The electronic and magnetic properties of the colossal magneto resistance (CMR) compound Sr2FeMoO6 have been studied using different experimental techniques, namely X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and X‐ray absorption spectroscopy (XAS). Furthermore, the magnetic properties have been studied in the temperature range of 4.2 K–800 K. The data confirm a highly ordered double perovskite crystal structure and is consistent with the tetragonal structure with 14/mmm symmetry. The Fe L edge has been probed by means of XAS, and comparison with results for a series of other iron oxides reveals a mixed valence state of Fe2+ and Fe3+. XPS of the Mo 3d and Fe 3s core levels confirms this point of view indicating a mixed valence state involving around 30% Fe3+–Mo5+ and 70% Fe2+–Mo6+ states, in good agreement with paramagnetic measurements which suggest 60% Fe2+ ions. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Possible modification of the structure of poly(acrylic) acid (PAA) membranes doped with graphite was investigated by UV-Vis and XRD techniques. The pure PAA membranes were characterized by good transparency in the domain 250-700 nm, with maximum absorption at 207 nm. The absorbance of membranes increased significantly after doping with graphite. The XRD patterns of pure membranes showed a low degree of order of the polymeric matrix.Some modifications of the parameters of the ordered domains of the polymer and of the graphite appeared at high concentrations of the dopant.

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The magnetic and x-ray photoelectron spectroscopy (XPS) studies on the transition metal substituted, dimeric polyoxotungstate [Fe4(H2O)10(β-SbW9O33)2]6− are reported. The magnetic data were analyzed by using an isotropic Heisenberg Hamiltonian. The ground state of the frustrated molecule has a total spin of S=2. The XPS Fe 2p spectra suggest a 2+ formal valence state. The deviation from the contained Fe3+ ions can be explained by charge-transfer effects.

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