Dynamics of Domain Wall in a Biaxial Ferromagnet With Spin-torque

TL;DR

This paper models the dynamics of a domain wall in a biaxial ferromagnet under spin-torque using a sine-Gordon equation with damping, deriving a current threshold for motion and analyzing damping effects.

Contribution

It introduces a coupled sine-Gordon and Gilbert damping model to describe domain wall dynamics and derives a current threshold dependent on damping.

Findings

Threshold current depends on Gilbert damping.

Domain wall motion analyzed for zero and nonzero damping.

Model self-consistently describes DW dynamics under spin-torque.

Abstract

The dynamics of the domain wall (DW) in a biaxial ferromagnet interacting with a spin-polarized current are described by sine-gordon (SG) equation coupled with Gilbert damping term in this paper. Within our frame-work of this model, we obtain a threshold of the current in the motion of a single DW with the perturbation theory on kink soliton solution to the corresponding ferromagnetic system, and the threshold is shown to be dependent on the Gilbert damping term. Also, the motion properties of the DW are discussed for the zero- and nonzero-damping cases, which shows that our theory to describe the dynamics of the DW are self-consistent.