Strain control of magnetic anisotropy in (Ga,Mn)As microbars

TL;DR

This study investigates how lithographically induced strain relaxation in (Ga,Mn)As microbars can be used to control magnetic anisotropy, combining experimental measurements and theoretical modeling.

Contribution

It provides a comprehensive analysis of strain-induced magnetic anisotropy control in (Ga,Mn)As microstructures through combined experimental and theoretical approaches.

Findings

Strain relaxation effects significantly influence magnetic anisotropy.

Experimental data aligns well with finite element simulations.

Micropatterning induces anisotropies originating from magnetocrystalline spin-orbit coupling.

Abstract

We present an experimental and theoretical study of magnetocrystalline anisotropies in arrays of bars patterned lithographically into (Ga,Mn)As epilayers grown under compressive lattice strain. Structural properties of the (Ga,Mn)As microbars are investigated by high-resolution X-ray diffraction measurements. The experimental data, showing strong strain relaxation effects, are in good agreement with finite element simulations. SQUID magnetization measurements are performed to study the control of magnetic anisotropy in (Ga,Mn)As by the lithographically induced strain relaxation of the microbars. Microscopic theoretical modeling of the anisotropy is performed based on the mean-field kinetic-exchange model of the ferromagnetic spin-orbit coupled band structure of (Ga,Mn)As. Based on the overall agreement between experimental data and theoretical modeling we conclude that the micropatterning induced anisotropies are of the magnetocrystalline, spin-orbit coupling origin.