Control of magnetic anisotropy in (Ga,Mn)As by lithography-induced strain relaxation

TL;DR

This study demonstrates that lithography-induced strain relaxation can precisely control magnetic anisotropy in (Ga,Mn)As, shifting easy axes and enhancing anisotropy strength without shape effects, as confirmed by advanced X-ray analysis.

Contribution

It introduces a method to manipulate magnetic anisotropy in (Ga,Mn)As through anisotropic strain relaxation induced by lithography, providing a new approach for magnetic property tuning.

Findings

Strain relaxation alters magnetic easy axes from biaxial to uniaxial.

Uniaxial strain increases magnetic anisotropy strength.

Lattice strain relaxation, not shape anisotropy, governs the magnetic behavior.

Abstract

We obtain control of magnetic anisotropy in epitaxial (Ga,Mn)As by anisotropic strain relaxation in patterned structures. The strain in the structures is characterized using sophisticated X-ray techniques. The magnetic anisotropy before patterning of the layer, which shows biaxial easy axes along [100] and [010], is replaced by a hard axis in the direction of large elastic strain relaxation and a uniaxial easy axis in the direction where pseudomorphic conditions are retained. This strong anisotropy can not be explained by shape anisotropy and is attributed solely to lattice strain relaxation. Upon increasing the uniaxial strain anisotropy in the (Ga,Mn)As stripes, we also observe an increase in magnetic anisotropy.