Magnetic skyrmion artificial synapse for neuromorphic computing

Magnetic skyrmions are topologically protected spin textures that have nanoscale dimensions and can be manipulated by an electric current. These properties make the structures potential information carriers in data storage, processing and transmission devices. However, the development of functional all-electrical electronic devices based on skyrmions remains challenging. Here we show that the current-induced creation, motion, detection and deletion of skyrmions at room temperature can be used to mimic the potentiation and depression behaviours of biological synapses. In particular, the accumulation and dissipation of magnetic skyrmions in ferrimagnetic multilayers can be controlled with electrical pulses to represent the variations in the synaptic weights. Using chip-level simulations, we demonstrate that such artificial synapses based on magnetic skyrmions could be used for neuromorphic computing tasks such as pattern recognition. For a handwritten pattern dataset, our system achieves a recognition accuracy of ~89%, which is comparable to the accuracy achieved with software-based ideal training (~93%). The electrical current-induced creation, motion, detection and deletion of skyrmions in ferrimagnetic multilayers can be used to mimic the behaviour of biological synapses, providing devices that could be used for neuromorphic computing tasks such as pattern recognition.

[1]  Yan Zhou,et al.  Current-driven dynamics and inhibition of the skyrmion Hall effect of ferrimagnetic skyrmions in GdFeCo films , 2017, Nature Communications.

[2]  A. Fert,et al.  Current-induced magnetization switching in atom-thick tungsten engineered perpendicular magnetic tunnel junctions with large tunnel magnetoresistance , 2017, Nature Communications.

[3]  George Bourianoff,et al.  Potential implementation of reservoir computing models based on magnetic skyrmions , 2017, 1709.08911.

[4]  Shimeng Yu,et al.  Compact Modeling of RRAM Devices and Its Applications in 1T1R and 1S1R Array Design , 2015, IEEE Transactions on Electron Devices.

[5]  Douglas M. Bishop,et al.  ECRAM as Scalable Synaptic Cell for High-Speed, Low-Power Neuromorphic Computing , 2018, 2018 IEEE International Electron Devices Meeting (IEDM).

[6]  S. Yuasa,et al.  A magnetic synapse: multilevel spin-torque memristor with perpendicular anisotropy , 2016, Scientific Reports.

[7]  Yan Zhou,et al.  Magnetic skyrmion-based synaptic devices , 2016, Nanotechnology.

[8]  A. Fert,et al.  Magnetic skyrmions: advances in physics and potential applications , 2017 .

[9]  G. Finocchio,et al.  A strategy for the design of skyrmion racetrack memories , 2014, Scientific Reports.

[10]  A. Locatelli,et al.  Room-temperature chiral magnetic skyrmions in ultrathin magnetic nanostructures. , 2016, Nature nanotechnology.

[11]  C. Pfleiderer,et al.  Emergent electrodynamics of skyrmions in a chiral magnet , 2012, Nature Physics.

[12]  Yan Zhou,et al.  Deterministic creation and deletion of a single magnetic skyrmion observed by direct time-resolved X-ray microscopy , 2017, 1706.06726.

[13]  J. Barker,et al.  Static and Dynamical Properties of Antiferromagnetic Skyrmions in the Presence of Applied Current and Temperature. , 2015, Physical review letters.

[14]  H. Hwang,et al.  Improved Conductance Linearity and Conductance Ratio of 1T2R Synapse Device for Neuromorphic Systems , 2017, IEEE Electron Device Letters.

[15]  Benjamin Krueger,et al.  Observation of room-temperature magnetic skyrmions and their current-driven dynamics in ultrathin metallic ferromagnets. , 2015, Nature materials.

[16]  I. Dzyaloshinsky.  A thermodynamic theory of “weak” ferromagnetism of antiferromagnetics , 1958 .

[17]  M. Titov,et al.  Stability and lifetime of antiferromagnetic skyrmions , 2017, Physical Review B.

[18]  T. Moriya.  Anisotropic Superexchange Interaction and Weak Ferromagnetism , 1960 .

[19]  Gerhard Jakob,et al.  Thermal skyrmion diffusion used in a reshuffler device , 2018, Nature Nanotechnology.

[20]  J J Hopfield,et al.  Neural networks and physical systems with emergent collective computational abilities. , 1982, Proceedings of the National Academy of Sciences of the United States of America.

[21]  A. Fert,et al.  Additive interfacial chiral interaction in multilayers for stabilization of small individual skyrmions at room temperature. , 2016, Nature nanotechnology.

[22]  Kazuya Ando,et al.  Dynamical generation of spin currents , 2014 .

[23]  Arata Tsukamoto,et al.  Vanishing skyrmion Hall effect at the angular momentum compensation temperature of a ferrimagnet , 2018, Nature Nanotechnology.

[24]  Y. Tokura,et al.  Real-space observation of a two-dimensional skyrmion crystal , 2010, Nature.

[25]  Damien Querlioz,et al.  Neuromorphic computing with nanoscale spintronic oscillators , 2017, Nature.

[26]  Yan Zhou,et al.  Control and manipulation of a magnetic skyrmionium in nanostructures , 2016, 1604.05909.

[27]  Y. Tokura,et al.  Topological properties and dynamics of magnetic skyrmions. , 2013, Nature nanotechnology.

[28]  S. Eisebitt,et al.  Fast current-driven domain walls and small skyrmions in a compensated ferrimagnet , 2018, Nature Nanotechnology.

[29]  E. Linfield,et al.  Discrete Hall resistivity contribution from Néel skyrmions in multilayer nanodiscs , 2017, Nature Nanotechnology.

[30]  Guohan Hu,et al.  Materials for spin-transfer-torque magnetoresistive random-access memory , 2018 .

[31]  Pietro Burrascano,et al.  Electrical detection of single magnetic skyrmion at room temperature , 2017 .

[32]  G. Beach,et al.  Accurate model of the stripe domain phase of perpendicularly magnetized multilayers , 2017 .

[33]  Motohiko Ezawa,et al.  Skyrmion-electronics: writing, deleting, reading and processing magnetic skyrmions toward spintronic applications , 2019, Journal of physics. Condensed matter : an Institute of Physics journal.

[34]  A. Fert,et al.  Room-Temperature Current-Induced Generation and Motion of sub-100 nm Skyrmions. , 2017, Nano letters.

[35]  P. Böni,et al.  Skyrmion Lattice in a Chiral Magnet , 2009, Science.

[36]  Farnood Merrikh-Bayat,et al.  Training and operation of an integrated neuromorphic network based on metal-oxide memristors , 2014, Nature.

[37]  Byoungil Lee,et al.  Nanoelectronic programmable synapses based on phase change materials for brain-inspired computing. , 2012, Nano letters.

[38]  G. Beach,et al.  Theory of isolated magnetic skyrmions: From fundamentals to room temperature applications , 2018, Scientific Reports.

[39]  Damien Querlioz,et al.  Vowel recognition with four coupled spin-torque nano-oscillators , 2017, Nature.

[40]  F. Buttner,et al.  Investigation of the Dzyaloshinskii-Moriya interaction and room temperature skyrmions in W/CoFeB/MgO thin films and microwires , 2017, 1706.05987.

[41]  H. Ohno,et al.  Tunnel magnetoresistance of 604% at 300K by suppression of Ta diffusion in CoFeB∕MgO∕CoFeB pseudo-spin-valves annealed at high temperature , 2008 .

[42]  D. Ralph,et al.  Spin transfer torques , 2007, 0711.4608.

[43]  A. Stashkevich,et al.  Current-induced skyrmion generation and dynamics in symmetric bilayers , 2016, Nature Communications.

[44]  Xiaochen Peng,et al.  NeuroSim+: An integrated device-to-algorithm framework for benchmarking synaptic devices and array architectures , 2017, 2017 IEEE International Electron Devices Meeting (IEDM).

[45]  Jörg Raabe,et al.  Deterministic field-free skyrmion nucleation at a nano-engineered injector device. , 2019, Nano letters.

[46]  A. Fert,et al.  Nucleation, stability and current-induced motion of isolated magnetic skyrmions in nanostructures. , 2013, Nature nanotechnology.

[47]  S. Eisebitt,et al.  Field-free deterministic ultrafast creation of magnetic skyrmions by spin-orbit torques. , 2017, Nature nanotechnology.

[48]  Kang L. Wang,et al.  Blowing magnetic skyrmion bubbles , 2015, Science.

[49]  E. Vianello,et al.  HfO2-Based OxRAM Devices as Synapses for Convolutional Neural Networks , 2015, IEEE Transactions on Electron Devices.

[50]  F. Buttner,et al.  Full phase diagram of isolated skyrmions in a ferromagnet , 2017, 1704.08489.

[51]  A. Fert,et al.  Electrical detection of single magnetic skyrmions in metallic multilayers at room temperature , 2018, Nature Nanotechnology.

[52]  Arata Tsukamoto,et al.  Bulk Dzyaloshinskii–Moriya interaction in amorphous ferrimagnetic alloys , 2019, Nature Materials.