Preparation, characterization, and conductivity of YLnTiZrO (Ln = La, Nd, Sm, and Eu).

The pyrochlore oxide of composition YLnTiZrO (Ln = La, Nd, Sm, and Eu) was prepared by sol-gel method. All the samples were characterized by powder X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), diffused reflectance spectroscopy, and impedance spectroscopy. The powder XRD and Raman studies reveal that these samples were crystallized in cubic lattice with pyrochlore structure. The Rietveld analysis of the samples was carried out to obtain the unit cell parameters and reliability factors. The broad Raman bands observed for all the samples are due to cation/anion disorder in the lattice and nanosize. The XPS analysis of the samples shows the characteristic peaks belonging to Y, Ln (Ln = La, Nd, Sm, and Eu), Ti, and Zr. Electrical conductivity of YLaTiZrO (YLTZ) and YEuTiZrO (YETZ) samples was calculated from the impedance as a function of frequency and temperature. These samples have shown conductivity of the order of 10 scm at 500 °C. [ABSTRACT FROM AUTHOR]