Gate-voltage control of alternating-current-driven skyrmion propagation in the ferromagnetic nanotrack devices

Abstract

Magnetic skyrmions, with topologically protected particle-like magnetization configurations, are promising information carriers for future spintronics devices with ultralow energy consumption. Generally, during motion, skyrmions suffer from the skyrmion Hall effect (SkHE) wherein the skyrmions deflect away from the intended path of the driving force. Numerous methods have been proposed to avoid this detrimental effect. In this study, we propose controllable alternating current (AC)-driven skyrmion propagation in a ferromagnetic nanowire based on the combination of gate-voltage-controlled magnetic anisotropy (VCMA) and SkHE. Micromagnetic simulations showed that a skyrmion oscillatory closed-loop-like in-situ motion that is driven by AC can be transformed into directional ratchet-like propagation along the nanotrack by creating a VCMA gates barrier. Additionally, we show that the skyrmion propagation conditions depend on the gate barrier potential and driving AC parameters, and they can be used for the optimal design of nanotrack devices. Moreover, this mechanism could be used to control skyrmion macroscopic propagation directions by dynamically alternating the voltage of another series of gates. We further show the dynamic control of the long-distance propagation of skyrmions along with the pinning state. The study results provide a promising route for designing future skyrmion-based spintronics logical and memory devices.