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Resonant soft X-ray scattering spectra of a La[sub 0.5]Ca[sub 0.5]MnO[sub 3] thin film were measured at varying energies of the incident photon beam across Mn 2p thresholds. The data are analyzed within the framework of the Anderson impurity model and full multiplet theory. The scattering profiles of the film are reasonably well reproduced by model calculations for the Mn[sup 3+] system, in contrast to the absorption spectrum at the Mn L[sub 2,3] edge for which the contribution of the Mn[sup 4+] sublattice is required to be taken into account. The obtained agreement between calculations and experiment indicates that in this case resonant inelastic scattering mainly probes the local electronic structure at the Mn[sup 3+] sites in the La[sub 0.5]Ca[sub 0.5]MnO[sub 3] film. In turn, Mn[sup 4+] sites mainly contribute to ordinary L[sub α,β] X-ray emission due to relaxations in the intermediate state of the spectroscopic process. Such a situation can occur when the system favors a phase separation rather than checkerboard charge ordering of Mn[sup 3+] and Mn[sup 4+] sites. [ABSTRACT FROM AUTHOR]

Abstract: Resonant ultra-soft X-ray scattering measurements performed on NiO, as a model system, and NdNiO3 reveal the presence of pronounced inelastic structures within a few eV below the elastic peak in both cases. A comparison of experimental data with the results of Anderson impurity model calculations indicates that for both oxides the inelastic part of recorded spectra mainly originates from the intra-atomic d–d excitations. Remarkably, no distinct signal from inter-site d–d transitions can be identified for both metallic and insulating NdNiO3 at small energy-losses. The lack of significant spectral contribution from the latter transitions in this compound indicates that states on the top (bottom) of the valence (conduction) band have predominantly O 2p character and the NdNiO3 insulator is rather of a p–p type. [Copyright &y& Elsevier]