The pyrochlore to defect fluorite phase transition in Y2Sn2-xZrxO7

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dc.contributor.authorde los Reyes, Men_AU
dc.contributor.authorWhittle, KRen_AU
dc.contributor.authorZhang, ZMen_AU
dc.contributor.authorAshbrook, SEen_AU
dc.contributor.authorMitchell, MRen_AU
dc.contributor.authorJang, LYen_AU
dc.contributor.authorLumpkin, GRen_AU
dc.date.accessioned2015-09-29T02:14:22Zen_AU
dc.date.available2015-09-29T02:14:22Zen_AU
dc.date.issued2013-01-30en_AU
dc.date.statistics2015-09-18en_AU
dc.description.abstractThe system Y2Sn2−xZrxO7 (0.0 ≤ x ≤ 2.0) undergoes a phase transformation from ordered pyrochlore (Fdm) to defect fluorite (Fmm) actuated by the substitution of Zr for Sn. X-ray diffraction patterns map the retention of the pyrochlore structure up to x = 1.2. For samples with x = 1.4–2.0 the structure can be described as defect fluorite in broad terms. Electron diffraction patterns are consistent with this interpretation; however, they also demonstrate that the defect fluorite phase exhibits a strain driven compositional/displacive modulation that changes gradually with increasing Zr content. Raman spectra are consistent with gradual anion disorder up to x = 1.0 and highly disordered anion distributions inferred for x > 1.4, but the spectra also suggest the presence of residual order due to the modulated structure. The phase transformation in this system occurs at a higher Zr content than predicted by classical radius ratio models, consistent with the covalent character of Sn–O bonding. An unusual finding of this work comes from 119Sn MAS NMR and Sn L3-edge XANES analyses, indicating that Sn4+ prefers to occupy lattice sites with a 6-fold local coordination environment throughout the series. These results suggest that the incorporation of Sn or other metal cations having significant covalent bonding or a strong preference for octahedral coordination in pyrochlore-based materials may have a detrimental effect on ionic conductivity. © 2013, The Royal Society of Chemistry.en_AU
dc.identifier.citationde los Reyes, M., Whittle, K. R., Zhang, Z., Ashbrook, S. E., Mitchell, M. R., Jang, L.-Y., & Lumpkin, G. R. (2013). The pyrochlore to defect fluorite phase transition in Y2Sn2-xZrxO7. RSC Advances, 3(15), 5090-5099. doi:10.1039/c3ra22704aen_AU
dc.identifier.govdoc6092en_AU
dc.identifier.issn2046-2069en_AU
dc.identifier.issue15en_AU
dc.identifier.journaltitleRSC Advancesen_AU
dc.identifier.pagination5090-5099en_AU
dc.identifier.urihttp://dx.doi.org/10.1039/c3ra22704aen_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/6244en_AU
dc.identifier.volume3en_AU
dc.language.isoenen_AU
dc.publisherRoyal Society of Chemistryen_AU
dc.subjectPyrochloreen_AU
dc.subjectX-ray diffractionen_AU
dc.subjectElectron diffractionen_AU
dc.subjectRaman spectraen_AU
dc.subjectCationsen_AU
dc.subjectIonic conductivityen_AU
dc.subjectFluoriteen_AU
dc.subjectZirconiumen_AU
dc.subjectPhase transformationsen_AU
dc.subjectAnionsen_AU
dc.titleThe pyrochlore to defect fluorite phase transition in Y2Sn2-xZrxO7en_AU
dc.typeJournal Articleen_AU
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