Electronic Structure of LnFeO3 (Ln = Rare Earth) Compounds: XANES Analysis

Oxygen K-edge x-ray absorption spectra of LnFeO3 (Lm=Sm, Eu, Nd) have been measured and theoretical calculations of O K-XANES and partial O p-, Fe s- and Fe d density of states on the basis of full multiple scattering formalism in the real space have been made. Unoccupied O p-states are found to be hybridized with both Fe 3d and RE if states in the conduction band of LnFeO3 and there are some indications that unoccupied oxygen p-states interact with Fe 3rf not in simple manner of states admixture but in a specific resonance manner when localized d states push oxygen p states out of the energy interval where these d states are localized. It was found that the observed shift of O K-XANES pre-edge can be explained by the changes in a value of indirect exchange interaction

Properties of SiO2CuOx Films for Nitrogen Dioxide Detection

SiOxCuOythin films were prepared by the deposition on to the Si/SiO2substrates from the alcoholic solutions employing the sol-gel technique. The various analytic techniques were applied to characterize structure and properties of the films under study . The both X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) studies showed the presence CuO as well as CuO2phases and formation of a dual-oxide CuSiO3with the average crystallites sizes of 35-50 nm. The conductance of the films was rather sensitive to the presence of 1-20 ppm NO2concentration at the operating temperatures in the range of 20–200◦C.</jats:p