Surface acoustic wave controlled skyrmion-based synapse devices

Abstract

Magnetic skyrmions, particle-like spin structures, are considered as ideal information carriers for neuromorphic computing devices due to their topological stability and nanoscale size. In this work, we proposed to control magnetic skyrmions by electric-field-excited surface acoustic waves in neuromorphic computing device structures. Our micromagnetic simulations show that the number of created skyrmions, which emulates the synaptic weight parameter, increases monotonically with increasing the amplitude of the surface acoustic waves. Additionally, the efficiency of skyrmion creation was investigated systemically with a wide range of the magnetic parameters, and the optimal values have been presented accordingly. Finally, the functionalities of short-term plasticity and long-term potentiation have been demonstrated via the skyrmion excitation by the sequence of surface acoustic waves with different intervals. The application of surface acoustic waves in the skyrmionic neuromorphic computing devices paves a novel way for low-power computing systems.

Trapping and manipulating skyrmions in two-dimensional films by surface acoustic waves

“…Our approach is based on surface acoustic waves (SAWs), by which magnetic textures can be manipulated electrically through piezoelectric and magnetoelastic effects. The SAW manipulation of magnetic textures has some merits such as low energy cost and long transmission distance 7 , and several attempts have been reported. The domain wall motion by SAWs was proposed theoretically 8 and later demonstrated experimentally 9 .…”

“…Recently, one of the present authors and coworkers adopted a similar SAW device structure and experimentally demonstrated the creation of skyrmions using a spatiotemporally varying inhomogeneous effective torque 10 . Based on the SAW creation of skyrmions, an artificial synapse for neuromorphic computing was proposed 7 . Nepal et al theoretically studied a one-dimensional control of skyrmions confined in nanowires 11 using counter-propagating SAWs.…”

Pattern recognition with neuromorphic computing using magnetic field–induced dynamics of skyrmions

“…Therefore, developing devices specialized for braininspired com puting, namely, neuromorphic devices, is highly required (4,5). In particular, nonlinearity and shortterm memory effects are essential functions for neuromorphic devices that various spintronic devices can offer (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). Among them, we focus on a topological spin structure called magnetic skyrmion (22)(23)(24)(25)(26)(27)(28)(29)(30)(31).…”

“…Among them, we focus on a topological spin structure called magnetic skyrmion (22)(23)(24)(25)(26)(27)(28)(29)(30)(31). So far, skyrmionbased neuro morphic devices, such as reservoir computing devices (9)(10)(11)(12)(13)(14), synapse devices (15,16), and probabilistic computing devices (17,18), have been studied to bring about high performance. However, a fully experimental evaluation of its ability for neuromorphic tasks such as pattern recognition is still lacking.…”

Trapping and manipulating skyrmions in two-dimensional films by surface acoustic waves

“…Recently, one of the present authors and coworkers adopted a similar SAW device structure and experimentally demonstrated the creation of skyrmions using a spatiotemporally varying inhomogeneous effective torque 10 . Based on the SAW creation of skyrmions, an artificial synapse for neuromorphic computing was proposed 7 . Nepal et al theoretically studied a one-dimensional control of skyrmions confined in nanowires 11 using counter-propagating SAWs.…”