Magnetic reversal under external field and current-driven domain wall motion in (Ga,Mn)As: influence of extrinsic pinning

TL;DR

This study examines magnetic reversal and domain wall motion in GaMnAs thin films, revealing anisotropic behavior, a power law relation between critical current and magnetization, and the significant impact of pinning centers.

Contribution

It provides new insights into the anisotropic magnetic reversal and current-driven domain wall dynamics in GaMnAs, highlighting the influence of extrinsic pinning centers.

Findings

Larger coercive field along [110] axis.

Power law J_C ∝ M^2.6 for domain wall motion.

Strong influence of pinning centers on domain wall dynamics.

Abstract

We investigate the anisotropy of magnetic reversal and current-driven domain wall motion in annealed Ga_0.95Mn_0.05As thin films and Hall bar devices with perpendicular magnetic anisotropy. Hall bars with current direction along the [110] and [1-10] crystallographic axes are studied. The [110] device shows larger coercive field than the [1-10] device. Strong anisotropy is observed during magnetic reversal between [110] and [1-10] directions. A power law dependence is found for both devices between the critical current (JC) and the magnetization (M), with J_C is proportional to M^2.6. The domain wall motion is strongly influenced by the presence of local pinning centres.