XPS study of RNi₄B compounds, where R = Nd, Tb, Dy, Ho and Er

Abstract

The RNi4B compounds with R = Nd, Tb, Dy, Ho and Er crystallize in CeCo4B-type structure. XPS measurements were performed at room temperature. The Ni 2p(1/2) and Ni 2p(3/2) core level lines reproduce well those of pure nickel. In all samples, the presence of Ni 6 eV satellite line was shown. This indicates the presence of holes in Ni 3d band, in agreement with magnetic measurements. The R 4d core levels are similar to those evidenced in pure R metals. The 4f orbitals keep their localized character and therefore the XPS spectra show multiplet structures. The small energy shift of R4d and R4f core level lines, as compared to R metals, may be correlated with minor changes in shielding which result from modification of electron concentrations when compounds are formed.