XPS study of the YST ceramics

Yttrium-doped strontium titanate  was prepared via conventional solid-state reaction method from Y2O3 (Sigma Aldrich, 99,9%), TiO2 (Sigma Aldrich, 99%) and SrCO3 (Sigma Aldrich,98%). For comparision, two other techniques were used for synthesis: Pechini and wet methods. Both kind of samples were measured, after and before reduction process (in a hydrogen). Chemical composition of manufactured samples was measured by XPS method. XPS analyses were carried out with X-ray photoelectron spectrometer (Omicron NanoTechnology) with 128-channel collector. XPS measurements were performed at room temperature in a ultra-high vacuum conditions, below 1.1 x10-8 mBar. The photoelectrons were excited by an Mg-Ka X-Ray source. The X-ray anode was operated at 15 keV and 300 W. Omicron Argus hemispherical electron analyser with round aperture of 4 mm was used for analysing of emitted photoelectrons. The binding energies were corrected using the background C1s line (285.0 eV). XPS spectra were analysed with Casa-XPS software using a Shirley background subtraction and Gaussian–Lorentzian curve as a fitting algorithm.