Study of the diffusion of Ni into amorphous Ni₅₀Zr₅₀ and the resulting strain formation

Abstract

A set of multilayers of Ni/amorphous Ni₅₀Zr₅₀ of various periodicities was deposited using dc planar magnetron sputtering. The diffusion of Ni into the amorphous phase and the strain build-up in the Ni layers were measured in situ from the reduction and shift in Bragg peak intensity and angle respectively. For short periodicities, a lowered interdiffusivity was observed in agreement with other earlier experimental observations and theoretical predictions of stress effects in some amorphous multilayers with a high viscosity. Furthermore, direct evidence of stress formation owing to an unbalanced diffusional flow of the two species in Ni-Zr was obtained. These findings give further support for Stephenson's theory for lowered interdiffusion due to restricted stress relaxation in amorphous alloys.