Magnetic domain structure and magnetic anisotropy in Ga1-xMnxAs -: art. no. 167206

Large, well-defined magnetic domains, on the scale of hundreds of micrometers, are observed in Ga1-xMnxAs epilayers using a high-resolution magneto-optical imaging technique. The orientations of the magnetic moments in the domains clearly show in-plane magnetic anisotropy, which changes through a second-order transition from a biaxial mode (easy axes nearly along [100] and [010]) at low temperatures to an unusual uniaxial mode (easy axis along [110]) as the temperature increases above about T-c/2. This transition is a result of the interplay between the natural cubic anisotropy of the GaMnAs zinc-blende structure and a uniaxial anisotropy which attribute to the effects of surface reconstruction.