The combined study of Dy sub(2)O sub(3)-HfO sub(2 ) nanocrystallites formation by means of EXAFS, PDF, XRD and SAXS

The process of double oxide Dy sub(2)O sub(3)-HfO sub(2 ) nano crystallites formation upon annealing to 1600[degrees]C was investigated with the combination of few X-ray and synchrotron methods. XRD and PDF show the mean crystal structure to be fluorite typical for the compounds of Ln sub(2)O sub(3)-MeO sub(2 ) type. The ordering of structure and the growth of nanocrystallites upon annealing was estimated independently from XRD patterns, PDF functions and SAXS scattering curves. Neither transition to pyrochlore phase, nor signs of recently shown in related Gd sub(2)O sub(3)-HfO sub(2 ) compounds pyrochlore-type superstructure is observed. However, EXAFS and the short range order of PDF clearly indicate the discrepancy between Dy and Hf local environment. Such a disorder of local crystal structure can not be described by the fluorite model.