The high-pressure structural phase transitions of sodium bismuth titanate
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Pamela A. Thomas
Abstract
The crystal structure of sodium bismuth titanate, Na0.5Bi0.5TiO3, as a function of pressure is reported. From a combination of neutron powder diffraction experiments using the instrument POLARIS at the ISIS pulsed neutron facility and synchrotron X-ray powder diffraction experiments at ID30 at ESRF, it is found that the rhombohedral ambient pressure perovskite structure (space group R3c on average) transforms to a lower-symmetry structure which has a strong resemblance to the CaTiO3 structure and is described by space group Pnma, at 40 kbar and above. A new refinement of earlier angle-dispersive neutron data collected at ambient pressure and temperature at D2B of the ILL, which gives Bi—O bond-lengths closer to the values suggested by subsequent EXAFS experiments, is also reported. This yields a model for disorder on the bismuth site within the ambient-pressure phase, average symmetry R3c, with locally triclinic displacements of the Bi atom off the (pseudocubic) [111] direction along the (pseudocubic) [10-1] direction.
© by Oldenbourg Wissenschaftsverlag, München
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Articles in the same Issue
- Phase Transitions
- Structural phase transitions in two-dimensional systems: Pb/Ge(111) and Sn/Ge(111)
- Theoretical approach to reconstructive and morphotropic phase transitions
- Surface relaxations at mineral surfaces
- Methods for pseudosymmetry evaluation: a comparison between the atomic displacements and electron density approaches
- Revised prediction of B1 to B2 phase transition pressures in YbN, YbP and YbAs
- Crossover from classical to 3d-Ising critical behaviour near the antiferrodistortive phase transition of lawsonite
- CaZrGeO5 and the triclinic instability of the titanite structure type
- The high-pressure structural phase transitions of sodium bismuth titanate
- Ferroelastic phase transitions and domain structures in powders
- Phase transitions in BaTiO3: a high-pressure neutron diffraction study
- Nanoscale phase transformations in relaxor-ferroelectric lead scandium tantalate and lead scandium niobate
- On the nanostructure of radiation-amorphized zircon and pyrochlores: a small-angle x-ray scattering study
