Geometric notch-manipulated skyrmion dynamics for reconfigurable diode and logic gates in synthetic antiferromagnetic nanotrack

Abstract

Skyrmions, as a topologically protected nanoscale spin texture, have emerged as promising candidates in the next generation of spintronic devices owing to their excellent properties. In this work, based on the Thiele equation, we have derived the velocity formulae for skyrmions driven by spin-orbit torque in a synthetic antiferromagnetic (SAF) nanotrack featuring asymmetric geometric notches. Building on the established dynamic equations, we have proposed a reconfigurable multifunctional skyrmion device manipulated by geometric notches, which can realize both a diode and logic gates in the same SAF nanotrack structure. Utilizing the developed dynamic equations, we demonstrate that a tilted nanotrack boundary alters the skyrmions' dynamic state, resulting in a decrease in their velocity, which explains the result that the average velocity of skyrmions passing through the notch channel decreases as the notch tilt angle increases. The implementation of the reconfigurable functionality of skyrmions depends on both notch channel geometry and threshold current density. This study provides a device design approach based on skyrmion dynamics, and its design concept is transferable to other spintronic devices, which is beneficial to the development of spintronic devices integrating multifunctionality and inherent low power consumption.