Studies with Ni/Ti multilayer films using X-ray photoelectron spectroscopy and neutron reflectometry: microscopic characterization of structure and chemical composition

X-ray photoelectron spectroscopy (XPS) and neutron reflectometry (NR) have been performed on Ni/Ti multilayer films, deposited by electron beam evaporation, under ultra high vacuum. Chemical composition of the layers has been obtained from XPS analysis. The layer thicknesses and densities have been obtained within few angstroms from NR. Impurities were detected in the film in the form of carbides and oxides in the Ti layers and in elemental form in the Ni layers. From an in situ XPS experiment on a Ti film with Ni overlayer we found that impurities get incorporated in the film during deposition.