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Issue 5, 2012
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Chemical control of octahedral tilting and off-axis A cation displacement allows ferroelectric switching in a bismuth-based perovskite

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Abstract

Bi(Fe2/8Mg3/8Ti3/8)O3 (BFTM) is a member of a small class of pure Bi3+ A site perovskites which are stable without recourse to high pressure synthesis. BFTM is polar in the R3c space group, but ferroelectric switching of the polarisation is not attainable in bulk ceramics. Formation of solid solutions with BaTiO3 produces enhanced functional behaviour. The composition 0.75Bi(Fe2/8Mg3/8Ti3/8)O3–0.25BaTiO3 displays ferroelectric hysteresis loops and piezoelectric response (high field d33 of 85 pC N−1 at 0.1 Hz and low field d33 of 16 pC N−1). This change in functional behaviour is associated with significant changes in the average structure, where the rhombohedral distortion is reduced and transformed to a pseudo-cubic R3m space group, as substitution of the larger Ba2+ cation suppresses tilting of the BO6 octahedra. Polar Bi displacements are refined solely along the pseudocubic <111>p direction of the perovskite subcell, with the off-axis displacements characteristic of BFTM being suppressed. The local structure deviates from the average structure in a similar way to PZT as shown by diffuse scattering in selected area electron diffraction, suggesting correlated <111>p displacements along directions other than the average rhombohedral unique axis. The switchable polarisation measured by PUND measurements is considerably smaller than the remanence measured in P(E) loops.

Graphical abstract: Chemical control of octahedral tilting and off-axis A cation displacement allows ferroelectric switching in a bismuth-based perovskite

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Publication details

The article was received on 23 Dec 2011, accepted on 20 Feb 2012 and first published on 20 Feb 2012


Article type: Edge Article
DOI: 10.1039/C2SC01115H
Citation: Chem. Sci., 2012,3, 1426-1435
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    Chemical control of octahedral tilting and off-axis A cation displacement allows ferroelectric switching in a bismuth-based perovskite

    M. Dolgos, U. Adem, X. Wan, Z. Xu, A. J. Bell, T. P. Comyn, T. Stevenson, J. Bennett, J. B. Claridge and M. J. Rosseinsky, Chem. Sci., 2012, 3, 1426
    DOI: 10.1039/C2SC01115H

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