Peking Univ, Sch Phys, Phys Mat Lab, Beijing 100871, Peoples R China
; Peking Univ, Res Ctr Wide Band Semicond, Beijing 100871, Peoples R China
; Peking Univ, State Key Lab Artificial Microstruct & Mesoscop P, Beijing 100871, Peoples R China
; Chinese Acad Sci, Inst High Energy Phys, Beijing Synchrotron Radiat Facil, Beijing 100049, Peoples R China
Epitaxial films of Ga1-xMnxN have been grown on c-sapphire substrates by low-pressure metal-organic vapour phase epitaxy. The samples show ferromagnetic behaviour up to a temperature of T = 380K with hysteresis curves showing a coercivity of 50-100 Oe. No ferromagnetic second phases and no significant deterioration in crystal quality with the incorporation of Mn can be detected by high-resolution x-ray diffraction. The result of x-ray absorption near-edge structures indicates that Mn atoms substitute for Ga atoms. The Mn concentrations of the layers are determined to reach x = 0.038 by proton-induced x-ray emission.