Interfacial Structure in Silver-Nickel Superlattices

Abstract

Silver-nickel multilayers have been prepared by cathodic sputtering on glass, silicon and carbon-covered mica substrates kept at 100 K. X-ray diffraction experiments show that highly textured, polycrystalline superlattices are formed. There exists a critical number of atomic planes n c = 3, below which non-crystalline samples are obtained. This critical number can even be lowered in samples with non-equal numbers of Ag and Ni atomic planes. The simulation of the X-ray spectra assuming sharp interfaces and Ag and Ni (111) distances slightly larger than the bulk values leads to a good agreement with the experimental spectra. Transmission x-ray and electron diffraction experiments show that equivalent crystallographic directions are aligned in the Ag and Ni (111) planes, with a noticeable relaxation of the in-plane distances at the interfaces. Preliminary high-resolution electron microscopy results are also presented.