Formation and Evolution of Local and Crystalline Structure of Tb2O3-HfO2 Compounds

The process of Tb2Hf2O7 nanocrystals formation upon calcinations up to 1600 °C has been investigated by means of X-ray absorption fine structure (XAFS) spectroscopy combined with X-ray diffraction (XRD) and analysis of pair distribution function (PDF). The structure ordering and the growth of nanocrystals upon calcination were estimated independently from XRD patterns and PDF. The probable content of Tb4+ cations in Tb2Hf2O7 was estimated from XANES. All studies indicate a high disorder and a large number of local structure defects in Tb2Hf2O7 pyrochlore structure.