Zeb, A, Hall, DA, Aslam, Z et al. (7 more authors) (2019) Structure-property relationships in the lead-free piezoceramic system K₀.₅Bi₀.₅TiO₃ - BiMg₀.₅Ti₀.₅O₃. Acta Materialia, 168. pp. 100-108. ISSN 1359-6454
Abstract
Distinctive structure-property relationships are revealed in the relaxor ferroelectric ceramic solid solution, (1-x)K ₀.₅ Bi ₀.₅ TiO₃ - xBiMg₀.₅ Ti ₀.₅ O₃ : 0.02 < x < 0.08. The constructed phase diagram and results of in-situ synchrotron X-ray diffraction provide explanations for temperature and electric field dependent anomalies in dielectric, ferroelectric and electromechanical properties. At room temperature a mixed phase tetragonal and pseudocubic phase field occurs for compositions 0 > x ≤ 0.07. As temperature rises to ≥150 °C, the ferroelectric tetragonal relaxor phase changes to a pseudocubic ergodic relaxor phase; this change in length scale of polar order is responsible for an inflection in relative permittivity - temperature plots. The transition is reversed by a sufficient electric field, thereby explaining the constricted form of polarisation-electric field loops measured at >150 °C. It is also responsible for a change in slope of the strain-electric field (S-E) plots which are relatively linear in the ferroelectric regime i.e. at temperatures up to 150 °C, giving unipolar strains of 0.11% at 20 °C and 0.14% at 150 °C (50 kV/cm field). The additional contribution from the effect of the field-induced pseudocubic to tetragonal transition, generates strains of ∼0.2% at 185 °C. Unusual for a piezoelectric solid solution, the maximum strains and charge coefficients (d ₃₃ = 150 pC/N, 20 °C) do not coincide with a morphotropic or polymorphic phase boundary.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 Acta Materialia Inc. Published by Elsevier Ltd. This is an author produced version of a paper published in Acta Materialia. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Lead-free piezoelectrics; Structure-properties; Potassium bismuth titanate; Perovskites |
Dates: |
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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) |
Funding Information: | Funder Grant number EPSRC (Engineering and Physical Sciences Research Council) EP/P015514/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 05 Mar 2019 14:56 |
Last Modified: | 23 Feb 2022 10:12 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.actamat.2019.02.011 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:143234 |
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