Electronic structure of YNi 1− xCu xBC studied by X-ray emission and photoelectron spectroscopy

Abstract

Results of first measurements of X-ray emission spectra (Ni Lα, Cu Lα and B Kα) and X-ray photoelectron spectra (valence band and core levels) of YNi 1− x Cu x BC ( x = 0.1-0.55) are presented. It is found that Ni and Cu 3d-states have predominantly metallic character and provide the main contribution to the density of states at the Fermi level N( E f ). N( E f ) progressively increases with x and correlates well with the magnetic susceptibility measurements, accounting for the increase in T c with copper doping. In Ni 2p 3 2 XPS a low intensity high-energy satellite peak is found which can be attributed to two-hole bound states. Selective oxidation of Y-atoms is found under exposure of the freshly cleaved surface of YNi 0.6Cu 0.4BC to air.