Spin-orbit coupling effect in (Ga,Mn)As films: anisotropic exchange   interactions and magnetocrystalline anisotropy
  The magneto-crystalline anisotropy (MCA) of (Ga,Mn)As films has been studied on the basis of ab-initio electronic structure theory by performing magnetic torque calculations. An appreciable contribution to the in-plane uniaxial anisotropy can be attributed to an extended region adjacent to the surface. Calculations of the exchange tensor allow to ascribe a significant part to the MCA to the exchange anisotropy, caused either by a tetragonal distortion of the lattice or by the presence of the surface or interface. 
S. Mankovsky, S. Polesya, S. Bornemann, J. Min\'ar, F. Hoffmann, C. H.   Back, H. Ebert
cond-mat.mtrl-sci