Properties of Amorphous Iron-Metalloid Thin Films

Amorphous Fe-B, Fe-Si-B, Fe-B-C and Fe-Si-C films 0.6 to 0.9 µm thick were prepared by the r.f. sputtering technique. The metalloid content in the films was varied in the range 10 to 30 atm.% and the soft magnetic properties and thermal stabilities were investigated. In the as-prepared state, most of the amorphous films had coercivities of less than 1 Oe. On annealing in a magnetic field, the coercivity of Fe 80 B 20 and Fe 73 Si 18 C 9 films decreased to 0.04 Oe. The anisotropy energy induced by the field annealing at 300°C is 3 to 5×10 3 erg/cm 3 , which is much larger than those of melt-quenched alloys. In thermal stability, Fe-B, Fe-B-C and Fe-Si-B films are nearly the same as or slightly worse than corresponding melt-quenched alloys, while Fe-Si-C films, which have not yet been prepared in ribbon form, have good thermal stability and continue to exhibit low coercivity after annealing at 400°C.