Domain imaging and domain wall propagation in (Ga,Mn)As thin films with tensile strain

TL;DR

This study investigates how tensile strain affects magnetic domain patterns and wall propagation in (Ga,Mn)As thin films, revealing that surface ripples and annealing influence magnetic anisotropy and domain behavior.

Contribution

The paper demonstrates that surface ripples and annealing modify magnetic anisotropy and domain wall propagation in strained (Ga,Mn)As films, offering insights into controlling magnetic domains.

Findings

Strong perpendicular magnetic anisotropy observed

Domain walls propagate along surface ripples in as-grown samples

Annealing alters domain wall propagation direction

Abstract

We have performed spatially resolved Polar Magneto-Optical Kerr Effect Microscopy measurements on as-grown and annealed Ga0.95Mn0.05As thin films with tensile strain. We find that the films exhibit very strong perpendicular magnetic anisotropy which is increased upon annealing. During magnetic reversal, the domain walls propagate along the direction of surface ripples for the as-grown sample at low temperatures and along the [110] direction for the annealed sample. This indicates that the magnetic domain pattern during reversal is determined by a combination of magnetocrystalline anisotropy and a distribution of pinning sites along the surface ripples that can be altered by annealing. These mechanisms could lead to an effective method of controlling domain wall propagation.