Dynamics of antiferromagnetic skyrmion in absence and presence of pinning defect

TL;DR

This paper develops a theoretical framework to understand the motion and pinning behavior of antiferromagnetic skyrmions, crucial for advancing spintronic applications involving antiferromagnetic materials.

Contribution

It introduces a reliable theoretical model for AFM skyrmion dynamics, including velocity derivation and depinning behavior in the presence of defects, based on the Thiele approach.

Findings

Skyrmion velocity depends on intrinsic parameters in defect-free systems.

Pinning and depinning fields are influenced by damping and defect strength.

Oscillations significantly affect the depinning process.

Abstract

A theoretical study on the dynamics of an antiferromagnetic (AFM) skyrmion is indispensable for revealing the underlying physics and understanding the numerical and experimental observations. In this work, we present a reliable theoretical treatment of the spin current induced motion of an AFM skyrmion in the absence and presence of pinning defect. For an ideal AFM system free of defect, the skyrmion motion velocity as a function of the intrinsic parameters can be derived, based on the concept that the skyrmion profile agrees well with the 360 domain wall formula, leading to an explicit description of the skyrmion dynamics. However, for an AFM lattice containing a defect, the skyrmion can be pinned and the depinning field as a function of damping constant and pinning strength can be described by the Thiele approach. It is revealed that the depinning behavior can be remarkably influenced by the time dependent oscillation of the skyrmion trajectory. The present theory provides a comprehensive scenario for manipulating the dynamics of AFM skyrmion, informative for future spintronic applications based on antiferromagnets.