Photophysical properties and Electronic structure of some rare earth based Perovskite Oxides

Perovskite oxides having the chemical formula RAlO3 (R =Eu, Pr), RGaO3 (R=Pr, Nd) and PrInO3 are synthesized by the sol‒gel method and SmAlO3, NdAlO3, R2LiRuO6 (R=Pr, Nd, Sm) have been synthesized by the solid state reaction method. Rietveld refinement of the room temperature X‒ray diffraction patterns of the materials have been performed to check the phase formation of the materials. Morphology of the sintered pellets is analyzed by using scanning electron microscopy. UV‒Vis spectroscopy is used to determine the band gap of the samples at room temperature. The electronic structure calculations of these compounds were initiated using the experimental lattice parameters obtained by the Rietveld refinement of the X-ray diffraction data of the synthesized samples. Two different density functional approaches, plane wave pseudo potential method and full potential linearized augmented plane wave method were used for the present study. The spin-polarized calculation has been carried out with on-site Coulomb potential U to consider the electron-electron correlation in the system. The X-ray photoemission (XP) spectroscopy study of these oxides have been performed over a wide energy range to verify the electronic structure calculations experimentally. The calculated total and partial density of states data are convoluted to explain the observed XP spectra in these materials. The electrical properties of these materials have also been studied by employing impedance spectroscopy at various temperature and frequency ranges.