elegant mechanism for propagation losses compensation. While partial compensation of the spin-wave losses has been achieved, true amplification - the exponential increase in the spin-wave intensity during propagation - has so far remained elusive. Here we evidence the operating conditions to achieve unambiguous amplification using clocked nanoseconds-long spin-orbit torque pulses in magnonic nano-waveguides, where the effective magnetization has been engineered to be close to zero to suppress the detrimental magnon scattering. We achieve an exponential increase in the intensity of propagating spin waves up to 500% at a propagation distance of several micrometers.
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Affiliation(s)
- H Merbouche
- Institute of Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
| | - B Divinskiy
- Institute of Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
| | - D Gouéré
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - R Lebrun
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - A El Kanj
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - V Cros
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - P Bortolotti
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - A Anane
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - S O Demokritov
- Institute of Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
| | - V E Demidov
- Institute of Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany.
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2
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Ukleev V, Ajejas F, Devishvili A, Vorobiev A, Steinke NJ, Cubitt R, Luo C, Abrudan RM, Radu F, Cros V, Reyren N, White JS. Observation by SANS and PNR of pure Néel-type domain wall profiles and skyrmion suppression below room temperature in magnetic [Pt/CoFeB/Ru] 10 multilayers. Sci Technol Adv Mater 2024; 25:2315015. [PMID: 38455384 PMCID: PMC10919321 DOI: 10.1080/14686996.2024.2315015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 01/29/2024] [Indexed: 03/09/2024]
Abstract
We report investigations of the magnetic textures in periodic multilayers [Pt(1 nm)/(CoFeB(0.8 nm)/Ru(1.4 nm)]10 using polarised neutron reflectometry (PNR) and small-angle neutron scattering (SANS). The multilayers are known to host skyrmions stabilized by Dzyaloshinskii-Moriya interactions induced by broken inversion symmetry and spin-orbit coupling at the asymmetric interfaces. From depth-dependent PNR measurements, we observed well-defined structural features and obtained the layer-resolved magnetization profiles. The in-plane magnetization of the CoFeB layers calculated from fitting of the PNR profiles is found to be in excellent agreement with magnetometry data. Using SANS as a bulk probe of the entire multilayer, we observe long-period magnetic stripe domains and skyrmion ensembles with full orientational disorder at room temperature. No sign of skyrmions is found below 250 K, which we suggest is due to an increase of an effective magnetic anisotropy in the CoFeB layer on cooling that suppresses skyrmion stability. Using polarised SANS at room temperature, we prove the existence of pure Néel-type windings in both stripe domain and skyrmion regimes. No Bloch-type winding admixture, i.e. an indication for hybrid windings, is detected within the measurement sensitivity, in good agreement with expectations according to our micromagnetic modelling of the multilayers. Our findings using neutron techniques provide valuable microscopic insights into the rich magnetic behavior of skyrmion-hosting multilayers, which are essential for the advancement of future skyrmion-based spintronic devices.
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Affiliation(s)
- Victor Ukleev
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), Villigen, Switzerland
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Fernando Ajejas
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | | | - Alexei Vorobiev
- Institut Laue-Langevin, Grenoble, France
- Department of Physics, Uppsala University, Uppsala, Sweden
| | | | | | - Chen Luo
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | | | - Florin Radu
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Vincent Cros
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - Nicolas Reyren
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - Jonathan S. White
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), Villigen, Switzerland
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3
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Wittrock S, Perna S, Lebrun R, Ho K, Dutra R, Ferreira R, Bortolotti P, Serpico C, Cros V. Non-hermiticity in spintronics: oscillation death in coupled spintronic nano-oscillators through emerging exceptional points. Nat Commun 2024; 15:971. [PMID: 38302454 PMCID: PMC10834588 DOI: 10.1038/s41467-023-44436-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 12/13/2023] [Indexed: 02/03/2024] Open
Abstract
The emergence of exceptional points (EPs) in the parameter space of a non-hermitian (2D) eigenvalue problem has long been interest in mathematical physics, however, only in the last decade entered the scope of experiments. In coupled systems, EPs give rise to unique physical phenomena, and enable the development of highly sensitive sensors. Here, we demonstrate at room temperature the emergence of EPs in coupled spintronic nanoscale oscillators and exploit the system's non-hermiticity. We observe amplitude death of self-oscillations and other complex dynamics, and develop a linearized non-hermitian model of the coupled spintronic system, which describes the main experimental features. The room temperature operation, and CMOS compatibility of our spintronic nanoscale oscillators means that they are ready to be employed in a variety of applications, such as field, current or rotation sensors, radiofrequeny and wireless devices, and in dedicated neuromorphic computing hardware. Furthermore, their unique and versatile properties, notably their large nonlinear behavior, open up unprecedented perspectives in experiments as well as in theory on the physics of exceptional points expanding to strongly nonlinear systems.
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Affiliation(s)
- Steffen Wittrock
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France.
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109, Berlin, Germany.
| | - Salvatore Perna
- Department of Electrical Engineering and ICT, University of Naples Federico II, 80125, Naples, Italy
| | - Romain Lebrun
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France
| | - Katia Ho
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France
| | - Roberta Dutra
- Centro Brasileiro de Pesquisas Fésicas (CBPF), Rua Dr. Xavier Sigaud 150, Rio de Janeiro, 22290-180, Brazil
| | - Ricardo Ferreira
- International Iberian Nanotechnology Laboratory (INL), 471531, Braga, Portugal
| | - Paolo Bortolotti
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France
| | - Claudio Serpico
- Department of Electrical Engineering and ICT, University of Naples Federico II, 80125, Naples, Italy
| | - Vincent Cros
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France.
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4
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El Kanj A, Gomonay O, Boventer I, Bortolotti P, Cros V, Anane A, Lebrun R. Antiferromagnetic magnon spintronic based on nonreciprocal and nondegenerated ultra-fast spin-waves in the canted antiferromagnet α-Fe 2O 3. Sci Adv 2023; 9:eadh1601. [PMID: 37566648 PMCID: PMC10421035 DOI: 10.1126/sciadv.adh1601] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 07/12/2023] [Indexed: 08/13/2023]
Abstract
Spin-waves in antiferromagnets hold the prospects for the development of faster, less power-hungry electronics and promising physics based on spin superfluids and coherent magnon condensates. For both these perspectives, addressing electrically coherent antiferromagnetic spin-waves is of importance, a prerequisite that has been so far elusive, because, unlike ferromagnets, antiferromagnets couple weakly to radiofrequency fields. Here, we demonstrate the detection of ultra-fast nonreciprocal spin-waves in the dipolar exchange regime of a canted antiferromagnet using both inductive and spintronic transducers. Using time-of-flight spin-wave spectroscopy on hematite (α-Fe2O3), we find that the magnon wave packets can propagate as fast as 20 kilometers/second for reciprocal bulk spin-wave modes and up to 6 kilometers/second for surface spin-waves propagating parallel to the antiferromagnetic Néel vector. We lastly achieve efficient electrical detection of nonreciprocal spin-wave transport using nonlocal inverse spin-Hall effects. The electrical detection of coherent nonreciprocal antiferromagnetic spin-waves paves the way for the development of antiferromagnetic and altermagnet-based magnonic devices.
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Affiliation(s)
- Aya El Kanj
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Olena Gomonay
- Institute of Physics, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
| | - Isabella Boventer
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Paolo Bortolotti
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Abdelmadjid Anane
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Romain Lebrun
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
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5
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Krishnia S, Sassi Y, Ajejas F, Sebe N, Reyren N, Collin S, Denneulin T, Kovács A, Dunin-Borkowski RE, Fert A, George JM, Cros V, Jaffrès H. Large Interfacial Rashba Interaction Generating Strong Spin-Orbit Torques in Atomically Thin Metallic Heterostructures. Nano Lett 2023; 23:6785-6791. [PMID: 37524333 PMCID: PMC10416352 DOI: 10.1021/acs.nanolett.2c05091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 06/22/2023] [Indexed: 08/02/2023]
Abstract
The hallmark of spintronics has been the ability of spin-orbit interactions to convert a charge current into a spin current and vice versa, mainly in the bulk of heavy metal thin films. Here, we demonstrate how a light metal interface profoundly affects both the nature of spin-orbit torques and its efficiency in terms of damping-like (HDL) and field-like (HFL) effective fields in ultrathin Co films. We measure unexpectedly HFL/HDL ratios much larger than 1 by inserting a nanometer-thin Al metallic layer in Pt|Co|Al|Pt as compared to a similar stacking, including Cu as a reference. From our modeling, these results evidence the existence of large Rashba interaction at the Co|Al interface generating a giant HFL, which is not expected from a metallic interface. The occurrence of such enhanced torques from an interfacial origin is further validated by demonstrating current-induced magnetization reversal showing a significant decrease of the critical current for switching.
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Affiliation(s)
- Sachin Krishnia
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Yanis Sassi
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Fernando Ajejas
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Nicolas Sebe
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Nicolas Reyren
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Sophie Collin
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Thibaud Denneulin
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C
1) and Peter Grünberg Institut (PGI-5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - András Kovács
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C
1) and Peter Grünberg Institut (PGI-5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Rafal E. Dunin-Borkowski
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C
1) and Peter Grünberg Institut (PGI-5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Albert Fert
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Jean-Marie George
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Vincent Cros
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Henri Jaffrès
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
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6
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Burgos-Parra E, Sassi Y, Legrand W, Ajejas F, Léveillé C, Gargiani P, Valvidares M, Reyren N, Cros V, Jaouen N, Flewett S. Probing of three-dimensional spin textures in multilayers by field dependent X-ray resonant magnetic scattering. Sci Rep 2023; 13:11711. [PMID: 37474533 PMCID: PMC10359410 DOI: 10.1038/s41598-023-38029-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 06/30/2023] [Indexed: 07/22/2023] Open
Abstract
In multilayers of magnetic thin films with perpendicular anisotropy, domain walls can take on hybrid configurations in the vertical direction which minimize the domain wall energy, with Néel walls in the top or bottom layers and Bloch walls in some central layers. These types of textures are theoretically predicted, but their observation has remained challenging until recently, with only a few techniques capable of realizing a three dimensional characterization of their magnetization distribution. Here we perform a field dependent X-ray resonant magnetic scattering measurements on magnetic multilayers exploiting circular dichroism contrast to investigate such structures. Using a combination of micromagnetic and X-ray resonant magnetic scattering simulations along with our experimental results, we characterize the three-dimensional magnetic texture of domain walls, notably the thickness resolved characterization of the size and position of the Bloch part in hybrid walls. We also take a step in advancing the resonant scattering methodology by using measurements performed off the multilayer Bragg angle in order to calibrate the effective absorption of the X-rays, and permitting a quantitative evaluation of the out of plane (z) structure of our samples. Beyond hybrid domain walls, this approach can be used to characterize other periodic chiral structures such as skyrmions, antiskyrmions or even magnetic bobbers or hopfions, in both static and dynamic experiments.
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Affiliation(s)
- Erick Burgos-Parra
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192, Gif-sur-Yvette, France.
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France.
- University of Santiago de Chile, Avenida Víctor Jara 3493, Estación Central, Santiago, Chile.
| | - Yanis Sassi
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - William Legrand
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Fernando Ajejas
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Cyril Léveillé
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192, Gif-sur-Yvette, France
| | - Pierluigi Gargiani
- ALBA Synchrotron Light Source, Cerdanyola del Vallès, 08290, Barcelona, Spain
| | - Manuel Valvidares
- ALBA Synchrotron Light Source, Cerdanyola del Vallès, 08290, Barcelona, Spain
| | - Nicolas Reyren
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Nicolas Jaouen
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192, Gif-sur-Yvette, France
| | - Samuel Flewett
- Pontificia Universidad Católica de Valparaíso, Avenida Universidad 330, Valparaiso, Chile
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7
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Romera M, Talatchian P, Tsunegi S, Yakushiji K, Fukushima A, Kubota H, Yuasa S, Cros V, Bortolotti P, Ernoult M, Querlioz D, Grollier J. Binding events through the mutual synchronization of spintronic nano-neurons. Nat Commun 2022; 13:883. [PMID: 35169115 PMCID: PMC8847428 DOI: 10.1038/s41467-022-28159-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 01/10/2022] [Indexed: 11/09/2022] Open
Abstract
The brain naturally binds events from different sources in unique concepts. It is hypothesized that this process occurs through the transient mutual synchronization of neurons located in different regions of the brain when the stimulus is presented. This mechanism of 'binding through synchronization' can be directly implemented in neural networks composed of coupled oscillators. To do so, the oscillators must be able to mutually synchronize for the range of inputs corresponding to a single class, and otherwise remain desynchronized. Here we show that the outstanding ability of spintronic nano-oscillators to mutually synchronize and the possibility to precisely control the occurrence of mutual synchronization by tuning the oscillator frequencies over wide ranges allows pattern recognition. We demonstrate experimentally on a simple task that three spintronic nano-oscillators can bind consecutive events and thus recognize and distinguish temporal sequences. This work is a step forward in the construction of neural networks that exploit the non-linear dynamic properties of their components to perform brain-inspired computations.
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Affiliation(s)
- Miguel Romera
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France.,GFMC, Departamento de Física de Materiales, Universidad Complutense de Madrid, 28040, Madrid, Spain.,Unidad Asociada UCM/CSIC, Laboratorio de Heteroestructuras con Aplicación en Espintrónica, 28049, Madrid, Spain
| | - Philippe Talatchian
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France.,Université Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, 38000, Grenoble, France
| | - Sumito Tsunegi
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan
| | - Kay Yakushiji
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan
| | - Akio Fukushima
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan
| | - Hitoshi Kubota
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan
| | - Shinji Yuasa
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Paolo Bortolotti
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Maxence Ernoult
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France.,Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France
| | - Damien Querlioz
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France.
| | - Julie Grollier
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France.
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8
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Divinskiy B, Merbouche H, Demidov VE, Nikolaev KO, Soumah L, Gouéré D, Lebrun R, Cros V, Youssef JB, Bortolotti P, Anane A, Demokritov SO. Evidence for spin current driven Bose-Einstein condensation of magnons. Nat Commun 2021; 12:6541. [PMID: 34764266 PMCID: PMC8585877 DOI: 10.1038/s41467-021-26790-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 10/22/2021] [Indexed: 11/26/2022] Open
Abstract
The quanta of magnetic excitations - magnons - are known for their unique ability to undergo Bose-Einstein condensation at room temperature. This fascinating phenomenon reveals itself as a spontaneous formation of a coherent state under the influence of incoherent stimuli. Spin currents have been predicted to offer electronic control of Bose-Einstein condensates, but this phenomenon has not been experimentally evidenced up to now. Here we show that current-driven Bose-Einstein condensation can be achieved in nanometer-thick films of magnetic insulators with tailored nonlinearities and minimized magnon interactions. We demonstrate that, above a certain threshold, magnons injected by the spin current overpopulate the lowest-energy level forming a highly coherent spatially extended state. We quantify the chemical potential of the driven magnon gas and show that, at the critical current, it reaches the energy of the lowest magnon level. Our results pave the way for implementation of integrated microscopic quantum magnonic and spintronic devices.
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Affiliation(s)
- B Divinskiy
- Institute for Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
| | - H Merbouche
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - V E Demidov
- Institute for Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany.
| | - K O Nikolaev
- Institute for Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
| | - L Soumah
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - D Gouéré
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - R Lebrun
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - V Cros
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Jamal Ben Youssef
- LABSTICC, UMR 6285 CNRS, Université de Bretagne Occidentale, 29238, Brest, France
| | - P Bortolotti
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - A Anane
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - S O Demokritov
- Institute for Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
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9
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Céspedes-Berrocal D, Damas H, Petit-Watelot S, Maccariello D, Tang P, Arriola-Córdova A, Vallobra P, Xu Y, Bello JL, Martin E, Migot S, Ghanbaja J, Zhang S, Hehn M, Mangin S, Panagopoulos C, Cros V, Fert A, Rojas-Sánchez JC. Current-Induced Spin Torques on Single GdFeCo Magnetic Layers. Adv Mater 2021; 33:e2007047. [PMID: 33604960 DOI: 10.1002/adma.202007047] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 12/20/2020] [Indexed: 06/12/2023]
Abstract
Spintronics exploit spin-orbit coupling (SOC) to generate spin currents, spin torques, and, in the absence of inversion symmetry, Rashba and Dzyaloshinskii-Moriya interactions. The widely used magnetic materials, based on 3d metals such as Fe and Co, possess a small SOC. To circumvent this shortcoming, the common practice has been to utilize the large SOC of nonmagnetic layers of 5d heavy metals (HMs), such as Pt, to generate spin currents and, in turn, exert spin torques on the magnetic layers. Here, a new class of material architectures is introduced, excluding nonmagnetic 5d HMs, for high-performance spintronics operations. Very strong current-induced torques exerted on single ferrimagnetic GdFeCo layers, due to the combination of large SOC of the Gd 5d states and inversion symmetry breaking mainly engineered by interfaces, are demonstrated. These "self-torques" are enhanced around the magnetization compensation temperature and can be tuned by adjusting the spin absorption outside the GdFeCo layer. In other measurements, the very large emission of spin current from GdFeCo, 80% (20%) of spin anomalous Hall effect (spin Hall effect) symmetry is determined. This material platform opens new perspectives to exert "self-torques" on single magnetic layers as well as to generate spin currents from a magnetic layer.
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Affiliation(s)
- David Céspedes-Berrocal
- Institute Jean Lamour, Université de Lorraine, CNRS, Nancy, F-54000, France
- Facultad de Ciencias, Universidad Nacional de Ingeniería, Rímac, Lima, 15333, Peru
| | - Heloïse Damas
- Institute Jean Lamour, Université de Lorraine, CNRS, Nancy, F-54000, France
| | | | - Davide Maccariello
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, Palaiseau, 91767, France
| | - Ping Tang
- Department of Physics, University of Arizona, Tucson, AZ, 85721, USA
| | - Aldo Arriola-Córdova
- Institute Jean Lamour, Université de Lorraine, CNRS, Nancy, F-54000, France
- Facultad de Ciencias, Universidad Nacional de Ingeniería, Rímac, Lima, 15333, Peru
| | - Pierre Vallobra
- Institute Jean Lamour, Université de Lorraine, CNRS, Nancy, F-54000, France
| | - Yong Xu
- Institute Jean Lamour, Université de Lorraine, CNRS, Nancy, F-54000, France
| | - Jean-Loïs Bello
- Institute Jean Lamour, Université de Lorraine, CNRS, Nancy, F-54000, France
| | - Elodie Martin
- Institute Jean Lamour, Université de Lorraine, CNRS, Nancy, F-54000, France
| | - Sylvie Migot
- Institute Jean Lamour, Université de Lorraine, CNRS, Nancy, F-54000, France
| | - Jaafar Ghanbaja
- Institute Jean Lamour, Université de Lorraine, CNRS, Nancy, F-54000, France
| | - Shufeng Zhang
- Department of Physics, University of Arizona, Tucson, AZ, 85721, USA
| | - Michel Hehn
- Institute Jean Lamour, Université de Lorraine, CNRS, Nancy, F-54000, France
| | - Stéphane Mangin
- Institute Jean Lamour, Université de Lorraine, CNRS, Nancy, F-54000, France
| | - Christos Panagopoulos
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, Palaiseau, 91767, France
| | - Albert Fert
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, Palaiseau, 91767, France
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10
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Fernández Scarioni A, Barton C, Corte-León H, Sievers S, Hu X, Ajejas F, Legrand W, Reyren N, Cros V, Kazakova O, Schumacher HW. Thermoelectric Signature of Individual Skyrmions. Phys Rev Lett 2021; 126:077202. [PMID: 33666484 DOI: 10.1103/physrevlett.126.077202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/26/2020] [Accepted: 11/02/2020] [Indexed: 06/12/2023]
Abstract
We experimentally study the thermoelectrical signature of individual skyrmions in chiral Pt/Co/Ru multilayers. Using a combination of controlled nucleation, single skyrmion annihilation, and magnetic field dependent measurements the thermoelectric signature of individual skyrmions is characterized. The observed signature is explained by the anomalous Nernst effect of the skyrmion's spin structure. Possible topological contributions to the observed thermoelectrical signature are discussed. Such thermoelectrical characterization allows for noninvasive detection and counting of skyrmions and enables fundamental studies of topological thermoelectric effects on the nanoscale.
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Affiliation(s)
| | - Craig Barton
- National Physical Laboratory, Teddington TW110LW, United Kingdom
| | | | - Sibylle Sievers
- Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany
| | - Xiukun Hu
- Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany
| | - Fernando Ajejas
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - William Legrand
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Nicolas Reyren
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Olga Kazakova
- National Physical Laboratory, Teddington TW110LW, United Kingdom
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11
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Finco A, Haykal A, Tanos R, Fabre F, Chouaieb S, Akhtar W, Robert-Philip I, Legrand W, Ajejas F, Bouzehouane K, Reyren N, Devolder T, Adam JP, Kim JV, Cros V, Jacques V. Imaging non-collinear antiferromagnetic textures via single spin relaxometry. Nat Commun 2021; 12:767. [PMID: 33536440 PMCID: PMC7859235 DOI: 10.1038/s41467-021-20995-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 01/04/2021] [Indexed: 01/30/2023] Open
Abstract
Antiferromagnetic materials are promising platforms for next-generation spintronics owing to their fast dynamics and high robustness against parasitic magnetic fields. However, nanoscale imaging of the magnetic order in such materials with zero net magnetization remains a major experimental challenge. Here we show that non-collinear antiferromagnetic spin textures can be imaged by probing the magnetic noise they locally produce via thermal populations of magnons. To this end, we perform nanoscale, all-optical relaxometry with a scanning quantum sensor based on a single nitrogen-vacancy (NV) defect in diamond. Magnetic noise is detected through an increase of the spin relaxation rate of the NV defect, which results in an overall reduction of its photoluminescence signal under continuous laser illumination. As a proof-of-concept, the efficiency of the method is demonstrated by imaging various spin textures in synthetic antiferromagnets, including domain walls, spin spirals and antiferromagnetic skyrmions. This imaging procedure could be extended to a large class of intrinsic antiferromagnets and opens up new opportunities for studying the physics of localized spin wave modes for magnonics.
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Affiliation(s)
- Aurore Finco
- Laboratoire Charles Coulomb, Université de Montpellier and CNRS, 34095, Montpellier, France
| | - Angela Haykal
- Laboratoire Charles Coulomb, Université de Montpellier and CNRS, 34095, Montpellier, France
| | - Rana Tanos
- Laboratoire Charles Coulomb, Université de Montpellier and CNRS, 34095, Montpellier, France
| | - Florentin Fabre
- Laboratoire Charles Coulomb, Université de Montpellier and CNRS, 34095, Montpellier, France
| | - Saddem Chouaieb
- Laboratoire Charles Coulomb, Université de Montpellier and CNRS, 34095, Montpellier, France
| | - Waseem Akhtar
- Laboratoire Charles Coulomb, Université de Montpellier and CNRS, 34095, Montpellier, France
- Department of Physics, JMI, Central University, New Delhi, India
| | - Isabelle Robert-Philip
- Laboratoire Charles Coulomb, Université de Montpellier and CNRS, 34095, Montpellier, France
| | - William Legrand
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Fernando Ajejas
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Karim Bouzehouane
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Nicolas Reyren
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Thibaut Devolder
- Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Saclay, 91120, Palaiseau, France
| | - Jean-Paul Adam
- Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Saclay, 91120, Palaiseau, France
| | - Joo-Von Kim
- Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Saclay, 91120, Palaiseau, France
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Vincent Jacques
- Laboratoire Charles Coulomb, Université de Montpellier and CNRS, 34095, Montpellier, France.
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12
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Wittrock S, Talatchian P, Tsunegi S, Crété D, Yakushiji K, Bortolotti P, Ebels U, Fukushima A, Kubota H, Yuasa S, Grollier J, Cibiel G, Galliou S, Rubiola E, Cros V. Influence of flicker noise and nonlinearity on the frequency spectrum of spin torque nano-oscillators. Sci Rep 2020; 10:13116. [PMID: 32753722 PMCID: PMC7403434 DOI: 10.1038/s41598-020-70076-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 07/22/2020] [Indexed: 11/23/2022] Open
Abstract
The correlation of phase fluctuations in any type of oscillator fundamentally defines its spectral shape. However, in nonlinear oscillators, such as spin torque nano-oscillators, the frequency spectrum can become particularly complex. This is specifically true when not only considering thermal but also colored 1/f flicker noise processes, which are crucial in the context of the oscillator’s long term stability. In this study, we address the frequency spectrum of spin torque oscillators in the regime of large-amplitude steady oscillations experimentally and as well theoretically. We particularly take both thermal and flicker noise into account. We perform a series of measurements of the phase noise and the spectrum on spin torque vortex oscillators, notably varying the measurement time duration. Furthermore, we develop the modelling of thermal and flicker noise in Thiele equation based simulations. We also derive the complete phase variance in the framework of the nonlinear auto-oscillator theory and deduce the actual frequency spectrum. We investigate its dependence on the measurement time duration and compare with the experimental results. Long term stability is important in several of the recent applicative developments of spin torque oscillators. This study brings some insights on how to better address this issue.
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Affiliation(s)
- Steffen Wittrock
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Univ. Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France.
| | - Philippe Talatchian
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Univ. Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France.,Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, 20899-6202, MD, USA
| | - Sumito Tsunegi
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan
| | - Denis Crété
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Univ. Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France
| | - Kay Yakushiji
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan
| | - Paolo Bortolotti
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Univ. Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France
| | - Ursula Ebels
- Univ. Grenoble Alpes, CEA, INAC-SPINTEC, CNRS, SPINTEC, 38000, Grenoble, France
| | - Akio Fukushima
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan
| | - Hitoshi Kubota
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan
| | - Shinji Yuasa
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan
| | - Julie Grollier
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Univ. Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France
| | - Gilles Cibiel
- Centre National d'Études Spatiales (CNES), 18 av. Edouard Belin, 31401, Toulouse, France
| | - Serge Galliou
- FEMTO-ST Institute, CNRS, Univ. Bourgogne Franche Comté, 25030, Besançon, France
| | - Enrico Rubiola
- FEMTO-ST Institute, CNRS, Univ. Bourgogne Franche Comté, 25030, Besançon, France
| | - Vincent Cros
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Univ. Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France
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13
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Fallon K, Hughes S, Zeissler K, Legrand W, Ajejas F, Maccariello D, McFadzean S, Smith W, McGrouther D, Collin S, Reyren N, Cros V, Marrows CH, McVitie S. Controlled Individual Skyrmion Nucleation at Artificial Defects Formed by Ion Irradiation. Small 2020; 16:e1907450. [PMID: 32141234 DOI: 10.1002/smll.201907450] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/14/2020] [Accepted: 02/17/2020] [Indexed: 06/10/2023]
Abstract
Magnetic skyrmions are particle-like deformations in a magnetic texture. They have great potential as information carriers in spintronic devices because of their interesting topological properties and favorable motion under spin currents. A new method of nucleating skyrmions at nanoscale defect sites, created in a controlled manner with focused ion beam irradiation, in polycrystalline magnetic multilayer samples with an interfacial Dzyaloshinskii-Moriya interaction, is reported. This new method has three notable advantages: 1) localization of nucleation; 2) stability over a larger range of external field strengths, including stability at zero field; and 3) existence of skyrmions in material systems where, prior to defect fabrication, skyrmions were not previously obtained by field cycling. Additionally, it is observed that the size of defect nucleated skyrmions is uninfluenced by the defect itself-provided that the artificial defects are controlled to be smaller than the inherent skyrmion size. All of these characteristics are expected to be useful toward the goal of realizing a skyrmion-based spintronic device. This phenomenon is studied with a range of transmission electron microscopy techniques to probe quantitatively the magnetic behavior at the defects with applied field and correlate this with the structural impact of the defects.
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Affiliation(s)
- Kayla Fallon
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Sean Hughes
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Katharina Zeissler
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, 91767, France
| | - William Legrand
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - Fernando Ajejas
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | | | - Samuel McFadzean
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
| | - William Smith
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Damien McGrouther
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Sophie Collin
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - Nicolas Reyren
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - Vincent Cros
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | | | - Stephen McVitie
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
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14
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Legrand W, Maccariello D, Ajejas F, Collin S, Vecchiola A, Bouzehouane K, Reyren N, Cros V, Fert A. Room-temperature stabilization of antiferromagnetic skyrmions in synthetic antiferromagnets. Nat Mater 2020; 19:34-42. [PMID: 31477905 DOI: 10.1038/s41563-019-0468-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 07/24/2019] [Indexed: 05/23/2023]
Abstract
Room-temperature skyrmions in ferromagnetic films and multilayers show promise for encoding information bits in new computing technologies. Despite recent progress, ferromagnetic order generates dipolar fields that prevent ultrasmall skyrmion sizes, and allows a transverse deflection of moving skyrmions that hinders their efficient manipulation. Antiferromagnetic skyrmions shall lift these limitations. Here we demonstrate that room-temperature antiferromagnetic skyrmions can be stabilized in synthetic antiferromagnets (SAFs), in which perpendicular magnetic anisotropy, antiferromagnetic coupling and chiral order can be adjusted concurrently. Utilizing interlayer electronic coupling to an adjacent bias layer, we demonstrate that spin-spiral states obtained in a SAF with vanishing perpendicular magnetic anisotropy can be turned into isolated antiferromagnetic skyrmions. We also provide model-based estimates of skyrmion size and stability, showing that room-temperature antiferromagnetic skyrmions below 10 nm in radius can be anticipated in further optimized SAFs. Antiferromagnetic skyrmions in SAFs may thus solve major issues associated with ferromagnetic skyrmions for low-power spintronic devices.
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Affiliation(s)
- William Legrand
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France.
| | - Davide Maccariello
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Fernando Ajejas
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Sophie Collin
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Aymeric Vecchiola
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Karim Bouzehouane
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Nicolas Reyren
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France.
| | - Albert Fert
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France
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15
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Devolder T, Rontani D, Petit-Watelot S, Bouzehouane K, Andrieu S, Létang J, Yoo MW, Adam JP, Chappert C, Girod S, Cros V, Sciamanna M, Kim JV. Chaos in Magnetic Nanocontact Vortex Oscillators. Phys Rev Lett 2019; 123:147701. [PMID: 31702206 DOI: 10.1103/physrevlett.123.147701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 08/05/2019] [Indexed: 06/10/2023]
Abstract
We present an experimental study of spin-torque driven vortex self-oscillations in magnetic nanocontacts. We find that, above a certain threshold in applied currents, the vortex gyration around the nanocontact is modulated by relaxation oscillations, which involve periodic reversals of the vortex core. This modulation leads to the appearance of commensurate but also, more interestingly here, incommensurate states, which are characterized by devil's staircases in the modulation frequency. We use frequency- and time-domain measurements together with advanced time-series analyses to provide experimental evidence of chaos in incommensurate states of vortex oscillations, in agreement with theoretical predictions.
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Affiliation(s)
- Thibaut Devolder
- Centre de Nanosciences et de Nanotechnologies, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91120 Palaiseau, France
| | - Damien Rontani
- Chaire Photonique, CentraleSupélec, Université Paris-Saclay, 57070 Metz, France
- Laboratoire Matériaux Optiques, Photonique et Systèmes, CentraleSupélec, Université de Lorraine, 57070 Metz, France
| | | | - Karim Bouzehouane
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Stéphane Andrieu
- Institut Jean Lamour, CNRS, Université de Lorraine, 54011 Nancy, France
| | - Jérémy Létang
- Centre de Nanosciences et de Nanotechnologies, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91120 Palaiseau, France
| | - Myoung-Woo Yoo
- Centre de Nanosciences et de Nanotechnologies, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91120 Palaiseau, France
| | - Jean-Paul Adam
- Centre de Nanosciences et de Nanotechnologies, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91120 Palaiseau, France
| | - Claude Chappert
- Centre de Nanosciences et de Nanotechnologies, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91120 Palaiseau, France
| | - Stéphanie Girod
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Marc Sciamanna
- Chaire Photonique, CentraleSupélec, Université Paris-Saclay, 57070 Metz, France
- Laboratoire Matériaux Optiques, Photonique et Systèmes, CentraleSupélec, Université de Lorraine, 57070 Metz, France
| | - Joo-Von Kim
- Centre de Nanosciences et de Nanotechnologies, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91120 Palaiseau, France
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16
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Riou M, Torrejon J, Garitaine B, Araujo FA, Bortolotti P, Cros V, Tsunegi S, Yakushiji K, Fukushima A, Kubota H, Yuasa S, Querlioz D, Stiles MD, Grollier J. Temporal pattern recognition with delayed feedback spin-torque nano-oscillators. Phys Rev Appl 2019; 12:10.1103/physrevapplied.12.024049. [PMID: 32118096 PMCID: PMC7047780 DOI: 10.1103/physrevapplied.12.024049] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The recent demonstration of neuromorphic computing with spin-torque nano-oscillators has opened a path to energy efficient data processing. The success of this demonstration hinged on the intrinsic short-term memory of the oscillators. In this study, we extend the memory of the spin-torque nano-oscillators through time-delayed feedback. We leverage this extrinsic memory to increase the efficiency of solving pattern recognition tasks that require memory to discriminate different inputs. The large tunability of these non-linear oscillators allows us to control and optimize the delayed feedback memory using different operating conditions of applied current and magnetic field.
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Affiliation(s)
- M Riou
- Unité Mixte de Physique CNRS, Thales,Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - J Torrejon
- Unité Mixte de Physique CNRS, Thales,Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - B Garitaine
- Unité Mixte de Physique CNRS, Thales,Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - F Abreu Araujo
- Unité Mixte de Physique CNRS, Thales,Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - P Bortolotti
- Unité Mixte de Physique CNRS, Thales,Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - V Cros
- Unité Mixte de Physique CNRS, Thales,Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - S Tsunegi
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronic Research Center, Tsukuba, Ibaraki 305-8568, Japan
| | - K Yakushiji
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronic Research Center, Tsukuba, Ibaraki 305-8568, Japan
| | - A Fukushima
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronic Research Center, Tsukuba, Ibaraki 305-8568, Japan
| | - H Kubota
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronic Research Center, Tsukuba, Ibaraki 305-8568, Japan
| | - S Yuasa
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronic Research Center, Tsukuba, Ibaraki 305-8568, Japan
| | - D Querlioz
- Center for Nanoscience and Nanotechnology, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
| | - M D Stiles
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6202, USA
| | - J Grollier
- Unité Mixte de Physique CNRS, Thales,Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
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17
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Romera M, Talatchian P, Tsunegi S, Abreu Araujo F, Cros V, Bortolotti P, Trastoy J, Yakushiji K, Fukushima A, Kubota H, Yuasa S, Ernoult M, Vodenicarevic D, Hirtzlin T, Locatelli N, Querlioz D, Grollier J. Vowel recognition with four coupled spin-torque nano-oscillators. Nature 2018; 563:230-234. [PMID: 30374193 DOI: 10.1038/s41586-018-0632-y] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 07/31/2018] [Indexed: 11/10/2022]
Abstract
In recent years, artificial neural networks have become the flagship algorithm of artificial intelligence1. In these systems, neuron activation functions are static, and computing is achieved through standard arithmetic operations. By contrast, a prominent branch of neuroinspired computing embraces the dynamical nature of the brain and proposes to endow each component of a neural network with dynamical functionality, such as oscillations, and to rely on emergent physical phenomena, such as synchronization2-6, for solving complex problems with small networks7-11. This approach is especially interesting for hardware implementations, because emerging nanoelectronic devices can provide compact and energy-efficient nonlinear auto-oscillators that mimic the periodic spiking activity of biological neurons12-16. The dynamical couplings between oscillators can then be used to mediate the synaptic communication between the artificial neurons. One challenge for using nanodevices in this way is to achieve learning, which requires fine control and tuning of their coupled oscillations17; the dynamical features of nanodevices can be difficult to control and prone to noise and variability18. Here we show that the outstanding tunability of spintronic nano-oscillators-that is, the possibility of accurately controlling their frequency across a wide range, through electrical current and magnetic field-can be used to address this challenge. We successfully train a hardware network of four spin-torque nano-oscillators to recognize spoken vowels by tuning their frequencies according to an automatic real-time learning rule. We show that the high experimental recognition rates stem from the ability of these oscillators to synchronize. Our results demonstrate that non-trivial pattern classification tasks can be achieved with small hardware neural networks by endowing them with nonlinear dynamical features such as oscillations and synchronization.
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Affiliation(s)
- Miguel Romera
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Philippe Talatchian
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Sumito Tsunegi
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, Japan
| | - Flavio Abreu Araujo
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, Palaiseau, France.,Institute of Condensed Matter and Nanosciences, UC Louvain, Louvain-la-Neuve, Belgium
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Paolo Bortolotti
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Juan Trastoy
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Kay Yakushiji
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, Japan
| | - Akio Fukushima
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, Japan
| | - Hitoshi Kubota
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, Japan
| | - Shinji Yuasa
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, Japan
| | - Maxence Ernoult
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, Palaiseau, France.,Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Damir Vodenicarevic
- Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Tifenn Hirtzlin
- Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Nicolas Locatelli
- Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Damien Querlioz
- Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Sud, Université Paris-Saclay, Orsay, France.
| | - Julie Grollier
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, Palaiseau, France.
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18
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Tsunegi S, Taniguchi T, Lebrun R, Yakushiji K, Cros V, Grollier J, Fukushima A, Yuasa S, Kubota H. Scaling up electrically synchronized spin torque oscillator networks. Sci Rep 2018; 8:13475. [PMID: 30194358 PMCID: PMC6128876 DOI: 10.1038/s41598-018-31769-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 08/21/2018] [Indexed: 11/29/2022] Open
Abstract
Synchronized nonlinear oscillators networks are at the core of numerous families of applications including phased array wave generators and neuromorphic pattern matching systems. In these devices, stable synchronization between large numbers of nanoscale oscillators is a key issue that remains to be demonstrated. Here, we show experimentally that synchronized spin-torque oscillator networks can be scaled up. By increasing the number of synchronized oscillators up to eight, we obtain that the emitted power and the quality factor increase linearly with the number of oscillators. Even more importantly, we demonstrate that the stability of synchronization in time exceeds 1.6 milliseconds corresponding to 105 periods of oscillation. Our study demonstrates that spin-torque oscillators are suitable for applications based on synchronized networks of oscillators.
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Affiliation(s)
- Sumito Tsunegi
- Spintronics Research Center, National Institute of Advanced Industrial Science And Technology (AIST), Tsukuba, 305-8568, Japan.
| | - Tomohiro Taniguchi
- Spintronics Research Center, National Institute of Advanced Industrial Science And Technology (AIST), Tsukuba, 305-8568, Japan
| | - Romain Lebrun
- Unité Mixte de Physique CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, 91767, Palaiseau, France
- Institute for Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Kay Yakushiji
- Spintronics Research Center, National Institute of Advanced Industrial Science And Technology (AIST), Tsukuba, 305-8568, Japan
| | - Vincent Cros
- Unité Mixte de Physique CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, 91767, Palaiseau, France.
| | - Julie Grollier
- Unité Mixte de Physique CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, 91767, Palaiseau, France
| | - Akio Fukushima
- Spintronics Research Center, National Institute of Advanced Industrial Science And Technology (AIST), Tsukuba, 305-8568, Japan
| | - Shinji Yuasa
- Spintronics Research Center, National Institute of Advanced Industrial Science And Technology (AIST), Tsukuba, 305-8568, Japan
| | - Hitoshi Kubota
- Spintronics Research Center, National Institute of Advanced Industrial Science And Technology (AIST), Tsukuba, 305-8568, Japan
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19
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Soumah L, Beaulieu N, Qassym L, Carrétéro C, Jacquet E, Lebourgeois R, Ben Youssef J, Bortolotti P, Cros V, Anane A. Ultra-low damping insulating magnetic thin films get perpendicular. Nat Commun 2018; 9:3355. [PMID: 30135521 PMCID: PMC6105659 DOI: 10.1038/s41467-018-05732-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/19/2018] [Indexed: 11/14/2022] Open
Abstract
A magnetic material combining low losses and large perpendicular magnetic anisotropy (PMA) is still a missing brick in the magnonic and spintronic fields. We report here on the growth of ultrathin Bismuth doped Y3Fe5O12 (BiYIG) films on Gd3Ga5O12 (GGG) and substituted GGG (sGGG) (111) oriented substrates. A fine tuning of the PMA is obtained using both epitaxial strain and growth-induced anisotropies. Both spontaneously in-plane and out-of-plane magnetized thin films can be elaborated. Ferromagnetic Resonance (FMR) measurements demonstrate the high-dynamic quality of these BiYIG ultrathin films; PMA films with Gilbert damping values as low as 3 × 10-4 and FMR linewidth of 0.3 mT at 8 GHz are achieved even for films that do not exceed 30 nm in thickness. Moreover, we measure inverse spin hall effect (ISHE) on Pt/BiYIG stacks showing that the magnetic insulator's surface is transparent to spin current, making it appealing for spintronic applications.
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Affiliation(s)
- Lucile Soumah
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris Saclay, 91767, Palaiseau, France
| | - Nathan Beaulieu
- LABSTICC, UMR 6285 CNRS, Université de Bretagne Occidentale, 29238, Brest, France
| | - Lilia Qassym
- Thales Research and Technology, Thales, 91767, Palaiseau, France
| | - Cécile Carrétéro
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris Saclay, 91767, Palaiseau, France
| | - Eric Jacquet
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris Saclay, 91767, Palaiseau, France
| | | | - Jamal Ben Youssef
- LABSTICC, UMR 6285 CNRS, Université de Bretagne Occidentale, 29238, Brest, France
| | - Paolo Bortolotti
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris Saclay, 91767, Palaiseau, France
| | - Vincent Cros
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris Saclay, 91767, Palaiseau, France
| | - Abdelmadjid Anane
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris Saclay, 91767, Palaiseau, France.
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20
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Legrand W, Chauleau JY, Maccariello D, Reyren N, Collin S, Bouzehouane K, Jaouen N, Cros V, Fert A. Hybrid chiral domain walls and skyrmions in magnetic multilayers. Sci Adv 2018; 4:eaat0415. [PMID: 30035224 PMCID: PMC6054507 DOI: 10.1126/sciadv.aat0415] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 06/11/2018] [Indexed: 05/24/2023]
Abstract
Noncollinear spin textures in ferromagnetic ultrathin films are currently the subject of renewed interest since the discovery of the interfacial Dzyaloshinskii-Moriya interaction (DMI). This antisymmetric exchange interaction selects a given chirality for the spin textures and allows stabilizing configurations with nontrivial topology including chiral domain walls (DWs) and magnetic skyrmions. Moreover, it has many crucial consequences on the dynamical properties of these topological structures. In recent years, the study of noncollinear spin textures has been extended from single ultrathin layers to magnetic multilayers with broken inversion symmetry. This extension of the structures in the vertical dimension allows room temperature stability and very efficient current-induced motion for both Néel DWs and skyrmions. We show how, in these multilayered systems, the interlayer interactions can actually lead to hybrid chiral magnetization arrangements. The described thickness-dependent reorientation of DWs is experimentally confirmed by studying demagnetized multilayers through circular dichroism in x-ray resonant magnetic scattering. We also demonstrate a simple yet reliable method for determining the magnitude of the DMI from static domain measurements even in the presence of these hybrid chiral structures by taking into account the actual profile of the DWs. The existence of these novel hybrid chiral textures has far-reaching implications on how to stabilize and manipulate DWs, as well as skymionic structures in magnetic multilayers.
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Affiliation(s)
- William Legrand
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Jean-Yves Chauleau
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
- Synchrotron SOLEIL, L’Orme des Merisiers, Gif-sur-Yvette 91192, France
| | - Davide Maccariello
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Nicolas Reyren
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Sophie Collin
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Karim Bouzehouane
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Nicolas Jaouen
- Synchrotron SOLEIL, L’Orme des Merisiers, Gif-sur-Yvette 91192, France
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Albert Fert
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
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21
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McVitie S, Hughes S, Fallon K, McFadzean S, McGrouther D, Krajnak M, Legrand W, Maccariello D, Collin S, Garcia K, Reyren N, Cros V, Fert A, Zeissler K, Marrows CH. A transmission electron microscope study of Néel skyrmion magnetic textures in multilayer thin film systems with large interfacial chiral interaction. Sci Rep 2018; 8:5703. [PMID: 29632330 PMCID: PMC5890272 DOI: 10.1038/s41598-018-23799-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 03/21/2018] [Indexed: 12/05/2022] Open
Abstract
Skyrmions in ultrathin ferromagnetic metal (FM)/heavy metal (HM) multilayer systems produced by conventional sputtering methods have recently generated huge interest due to their applications in the field of spintronics. The sandwich structure with two correctly-chosen heavy metal layers provides an additive interfacial exchange interaction which promotes domain wall or skyrmion spin textures that are Néel in character and with a fixed chirality. Lorentz transmission electron microscopy (TEM) is a high resolution method ideally suited to quantitatively image such chiral magnetic configurations. When allied with physical and chemical TEM analysis of both planar and cross-sectional samples, key length scales such as grain size and the chiral variation of the magnetisation variation have been identified and measured. We present data showing the importance of the grain size (mostly < 10 nm) measured from direct imaging and its potential role in describing observed behaviour of isolated skyrmions (diameter < 100 nm). In the latter the region in which the magnetization rotates is measured to be around 30 nm. Such quantitative information on the multiscale magnetisation variations in the system is key to understanding and exploiting the behaviour of skyrmions for future applications in information storage and logic devices.
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Affiliation(s)
- S McVitie
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom.
| | - S Hughes
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - K Fallon
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - S McFadzean
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - D McGrouther
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - M Krajnak
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom.,Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - W Legrand
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau, France
| | - D Maccariello
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau, France
| | - S Collin
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau, France
| | - K Garcia
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau, France
| | - N Reyren
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau, France
| | - V Cros
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau, France
| | - A Fert
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau, France
| | - K Zeissler
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - C H Marrows
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom
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22
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Maccariello D, Legrand W, Reyren N, Garcia K, Bouzehouane K, Collin S, Cros V, Fert A. Electrical detection of single magnetic skyrmions in metallic multilayers at room temperature. Nat Nanotechnol 2018; 13:233-237. [PMID: 29379203 DOI: 10.1038/s41565-017-0044-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 12/05/2017] [Indexed: 06/07/2023]
Abstract
Magnetic skyrmions are topologically protected whirling spin textures that can be stabilized in magnetic materials by an asymmetric exchange interaction between neighbouring spins that imposes a fixed chirality. Their small size, together with the robustness against external perturbations, make magnetic skyrmions potential storage bits in a novel generation of memory and logic devices. To this aim, their contribution to the electrical transport properties of a device must be characterized-however, the existing demonstrations are limited to low temperatures and mainly in magnetic materials with a B20 crystal structure. Here we combine concomitant magnetic force microscopy and Hall resistivity measurements to demonstrate the electrical detection of sub-100 nm skyrmions in a multilayered thin film at room temperature. Furthermore, we detect and analyse the Hall signal of a single skyrmion, which indicates that it arises from the anomalous Hall effect with a negligible contribution from the topological Hall effect.
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Affiliation(s)
- Davide Maccariello
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - William Legrand
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Nicolas Reyren
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Karin Garcia
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Karim Bouzehouane
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Sophie Collin
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France.
| | - Albert Fert
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France
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23
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Chauleau JY, Legrand W, Reyren N, Maccariello D, Collin S, Popescu H, Bouzehouane K, Cros V, Jaouen N, Fert A. Chirality in Magnetic Multilayers Probed by the Symmetry and the Amplitude of Dichroism in X-Ray Resonant Magnetic Scattering. Phys Rev Lett 2018; 120:037202. [PMID: 29400492 DOI: 10.1103/physrevlett.120.037202] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Indexed: 05/27/2023]
Abstract
Chirality in condensed matter has recently become a topic of the utmost importance because of its significant role in the understanding and mastering of a large variety of new fundamental physical mechanisms. Versatile experimental approaches, capable to reveal easily the exact winding of order parameters, are therefore essential. Here we report x-ray resonant magnetic scattering as a straightforward tool to reveal directly the properties of chiral magnetic systems. We show that it can straightforwardly and unambiguously determine the main characteristics of chiral magnetic distributions: i.e., its chiral nature, the quantitative winding sense (clockwise or counterclockwise), and its type, i.e., Néel [cycloidal] or Bloch [helical]. This method is model independent, does not require a priori knowledge of the magnetic parameters, and can be applied to any system with magnetic domains ranging from a few nanometers (wavelength limited) to several microns. By using prototypical multilayers with tailored magnetic chiralities driven by spin-orbit-related effects at Co|Pt interfaces, we illustrate the strength of this method.
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Affiliation(s)
- Jean-Yves Chauleau
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Gif-sur-Yvette, France
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - William Legrand
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Nicolas Reyren
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Davide Maccariello
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Sophie Collin
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Horia Popescu
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Gif-sur-Yvette, France
| | - Karim Bouzehouane
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Nicolas Jaouen
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Gif-sur-Yvette, France
| | - Albert Fert
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
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24
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Bousquet J, Bourret R, Camuzat T, Augé P, Bringer J, Noguès M, Jonquet O, de la Coussaye JE, Ankri J, Cesari M, Guérin O, Vellas B, Blain H, Arnavielhe S, Avignon A, Combe B, Canovas G, Daien C, Dray G, Dupeyron A, Jeandel C, Laffont I, Laune D, Marion C, Pastor E, Pélissier JY, Galan B, Reynes J, Reuzeau JC, Bedbrook A, Granier S, Adnet PA, Amouyal M, Alomène B, Bernard PL, Berr C, Caimmi D, Claret PG, Costa DJ, Cristol JP, Fesler P, Hève D, Millot-Keurinck J, Morquin D, Ninot G, Picot MC, Raffort N, Roubille F, Sultan A, Touchon J, Attalin V, Azevedo C, Badin M, Bakhti K, Bardy B, Battesti MP, Bobia X, Boegner C, Boichot S, Bonnin HY, Bouly S, Boubakri C, Bourrain JL, Bourrel G, Bouix V, Bruguière V, Cade S, Camu W, Carre V, Cavalli G, Cayla G, Chiron R, Coignard P, Coroian F, Costa P, Cottalorda J, Coulet B, Coupet AL, Courrouy-Michel MC, Courtet P, Cros V, Cuisinier F, Danko M, Dauenhauer P, Dauzat M, David M, Davy JM, Delignières D, Demoly P, Desplan J, Dujols P, Dupeyron G, Engberink O, Enjalbert M, Fattal C, Fernandes J, Fouletier M, Fraisse P, Gabrion P, Gellerat-Rogier M, Gelis A, Genis C, Giraudeau N, Goucham AY, Gouzi F, Gressard F, Gris JC, Guillot B, Guiraud D, Handweiler V, Hayot M, Hérisson C, Heroum C, Hoa D, Jacquemin S, Jaber S, Jakovenko D, Jorgensen C, Kouyoudjian P, Lamoureux R, Landreau L, Lapierre M, Larrey D, Laurent C, Léglise MS, Lemaitre JM, Le Quellec A, Leclercq F, Lehmann S, Lognos B, Lussert CM, Makinson A, Mandrick K, Mares P, Martin-Gousset P, Matheron A, Mathieu G, Meissonnier M, Mercier G, Messner P, Meunier C, Mondain M, Morales R, Morel J, Mottet D, Nérin P, Nicolas P, Nouvel F, Paccard D, Pandraud G, Pasdelou MP, Pasquié JL, Patte K, Perrey S, Pers YM, Portejoie F, Pujol JLE, Quantin X, Quéré I, Ramdani S, Ribstein J, Rédini-Martinez I, Richard S, Ritchie K, Riso JP, Rivier F, Robine JM, Rolland C, Royère E, Sablot D, Savy JL, Schifano L, Senesse P, Sicard R, Stephan Y, Strubel D, Tallon G, Tanfin M, Tassery H, Tavares I, Torre K, Tribout V, Uziel A, Van de Perre P, Venail F, Vergne-Richard C, Vergotte G, Vian L, Vialla F, Viart F, Villain M, Viollet E, Ychou M, Mercier J. MACVIA-LR (Fighting Chronic Diseases for Active and Healthy Ageing in Languedoc-Roussillon): A Success Story of the European Innovation Partnership on Active and Healthy Ageing. J Frailty Aging 2017; 5:233-241. [PMID: 27883170 DOI: 10.14283/jfa.2016.105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The Région Languedoc Roussillon is the umbrella organisation for an interconnected and integrated project on active and healthy ageing (AHA). It covers the 3 pillars of the European Innovation Partnership on Active and Healthy Ageing (EIP on AHA): (A) Prevention and health promotion, (B) Care and cure, (C) and (D) Active and independent living of elderly people. All sub-activities (poly-pharmacy, falls prevention initiative, prevention of frailty, chronic respiratory diseases, chronic diseases with multimorbidities, chronic infectious diseases, active and independent living and disability) have been included in MACVIA-LR which has a strong political commitment and involves all stakeholders (public, private, patients, policy makers) including CARSAT-LR and the Eurobiomed cluster. It is a Reference Site of the EIP on AHA. The framework of MACVIA-LR has the vision that the prevention and management of chronic diseases is essential for the promotion of AHA and for the reduction of handicap. The main objectives of MACVIA-LR are: (i) to develop innovative solutions for a network of Living labs in order to reduce avoidable hospitalisations and loss of autonomy while improving quality of life, (ii) to disseminate the innovation. The three years of MACVIA-LR activities are reported in this paper.
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Affiliation(s)
- J Bousquet
- Professor Jean Bousquet, CHRU, 371 Avenue du Doyen Gaston Giraud, 34295 Montpellier Cedex 5, France, Tel +33 611 42 88 47,
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25
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Li Y, de Milly X, Abreu Araujo F, Klein O, Cros V, Grollier J, de Loubens G. Probing Phase Coupling Between Two Spin-Torque Nano-Oscillators with an External Source. Phys Rev Lett 2017; 118:247202. [PMID: 28665656 DOI: 10.1103/physrevlett.118.247202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Indexed: 06/07/2023]
Abstract
Phase coupling between auto-oscillators is central for achieving coherent responses such as synchronization. Here we present an experimental approach to probe it in the case of two dipolarly coupled spin-torque vortex nano-oscillators using an external microwave field. By phase locking one oscillator to the external source, we observe frequency pulling on the second oscillator. From coupled phase equations we show analytically that this frequency pulling results from concerted actions of oscillator-oscillator and source-oscillator couplings. The analysis allows us to determine the strength and phase shift of coupling between two oscillators, yielding important information for the implementation of large interacting oscillator networks.
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Affiliation(s)
- Yi Li
- Service de Physique de l'État Condensé, CEA, CNRS, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - Xavier de Milly
- Service de Physique de l'État Condensé, CEA, CNRS, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - Flavio Abreu Araujo
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Olivier Klein
- SPINTEC, Université Grenoble Alpes, CEA, CNRS, 38000 Grenoble, France
| | - Vincent Cros
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Julie Grollier
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Grégoire de Loubens
- Service de Physique de l'État Condensé, CEA, CNRS, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
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26
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Legrand W, Maccariello D, Reyren N, Garcia K, Moutafis C, Moreau-Luchaire C, Collin S, Bouzehouane K, Cros V, Fert A. Room-Temperature Current-Induced Generation and Motion of sub-100 nm Skyrmions. Nano Lett 2017; 17:2703-2712. [PMID: 28358984 DOI: 10.1021/acs.nanolett.7b00649] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Magnetic skyrmions are nanoscale windings of the spin configuration that hold great promise for technology due to their topology-related properties and extremely reduced sizes. After the recent observation at room temperature of sub-100 nm skyrmions stabilized by interfacial chiral interaction in magnetic multilayers, several pending questions remain to be solved, notably about the means to nucleate individual compact skyrmions or the exact nature of their motion. In this study, a method leading to the formation of magnetic skyrmions in a micrometer-sized track using homogeneous current injection is evidenced. Spin-transfer-induced motion of these small electrical-current-generated skyrmions is then demonstrated and the role of the out-of-plane magnetic field in the stabilization of the moving skyrmions is also analyzed. The results of these experimental observations of spin torque induced motion are compared to micromagnetic simulations reproducing a granular type, nonuniform magnetic multilayer in order to address the particularly important role of the magnetic inhomogeneities on the current-induced motion of sub-100 nm skyrmions for which the material grains size is comparable to the skyrmion diameter.
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Affiliation(s)
- William Legrand
- Unité Mixte de Physique, CNRS, Thales , Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Davide Maccariello
- Unité Mixte de Physique, CNRS, Thales , Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Nicolas Reyren
- Unité Mixte de Physique, CNRS, Thales , Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Karin Garcia
- Unité Mixte de Physique, CNRS, Thales , Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Christoforos Moutafis
- School of Computer Science, University of Manchester , Manchester M13 9PL, United Kingdom
| | - Constance Moreau-Luchaire
- Unité Mixte de Physique, CNRS, Thales , Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Sophie Collin
- Unité Mixte de Physique, CNRS, Thales , Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Karim Bouzehouane
- Unité Mixte de Physique, CNRS, Thales , Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales , Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Albert Fert
- Unité Mixte de Physique, CNRS, Thales , Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
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27
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Riou M, Araujo FA, Torrejon J, Tsunegi S, Khalsa G, Querlioz D, Bortolotti P, Cros V, Yakushiji K, Fukushima A, Kubota H, Yuasa S, Stiles MD, Grollier J. Neuromorphic Computing through Time-Multiplexing with a Spin-Torque Nano-Oscillator. IEEE Trans Electron Devices 2017; IEDM 2017:10.1109/IEDM.2017.8268505. [PMID: 31080272 PMCID: PMC6508600 DOI: 10.1109/iedm.2017.8268505] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Fabricating powerful neuromorphic chips the size of a thumb requires miniaturizing their basic units: synapses and neurons. The challenge for neurons is to scale them down to submicrometer diameters while maintaining the properties that allow for reliable information processing: high signal to noise ratio, endurance, stability, reproducibility. In this work, we show that compact spin-torque nano-oscillators can naturally implement such neurons, and quantify their ability to realize an actual cognitive task. In particular, we show that they can naturally implement reservoir computing with high performance and detail the recipes for this capability.
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Affiliation(s)
- M Riou
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, France
| | - F Abreu Araujo
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, France
| | - J Torrejon
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, France
| | - S Tsunegi
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Japan
| | - G Khalsa
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD, USA
| | - D Querlioz
- Centre de Nanosciences et de Nanotechnologies, CNRS, Univ. Paris-Sud, Université Paris-Saclay, France
| | - P Bortolotti
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, France
| | - V Cros
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, France
| | - K Yakushiji
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Japan
| | - A Fukushima
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Japan
| | - H Kubota
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Japan
| | - S Yuasa
- National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Japan
| | - M D Stiles
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD, USA
| | - J Grollier
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, France
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28
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Lequeux S, Sampaio J, Cros V, Yakushiji K, Fukushima A, Matsumoto R, Kubota H, Yuasa S, Grollier J. A magnetic synapse: multilevel spin-torque memristor with perpendicular anisotropy. Sci Rep 2016; 6:31510. [PMID: 27539144 PMCID: PMC4990964 DOI: 10.1038/srep31510] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 07/21/2016] [Indexed: 11/09/2022] Open
Abstract
Memristors are non-volatile nano-resistors which resistance can be tuned by applied currents or voltages and set to a large number of levels. Thanks to these properties, memristors are ideal building blocks for a number of applications such as multilevel non-volatile memories and artificial nano-synapses, which are the focus of this work. A key point towards the development of large scale memristive neuromorphic hardware is to build these neural networks with a memristor technology compatible with the best candidates for the future mainstream non-volatile memories. Here we show the first experimental achievement of a multilevel memristor compatible with spin-torque magnetic random access memories. The resistive switching in our spin-torque memristor is linked to the displacement of a magnetic domain wall by spin-torques in a perpendicularly magnetized magnetic tunnel junction. We demonstrate that our magnetic synapse has a large number of intermediate resistance states, sufficient for neural computation. Moreover, we show that engineering the device geometry allows leveraging the most efficient spin torque to displace the magnetic domain wall at low current densities and thus to minimize the energy cost of our memristor. Our results pave the way for spin-torque based analog magnetic neural computation.
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Affiliation(s)
- Steven Lequeux
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau, France
| | - Joao Sampaio
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau, France.,Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau, France
| | - Kay Yakushiji
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - Akio Fukushima
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - Rie Matsumoto
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - Hitoshi Kubota
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - Shinji Yuasa
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - Julie Grollier
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau, France
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29
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Moreau-Luchaire C, Moutafis C, Reyren N, Sampaio J, Vaz CAF, Van Horne N, Bouzehouane K, Garcia K, Deranlot C, Warnicke P, Wohlhüter P, George JM, Weigand M, Raabe J, Cros V, Fert A. Erratum: Additive interfacial chiral interaction in multilayers for stabilization of small individual skyrmions at room temperature. Nat Nanotechnol 2016; 11:731. [PMID: 27485585 DOI: 10.1038/nnano.2016.107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
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30
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Moreau-Luchaire C, Mouta S C, Reyren N, Sampaio J, Vaz CAF, Van Horne N, Bouzehouane K, Garcia K, Deranlot C, Warnicke P, Wohlhüter P, George JM, Weigand M, Raabe J, Cros V, Fert A. Additive interfacial chiral interaction in multilayers for stabilization of small individual skyrmions at room temperature. Nat Nanotechnol 2016; 11:444-8. [PMID: 26780660 DOI: 10.1038/nnano.2015.313] [Citation(s) in RCA: 270] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 11/30/2015] [Indexed: 05/12/2023]
Abstract
Facing the ever-growing demand for data storage will most probably require a new paradigm. Nanoscale magnetic skyrmions are anticipated to solve this issue as they are arguably the smallest spin textures in magnetic thin films in nature. We designed cobalt-based multilayered thin films in which the cobalt layer is sandwiched between two heavy metals and so provides additive interfacial Dzyaloshinskii-Moriya interactions (DMIs), which reach a value close to 2 mJ m(-2) in the case of the Ir|Co|Pt asymmetric multilayers. Using a magnetization-sensitive scanning X-ray transmission microscopy technique, we imaged small magnetic domains at very low fields in these multilayers. The study of their behaviour in a perpendicular magnetic field allows us to conclude that they are actually magnetic skyrmions stabilized by the large DMI. This discovery of stable sub-100 nm individual skyrmions at room temperature in a technologically relevant material opens the way for device applications in the near future.
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Affiliation(s)
- C Moreau-Luchaire
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - C Mouta S
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
- School of Computer Science, University of Manchester, Manchester M13 9PL, UK
| | - N Reyren
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - J Sampaio
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - C A F Vaz
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - N Van Horne
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - K Bouzehouane
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - K Garcia
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - C Deranlot
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - P Warnicke
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - P Wohlhüter
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - J-M George
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - M Weigand
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - J Raabe
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - V Cros
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - A Fert
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
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31
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Yu H, d' Allivy Kelly O, Cros V, Bernard R, Bortolotti P, Anane A, Brandl F, Heimbach F, Grundler D. Approaching soft X-ray wavelengths in nanomagnet-based microwave technology. Nat Commun 2016; 7:11255. [PMID: 27063401 PMCID: PMC4831022 DOI: 10.1038/ncomms11255] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 03/07/2016] [Indexed: 12/25/2022] Open
Abstract
Seven decades after the discovery of collective spin excitations in microwave-irradiated ferromagnets, there has been a rebirth of magnonics. However, magnetic nanodevices will enable smart GHz-to-THz devices at low power consumption only, if such spin waves (magnons) are generated and manipulated on the sub-100 nm scale. Here we show how magnons with a wavelength of a few 10 nm are exploited by combining the functionality of insulating yttrium iron garnet and nanodisks from different ferromagnets. We demonstrate magnonic devices at wavelengths of 88 nm written/read by conventional coplanar waveguides. Our microwave-to-magnon transducers are reconfigurable and thereby provide additional functionalities. The results pave the way for a multi-functional GHz technology with unprecedented miniaturization exploiting nanoscale wavelengths that are otherwise relevant for soft X-rays. Nanomagnonics integrated with broadband microwave circuitry offer applications that are wide ranging, from nanoscale microwave components to nonlinear data processing, image reconstruction and wave-based logic.
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Affiliation(s)
- Haiming Yu
- Physik Department E10, Technische Universität München, James-Franck-Strasse 1, D-85748 Garching bei München, Germany.,Fert Beijing Institute, School of Electronic and Information Engineering, Beihang University, Xueyuan Road 37, Beijing 100191, China
| | - O d' Allivy Kelly
- Unité Mixte de Physique, CNRS, Thales, Univ Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - V Cros
- Unité Mixte de Physique, CNRS, Thales, Univ Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - R Bernard
- Unité Mixte de Physique, CNRS, Thales, Univ Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - P Bortolotti
- Unité Mixte de Physique, CNRS, Thales, Univ Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - A Anane
- Unité Mixte de Physique, CNRS, Thales, Univ Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - F Brandl
- Physik Department E10, Technische Universität München, James-Franck-Strasse 1, D-85748 Garching bei München, Germany
| | - F Heimbach
- Physik Department E10, Technische Universität München, James-Franck-Strasse 1, D-85748 Garching bei München, Germany
| | - D Grundler
- Physik Department E10, Technische Universität München, James-Franck-Strasse 1, D-85748 Garching bei München, Germany.,Laboratory of Nanoscale Magnetic Materials and Magnonics, Institute of Materials, School of Engineering, École Polytechnique Fédérale de Lausanne, STI-IMX-LMGN, Station 17, CH-1015 Lausanne, Switzerland
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32
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Jenkins AS, Lebrun R, Grimaldi E, Tsunegi S, Bortolotti P, Kubota H, Yakushiji K, Fukushima A, de Loubens G, Klein O, Yuasa S, Cros V. Spin-torque resonant expulsion of the vortex core for an efficient radiofrequency detection scheme. Nat Nanotechnol 2016; 11:360-364. [PMID: 26727200 DOI: 10.1038/nnano.2015.295] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 11/17/2015] [Indexed: 06/05/2023]
Abstract
It has been proposed that high-frequency detectors based on the so-called spin-torque diode effect in spin transfer oscillators could eventually replace conventional Schottky diodes due to their nanoscale size, frequency tunability and large output sensitivity. Although a promising candidate for information and communications technology applications, the output voltage generated from this effect has still to be improved and, more pertinently, reduces drastically with decreasing radiofrequency (RF) current. Here we present a scheme for a new type of spintronics-based high-frequency detector based on the expulsion of the vortex core in a magnetic tunnel junction (MTJ). The resonant expulsion of the core leads to a large and sharp change in resistance associated with the difference in magnetoresistance between the vortex ground state and the final C-state configuration. Interestingly, this reversible effect is independent of the incoming RF current amplitude, offering a fast real-time RF threshold detector.
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Affiliation(s)
- A S Jenkins
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 91767 Palaiseau, France
| | - R Lebrun
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 91767 Palaiseau, France
| | - E Grimaldi
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 91767 Palaiseau, France
| | - S Tsunegi
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 91767 Palaiseau, France
- Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, 305-8560 Japan
| | - P Bortolotti
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 91767 Palaiseau, France
| | - H Kubota
- Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, 305-8560 Japan
| | - K Yakushiji
- Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, 305-8560 Japan
| | - A Fukushima
- Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, 305-8560 Japan
| | - G de Loubens
- Service de Physique de l'Etat Condensé (CNRS URA 2464), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - O Klein
- Service de Physique de l'Etat Condensé (CNRS URA 2464), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - S Yuasa
- Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, 305-8560 Japan
| | - V Cros
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 91767 Palaiseau, France
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Collet M, de Milly X, d'Allivy Kelly O, Naletov VV, Bernard R, Bortolotti P, Ben Youssef J, Demidov VE, Demokritov SO, Prieto JL, Muñoz M, Cros V, Anane A, de Loubens G, Klein O. Generation of coherent spin-wave modes in yttrium iron garnet microdiscs by spin-orbit torque. Nat Commun 2016; 7:10377. [PMID: 26815737 PMCID: PMC4737803 DOI: 10.1038/ncomms10377] [Citation(s) in RCA: 188] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 12/04/2015] [Indexed: 12/02/2022] Open
Abstract
In recent years, spin–orbit effects have been widely used to produce and detect spin currents in spintronic devices. The peculiar symmetry of the spin Hall effect allows creation of a spin accumulation at the interface between a metal with strong spin–orbit interaction and a magnetic insulator, which can lead to a net pure spin current flowing from the metal into the insulator. This spin current applies a torque on the magnetization, which can eventually be driven into steady motion. Tailoring this experiment on extended films has proven to be elusive, probably due to mode competition. This requires the reduction of both the thickness and lateral size to reach full damping compensation. Here we show clear evidence of coherent spin–orbit torque-induced auto-oscillation in micron-sized yttrium iron garnet discs of thickness 20 nm. Our results emphasize the key role of quasi-degenerate spin-wave modes, which increase the threshold current. Spin-orbit interactions allow for pure spin current to be injected into a ferromagnetic insulator from a current-carrying heavy metal, generating torque on the magnetization. Here, the authors evidence magnetic auto-oscillations driven by spin-orbit torque in thin film microdiscs of yttrium iron garnet.
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Affiliation(s)
- M Collet
- Unité Mixte de Physique CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 1 avenue A. Fresnel, 91767 Palaiseau, France
| | - X de Milly
- Service de Physique de l'État Condensé, CEA, CNRS, Université Paris-Saclay, CEA Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette, France
| | - O d'Allivy Kelly
- Unité Mixte de Physique CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 1 avenue A. Fresnel, 91767 Palaiseau, France
| | - V V Naletov
- INAC-SPINTEC, CEA, CNRS and Université Grenoble Alpes, 17 avenue des Martyrs, 38000 Grenoble, France.,Institute of Physics, Kazan Federal University, Kazan 420008, Russian Federation
| | - R Bernard
- Unité Mixte de Physique CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 1 avenue A. Fresnel, 91767 Palaiseau, France
| | - P Bortolotti
- Unité Mixte de Physique CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 1 avenue A. Fresnel, 91767 Palaiseau, France
| | - J Ben Youssef
- Laboratoire de Magnétisme de Bretagne CNRS, Université de Bretagne Occidentale, 6 Avenue Le Gorgeu, 29285 Brest, France
| | - V E Demidov
- Department of Physics, University of Muenster, Correnstrasse 2-4, 48149 Muenster, Germany
| | - S O Demokritov
- Department of Physics, University of Muenster, Correnstrasse 2-4, 48149 Muenster, Germany.,Institute of Metal Physics, Ural Division of RAS, Yekaterinburg 620041, Russian Federation
| | - J L Prieto
- Instituto de Sistemas Optoelectrónicos y Microtecnologa (UPM), Ciudad Universitaria, Madrid 28040, Spain
| | - M Muñoz
- IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC), Isaac Newton 8, PTM, Tres Cantos, Madrid E-28760, Spain
| | - V Cros
- Unité Mixte de Physique CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 1 avenue A. Fresnel, 91767 Palaiseau, France
| | - A Anane
- Unité Mixte de Physique CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 1 avenue A. Fresnel, 91767 Palaiseau, France
| | - G de Loubens
- Service de Physique de l'État Condensé, CEA, CNRS, Université Paris-Saclay, CEA Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette, France
| | - O Klein
- INAC-SPINTEC, CEA, CNRS and Université Grenoble Alpes, 17 avenue des Martyrs, 38000 Grenoble, France
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34
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Locatelli N, Hamadeh A, Abreu Araujo F, Belanovsky AD, Skirdkov PN, Lebrun R, Naletov VV, Zvezdin KA, Muñoz M, Grollier J, Klein O, Cros V, de Loubens G. Efficient Synchronization of Dipolarly Coupled Vortex-Based Spin Transfer Nano-Oscillators. Sci Rep 2015; 5:17039. [PMID: 26608230 PMCID: PMC4660301 DOI: 10.1038/srep17039] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 10/08/2015] [Indexed: 11/09/2022] Open
Abstract
Due to their nonlinear properties, spin transfer nano-oscillators can easily adapt their frequency to external stimuli. This makes them interesting model systems to study the effects of synchronization and brings some opportunities to improve their microwave characteristics in view of their applications in information and communication technologies and/or to design innovative computing architectures. So far, mutual synchronization of spin transfer nano-oscillators through propagating spinwaves and exchange coupling in a common magnetic layer has been demonstrated. Here we show that the dipolar interaction is also an efficient mechanism to synchronize neighbouring oscillators. We experimentally study a pair of vortex-based spin transfer nano-oscillators, in which mutual synchronization can be achieved despite a significant frequency mismatch between oscillators. Importantly, the coupling efficiency is controlled by the magnetic configuration of the vortices, as confirmed by an analytical model and micromagnetic simulations highlighting the physics at play in the synchronization process.
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Affiliation(s)
- Nicolas Locatelli
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, F91767 Palaiseau, France
| | - Abbass Hamadeh
- Service de Physique de l'Etat Condensé, CEA, CNRS, Université Paris-Saclay, CEA Saclay, F91191 Gif-sur-Yvette, France
| | - Flavio Abreu Araujo
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, BE-1348 Louvain-la-Neuve, Belgium
| | - Anatoly D Belanovsky
- Moscow Institute of Physics and Technology (State University), Institutskiy per. 9, 141700 Dolgoprudny, Russia.,A. M. Prokhorov General Physics Institute, RAS, Vavilova 38, Moscow, Russia
| | - Petr N Skirdkov
- Moscow Institute of Physics and Technology (State University), Institutskiy per. 9, 141700 Dolgoprudny, Russia.,A. M. Prokhorov General Physics Institute, RAS, Vavilova 38, Moscow, Russia
| | - Romain Lebrun
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, F91767 Palaiseau, France
| | - Vladimir V Naletov
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, F91767 Palaiseau, France.,Service de Physique de l'Etat Condensé, CEA, CNRS, Université Paris-Saclay, CEA Saclay, F91191 Gif-sur-Yvette, France.,Institute of Physics, Kazan Federal University, Kazan 420008, Russian Federation
| | - Konstantin A Zvezdin
- Moscow Institute of Physics and Technology (State University), Institutskiy per. 9, 141700 Dolgoprudny, Russia.,A. M. Prokhorov General Physics Institute, RAS, Vavilova 38, Moscow, Russia.,Istituto P.M. srl, Via Grassi 4, Torino, Italy
| | - Manuel Muñoz
- Instituto de Microelectrónica de Madrid-IMM (CNM-CSIC), Isaac Newton 8-PTM, 28760 Tres Cantos, Madrid, Spain
| | - Julie Grollier
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, F91767 Palaiseau, France
| | - Olivier Klein
- Service de Physique de l'Etat Condensé, CEA, CNRS, Université Paris-Saclay, CEA Saclay, F91191 Gif-sur-Yvette, France
| | - Vincent Cros
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, F91767 Palaiseau, France
| | - Grégoire de Loubens
- Service de Physique de l'Etat Condensé, CEA, CNRS, Université Paris-Saclay, CEA Saclay, F91191 Gif-sur-Yvette, France
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Bousquet J, Bourret R, Camuzat T, Augé P, Domy P, Bringer J, Best N, Jonquet O, de la Coussaye JE, Noguès M, Robine JM, Avignon A, Blain H, Combe B, Dray G, Dufour V, Fouletier M, Giraudeau N, Hève D, Jeandel C, Laffont I, Larrey D, Laune D, Laurent C, Mares P, Marion C, Pastor E, Pélissier JY, Radier-Pontal F, Reynes J, Royère E, Ychou M, Bedbrook A, Granier S, Abecassis F, Albert S, Adnet PA, Alomène B, Amouyal M, Arnavielhe S, Asteriou T, Attalin V, Aubas P, Azevedo C, Badin M, Bakhti, Baptista G, Bardy B, Battesti MP, Bénézet O, Bernard PL, Berr C, Berthe J, Bobia X, Bockaert J, Boegner C, Boichot S, Bonnin HY, Boulet P, Bouly S, Boubakri C, Bourdin A, Bourrain JL, Bourrel G, Bouix V, Breuker C, Bruguière V, Burille J, Cade S, Caimmi D, Calmels MV, Camu W, Canovas G, Carre V, Cavalli G, Cayla G, Chiron R, Claret PG, Coignard P, Coroian F, Costa DJ, Costa P, Cottalorda, Coulet B, Coupet AL, Courrouy-Michel MC, Courtet P, Cristol JP, Cros V, Cuisinier F, Daien C, Danko M, Dauenhauer P, Dauzat M, David M, Davy JM, Delignières D, Demoly P, Desplan J, Dhivert-Donnadieu H, Dujols P, Dupeyron A, Dupeyron G, Engberink O, Enjalbert M, Fattal C, Fernandes J, Fesler P, Fraisse P, Froger J, Gabrion P, Galano E, Gellerat-Rogier M, Gellis A, Goucham AY, Gouzi F, Gressard F, Gris JC, Guillot B, Guiraud D, Handweiler V, Hantkié H, Hayot M, Hérisson C, Heroum C, Hoa D, Jacquemin S, Jaber S, Jakovenko D, Jorgensen C, Journot L, Kaczorek M, Kouyoudjian P, Labauge P, Landreau L, Lapierre M, Leblond C, Léglise MS, Lemaitre JM, Le Moing V, Le Quellec A, Leclercq F, Lehmann S, Lognos B, Lussert JM, Makinson A, Mandrick K, Marmelat V, Martin-Gousset P, Matheron A, Mathieu G, Meissonnier M, Mercier G, Messner P, Meunier C, Mondain M, Morales R, Morel J, Morquin D, Mottet D, Nérin P, Nicolas P, Ninot G, Nouvel F, Ortiz JP, Paccard D, Pandraud G, Pasdelou MP, Pasquié JL, Patte K, Perrey S, Pers YM, Picot MC, Pin JP, Pinto N, Porte E, Portejoie F, Pujol JL, Quantin X, Quéré I, Raffort N, Ramdani S, Ribstein J, Rédini-Martinez I, Richard S, Ritchie K, Riso JP, Rivier F, Rolland C, Roubille F, Sablot D, Savy JL, Schifano L, Senesse P, Sicard R, Soua B, Stephan Y, Strubel D, Sultan A, Taddei-Ologeanu, Tallon G, Tanfin M, Tassery H, Tavares I, Torre K, Touchon J, Tribout V, Uziel A, Van de Perre P, Vasquez X, Verdier JM, Vergne-Richard C, Vergotte G, Vian L, Viarouge-Reunier C, Vialla F, Viart F, Villain M, Villiet M, Viollet E, Wojtusciszyn A, Aoustin M, Bourquin C, Mercier J. Introduction. Presse Med 2015; 44 Suppl 1:S1-5. [DOI: 10.1016/j.lpm.2015.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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36
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Laffont I, Jourdan C, Coroian F, Blain H, Carre V, Viollet E, Tavares I, Fattal C, Gelis A, Nouvel F, Bakhti K, Cros V, Patte K, Schifano L, Porte M, Galano E, Dray G, Fouletier M, Rivier F, Morales R, Labauge P, Camu W, Combe B, Morel J, Froger J, Coulet B, Cottalorda J, Kouyoumdjian P, Jonquet O, Landreau L, Bonnin HY, Hantkié O, Nicolas P, Enjalbert M, Leblond C, Soua B, Coignard P, Guiraud D, Azevedo C, Mottet D, Fraisse P, Pastor E, Mercier J, Bourret R, Bousquet J, Pélissier J, Bardy B, Herisson C, Dupeyron A. [Living Lab MACVIA. Disability]. Presse Med 2015; 44 Suppl 1:S60-9. [PMID: 26482491 DOI: 10.1016/j.lpm.2015.07.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
- I Laffont
- CHRU de Montpellier, département de médecine physique et de réadaptation, 34090 Montpellier, France; Movement to Health (M2H), Euromov, université de Montpellier, Montpellier, France.
| | - C Jourdan
- CHRU de Montpellier, département de médecine physique et de réadaptation, 34090 Montpellier, France
| | - F Coroian
- CHRU de Montpellier, département de médecine physique et de réadaptation, 34090 Montpellier, France; Movement to Health (M2H), Euromov, université de Montpellier, Montpellier, France
| | - H Blain
- Movement to Health (M2H), Euromov, université de Montpellier, Montpellier, France; CHRU de Montpellier, département de gériatrie, 34090 Montpellier, France
| | - V Carre
- CHRU de Montpellier, département de médecine physique et de réadaptation, 34090 Montpellier, France
| | - E Viollet
- CHU de Nîmes, hôpital Carémeau et du Grau du Roi, département de médecine physique et de réadaptation, 30029 Nîmes, France; CHU Carémeau, CEDMH, 30029 Nîmes, France
| | - I Tavares
- CHRU de Montpellier, département de médecine physique et de réadaptation, 34090 Montpellier, France
| | - C Fattal
- Association APPROCHE, CMRRF de Kerpape, BP 78, 56275 Ploemeur cedex, France
| | - A Gelis
- Centre Mutualiste Propara, 34000 Montpellier, France
| | - F Nouvel
- CHU Carémeau, CEDMH, 30029 Nîmes, France
| | - K Bakhti
- CHRU de Montpellier, département de médecine physique et de réadaptation, 34090 Montpellier, France; Movement to Health (M2H), Euromov, université de Montpellier, Montpellier, France
| | - V Cros
- CHRU de Montpellier, département de médecine physique et de réadaptation, 34090 Montpellier, France
| | - K Patte
- Institut Marin Saint-Pierre, 34250 Palavas les Flots, France
| | - L Schifano
- Institut Marin Saint-Pierre, 34250 Palavas les Flots, France
| | - M Porte
- CHU de Nîmes, hôpital Carémeau et du Grau du Roi, département de médecine physique et de réadaptation, 30029 Nîmes, France
| | - E Galano
- CHU de Nîmes, hôpital Carémeau et du Grau du Roi, département de médecine physique et de réadaptation, 30029 Nîmes, France
| | - G Dray
- École des Mines d'Alès, 30100 Alès, France
| | | | - F Rivier
- CHU de Montpellier, centre de référence Grand Sud des maladies neuromusculaires, département de neuropédiatrie, 34090 Montpellier, France
| | - R Morales
- CHRU de Montpellier, département de neurologie, 34090 Montpellier, France
| | - P Labauge
- CHRU de Montpellier, département de neurologie, 34090 Montpellier, France
| | - W Camu
- CHRU de Montpellier, département de neurologie, 34090 Montpellier, France
| | - B Combe
- CHRU de Montpellier, département de rhumatologie, 34090 Montpellier, France
| | - J Morel
- CHRU de Montpellier, département de rhumatologie, 34090 Montpellier, France
| | - J Froger
- Movement to Health (M2H), Euromov, université de Montpellier, Montpellier, France; CHU de Nîmes, hôpital Carémeau et du Grau du Roi, département de médecine physique et de réadaptation, 30029 Nîmes, France
| | - B Coulet
- CHRU de Montpellier, département de chirurgie orthopédique, 34090 Montpellier, France
| | - J Cottalorda
- CHRU de Montpellier, département de chirurgie orthopédique et plastique infantile, 34090 Montpellier, France
| | - P Kouyoumdjian
- CHU Carémeau, département de chirurgie orthopédique, 30029 Nîmes, France
| | - O Jonquet
- CHRU de Montpellier, département de réanimation, 34090 Montpellier, France
| | - L Landreau
- CHRU de Montpellier, département de réanimation, 34090 Montpellier, France
| | - H-Y Bonnin
- Movement to Health (M2H), Euromov, université de Montpellier, Montpellier, France; CHU de Nîmes, hôpital Carémeau et du Grau du Roi, département de médecine physique et de réadaptation, 30029 Nîmes, France
| | - O Hantkié
- Centre Bourgès, groupe Oc Santé, 34173 Castelneau-le-lez cedex, France
| | - P Nicolas
- Centre Bourgès, groupe Oc Santé, 34173 Castelneau-le-lez cedex, France
| | - M Enjalbert
- Centre Bouffard-Vercelli, 66290 Cerbère, France; Association APPROCHE, CMRRF de Kerpape, BP 78, 56275 Ploemeur cedex, France
| | - C Leblond
- Centre Bouffard-Vercelli, 66290 Cerbère, France
| | - B Soua
- Association ADAGES, Les Fontaines d'Ô, 34000 Montpellier, France
| | - P Coignard
- Association APPROCHE, CMRRF de Kerpape, BP 78, 56275 Ploemeur cedex, France
| | - D Guiraud
- Université de Montpellier, laboratoire d'informatique, de robotique et de microélectronique de Montpellier, 34090 Montpellier, France; Institut national de recherche en informatique et en automatique, LIRMM, université de Montpellier, 34090 Montpellier, France
| | - C Azevedo
- Université de Montpellier, laboratoire d'informatique, de robotique et de microélectronique de Montpellier, 34090 Montpellier, France; Institut national de recherche en informatique et en automatique, LIRMM, université de Montpellier, 34090 Montpellier, France
| | - D Mottet
- Movement to Health (M2H), Euromov, université de Montpellier, Montpellier, France
| | - P Fraisse
- Université de Montpellier, laboratoire d'informatique, de robotique et de microélectronique de Montpellier, 34090 Montpellier, France
| | - E Pastor
- CCAS de Lattes, 34970 Lattes, France
| | - J Mercier
- CHRU de Montpellier, U1046 Inserm, université Montpellier 1, 34090 Montpellier, France
| | - R Bourret
- CHRU de Montpellier, Direction générale, 34090 Montpellier, France
| | | | - J Pélissier
- Movement to Health (M2H), Euromov, université de Montpellier, Montpellier, France; CHU de Nîmes, hôpital Carémeau et du Grau du Roi, département de médecine physique et de réadaptation, 30029 Nîmes, France
| | - B Bardy
- Movement to Health (M2H), Euromov, université de Montpellier, Montpellier, France
| | - C Herisson
- CHRU de Montpellier, département de médecine physique et de réadaptation, 34090 Montpellier, France; Movement to Health (M2H), Euromov, université de Montpellier, Montpellier, France
| | - A Dupeyron
- Movement to Health (M2H), Euromov, université de Montpellier, Montpellier, France; CHU de Nîmes, hôpital Carémeau et du Grau du Roi, département de médecine physique et de réadaptation, 30029 Nîmes, France; CHU Carémeau, CEDMH, 30029 Nîmes, France
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Lebrun R, Jenkins A, Dussaux A, Locatelli N, Tsunegi S, Grimaldi E, Kubota H, Bortolotti P, Yakushiji K, Grollier J, Fukushima A, Yuasa S, Cros V. Understanding of Phase Noise Squeezing Under Fractional Synchronization of a Nonlinear Spin Transfer Vortex Oscillator. Phys Rev Lett 2015; 115:017201. [PMID: 26182117 DOI: 10.1103/physrevlett.115.017201] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Indexed: 06/04/2023]
Abstract
We investigate experimentally the synchronization of vortex based spin transfer nano-oscillators to an external rf current whose frequency is at multiple integers, as well as at an integer fraction, of the oscillator frequency. Through a theoretical study of the locking mechanism, we highlight the crucial role of both the symmetries of the spin torques and the nonlinear properties of the oscillator in understanding the phase locking mechanism. In the locking regime, we report a phase noise reduction down to -90 dBc/Hz at 1 kHz offset frequency. Our demonstration that the phase noise of these nanoscale nonlinear oscillators can be tuned and eventually lessened, represents a key achievement for targeted radio frequency applications using spin torque devices.
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Affiliation(s)
- R Lebrun
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 1 Avenue Fresnel, 91767 Palaiseau, France
| | - A Jenkins
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 1 Avenue Fresnel, 91767 Palaiseau, France
| | - A Dussaux
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 1 Avenue Fresnel, 91767 Palaiseau, France
| | - N Locatelli
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 1 Avenue Fresnel, 91767 Palaiseau, France
| | - S Tsunegi
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 1 Avenue Fresnel, 91767 Palaiseau, France
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - E Grimaldi
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 1 Avenue Fresnel, 91767 Palaiseau, France
| | - H Kubota
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - P Bortolotti
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 1 Avenue Fresnel, 91767 Palaiseau, France
| | - K Yakushiji
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - J Grollier
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 1 Avenue Fresnel, 91767 Palaiseau, France
| | - A Fukushima
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - S Yuasa
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - V Cros
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, 1 Avenue Fresnel, 91767 Palaiseau, France
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38
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Hamadeh A, d'Allivy Kelly O, Hahn C, Meley H, Bernard R, Molpeceres AH, Naletov VV, Viret M, Anane A, Cros V, Demokritov SO, Prieto JL, Muñoz M, de Loubens G, Klein O. Full control of the spin-wave damping in a magnetic insulator using spin-orbit torque. Phys Rev Lett 2014; 113:197203. [PMID: 25415921 DOI: 10.1103/physrevlett.113.197203] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Indexed: 06/04/2023]
Abstract
It is demonstrated that the threshold current for damping compensation can be reached in a 5 μm diameter YIG(20 nm)|Pt(7 nm) disk. The demonstration rests upon the measurement of the ferromagnetic resonance linewidth as a function of I(dc) using a magnetic resonance force microscope (MRFM). It is shown that the magnetic losses of spin-wave modes existing in the magnetic insulator can be reduced or enhanced by at least a factor of 5 depending on the polarity and intensity of an in-plane dc current I(dc) flowing through the adjacent normal metal with strong spin-orbit interaction. Complete compensation of the damping of the fundamental mode by spin-orbit torque is reached for a current density of ∼3×10(11) A·m(-2), in agreement with theoretical predictions. At this critical threshold the MRFM detects a small change of static magnetization, a behavior consistent with the onset of an auto-oscillation regime.
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Affiliation(s)
- A Hamadeh
- Service de Physique de l'État Condensé (CNRS URA 2464), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - O d'Allivy Kelly
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 avenue Fresnel, 91767 Palaiseau, France
| | - C Hahn
- Service de Physique de l'État Condensé (CNRS URA 2464), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - H Meley
- Service de Physique de l'État Condensé (CNRS URA 2464), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - R Bernard
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 avenue Fresnel, 91767 Palaiseau, France
| | - A H Molpeceres
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 avenue Fresnel, 91767 Palaiseau, France
| | - V V Naletov
- Service de Physique de l'État Condensé (CNRS URA 2464), CEA Saclay, 91191 Gif-sur-Yvette, France and Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 avenue Fresnel, 91767 Palaiseau, France and Institute of Physics, Kazan Federal University, Kazan 420008, Russian Federation
| | - M Viret
- Service de Physique de l'État Condensé (CNRS URA 2464), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - A Anane
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 avenue Fresnel, 91767 Palaiseau, France
| | - V Cros
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 avenue Fresnel, 91767 Palaiseau, France
| | - S O Demokritov
- Department of Physics, University of Muenster, 48149 Muenster, Germany and Institute of Metal Physics, Ural Division of RAS, Yekaterinburg 620041, Russia
| | - J L Prieto
- Instituto de Sistemas Optoelectrónicos y Microtecnología (UPM), Madrid 28040, Spain
| | - M Muñoz
- Instituto de Microelectrónica de Madrid (CNM, CSIC), Madrid 28760, Spain
| | - G de Loubens
- Service de Physique de l'État Condensé (CNRS URA 2464), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - O Klein
- Service de Physique de l'État Condensé (CNRS URA 2464), CEA Saclay, 91191 Gif-sur-Yvette, France and SPINTEC, UMR CEA/CNRS/UJF-Grenoble 1/Grenoble-INP, INAC, 38054 Grenoble, France
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Hamadeh A, Locatelli N, Naletov VV, Lebrun R, de Loubens G, Grollier J, Klein O, Cros V. Origin of spectral purity and tuning sensitivity in a spin transfer vortex nano-oscillator. Phys Rev Lett 2014; 112:257201. [PMID: 25014825 DOI: 10.1103/physrevlett.112.257201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Indexed: 06/03/2023]
Abstract
We investigate the microwave characteristics of a spin transfer nano-oscillator (STNO) based on coupled vortices as a function of the perpendicular magnetic field H(⊥). Interestingly, we find that our vortex-based oscillator is quasi-isochronous independently of H(⊥) and for a dc current ranging between 18 and 25 mA. It means that the severe nonlinear broadening usually observed in STNOs can be suppressed on a broad range of bias. Still, the generation linewidth displays strong variations on H(⊥) (from 40 kHz to 1 MHz), while the frequency tunability in current remains almost constant (7 MHz/mA). This demonstrates that isochronicity does not necessarily imply a loss of frequency tunability, which is here governed by the current induced Oersted field. It is not sufficient either to achieve the highest spectral purity in the full range of H(⊥). We show that the observed linewidth broadenings are due to the excited mode interacting with a lower energy overdamped mode, which occurs at the successive crossings between harmonics of these two modes. These findings open new possibilities for the design of STNOs and the optimization of their performance.
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Affiliation(s)
- A Hamadeh
- Service de Physique de l'État Condensé (CNRS URA 2464), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - N Locatelli
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Avenue Fresnel, 91767 Palaiseau, France
| | - V V Naletov
- Service de Physique de l'État Condensé (CNRS URA 2464), CEA Saclay, 91191 Gif-sur-Yvette, France and Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Avenue Fresnel, 91767 Palaiseau, France and Institute of Physics, Kazan Federal University, Kazan 420008, Russian Federation
| | - R Lebrun
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Avenue Fresnel, 91767 Palaiseau, France
| | - G de Loubens
- Service de Physique de l'État Condensé (CNRS URA 2464), CEA Saclay, 91191 Gif-sur-Yvette, France
| | - J Grollier
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Avenue Fresnel, 91767 Palaiseau, France
| | - O Klein
- Service de Physique de l'État Condensé (CNRS URA 2464), CEA Saclay, 91191 Gif-sur-Yvette, France and SPINTEC, UMR CEA/CNRS/UJF-Grenoble 1/Grenoble-INP, INAC, 38054 Grenoble, France
| | - V Cros
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Avenue Fresnel, 91767 Palaiseau, France
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Abstract
The discovery of the spin-torque effect has made magnetic nanodevices realistic candidates for active elements of memory devices and applications. Magnetoresistive effects allow the read-out of increasingly small magnetic bits, and the spin torque provides an efficient tool to manipulate - precisely, rapidly and at low energy cost - the magnetic state, which is in turn the central information medium of spintronic devices. By keeping the same magnetic stack, but by tuning a device's shape and bias conditions, the spin torque can be engineered to build a variety of advanced magnetic nanodevices. Here we show that by assembling these nanodevices as building blocks with different functionalities, novel types of computing architecture can be envisaged. We focus in particular on recent concepts such as magnonics and spintronic neural networks.
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Affiliation(s)
- N Locatelli
- Unité Mixte de Physique CNRS/Thales, 1 Avenue Augustin Fresnel, Campus de l'Ecole Polytechnique, 91767 Palaiseau, France, and Université Paris-Sud, 91405 Orsay, France
| | - V Cros
- Unité Mixte de Physique CNRS/Thales, 1 Avenue Augustin Fresnel, Campus de l'Ecole Polytechnique, 91767 Palaiseau, France, and Université Paris-Sud, 91405 Orsay, France
| | - J Grollier
- Unité Mixte de Physique CNRS/Thales, 1 Avenue Augustin Fresnel, Campus de l'Ecole Polytechnique, 91767 Palaiseau, France, and Université Paris-Sud, 91405 Orsay, France
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Sampaio J, Cros V, Rohart S, Thiaville A, Fert A. Nucleation, stability and current-induced motion of isolated magnetic skyrmions in nanostructures. Nat Nanotechnol 2013; 8:839-44. [PMID: 24162000 DOI: 10.1038/nnano.2013.210] [Citation(s) in RCA: 371] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 09/16/2013] [Indexed: 05/13/2023]
Abstract
Magnetic skyrmions are topologically stable spin configurations, which usually originate from chiral interactions known as Dzyaloshinskii-Moriya interactions. Skyrmion lattices were initially observed in bulk non-centrosymmetric crystals, but have more recently been noted in ultrathin films, where their existence is explained by interfacial Dzyaloshinskii-Moriya interactions induced by the proximity to an adjacent layer with strong spin-orbit coupling. Skyrmions are promising candidates as information carriers for future information-processing devices due to their small size (down to a few nanometres) and to the very small current densities needed to displace skyrmion lattices. However, any practical application will probably require the creation, manipulation and detection of isolated skyrmions in magnetic thin-film nanostructures. Here, we demonstrate by numerical investigations that an isolated skyrmion can be a stable configuration in a nanostructure, can be locally nucleated by injection of spin-polarized current, and can be displaced by current-induced spin torques, even in the presence of large defects.
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Affiliation(s)
- J Sampaio
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud, Palaiseau, France
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Affiliation(s)
- Albert Fert
- Unité Mixte de Physique CNRS/Thales and Université Paris-Sud, Palaiseau, France.
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Wang T, Zhu D, Wu B, Graves C, Schaffert S, Rander T, Müller L, Vodungbo B, Baumier C, Bernstein DP, Bräuer B, Cros V, de Jong S, Delaunay R, Fognini A, Kukreja R, Lee S, López-Flores V, Mohanty J, Pfau B, Popescu H, Sacchi M, Sardinha AB, Sirotti F, Zeitoun P, Messerschmidt M, Turner JJ, Schlotter WF, Hellwig O, Mattana R, Jaouen N, Fortuna F, Acremann Y, Gutt C, Dürr HA, Beaurepaire E, Boeglin C, Eisebitt S, Grübel G, Lüning J, Stöhr J, Scherz AO. Femtosecond single-shot imaging of nanoscale ferromagnetic order in Co/Pd multilayers using resonant x-ray holography. Phys Rev Lett 2012; 108:267403. [PMID: 23005013 DOI: 10.1103/physrevlett.108.267403] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Indexed: 05/23/2023]
Abstract
We present the first single-shot images of ferromagnetic, nanoscale spin order taken with femtosecond x-ray pulses. X-ray-induced electron and spin dynamics can be outrun with pulses shorter than 80 fs in the investigated fluence regime, and no permanent aftereffects in the samples are observed below a fluence of 25 mJ/cm(2). Employing resonant spatially muliplexed x-ray holography results in a low imaging threshold of 5 mJ/cm(2). Our results open new ways to combine ultrafast laser spectroscopy with sequential snapshot imaging on a single sample, generating a movie of excited state dynamics.
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Affiliation(s)
- Tianhan Wang
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94035, USA.
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Uhlíř V, Vogel J, Rougemaille N, Fruchart O, Ishaque Z, Cros V, Camarero J, Cezar JC, Sirotti F, Pizzini S. Current-induced domain wall motion and magnetization dynamics in CoFeB/Cu/Co nanostripes. J Phys Condens Matter 2012; 24:024213. [PMID: 22173430 DOI: 10.1088/0953-8984/24/2/024213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Current-induced domain wall motion and magnetization dynamics in the CoFeB layer of CoFeB/Cu/Co nanostripes were studied using photoemission electron microscopy combined with x-ray magnetic circular dichroism (XMCD-PEEM). Quasi-static measurements show that current-induced domain wall motion in the CoFeB layer is similar to the one observed in the NiFe layer of NiFe/Cu/Co trilayers, although the threshold current densities for domain wall depinning are lower. Time-resolved XMCD-PEEM measurements are used as an efficient probe of domain wall depinning statistics. They also reveal that, during the application of current pulses, the CoFeB magnetization rotates in the direction transverse to the nanostripe. The corresponding tilt angles have been quantified and compared to analytical and micromagnetic calculations, highlighting the influence of magnetostatic interactions between the two magnetic layers on the magnetization rotation.
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Affiliation(s)
- V Uhlíř
- Institut Néel, CNRS and UJF, BP 166, 38042 Grenoble Cedex 9, France
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Dussaux A, Georges B, Grollier J, Cros V, Khvalkovskiy AV, Fukushima A, Konoto M, Kubota H, Yakushiji K, Yuasa S, Zvezdin KA, Ando K, Fert A. Large microwave generation from current-driven magnetic vortex oscillators in magnetic tunnel junctions. Nat Commun 2010; 1:8. [PMID: 20975671 DOI: 10.1038/ncomms1006] [Citation(s) in RCA: 300] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Accepted: 03/04/2010] [Indexed: 11/09/2022] Open
Abstract
Spin-polarized current can excite the magnetization of a ferromagnet through the transfer of spin angular momentum to the local spin system. This pure spin-related transport phenomenon leads to alluring possibilities for the achievement of a nanometer scale, complementary metal oxide semiconductor-compatible, tunable microwave generator that operates at low bias for future wireless communication applications. Microwave emission generated by the persistent motion of magnetic vortices induced by a spin-transfer effect seems to be a unique manner to reach appropriate spectral linewidth. However, in metallic systems, in which such vortex oscillations have been observed, the resulting microwave power is much too small. In this study, we present experimental evidence of spin-transfer-induced vortex precession in MgO-based magnetic tunnel junctions, with an emitted power that is at least one order of magnitude stronger and with similar spectral quality. More importantly and in contrast to other spin-transfer excitations, the thorough comparison between experimental results and analytical predictions provides a clear textbook illustration of the mechanism of spin-transfer-induced vortex precession.
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Affiliation(s)
- A Dussaux
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, Palaiseau, France
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Copie O, Rode K, Mattana R, Bibes M, Cros V, Herranz G, Anane A, Ranchal R, Jacquet E, Bouzehouane K, Arrio MA, Bencok P, Brookes NB, Petroff F, Barthélémy A. Structural and magnetic properties of Co-doped (La,Sr)TiO(3) epitaxial thin films probed using x-ray magnetic circular dichroism. J Phys Condens Matter 2009; 21:406001. [PMID: 21832426 DOI: 10.1088/0953-8984/21/40/406001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report a study of Co-doped La(0.37)Sr(0.63)TiO(3-δ) thin films grown by pulsed laser deposition in various oxygen pressure conditions. X-ray absorption spectroscopy and magnetic circular dichroism measurements at the Co L(2,3) edges reveal that the cobalt mainly substitutes for the titanium and is in an ionic state. Nevertheless, in some films, indications of additional cobalt metallic impurities were found, suggesting that the intrinsic character of this magnetic system remains questionable.
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Affiliation(s)
- O Copie
- Unité Mixte de Physique CNRS/Thales, Campus de l'Ecole Polytechnique, 1 Avenue A Fresnel, 91767 Palaiseau, France and Université Paris-Sud 11, 91405 Orsay, France
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Ruotolo A, Cros V, Georges B, Dussaux A, Grollier J, Deranlot C, Guillemet R, Bouzehouane K, Fusil S, Fert A. Phase-locking of magnetic vortices mediated by antivortices. Nat Nanotechnol 2009; 4:528-532. [PMID: 19662017 DOI: 10.1038/nnano.2009.143] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Accepted: 05/05/2009] [Indexed: 05/28/2023]
Abstract
Synchronized spin-valve oscillators may lead to nanosized microwave generators that do not require discrete elements such as capacitors or inductors. Uniformly magnetized oscillators have been synchronized, but offer low power. Gyrating magnetic vortices offer greater power, but vortex synchronization has yet to be demonstrated. Here we find that vortices can interact with each other through the mediation of antivortices, leading to synchronization when they are closely spaced. The synchronization does not require a magnetic field, making the system attractive for electronic device integration. Also, because each vortex is a topological soliton, this work presents a model experimental system for the study of interacting solitons.
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Affiliation(s)
- A Ruotolo
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, Palaiseau, France.
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Béa H, Dupé B, Fusil S, Mattana R, Jacquet E, Warot-Fonrose B, Wilhelm F, Rogalev A, Petit S, Cros V, Anane A, Petroff F, Bouzehouane K, Geneste G, Dkhil B, Lisenkov S, Ponomareva I, Bellaiche L, Bibes M, Barthélémy A. Evidence for room-temperature multiferroicity in a compound with a giant axial ratio. Phys Rev Lett 2009; 102:217603. [PMID: 19519136 DOI: 10.1103/physrevlett.102.217603] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Indexed: 05/12/2023]
Abstract
In the search for multiferroic materials magnetic compounds with a strongly elongated unit-cell (large axial ratio c/a) have been scrutinized intensely. However, none was hitherto proven to have a switchable polarization, an essential feature of ferroelectrics. Here, we provide evidence for the epitaxial stabilization of a monoclinic phase of BiFeO3 with a giant axial ratio (c/a=1.23) that is both ferroelectric and magnetic at room temperature. Surprisingly, and in contrast with previous theoretical predictions, the polarization does not increase dramatically with c/a. We discuss our results in terms of the competition between polar and antiferrodistortive instabilities and give perspectives for engineering multiferroic phases.
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Affiliation(s)
- H Béa
- Unité Mixte de Physique CNRS/Thales, Campus de l'Ecole Polytechnique, 1 Av. A. Fresnel, 91767 Palaiseau, France
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Khvalkovskiy AV, Zvezdin KA, Gorbunov YV, Cros V, Grollier J, Fert A, Zvezdin AK. High Domain Wall Velocities due to Spin Currents Perpendicular to the Plane. Phys Rev Lett 2009; 102:067206. [PMID: 19257631 DOI: 10.1103/physrevlett.102.067206] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Revised: 01/30/2009] [Indexed: 05/27/2023]
Abstract
We consider long and narrow spin valves composed of a first magnetic layer with a single domain wall (DW), a normal metal spacer, and a second magnetic layer that is a planar or a perpendicular polarizer. For these structures, we study numerically DW dynamics taking into account the spin torques due to the perpendicular spin currents. We obtain high DW velocities: 5 m/s for planar polarizer and 80 m/s for perpendicular polarizer for I=0.01 mA. These values are much larger than those predicted and observed for DW motion due to the in-plane spin currents. The ratio of the magnitudes of the torques, which generate the DW motion in the respective cases, is responsible for these large differences.
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Affiliation(s)
- A V Khvalkovskiy
- A. M. Prokhorov General Physics Institute of RAS, 119991 Moscow, Russia.
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50
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Georges B, Grollier J, Darques M, Cros V, Deranlot C, Marcilhac B, Faini G, Fert A. Coupling efficiency for phase locking of a spin transfer nano-oscillator to a microwave current. Phys Rev Lett 2008; 101:017201. [PMID: 18764148 DOI: 10.1103/physrevlett.101.017201] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Indexed: 05/26/2023]
Abstract
The phase locking behavior of spin transfer nano-oscillators (STNOs) to an external microwave signal is experimentally studied as a function of the STNO intrinsic parameters. We extract the coupling strength from our data using the derived phase dynamics of a forced STNO. The predicted trends on the coupling strength for phase locking as a function of intrinsic features of the oscillators, i.e., power, linewidth, agility in current, are central to optimize the emitted power in arrays of mutually coupled STNOs.
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Affiliation(s)
- B Georges
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, RD 128, 91767 Palaiseau, France
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