Core level spectra of disordered Cu-Ni alloys

We investigate the core levels of Cu1-xNix (x=0, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0) alloys using high resolution photoemission spectroscopy. The Cu 2p core level exhibits a gradual shift to lower binding energy with increase in Ni concentration. The maximum core level shift (CLS) observed for x=0.9 is about 0.35 eV. The observed CLS show a linear dependence on Ni concentration and are in qualitative agreement with the non-magnetic calculations performed on Cu-Ni alloy system under complete screening picture by Olovsson et. al.