Crystal structures and magnetic properties of Fe-N thin films deposited by dc magnetron sputtering

Fe-N thin films were deposited on glass substrates by dc magnetron sputtering under various Ar/N-2 discharge conditions. Crystal structures and elemental compositions of the films were characterized by X-ray diffraction and X-ray photoelectron spectroscopy. Magnetic properties of the films were measured using a superconducting quantum interference device magnetometer. Films deposited at different N-2/(Ar+N-2) flow ratios were found to have different crystal structures and different nitrogen contents. When the flow ratios were 60%, 50%, and 30%, a nonmagnetic single-phase FeN was formed in the films. At the flow ratio of 10%, two crystal phases of gamma'-Fe4N and epsilon-Fe3N were detected. When the flow ratio reduced to 5%, a mixture of alpha-Fe, epsilon-Fe3N, FeN0.056, and alpha"-Fe16N2 phases was obtained. The value of saturation magnetization for the mixture was found to be larger than that of pure Fe. (C) 2004 International Centre for Diffraction Data.