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We present a study of the electronic structure of oxygen-deficient ferrites SrFeO x (x = 2.46, 2.52, 2.68, and 2.82) by means of X-ray photoelectron, X-ray emission, and X-ray absorption spectroscopies. From the Fe 3s photoelectron splitting, the magnetic moments are estimated. It is found that the doped holes are localized in both Fe 3d and O 2p states. The valence band structure is analyzed. It is shown that the band gap decreases with the increase of oxygen concentration.

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The nearest-neighbor coordination and electronic structure in C:Ni(∼30 at.%) nanocomposite films grown by ion beam cosputtering in the temperature range of room temperatue (RT) to 500 °C are investigated by the means of extended X-ray absorption fine structure (EXAFS), X-ray absorption near-edge spectroscopy (XANES) and X-ray photoelectron spectroscopy (XPS). The obtained results are correlated with the composite nanostructure published elsewhere and magnetic properties determined by the means of X-ray magnetic circular dichroism (XMCD) and superconducting quantum interference device (SQUID) magnetometry. A combined use of EXAFS, XANES, and XPS shows that a carbidic Ni phase exhibiting only local atomic ordering is formed at low growth temperatures (e200 °C), while ordered carbidic Ni phase forms at ∼300 °C. Further increase in growth temperature results in the formation of face-centered cubic (fcc) Ni with a high degree of crystallinity. On the other hand, Ni incorporation strongly promotes the formation of carbon structures with the prominent peak in C K-edge XANES spectra positioned at 288.5 eV in the whole growth temperature range. The magnetic measurements show no magnetic response for the films grown at RT to 200 °C, superparamagnetic behavior for the film grown at 500 °C with >90% of the Ni atoms in metallic state, and a weak magnetic response for the film grown at 300 °C, indicating the presence of Ni-rich regions within carbon containing Ni nanoparticles with ∼3% of Ni atoms in metallic state.