Strong room-temperature ferromagnetism in Cu-implanted nonpolar GaN films

Abstract

Diluted magnetic nonpolar GaN:Cu films with ferromagnetic properties up to 380 K have been fabricated by implantation of Cu ions into nonpolar a-plane GaN films and a subsequent thermal annealing process. The nonpolar GaN:Cu films exhibit a strong saturation magnetization about 1.54 μB/Cu atom, while polar GaN:Cu films can only show a weak saturation magnetization of 0.36 μB/Cu atom. Moreover, according to the x-ray photoelectron spectroscopy results, the stronger ferromagnetism of nonpolar GaN:Cu films may be resulted from the higher Cu incorporation efficiency in nonpolar GaN films.