We report a comparative study of Ln 2 M 2 O 7 (Ln = Gd, Tb, Dy; M = Ti, Zr) synthesized by combination of the sol-gel and coprecipitation methods followed by calcination at elevated temperatures. The long-range average crystal as well as short-range local structure in the samples were analyzed using X-ray diffraction, X-ray absorption spectroscopy (XAFS) and Raman spectroscopy. It has been found that Ln-Ti precursors crystallize directly to pyrochlore phase, whereas crystallization of Ln-Zr precursors to pyrochlore phase goes through intermediate fluorite phase. We have shown that X-ray absorption data make possible to detect the crystallization and phase transition features in Ln 2 M 2 O 7 such as splitting of Ln-O coordination shells and changes of the symmetry in local environment.
Popov V.V., Menushenkov A.P., Ivanov A.A., Gaynanov B.R., Yastrebtsev A.A., d'Acapito F., et al. (2019). Comparative analysis of long- and short-range structures features in titanates Ln 2 Ti 2 O 7 and zirconates Ln 2 Zr 2 O 7 (Ln = Gd, Tb, Dy) upon the crystallization process. JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS, 130, 144-153 [10.1016/j.jpcs.2019.02.019].
Comparative analysis of long- and short-range structures features in titanates Ln 2 Ti 2 O 7 and zirconates Ln 2 Zr 2 O 7 (Ln = Gd, Tb, Dy) upon the crystallization process
Puri A.;
2019
Abstract
We report a comparative study of Ln 2 M 2 O 7 (Ln = Gd, Tb, Dy; M = Ti, Zr) synthesized by combination of the sol-gel and coprecipitation methods followed by calcination at elevated temperatures. The long-range average crystal as well as short-range local structure in the samples were analyzed using X-ray diffraction, X-ray absorption spectroscopy (XAFS) and Raman spectroscopy. It has been found that Ln-Ti precursors crystallize directly to pyrochlore phase, whereas crystallization of Ln-Zr precursors to pyrochlore phase goes through intermediate fluorite phase. We have shown that X-ray absorption data make possible to detect the crystallization and phase transition features in Ln 2 M 2 O 7 such as splitting of Ln-O coordination shells and changes of the symmetry in local environment.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
