Prospects of swift heavy ion induced mixing across Pd/Si and Ni/Si interfaces from inelastic thermal spike model calculation

The sensitivity of materials towards swift heavy ion (SHI) irradiation, as determined by the widely accepted inelastic thermal spike (i-TS) model, has been found to be inaccurate in certain cases where predictably insensitive materials show SHI induced mixing (SHI mixing) across their interfaces. Conventionally, creation of SHI induced transient molten zones, not predictable in SHI insensitive materials, is largely believed to be the essential prerequisite for observing SHI mixing. In this work, prospects of 100 MeV Au ion induced mixing across Pd/Si and Ni/Si interfaces have been explored by examining whether molten state can be achieved according to the i-TS model calculations. Possibilities of melting in bulk Pd and Ni, and in the vicinity of Pd (20 nm)/Si and Ni (20 nm)/Si interfaces, have been investigated. The results indicate that although bulk Pd and Ni are SHI insensitive, melting is possible on both the sides of both the interfaces, and hence SHI mixing could occur in these two systems.