Magnetic properties of sequentially sputtered amorphous Fe-Ge thin films

Fe_xGe_100-x films with compositions in the range 50⩽x⩽82 at 300 K were deposited by rf diode, sequential sputtering from elemental targets. All the films were amorphous at 300 K indicating that the Fe concentration in the stable amorphous films was increased by more than 10 at. % over that obtained by vapor deposition. The sequentially sputtered Fe-Ge films exhibited a heteroamorphous morphology with nanoscale features that varied with composition. The variations in the 4πM_s and T_c for the sputtered Fe rich films, agreed well with data extrapolated from measurements on Ge rich evaporated films. The improvement in the soft magnetic properties produced in these films by rotating magnetic field annealing (RFA) was shown to be correlated with changes in film morphology