Cabral, M, Brown, AP orcid.org/0000-0001-9692-2154, Bultitude, J et al. (9 more authors) (2023) Structural investigation of the temperature-stable relaxor dielectric Ba0.8Ca0.2TiO3-Bi(Mg0.5Ti0.5)O3. Journal of the European Ceramic Society, 43 (2). pp. 362-369. ISSN 0955-2219
Abstract
Aberration corrected scanning transmission electron microscopy (STEM) and electron diffraction have been used to disclose local structure and nano-chemistry in a Ca modified BaTiO3-Bi(Mg0.5Ti0.5)O3 relaxor dielectric ceramic which exhibits high and near-invariant relative permittivity over a wide temperature range. High-resolution, synchrotron X-ray diffraction indicated a globally cubic structure (Pm3m), but direct atomic-scale imaging by STEM revealed local tetragonal distortions. Nanopolar clusters were identified from B-site atomic displacement vectors measured relative to oxygen ion positions along < 100 > and < 110 > zone axes of integrated differential phase contrast (iDPC) STEM images, highlighting cluster sizes of 2–5 nm. Chemical analysis by STEM-energy dispersive X-ray spectroscopy and full pattern refinements of X-ray powder diffraction data each implied high levels of Bi vacancies within the matrix. The possibility that these A-site vacancies modulate the nanopolar structure and promote flattening of the permittivity-temperature response in this class of dielectric is discussed.
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Copyright, Publisher and Additional Information: | © 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). | ||||||||||
Keywords: | Microstructure; Nanostructure; Structure-Property Relationships; dielectrics; X-ray; diffraction | ||||||||||
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Institution: | The University of Leeds | ||||||||||
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) | ||||||||||
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Depositing User: | Symplectic Publications | ||||||||||
Date Deposited: | 05 Oct 2022 16:02 | ||||||||||
Last Modified: | 25 Jun 2023 23:06 | ||||||||||
Status: | Published | ||||||||||
Publisher: | Elsevier | ||||||||||
Identification Number: | https://doi.org/10.1016/j.jeurceramsoc.2022.09.039 |