Dependence of soft-magnetic properties on film thickness and high frequency characteristics for Fe-Co-Cr-N alloy films

摘要

Fe-Co-Cr-N thin films with various thicknesses were deposited by substrate rotation during magnetron co-sputtering. The dependence of structural and soft-magnetic properties on film thickness was investigated. It was found that all the thin films were amorphous-like and the thin films with a thickness of about 110 nm or less showed evident in-plane uniaxial magnetic anisotropy, while increasing film thickness resulted in isotropic magnetic properties. Fe-Co-Cr-N thin films with a thickness of 110 nm exhibited the most excellent soft-magnetic properties with coercivity of 4.0 Oe (318 A/m) and 2.9 Oe (230 A/m) in easy and hard axis respectively, saturation magnetization of 1.71 T (Wb/m~2) and in-plane magnetic anisotropy field of 15.5 Oe (1234 A/m). In order to further improve the high frequency characteristics of the film above, we investigated another thin film sample deposited in the same sputtering condition except that an additional static magnetic field of about 200 Oe (1.6 X 10~4 A/m) was applied to the surface of substrates.