Influence of magnetic viscosity on domain wall dynamics under spin-polarized currents

TL;DR

This paper theoretically investigates how magnetic viscosity affects the movement of domain walls driven by spin-polarized currents, focusing on depinning transitions influenced by thermal activation and spin-torques.

Contribution

It introduces a model showing that the Arrhenius law applies to current-driven depinning with a current-dependent energy barrier influenced by nonadiabatic spin torque.

Findings

Arrhenius law remains valid with current-dependent barriers

Energy barrier linearly depends on current under typical conditions

Barrier variation is governed by the nonadiabatic spin torque coefficient beta

Abstract

We present a theoretical study of the influence of magnetic viscosity on current-driven domain wall dynamics. In particular we examine how domain wall depinning transitions, driven by thermal activation, are influenced by the adiabatic and nonadiabatic spin-torques. We find the Arrhenius law that describes the transition rate for activation over a single energy barrier remains applicable under currents but with a current-dependent barrier height. We show that the effective energy barrier is dominated by a linear current dependence under usual experimental conditions, with a variation that depends only on the nonadiabatic spin torque coefficient beta.