Structural, electrical and magnetic properties of Fe-Co-Cr and Fe-Co-Cr-N nanocrystalline alloy films

Fe-Co-Cr and Fe-Co-Cr-N thin films were fabricated by magnetron co-sputtering at room temperature, and their structural, electrical and magnetic properties were examined by various analytic techniques. It was observed that with the increase of Cr-target power, for Fe-Co-Cr thin films the resistivity increased and surface morphology was changed. As the nitrogen gas flow ratio increased, for Fe-Co-Cr-N thin films the grain size decreased and the resistivity monotonically increased. Fe-Co-Cr thin films exhibited the best soft-magnetic properties with a relatively large saturation magnetization (Ms) of 1.77 Wb/m2 and a small coercivity (Hc) of 748 A/m at a Cr-target power of 80 W, whereas Fe-Co-Cr-N thin films had the best soft-magnetic properties with a high saturation magnetization (Ms) of 1.64 Wb/m2 and a minimum coercivity (Hc) of 279 Wb/m2 at a nitrogen gas flow ratio of 20%. The grain refinement mechanism of chromium and nitrogen in the FeCo-based films was also discussed.