Diffusion of Mn interstitials in (Ga,Mn)As epitaxial layers
  Magnetic properties of thin (Ga,Mn)As layers improve during annealing by out-diffusion of interstitial Mn ions to a free surface. Out-diffused Mn atoms participate in the growth of a Mn-rich surface layer and a saturation of this layer causes an inhibition of the out-diffusion. We combine high-resolution x-ray diffraction with x-ray absorption spectroscopy and a numerical solution of the diffusion problem for the study of the out-diffusion of Mn interstitials during a sequence of annealing steps. Our data demonstrate that the out-diffusion of the interstitials is substantially affected by the internal electric field caused by an inhomogeneous distribution of charges in the (Ga,Mn)As layer. 
L. Hor\'ak, J. Mat\v{e}jov\'a, X. Mart\'i, V. Hol\'y, V. Nov\'ak, Z.   \v{S}ob\'a\v{n}, S. Mangold, and F. Jim\'enez-Villacorta
cond-mat.mtrl-sci