Srikanth, V. ; Idink, H. ; White, W. B. ; Subbarao, E. C. ; Rajagopal, H. ; Sequeira, A. (1996) Cation disorder in ferroelectric PbBi2Nb2O9 Acta Crystallographica Section B, 52 . pp. 432-439. ISSN 0108-7681
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Official URL: http://scripts.iucr.org/cgi-bin/paper?br0024
Related URL: http://dx.doi.org/10.1107/S0108768195015072
Abstract
The ferroelectric Curie temperature, Tc, of PbBi2Nb2O9 was found to shift from 833 K in samples slowly cooled from 1373 K to Tc's up to 883 K when the samples were quenched from various temperatures in the range 973-1373 K. The variation of Tc with heat treatment was fully reversible. Extra Raman modes appear and the width of some Raman bands change as a function of heat treatment. These results are interpreted in terms of cation order-disorder involving the Pb2+ and Bi3+ ions in the perovskite units and the Bi2O2 layer. Neutron Rietveld analyses of the structures (orthorhombic, A21am, Z = 4, λ = 1.216) indicate a possible change in cationic order-disorder, with Pb2+ ions preferentially occupying the perovskite A-sites to the extent of 91 (7) and 80 (7)%, respectively, in the quenched and slowly cooled samples.
| Item Type: | Article |
|---|---|
| Source: | Copyright of this article belongs to International Union of Crystallography. |
| ID Code: | 76348 |
| Deposited On: | 31 Dec 2011 12:30 |
| Last Modified: | 31 Dec 2011 12:30 |
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