Contrasting Structural Behavior in the Aurivillius Phase Ferroelectrics Bi4Ti3O12, BaBi4Ti4O 15 and Ba2Bi4Ti4O18

Philip Lightfoot*, Alan Snedden, Susan M. Blake, Kevin S. Knight

*Corresponding author for this work

Research output: Contribution to conferencePaperpeer-review

13 Citations (Scopus)

Abstract

The crystal structures of the Aurivillius phase ferroelectrics Bi 4Ti3O12 BaBi4Ti4O 15 and Ba2Bi4Ti5O15, containing perovskite-like layers consisting of three, four and five adjacent TiO6 octahedra, respectively, have been analysed using high-resolution powder neutron diffraction data. At 2K the structure of Bi 4Ti3O12 can be successfully modelled in the orthorhombic space group B2cb, with no evidence of the monoclinic distortion in the ferroelectric phase suggested by previous single crystal studies. At 298K BaBi4Ti4O15 shows a subtle orthorhombic distortion, but without the octahedral tilting seen in related ferroelectric phases, and is refined in space group F2mm. At 298 K. Ba2Bi 4Ti5O18 adopts a tetragonal polar phase (I4mm), thus displaying a third type of polar distortion within this family. It is suggested that these differences arise from a 'tolerance factor' type mechanism whereby the increasing content of the large Ba2+ cation causes a shift from underbonding at the perovskite A-site to underbonding at the perovskite B-site resulting in a change in the mechanism of ferroelectricity from A-site displacements to B-site displacements, akin to the mechanism in BaTiO3.

Original languageEnglish
Pages89-96
Number of pages8
Publication statusPublished - 10 Nov 2003
EventSolid-State Chemistry of Inorganic Materials IV - Boston, MA, United States
Duration: 2 Dec 20026 Dec 2002

Conference

ConferenceSolid-State Chemistry of Inorganic Materials IV
Country/TerritoryUnited States
CityBoston, MA
Period2/12/026/12/02

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