Magnetic properties of Fe-Co-M(M:Mn,V) films by ion beam sputtering

The changes in the soft magnetic properties of ion beam sputtered films of Fe-Co alloy with substitution of Mn or V have been investigated. Thin films deposited at a substrate temperature Ts as low as 70°C have high coercive force Hc above 150 Oe and large perpendicular magnetic anisotropy mainly induced by internal stress. On the other hand, the perpendicular magnetic anisotropy and Hc decrease with increase of Ts. The anisotropy disappears in the Fe-Co-M(M:Mn,V) alloy films deposited at Ts above 250°C, which results in the improvement of soft magnetic properties, although the minimum Hc attained in this work is 16 Oe. This value is larger than that for Fe-Co binary alloy films. The perpendicular magnetic anisotropy and Hc of the films are decreased by an annealing in a vacuum, though their soft magnetic properties are not sufficiently low to use as the soft magnetic layer in the thin film type of head. As a result, it seems that the substitution of Mn or V is not effective to improve the soft magnetic properties of Fe-Co alloy films.