Dependence of the Magnetization on the Layer Thickness in Compositionally Modulated Fe/Y Thin Films

Compositionally modulated thin films of Fe and Y--which normally form an amorphous alloy--were fabricated to investigate the variation in magnetism with the thickness of each layer. It was found that magnetization disappeared at dFe ¿2.4 Å, corresponding to a Fe0.4 Y0.6 composition alloy, agreeing with an Fe-Y amorphous alloy critical composition. When 6 Å ¿ dFe ¿ 12 Å, Mo was almost constant with respect to dFe. The central region of the Fe layer was composed of pure Fe but had reduced magnetization. This structure is peculiar to compositionally modulated films.