Computer simulation of the interface in Cu/Ni multilayer films

Abstract

X-ray diffraction of Cu/Ni (1 0 0) bicrystalline multilayer thin films was studied by atomistic simulation. Atomic position equilibrium was reached by using a molecular dynamics method to simulate interface structure with Morse potentials to model interatomic interactions. It was found that X-ray profiles were sensitive to the interface structure and some “extra” peaks appeared other than the regular peaks of copper or nickel crystals. The number of “extra” peaks increased with increasing modulation length of the multilayer. The “extra” peaks result from the diffraction between interfaces and also from the diffraction of the modulated structure. The variation of spacing normal to the interface could be described as a near-square wave. The interface region approximately includes five atomic layers for Cu/Ni (1 0 0) multilayer thin film when its modulation length is not too small. When the modulation length is small enough, the interface regions overlap, and the average atom potential energy is high.