Study of interdiffusion of Ni/Fe layers by Auger Sputter profiling

Bulk and grain boundary diffusion of Fe into Ni films has been studied under UHV in the temperature range of ?150 to 500°C using AES and sputter profiling methods. The concentration profiles at the interface are corrected for the various broadening and damage effects inherent in ion bombardment. Grain boundary diffusion coefficients are derived on the basis of the Whipple model. The measured activation energies are 46 $\text{kcal}\text{mole}$ for bulk diffusion and 34 $\text{kcal}\text{mole}$ for grain boundary diffusion. An additional migration phenomenon not previously resolved is observed for very thin films annealed at relatively low temperatures (150–250°C). A possible mechanism involved in this initial “interface healing” is discussed.