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Neutron Powder Diffraction Studies of Fluorite and Pyrochlore Nd x Zr 1−x O 2−x/2 Solid Solutions with 0.25<x<0.55
Author(s) -
Van Dijk T.,
Helmholdt R. B.,
Burggraaf A. J.
Publication year - 1980
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221010239
Subject(s) - pyrochlore , stoichiometry , fluorite , neutron diffraction , phase (matter) , materials science , crystallography , x ray crystallography , solid solution , analytical chemistry (journal) , diffraction , crystal structure , chemistry , metallurgy , physics , optics , organic chemistry , chromatography
Neutron powder diffraction studies on stoichiometric and non‐stoichiometric pyrochlore phases of the ZrO 2 ‐ Nd 2 O 3 system show remarkable differences in the occupation factor of the 8b site of space group Fd3m to which the pyrochlore phase belongs. Stoichiometric Nd 2 Zr 2 O 7 can be described as a perfect pyrochlore phase in which the 8b site is either vacant or at least has a low occupation factor. The occupation factors of the 8b sites of non‐stoichiometric Nd x Zr 1−x O 2−x/2 pyrochlores reveal that these contain a large degree of disorder in the anion sublattice. Best refinement results on non‐stoichiometric materials are achieved when the overall structure of the non‐stoichiometric pyrochlore phase is described as a hybrid phase consisting of a major volume fraction of the stoichiometric pyrochlore phase and a minor fraction of the defect fluorite phase.