Abstrakt
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. Magnetization measurements are performed using a superconducting quantum interference device 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 magnetocrystalline, spin-orbit coupling origin.