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 d
_Fe
≳2.4 Å, corresponding to a Fe
_0.4
Y
_0.6
composition alloy, agreeing with an Fe-Y amorphous alloy critical composition. When 6 Å ≳ d
_Fe
≳ 12 Å, M
_o
was almost constant with respect to d
_Fe
. The central region of the Fe layer was composed of pure Fe but had reduced magnetization. This structure is peculiar to compositionally modulated films.