Sol-Gel Production and XPS Study of Sodium-Vanadium Oxide Bronze β-Phase

A β-phase of sodium-vanadium oxide bronze thin film has been synthesized by using sol-gel technology from $V_2O_5$ and $Na_2SO_4$. The powders of these materials in suitable proportion were dissolved in hydrogen peroxide and heated up to 350 K for the dissociation of peroxide complexes. The obtained gel was deposited onto a metallic substrate and dried in air at room temperature. The produced xerogel was heated up to 580 K in air atmosphere for the removal of water from xerogel. Starting materials, xerogel, as well as a final product were investigated by means of X-ray photoelectron spectroscopy method. X-ray photoelectron spectra testify that the chemical bonds of vanadium, oxygen and sodium in the bronze differ from the similar bonds in the starting materials. The sulphur presence was detected in the xerogel but not in the final bronze composition

The surface hydro-oxidation of LaNiO3−xLaNiO_{3-x} thin films

The high-energy X-ray photoelectron spectroscopy was used to determine the composition and chemical structure of epitaxial LaNiO$\text{}_{3-x}$ films obtained by a reactive dc magnetron sputtering. It was found that the oxide and hydroxide species of La and Ni are on the films surface. The thickness of hydroxide enriched layer, estimated from the oxide and hydroxide peak intensities, is about 2 nm

Valence states of metal ions in La0.7Ce0.3MnO3La_{0.7}Ce_{0.3}MnO_{3} thin films

We report valence states of ions in $La_{0.7}Ce_{0.3}MnO_3$ thin films grown by a reactive dc magnetron sputtering. The measurements were performed by means of high-energy X-ray photoelectron spectroscopy using synchrotron radiation. It was found that Ce ion in the compound is either in tetravalent or trivalent chemical state, manganese is in divalent, trivalent and tetravalent states, while La ion existing in oxide and hydroxide chemical species is in trivalent state