McCartan, S. J., Calisir, I., Paterson, G. W. , Webster, R. W.H., Macgregor, T. A., Hall, D. A. and MacLaren, I. (2021) Correlative chemical and structural nanocharacterization of a pseudo-binary 0.75Bi(Fe0.97Ti0.03)O3–0.25BaTiO3 ceramic. Journal of the American Ceramic Society, 104(5), pp. 2388-2397. (doi: 10.1111/jace.17599)
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Abstract
Fast‐cooling after sintering or annealing of BiFeO3‐BaTiO3 mixed oxide ceramics yields core‐shell structures that give excellent functional properties, but their precise phase assemblage and nanostructure remains an open question. By comparing conventional electron energy loss spectroscopy (EELS) with scanning precession electron diffraction (SPED) mapping using a direct electron detector, we correlate chemical composition with the presence or absence of octahedral tilting and with changes in lattice parameters. This reveals that some grains have a 3‐phase assemblage of a BaTiO3‐rich pseudocubic shell; a BiFeO3‐rich outer core with octahedral tilting consistent with an R3c structure; and an inner core richer in Ba and even poorer in Ti, which seems to show a pseudocubic structure of slightly smaller lattice parameter than the shell region. This last structure has not been previously identified in these materials, but the composition and structure fit with previous studies. These inner cores are likely to be non‐polar and play no part in the ferroelectric properties. Nevertheless, the combination of EELS and SPED clearly provides a novel way to examine heterogeneous microstructures with high spatial resolution, thus revealing the presence of phases that may be too subtle to detect with more conventional techniques.
Item Type: | Articles |
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Additional Information: | S.J.M would like to acknowledge the CDT in Photonic Integration and Advanced Data Storage (PIADS) for the funding of his PhD through the EPSRC grant (EP/L015323/1). We gratefully acknowledge funding from EPSRC which has supported the development of the detector (through “Fast Pixel Detectors: a paradigm shift in STEM imaging” (EP/M009963/1) and Impact Acceleration Accounts (EP/K503903/1 and EP/R511705/1)). Funding from EPSRC (EP/R511705/1) and NanoMEGAS supported integration of the Merlin for EM detector with the ASTAR system. |
Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Macgregor, Mr Thomas and MacLaren, Dr Ian and Webster, Mr Robert and Paterson, Dr Gary |
Authors: | McCartan, S. J., Calisir, I., Paterson, G. W., Webster, R. W.H., Macgregor, T. A., Hall, D. A., and MacLaren, I. |
College/School: | College of Science and Engineering > School of Physics and Astronomy |
Journal Name: | Journal of the American Ceramic Society |
Publisher: | Wiley |
ISSN: | 0002-7820 |
ISSN (Online): | 1551-2916 |
Published Online: | 02 December 2020 |
Copyright Holders: | Copyright © 2020 The Authors |
First Published: | First published in Journal of the American Ceramic Society 104(5): 2388-2397 |
Publisher Policy: | Reproduced under a Creative Commons License |
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