Structural, optical and impedance spectroscopic characterizations of RE2Zr2O7 (RE = La, Y) ceramics

Nanocrystalline RE2Zr2O7 (RE = La, Y) ceramics with cubic pyrochlore and defect fluorite structure are prepared through the modified combustion technique. The structure and symmetry of the nanoparticles are investigated using X-ray diffraction and vibrational analysis. The particulate properties investigated through TEM analysis are in good agreement with XRD results. The optical properties are studied using the UV-visible and photoluminescent spectroscopy. The prepared samples are sintered by adding 1.6 wt% of ZnO or Ce2O3. The impedance spectroscopic studies show that oxygen vacancies play an important role in ionic conduction of these structures. Number of mobile oxide ions and conductivity are increased by ZnO addition whereas decreased by Ce2O3 addition. The high ionic conductivity values suggest that these materials are useful for electrolytes in intermediate temperature solid oxide fuel cells (IT-SOFC).