PACS 75.50. Pp, 75.70.AkThe behavior of precipitates in magnetic GaMnN films upon annealing was investigated. The major precipitate was Mn 3 GaN phase in GaMnN layers grown via molecular beam epitaxy using a single GaN precursor under high Mn flux. With heat treatment of the films, the Mn 3 GaN phase decomposed and a part of it was converted to magnetic Mn 3 Ga phase through detachment of nitrogen. The decomposition kinetics was further accelerated by neutron irradiation, which generated defects in the lattice and assisted the decomposition of the precipitates. The saturation magnetization of the homogeneous GaMnN layer was increased after the heat treatment while it was decreased in the precipitated GaMnN layer. The increase and decrease of the magnetization of the heat-treated GaMnN films was explained consistently by the role of the precipitates in the films.

PACS 75.50. Pp, 75.70.Ak, 81.15.Hi GaMnN magnetic thin films were grown using a single GaN precursor of Et 2 Ga(N 3 )NH 2 C(CH 3 ) 3 , and their structural and magnetic properties were investigated. The GaN layers were grown with c-axis texture orientation. The films, however, revealed a great improvement in the crystallinity upon in-situ and ex-situ annealing at higher temperatures. Incorporation of Mn, however, randomized the growth direction as revealed by investigations of X-ray diffraction and transmission electron microscopy. For high Mn flux, a cubic second phase, Mn 3 GaN, has precipitated. It is a structure seldom observed in other conventional molecular beam epitaxy growth. It, however, offered a high conductivity to the GaMnN matrix. The precipitated films showed a uniaxial anisotropy in the magneto-transport.