Advanced resistivity model for arbitrary magnetization orientation applied to a series of compressive- to tensile-strained (Ga,Mn)As layers

TL;DR

This paper develops a comprehensive resistivity model for (Ga,Mn)As layers with varying strain, accurately describing magnetization-dependent resistivities and incorporating anisotropic effects, validated through theoretical and experimental comparison.

Contribution

It introduces a generalized analytical resistivity model for cubic and tetragonal ferromagnets with arbitrary surface orientations and magnetization directions, including higher-order terms.

Findings

Resistivity parameters vary systematically with strain.

The model accurately fits experimental data across strain states.

Inclusion of fourth-order terms improves model precision.

Abstract

The longitudinal and transverse resistivities of differently strained (Ga,Mn)As layers are theoretically and experimentally studied as a function of the magnetization orientation. The strain in the series of (Ga,Mn)As layers is gradually varied from compressive to tensile using (In,Ga)As templates with different In concentrations. Analytical expressions for the resistivities are derived from a series expansion of the resistivity tensor with respect to the direction cosines of the magnetization. In order to quantitatively model the experimental data, terms up to the fourth order have to be included. The expressions derived are generally valid for any single-crystalline cubic and tetragonal ferromagnet and apply to arbitrary surface orientations and current directions. The model phenomenologically incorporates the longitudinal and transverse anisotropic magnetoresistance as well as the anomalous Hall effect. The resistivity parameters obtained from a comparison between experiment and theory are found to systematically vary with the strain in the layer.