Hard and soft X-ray photoemission spectroscopies of ferromagnetic Sm 4As 3

Abstract

We have investigated the bulk and surface electronic structures of Sm 4As 3 by using hard and soft X-ray photoemission spectroscopies (PESs). The valence band spectral shape changes much with photon energies ( h ν s) due to the variation of both photoionization cross sections and bulk sensitivity. PES with the wide range of h ν s between 220 and 2450 eV demonstrates that the valence of the Sm ions is definitely trivalent in the bulk and divalent at the surface.