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We investigate the electronic structures of hole-doped, La0.7Ca0.3MnO3, and electron-doped, La0.7Ce0.3MnO3, manganites by x-ray absorption near edge structure (XANES) spectroscopy at the O and Mn K-edges. While, the O K-edge XANES results indicate that Ca and Ce doping induce holes in O 2 p derived states, the Mn K-edge XANES do not give any evidence for creation of the Mn4+ (or Mn2+) ions by Ca (or Ce) dopants. Such results further questions the validity of double exchange mechanism in understanding the anomalous properties of manganites. [ABSTRACT FROM AUTHOR]

This work presents N, O K-edge x-ray absorption near-edge structure (XANES) and Ta L3-edge extended x-ray absorption fine structure (EXAFS) studies of amorphous Ta(N,O) films prepared with various flow rate ratios of N2/O2. The N and O K-edge XANES and Ta L3-edge EXAFS spectra demonstrate the presence of N2 molecules. These spectra also show that Ta(N,O) films have similar local atomic structure as that of Ta2O5. No evidence of the formation of Ta–N bond was obtained. The intensities of the π* feature in the N K-edge spectra and the features of O 2p–Ta 5d hybridized states were found to correlate with the residual stress and the refractive index, respectively. [ABSTRACT FROM AUTHOR]

The electronic structure and magnetic properties of Al-doped Fe3O4 films at various Al concentrations were investigated by Al and O K-edge x-ray absorption near-edge structure (XANES) and Fe L3,2-edge magnetic circular dichroism (MCD) measurements. The O K-edge XANES spectra reveal that the intensity of O 2p–Fe 3d hybridized states decreases linearly as the Al concentration increases, suggesting that nonmagnetic Al substitution reduces couplings of the O 2p with Fe 3d orbitals. The Fe L3-edge MCD spectra show that the intensities of MCD features decrease as the Al concentration increases, which suggests that Al substitution reduces the magnetic moments of Fe ions. The Fe L3,2 XANES spectra suggest the absence of mixed valence states in agreement with previous x-ray resonance scattering measurements. [ABSTRACT FROM AUTHOR]