Polarized XAS studies of ternary nickel oxides

High magnetic ordering temperature in the perovskites Sr4−La Fe3ReO12 (x=0.0, 1.0, 2.0)

“…The notion of a pure integral valence state for the transition metals in such solid state compounds is a first step simplified approximation. Cluster model interpretations of 3d row compounds invariably involve superpositions of different d-occupancy configurations [46,47]. In the case of a 5d-row compound (e.g., like Re) the spatial extent and band width of the 5d-orbitals further reduces the validity of the integral valence approximation.…”

Reversible changes of epitaxial thin films from perovskite LaNiO3 to infinite-layer structure LaNiO2

“…The Ni K absorption edge energy of LaNiO 3 was 8348 eV, which agrees with the reported values for octahedrally coordinated Ni 3+ ions in oxides. 12 The absorption edge energy of the LaNiO 2 thin film, on the other hand, was about 2.0 eV lower than that of the LaNiO 3 thin film. This significant chemical shift implies that the oxidation state of Ni ions was reduced through the reduction process.…”

Electronic, Magnetic, and Magnetoresistance Properties of the n=2 Ruddlesden–Popper Phases Sr3Fe2−xCoxO7−δ (0.25≤x≤1.75)

“…6, the 4p feature is clearly split into at least two features, B 1 (d 10 L, where the L denotes an O-ligand hole), and B 2 (d 9 ). Within the cluster model interpretation, these features arise from the mixing of these two d-configurations due to Cu-O covalency (25,26 Fig. 8 (bottom …”