Steady high-frequency antiskyrmion oscillator with anisotropic Dzyaloshinskii-Moriya interaction

Abstract

Magnetic skyrmions have garnered significant interest in recent years due to their potential applications in spintronic devices, such as spin-torque nano-oscillators (STNOs) and racetrack memory. However, the development of skyrmion-based STNOs has been hindered by their sub-GHz operational frequencies and propensity for annihilation under high current densities. In this study, stable antiskyrmion auto-oscillations in nanodisk geometries driven by spinpolarized currents enabled by anisotropic Dzyaloshinskii-Moriya interaction (DMI) were demonstrated. Through systematic comparisons of isotropic and anisotropic DMI systems, we uncover distinct topological stabilization mechanisms and current–density-dependent dynamics. At intermediate current densities (10–15 × 10¹¹ A·m⁻²), antiskyrmions exhibit a hybrid breathing-rotational mode, achieving oscillation frequencies of 9.66 GHz (in-plane) and 38.8 GHz (out-of-plane), with a robust frequency ratio of 3.9–4.1. Notably, antiskyrmions sustain current densities up to 400 % of the annihilation thresholds for conventional skyrmions, attributed to their unique chirality-dependent force equilibration. The tangential velocity of antiskyrmions reaches 587 m/s at 15 × 10¹¹ A·m⁻², governed by competing dependencies on current density and size contraction. These findings establish antiskyrmion-based STNOs as promising platforms for high-frequency, low-power spintronic applications, overcoming critical limitations of conventional skyrmion systems.