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%).
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The data that support the plots within this paper and other findings of this study are available from the corresponding authors upon reasonable request.
The micromagnetic simulator OOMMF used in this work is publicly accessible at http://math.nist.gov/oommf.
Fert, A., Reyren, N. & Cros, V. Magnetic skyrmions: advances in physics and potential applications. Nat. Rev. Mater. 2, 17031 (2017).
Zhang, X. et al. Skyrmion-electronics: writing, deleting, reading and processing magnetic skyrmions toward spintronic applications. J. Phys. Condens. Matter 32, 143001 (2020).
Mühlbauer, S. et al. Skyrmion lattice in a chiral magnet. Science 323, 915–919 (2009).
Yu, X. Z. et al. Real-space observation of a two-dimensional skyrmion crystal. Nature 465, 901–904 (2010).
Dzyaloshinsky, I. A thermodynamic theory of ‘weak’ ferromagnetism of antiferromagnetics. J. Phys. Chem. Solids 4, 241–255 (1958).
Moriya, T. Anisotropic superexchange interaction and weak ferromagnetism. Phys. Rev. 120, 91–98 (1960).
Jiang, W. et al. Blowing magnetic skyrmion bubbles. Science 349, 283–286 (2015).
Woo, S. et al. Observation of room-temperature magnetic skyrmions and their current-driven dynamics in ultrathin metallic ferromagnets. Nat. Mater. 15, 501–506 (2016).
Legrand, W. et al. Room-temperature current-induced generation and motion of sub-100 nm skyrmions. Nano Lett. 17, 2703–2712 (2017).
Hrabec, A. et al. Current-induced skyrmion generation and dynamics in symmetric bilayers. Nat. Commun. 8, 15765 (2017).
Büttner, F. et al. Field-free deterministic ultrafast creation of magnetic skyrmions by spin–orbit torques. Nat. Nanotechnol. 12, 1040–1044 (2017).
Woo, S. et al. Deterministic creation and deletion of a single magnetic skyrmion observed by direct time-resolved X-ray microscopy. Nat. Electron. 1, 288–296 (2018).
Woo, S. et al. Current-driven dynamics and inhibition of the skyrmion Hall effect of ferrimagnetic skyrmions in GdFeCo films. Nat. Commun. 9, 959 (2018).
Maccariello, D. et al. Electrical detection of single magnetic skyrmions in metallic multilayers at room temperature. Nat. Nanotechnol. 13, 233–237 (2018).
Zeissler, K. et al. Discrete Hall resistivity contribution from Néel skyrmions in multilayer nanodiscs. Nat. Nanotechnol. 13, 1161–1166 (2018).
Hopfield, J. J. Neural networks and physical systems with emergent collective computational abilities. Proc. Natl Acad. Sci. USA 79, 2554–2558 (1982).
Kuzum, D., Jeyasingh, R. G. D., Lee, B. & Wong, H.-S. P. Nanoelectronic programmable synapses based on phase change materials for brain-inspired computing. Nano Lett. 12, 2179–2186 (2012).
Prezioso, M. et al. Training and operation of an integrated neuromorphic network based on metal-oxide memristors. Nature 521, 61–64 (2015).
Lequeux, S. et al. A magnetic synapse: multilevel spin–torque memristor with perpendicular anisotropy. Sci. Rep. 6, 31510 (2016).
Nagaosa, N. & Tokura, Y. Topological properties and dynamics of magnetic skyrmions. Nat. Nanotechnol. 8, 899–911 (2013).
Huang, Y., Kang, W., Zhang, X., Zhou, Y. & Zhao, W. Magnetic skyrmion-based synaptic devices. Nanotechnology 28, 08LT02 (2017).
Torrejon, J. et al. Neuromorphic computing with nanoscale spintronic oscillators. Nature 547, 428–431 (2017).
Romera, M. et al. Vowel recognition with four coupled spin–torque nano-oscillators. Nature 563, 230–234 (2018).
Bourianoff, G., Pinna, D., Sitte, M. & Everschor-Sitte, K. Potential implementation of reservoir computing models based on magnetic skyrmions. AIP Adv. 8, 055602 (2018).
Zázvorka, J. et al. Thermal skyrmion diffusion used in a reshuffler device. Nat. Nanotechnol. 14, 658–661 (2019).
Kim, D.-H. et al. Bulk Dzyaloshinskii–Moriya interaction in amorphous ferrimagnetic alloys. Nat. Mater. 18, 685–690 (2019).
Hirata, Y. et al. Vanishing skyrmion Hall effect at the angular momentum compensation temperature of a ferrimagnet. Nat. Nanotechnol. 14, 232–236 (2019).
Barker, J. & Tretiakov, O. A. Static and dynamical properties of antiferromagnetic skyrmions in the presence of applied current and temperature. Phys. Rev. Lett. 116, 147203 (2016).
Büttner, F., Lemesh, I. & Beach, G. S. D. Theory of isolated magnetic skyrmions: from fundamentals to room temperature applications. Sci. Rep. 8, 4464 (2018).
Bessarab, P. F. et al. Stability and lifetime of antiferromagnetic skyrmions. Phys. Rev. B 99, 140411 (2019).
Finizio, S. et al. Deterministic field-free skyrmion nucleation at a nanoengineered injector device. Nano Lett. 19, 7246–7255 (2019).
Chen, P.-Y., Peng, X. & Yu, S. NeuroSim+: an integrated device-to-algorithm framework for benchmarking synaptic devices and array architectures. In 2017 IEEE International Electron Devices Meeting 6.1.1–6.1.4 (IEEE, 2017).
Garbin, D. et al. HfO2-based OxRAM devices as synapses for convolutional neural networks. IEEE Trans. Electron Devices 62, 2494–2501 (2015).
Tang, J. et al. ECRAM as scalable synaptic cell for high-speed, low-power neuromorphic computing. In 2018 IEEE International Electron Devices Meeting 13.1.1–13.1.4 (2018); https://doi.org/10.1109/IEDM.2018. 8614551
Caretta, L. et al. Fast current-driven domain walls and small skyrmions in a compensated ferrimagnet. Nat. Nanotechnol. 13, 1154–1160 (2018).
Tomasello, R. et al. Electrical detection of single magnetic skyrmion at room temperature. AIP Adv. 7, 056022 (2017).
Ikeda, S. et al. Tunnel magnetoresistance of 604% at 300 K by suppression of Ta diffusion in CoFeB/MgO/CoFeB pseudo-spin-valves annealed at high temperature. Appl. Phys. Lett. 93, 082508 (2008).
Wang, M. et al. Current-induced magnetization switching in atom-thick tungsten engineered perpendicular magnetic tunnel junctions with large tunnel magnetoresistance. Nat. Commun. 9, 671 (2018).
Chen, P. & Yu, S. Compact modeling of RRAM devices and its applications in 1T1R and 1S1R array design. IEEE Trans. Electron Devices 62, 4022–4028 (2015).
Moon, K., Kwak, M., Park, J., Lee, D. & Hwang, H. Improved conductance linearity and conductance ratio of 1T2R synapse device for neuromorphic systems. IEEE Electron Device Lett. 38, 1023–1026 (2017).
Yuasa, S., Hono, K., Hu, G. & Worledge, D. C. Materials for spin-transfer-torque magnetoresistive random-access memory. MRS Bull. 43, 352–357 (2018).
Donahue, M. J. & Porter, D. G. OOMMF User’s Guide, Version 1.0 (NIST, 1999).
Ralph, D. C. & Stiles, M. D. Spin transfer torques. J. Magn. Magn. Mater. 320, 1190–1216 (2008).
Ando, K. Dynamical generation of spin currents. Semicond. Sci. Technol. 29, 043002 (2014).
Sampaio, J., Cros, V., Rohart, S., Thiaville, A. & Fert, A. Nucleation, stability and current-induced motion of isolated magnetic skyrmions in nanostructures. Nat. Nanotechnol. 8, 839–844 (2013).
Tomasello, R. et al. A strategy for the design of skyrmion racetrack memories. Sci. Rep. 4, 6784 (2014).
Zhang, X. et al. Control and manipulation of a magnetic skyrmionium in nanostructures. Phys. Rev. B 94, 094420 (2016).
This work was mainly supported by a KIST Institutional Program (2E29410). S.W. acknowledges support from IBM Research and management support from G. Hu and D. Worledge. S.W. also acknowledges K.-Y. Lee for providing the artwork included in Fig. 2. K.M.S., S.C., T.-E.P. and J.C. acknowledge support from the National Research Council of Science and Technology (NST; grant no. CAP-16-01-KIST) by the Korean government (MSIP). K.K. acknowledges support from the Basic Research Laboratory Program through the National Research Foundation of Korea (NRF) funded by MSIT (NRF-2018R1A4A1020696). J.-S.J. and H.J. acknowledge support from the Korea National Research Foundation programme (NRF-2017R1E1A1A01077484), which was particularly utilized to conduct the MNIST pattern work of this research. J.C. acknowledges support from the Yonsei-KIST Convergence Research Institute. The PolLux endstation was financed by the German Bundesministerium für Bildung und Forschung under grant no. 05K16WED and 05K19WE2. X.Z. was supported by the Guangdong Basic and Applied Basic Research Fund (grant no. 19201910240003361), and the Presidential Postdoctoral Fellowship of The Chinese University of Hong Kong, Shenzhen (CUHKSZ). Y.Z. acknowledges support by the President’s Fund of CUHKSZ, Longgang Key Laboratory of Applied Spintronics, National Natural Science Foundation of China (grant nos. 11974298 and 61961136006), Shenzhen Fundamental Research Fund (grant no. JCYJ20170410171958839) and Shenzhen Peacock Group Plan (grant no. KQTD20180413181702403). W.Z. and W.K. acknowledge support by the National Natural Science Foundation of China (grant no. 61627813), the International Collaboration Project B16001 and the National Key Technology Program of China (2017ZX01032101). Parts of this work were performed at the PolLux (X07DA) endstation of the Swiss Light Source, Paul Scherrer Institut, Switzerland.
The authors declare no competing interests.
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Song, K.M., Jeong, JS., Pan, B. et al. Skyrmion-based artificial synapses for neuromorphic computing. Nat Electron 3, 148–155 (2020). https://doi.org/10.1038/s41928-020-0385-0
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