NdNi4B and DyNi4B compounds studied by X-ray photoemission spectroscopy

The hexagonal NdNi4B and DyNi4B compounds were studied by X-ray photoemission spectroscopy. Both valence band and core level spectra were analyzed. A comparison of the valence bands showed that the Dy(4f) levels were well localized, whereas Nd(4f) levels overlapped strongly with the Ni(3d) peak below the Fermi level. The 3d5/2 and 3d3/2 bands of NdNi4B revealed additional satellites. The values of the 3d spin–orbit splitting ELS were equal to 22.8 eV for R=Nd and 38 eV for R=Dy. The coupling between the f-orbitals and the conduction states, Δ≈23 meV, was estimated for NdNi4B basing on the Gunnarsson–Schönhammer model.