The evolution of the magnetic, electronic and structural properties of annealed epilayers of Ga1–xMnxAs, grown via low-temperature molecular beam epitaxy, was studied. Annealing at the optimum temperature of 250C, for less than 2h, significantly enhanced the conductivity and ferromagnetism. Annealing for longer times suppressed both. The data indicated that such annealing caused the defects to evolve due to at least 2 different processes, thus suggesting the occurrence of a complex interplay between various defects and ferromagnetism.

Effects of Annealing Time on Defect-Controlled Ferromagnetism in Ga1–xMnxAs. S.J.Potashnik, K.C.Ku, S.H.Chun, J.J.Berry, N.Samarth, P.Schiffer: Applied Physics Letters, 2001, 79[10], 1495-7