Unusual High-Temperature Structural Behaviour in Ferroelectric Bi2WO6

N.A. McDowell, K.S. Knight, Philip Lightfoot

Research output: Contribution to journalArticlepeer-review

134 Citations (Scopus)

Abstract

The crystal structure of Aurivillius phase ferroelectric Bi2WO6 has been studied in detail as a function of temperature by using high-resolution powder neutron diffraction. In agreement with an earlier study, a transition from space group P2(1)ab to B2cb occurs at about 660 degrees C. This transition corresponds to the loss of one octahedral tilt mode within the perovskite-like WO4 layer of the structure. A second, reconstructive, phase transition occurs around 960 degrees C, corresponding to the ferroelectric Curie point; in contrast to previous suggestions, the structure of this high-temperature phase contains layers of stoichiometry WO4, with WO6 octahedra sharing edges and corners, and with the fluorite-like Bi2O2 layers remaining essentially unchanged. This structure is closely related to that of the ambient temperature phase of lanthanide-doped derivatives, for example, Bi0.7Yb1.3WO6 recently reported. This phase-transition behaviour is in stark contrast to that of other members of the Aurivillius family, such as SrBi2Ta2O9 and Bi4Ti3O12, which retain the archetypal Aurivillius connectivity at all temperatures.

Original languageEnglish
Pages (from-to)1493-1499
Number of pages7
JournalChemistry - A European Journal
Volume12
Issue number5
DOIs
Publication statusPublished - 1 Feb 2006

Keywords

  • bismuth oxide
  • ferroelectric
  • neutron diffraction
  • perovskite phases
  • phase transitions
  • tungsten
  • CRYSTAL-STRUCTURE
  • SOLID-SOLUTIONS
  • POLYMORPHISM
  • TUNGSTATE
  • BI4TI3O12

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