In-plane uniaxial anisotropy rotations in (Ga,Mn)As thin films

TL;DR

This study demonstrates that in (Ga,Mn)As thin films, the in-plane uniaxial magnetic easy axis can be rotated between crystallographic directions through low-temperature annealing, with behavior dependent on hole density and explained by the p-d Zener model.

Contribution

It reveals the controllable rotation of magnetic easy axes in (Ga,Mn)As films via annealing and links this to hole density and crystal distortion, advancing understanding of magnetic anisotropy.

Findings

Uniaxial anisotropy direction can be rotated by annealing.

Anisotropy depends on hole density and temperature.

Behavior explained by p-d Zener model with trigonal distortion.

Abstract

We show, by SQUID magnetometry, that in (Ga,Mn)As films the in-plane uniaxial magnetic easy axis is consistently associated with particular crystallographic directions and that it can be rotated from the [-110] direction to the [110] direction by low temperature annealing. We show that this behavior is hole-density-dependent and does not originate from surface anisotropy. The presence of uniaxial anisotropy as well its dependence on the hole-concentration and temperature can be explained in terms of the p-d Zener model of the ferromagnetism assuming a small trigonal distortion.