The effect of low-temperature annealing on ferromagnetic

A systematic photoemission and variable temperature resistivity measurements are carried out on Ga0.946Mn0.054As ferromagnetic semiconductors. It is showed that the Mn 3d valence band and the As 3d core-level spectrum are modified by the annealing treatment. Correlating these modifications with the observed changes in the resistivity and Curie temperatures, we have identified that the low-temperature annealing most likely induces three changes: interstitial Mn out-diffusion, slight increase of the substitution Mn components, and reduction of excess As