The fluorite related modulated structures of the Gd{sub 2}(Zr{sub 2-x}Ce{sub x})O{sub 7} solid solution: An analogue for Pu disposition
- Immobilisation Science Laboratory, Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)
We present an overview of the Gd{sub 2}(Zr{sub 2-x}Ce{sub x})O{sub 7} phase diagram, of interest as a model system for ceramic disposition of Pu (with Ce as a Pu surrogate). The fluorite related structures of this solid solution were determined using a modulated structure approach, to identify the underlying cation and vacancy ordering mechanisms from analysis of key satellite reflections in selected zone axis electron diffraction patterns. This revealed the formation of four structure types: pyrochlore for x<0.25, defect fluorite for 0.51.50. X-ray absorption (XAS) and electron energy loss (EELS) spectra confirmed the presence of Ce{sup 4+} as the dominant species in compositions across this system, remaining analogous to Pu{sup 4+}. - Graphical abstract: Electron diffraction reveals the cation vacancy ordering mechanisms leading to fluorite related superstructures in the Gd{sub 2}(Zr{sub 2-x}Ce{sub x})O{sub 7} solid solution. Highlights: Black-Right-Pointing-Pointer The fluorite related solid solution Gd{sub 2}(Zr{sub 1-x}Ce{sub x})O{sub 7} was prepared by solid state synthesis. Black-Right-Pointing-Pointer Ce L{sub 3} edge XAS and Ce M{sub 4,5} EELS measurements show Ce substitutes as Ce{sup 4+}. Black-Right-Pointing-Pointer Cation and oxygen vacancy ordering results in four fluorite related structures.
- OSTI ID:
- 22012163
- Journal Information:
- Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Vol. . 191; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- United States
- Language:
- English
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