Interface reaction kinetics for permalloy-tantalum thin film couples

Thermal interdiffusion mechanisms and kinetics have been studied for Ta-Permalloy (Ni80Fe20), Ta-Ni and Ta-Fe thin film couples in the temperature range 300 °C - 600 °C. Interaction modes identified for the Ta-NiFe system include: fast diffusion of Ta into grain boundaries of NiFe, and nucleation and growth of Ni3Ta, with consequent depletion of Ni in the remaining NiFe, and eventual segregation of Fe.