Hard and soft X-ray spectroscopy of Sm-based heavy-fermion compounds SmFe4 P12 and SmOs4 Sb12

We have carried out soft and hard X-ray spectroscopy of Sm-based filled skutterudites SmFe 4 P 12 and SmOs 4 Sb 12 . Sm 3d–4f resonant photoemission and Sm 3d–4f X-ray absorption spectra suggest that SmOs 4 Sb 12 has much more strongly mixed Sm valence state than SmFe 4 P 12 in the bulk. On the other hand, the Sm trivalent state is dominant on the surface of SmOs 4 Sb 12 .