Solid State Ionics, Vol.335, 32-37, 2019
Differences in local structures around zirconium atoms in Eu2Zr2O7 and La2Zr2O7
Extended X-ray absorption fine structure (EXAFS) analyses of the Eu2Zr2O7 and La(2)Zr(2)O(7 )pyrochlore composition oxides were performed to examine differences in the local structures around the Zr atoms. In the EXAFS analyses of Eu2Zr2O7, the amplitude reduction factor of Zr-16c-O-8a was considerably large, indicating that a part of the oxygen vacancy site (8a) was occupied by oxide ions. Furthermore, the occupancy of the 8a site determined by Rietveld refinement of the X-ray diffraction data for Eu2Zr2O7 was 0.32(2), which was consistent with the EXAFS results. From the EXAFS analyses of La2Zr2O7, oscillation in the high wavenumber k-range sharpened with decreasing temperature, and the mean square relative displacement (MSRD) values of the Zr-O peak in the R-space were small compared to those of Eu2Zr2O7. Therefore, the disorder in the local structures around the Zr atoms of La2Zr2O7 was determined to be smaller than that of Eu2Zr2O7.