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Neutron Rietveld Analysis of Anion and Cation Disorder in the Fast-Ion Conducting Pyrochlore System Y2(ZrxTi1−x)2O7

Published online by Cambridge University Press:  21 February 2011

Sossina M. Haile
Affiliation:
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
B. J. Wuensch
Affiliation:
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
E. Prince
Affiliation:
Reactor Radiation Division, National Institute of Standards and Technology, Gaithersburg, MD 20899
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Abstract

All information on the site occupancies and atomic displacements which relate a pyrochlore superstructure to the parent fluorite-type subcell is contained in the normally-weak superstructure diffraction intensities. As Ti has a negative scattering length, the supercell maxima in the present phases are up to three times as intense as the fluorite-like reflections, and neutron diffraction provides an especially sensitive probe of the state of disorder. Y2Ti2O7 is found to have a fullyordered anion array and slight disorder, Y0.984Ti0.015, among the cations. In Y2(Zro.6TiO.4)2O7 the oxygen site normally vacant in pyrochlore is half filled and on the order of 15% exchange between cation sites has occurred.

Type
Research Article
Copyright
Copyright © Materials Research Society 1990

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References

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