Magnetic properties of compositionally modulated nitride amorphous alloy films

Superstructured Co-based amorphous alloy films comprising non-nitride and nitride layers are prepared by sputtering alternatingly in Ar and in N
2
mixed Ar gas. The layered structure changes into compositionally modulated structure by high temperature annealing above 400°C. The films with modulation wave length λ < 600 Å show appreciable soft magnetic properties. The saturation magnetization, Curie temperature and crystallization temperature increase by nitriding. The obtained compositionally modulated films mainly composed of Co-Nb-N are found to have high saturation magnetization (
4\piM_{s} \approx 10,000
G) as well as high permeability (
\mui \geq 1,000
at 10 MHz) and show high thermal stability even up to 580°C, which was impossible to attain for conventional amorphous films.