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

Abstract

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 ( M s) of 1.77 Wb/m 2 and a small coercivity ( H c) 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 ( M s) of 1.64 Wb/m 2 and a minimum coercivity ( H c) of 279 Wb/m 2 at a nitrogen gas flow ratio of 20%. The grain refinement mechanism of chromium and nitrogen in the FeCo-based films was also discussed.