Hetero-amorphous Fe-Co-B-C soft magnetic thin films with uniaxial magnetic anisotropy and large magnetostriction

Hetero-amorphous (Fe/sub 0.75/Co/sub 0.25/)/sub 1-x/(B/sub 1-y/C/sub y/)/sub x/ films have been obtained by RF magnetron sputtering. Magnetic properties strongly depended on the hetero-amorphous substructure of the films. The film with a fine substructure less than 10 nm in mean diameter exhibited low coercive force of 40 A/m along the hard axis, large spontaneous magnetization of 1.6 T, and in-plane anisotropy field of 1.2 kA/m induced by field-annealing although the film had a large magnetostriction constant of 39/spl times/10/sup -6/.