Modified current induced domain wall motion in GaMnAs nanowire

TL;DR

This paper investigates current-induced domain wall motion in GaMnAs nanowires, revealing an unexpected slowdown linked to longitudinal wall elongation and suggesting evidence of transverse spin diffusion.

Contribution

It introduces a modified understanding of domain wall dynamics in GaMnAs wires, highlighting the impact of longitudinal wall elongation on velocity and proposing a new mechanism involving spin diffusion.

Findings

Slowing down of domain wall velocity when extending over half the wire width

Energy balance calculations match experimental velocity changes

Evidence suggesting transverse spin diffusion along the domain wall

Abstract

We report on current induced domain wall propagation in a patterned GaMnAs microwire with perpendicular magnetization. An unexpected slowing down of the propagation velocity has been found when the moving domain wall extends over only half of the width of the wire. This slowing down is related to the elongation of a longitudinal wall along the axis of the wire. By using an energy balance argument, the expected theoretical dependence of the velocity change has been calculated and compared with the experimental results. According to this, the energy associated to the longitudinal domain wall should change when a current passes through the wire. These results provide possible evidence of transverse spin diffusion along a longitudinal domain wall.