Effect of La concentration on phase formation, local structure and optical properties of Sr1-xLaxTiO3 nanoparticles

The objective of this paper is to give information about phase formation, local structure and optical characteristics measured of the Sr1-xLaxTiO3 (x = 0-0.10; SLTO) nanoparticles. These nanoparticles have been synthesized by microwave-assisted sol-gel auto combustion method. Experimentally, the structural information was gathered by using the X-ray diffractometer and showed a pure phase with cubic perovskite structure of all samples. As well, the crystallite size and particle size of the SLTO samples decreased as the La doping content increased. The micro-strain (varying between 0.63 x 10-3 and 1.48 x 10-3) produced in the samples through Williamson-hall plot. The optical properties were determined using UV-Vis spectrophotometer. The band gap (Eg) was determined for all samples to be 4.10 eV. The study of local structure was performed by utilizing the synchrotron radiation X-ray absorption near edge structure (XANES) technique. The analyses XANES spectra clearly showed that the oxidation state of Sr, La and Ti ions are +2, +3 and + 4, respectively. The clear agreement between measured and calculated XANES spectra was the strongest evidence of La atoms occupies A-site (Sr) in SrTiO3 structure.