Synthesis and magnetic properties of iron nitride films deposited on Ge(100) by reactive ion beam sputtering

Iron nitride films were deposited on Ge(100) wafers by a reactive ion beam sputter deposition of iron in an ammonia atmosphere, The composition and microstructure of these films were monitored by Rutherford backscattering spectroscopy analyses and x-ray diffraction experiments. The magnetic properties of these films were determined by a vibrating sample magnetometer. It was found that Ge(100) substrate is profitable for epitaxial growth of the alpha '' phase, The optimum ammonia pressure for alpha'/alpha '' phase formation was about 5 x 10(-4) Torr. The saturation magnelization sigma(s) of each as-deposited Fe-N film is higher than that of a pure iron film. However, the film with the highest alpha'/alpha '' phase content did not exhibit the largest alpha(s) value. The variation of sigma(s) of the Fe-N films during annealing at a temperature of 180 degrees C in a flowing nitrogen atmosphere was also investigated. It was found that there is no direct relationship between the higher sigma(s) values and the alpha'/alpha '' phase in these Fe-N films. (C) 1997 American Institute of Physics.