Soft magnetic properties of ion beam reactively sputtered Fe-N thin films on Ge(100)

Several iron nitride thin films with nitrogen concentration less than 15 at.% were synthesized on Ge(100) wafers by a reactive ion beam sputtering method in an ammonia atmosphere. The composition and microstructure of these films were monitored by Rutherford backscattering spectroscopy analyses and X-ray diffraction experiments. The soft magnetic properties of these films were measured by a vibrating sample magnetometer. The changes in microstructure and magnetic properties during an annealing process at 180 degrees C under a Bowing nitrogen atmosphere were investigated. It was found that both the saturation magnetization sigma(s) and the coercivity H-c of these Fe-N films are higher than that of pure iron film. However, no direct relationship between the higher a, values and the alpha' + alpha" phase could be found in the as-synthesized and annealed iron nitride films. (C) 1998 Elsevier Science S.A.