Valence states of transition-metal ions in cubic perovskites SrMn1−xFexO3

Abstract

The electronic structures of SrMn1−xFexO3 (0⩽x⩽1) have been investigated by using photoemission spectroscopy (PES) and soft x-ray absorption spectroscopy (XAS). Mn ions in SrMnO3 are found to be in the nearly tetravalent (Mn4+) states, but with a small mixture of the Mn2+ configuration. With increasing x in SrMn1−xFexO3, Mn ions remain in the 4+ states. Fe ions in SrMn1−xFexO3 are also in the nearly tetravalent (Fe4+) states for the whole range of x. Valence-band PES reveals that the occupied Mn t2g3 states are located about 2.5eV below EF, while the occupied Fe t2g3eg1 states are broader than the Mn 3d occupied states, and are located between 3 and 6eV below EF. The large overlap between Fe 3d and the O 2p states is found in SrFeO3, reflecting the strong hybridization between the Fe 3d states and the O 2p states, in agreement with the metallic nature of SrFeO3.