Skyrmion Dynamics in the Presence of Deformation

TL;DR

This paper develops an extended analytical model for magnetic skyrmion dynamics considering deformation effects caused by current-induced symmetry breaking, aligning well with simulations and suggesting ways to control skyrmion shape.

Contribution

It introduces a novel extension of Thiele's model that accounts for skyrmion deformation due to current and magnetic field effects.

Findings

Model accurately predicts skyrmion radius and nonlinear behavior.

Applying in-plane magnetic fields can suppress deformation.

Deformation control enables potential skyrmion-based applications.

Abstract

Magnetic skyrmions are topological spin textures promising for future high-density and nonvolatile memory. It is crucial to understand the current-driven skyrmion dynamics in the presence of deformation, of which an analytical model, however, remains elusive. Here we extend Thiele's model by considering both the radial and tangential forces. Our model attributes the skyrmion deformation to the current-induced rotational symmetry breaking, which includes magnetization canting and domain wall width variation. Our predictions of skyrmion radius and nonlinear dynamics are consistent with micromagnetic simulation results. Besides, we show that by applying an in-plane magnetic field, the deformation of a skyrmion can be suppressed, and even the compression of a skyrmion can be achieved. Our model provides a generic way to analyze the skyrmion deformation and may inspire applications based on nonlinear skyrmion dynamics.