Annealing-induced changes of the magnetic anisotropy of (Ga,Mn)As epilayers

The dependence of the magnetic anisotropy of As-capped (Ga,Mn)As epilayers on the annealing parameters—temperature and time—has been investigated. A uniaxial magnetic anisotropy is evidenced, whose orientation with respect to the crystallographic axes changes upon annealing from [1 ¯10] for the as-grown samples to [110] for the annealed samples. Both cubic and uniaxial anisotropies are tightly linked to the magnetic transition temperature, and hence, to the concentration of charge carriers, the magnitude of which is controlled by the annealing process.