Electronic structures of SrMn1–xMoxO3 (≤x≤.75) perovskite oxides investigated by XAS and PES

Abstract

Electronic structures of perovskite oxides of SrMn1-xMoxO3 (0 ≤x≤ 0.75) have been investigated by employing soft x-ray absorption spectroscopy (XAS) and photoemission spectroscopy (PES). It is found that the valence states of Mn ions change systematically from Mn4+ for x = 0, to nearly Mn3+ for x = 0.3, and Mn2+ for x = 0.5, and then remain as Mn2+ for x≥0.5. Both the Mo 3d core-level PES and Mo 3p XAS spectra show that the valence states of Mo ions remain unchanged as being hexavalent (Mo6+) for x≤0.5 but that they decrease for x>0.5 with increasing x. This study shows that Mo ions are mixed-valent for x>0.5 in SrMn1-xMoxO3, either with the Mo4+–Mo6+ configuration or with the Mo4+–Mo5+–Mo6+ configuration.