Angle-dependent magnetotransport in cubic and tetragonal ferromagnets: Application to (001)- and (113)A-oriented (Ga,Mn)As

TL;DR

This paper develops theoretical models for angle-dependent magnetotransport in cubic and tetragonal ferromagnets, applying them to strained (Ga,Mn)As films to analyze magnetic anisotropy and magnetoresistance.

Contribution

It introduces general resistivity expressions based on magnetization orientation and applies them to experimental data on (Ga,Mn)As, linking magnetotransport with magnetic anisotropy analysis.

Findings

Model accurately fits angular resistivity data

Magnetic anisotropy parameters agree with ferromagnetic resonance

Magnetotransport effectively probes magnetic properties

Abstract

General expressions for the longitudinal and transverse resistivities of single-crystalline cubic and tetragonal ferromagnets are derived from a series expansion of the resistivity tensor with respect to the magnetization orientation. They are applied to strained (Ga,Mn)As films, grown on (001)- and (113)A-oriented GaAs substrates, where the resistivities are theoretically and experimentally studied for magnetic fields rotated within various planes parallel and perpendicular to the sample surface. We are able to model the measured angular dependences of the resistivities within the framework of a single ferromagnetic domain, calculating the field-dependent orientation of the magnetization by numerically minimizing the free-enthalpy density. Angle-dependent magnetotransport measurements are shown to be a powerful tool for probing both anisotropic magnetoresistance and magnetic anisotropy. The anisotropy parameters of the (Ga,Mn)As films inferred from the magnetotransport measurements agree with those obtained by ferromagnetic resonance measurements within a factor of two.