Relationship between Interfacial Strain and the Elastic Response of Multilayer Metal Films

Abstract

We have investigated the structural and elastic properties of three distinct multilayer systems: Mo/Ni, Pt/Ni, and Ti/Ni. We demonstrate that the commonly observed lattice expansion perpendicular to the film plane is not a bulk effect, but is localized at the interface between the contacting metals. Incorporating the measured interfacial expansion into a universal binding relation, we show that the measured elastic softening versus compositional-repeat distance can result from the interfacial strain.