α-Pbo2-related phase appearing in the SnIV-Ta-O system transformed from cation-ordered fluorite-related phase

Masao Kita, Takahisa Omata, Shinya Otsuka-Yao-Matsuo, Motomi Katada

Research output: Contribution to journalArticlepeer-review

Abstract

The cation-ordered α-PbO2-related SnIV0.82(Ta0.94SnIV0.06)O 4.11 phase, which is a triclinic or monoclinic system with lattice parameters of a = 0.769 nm, b = 0.947 nm, c = 0.769 nm, α = 90°, β = 96.34° and γ = 90°, was synthesized by annealing of the cation-ordered fluorite-related SnIV0.82(Ta0.94SnIV0.06)O4.11 phase at 973 ≤ T ≤ 1073K in O2; the cation-ordered fluorite-related phase was prepared by the oxidation of the SnII1.64(Ta1.88SnIV0.12)O6.58 pyrochlore. The SnIV and [0.94Ta + 0.06SnIV] were respectively ordered similar to that of SnII and [0.94Ta + 0.06SnIV] as observed in the precursor pyrochlore phase. The superlattice diffraction due to the cation-ordering did not appear in its XRD because of the high density of the anti-phase domain boundaries parallel to {101} direction. The transformation temperature from the fluorite-related form to the α-PbO2-related form for the SnIV0.82(Ta0.94SnIV0.06)O4.11 was approximately 250K higher than that observed for the previous SnIV0.81(Nb0.93SnIV0.07) O4.085. The difference in the transformation behavior starting from the precursor pyrochlore phase between the present Sn-Ta-O and the previous SnNbO systems was discussed on the basis of the characteristics of the Ta- and Nb-ions.

Original languageEnglish
Pages (from-to)902-907
Number of pages6
JournalJournal of the Ceramic Society of Japan
Volume122
Issue number1430
DOIs
Publication statusPublished - 2014 Oct 1

Keywords

  • Cation-ordered structure
  • Fluorite structure
  • Metastable phase
  • Phase transformation
  • Tin niobate
  • Tin tantalate
  • α-PbO structure

ASJC Scopus subject areas

  • Ceramics and Composites
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry

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