Harmonic oscillator model for current- and field-driven magnetic vortices

TL;DR

This paper presents an analytical and numerical study of the gyroscopic motion of magnetic vortices driven by current and magnetic fields, revealing elliptical core rotations influenced by excitation parameters.

Contribution

It introduces a harmonic oscillator model to describe vortex dynamics under both current and field-driven excitations, clarifying their effects on vortex motion.

Findings

Vortex cores perform elliptical rotations under small harmonic excitations.

The phase and shape of the rotation depend on excitation frequency and amplitude.

The model helps distinguish effects of spin torque and Oersted fields in experiments.

Abstract

In experiments the distinction between spin-torque and Oersted-field driven magnetization dynamics is still an open problem. Here, the gyroscopic motion of current- and field-driven magnetic vortices in small thin-film elements is investigated by analytical calculations and by numerical simulations. It is found that for small harmonic excitations the vortex core performs an elliptical rotation around its equilibrium position. The global phase of the rotation and the ratio between the semi-axes are determined by the frequency and the amplitude of the Oersted field and the spin torque.