Detailed transport investigation of the magnetic anisotropy of (Ga,Mn)As

TL;DR

This study employs transport methods, especially the anisotropy fingerprint technique, to analyze the magnetic anisotropy in (Ga,Mn)As films, revealing consistent presence of three anisotropy components and their temperature dependence.

Contribution

It extends the anisotropy fingerprint technique to layers with uniaxial anisotropy and provides detailed analysis of anisotropy components in (Ga,Mn)As.

Findings

All studied films exhibit three anisotropy components.

The primary biaxial and two uniaxial anisotropy components are always present.

Temperature affects the magnetic anisotropy and domain wall nucleation energy.

Abstract

This paper discusses transport methods for the investigation of the (Ga,Mn)As magnetic anisotropy. Typical magnetoresistance behaviour for different anisotropy types is discussed, focusing on an in depth discussion of the anisotropy fingerprint technique and extending it to layers with primarily uniaxial magnetic anisotropy. We find that in all (Ga,Mn)As films studied, three anisotropy components are always present. The primary biaxial along ([100] and [010]) along with both uniaxial components along the [110] and [010] crystal directions which are often reported separately. Various fingerprints of typical (Ga,Mn)As transport samples at 4 K are included to illustrate the variation of the relative strength of these anisotropy terms. We further investigate the temperature dependence of the magnetic anisotropy and the domain wall nucleation energy with the help of the fingerprint method.