Ward, R.E., Freeman, C.L. orcid.org/0000-0002-6326-1211, Dean, J.S. orcid.org/0000-0001-7234-1822
et al. (2 more authors)
(2020)
Using metadynamics to obtain the free energy landscape for cation diffusion in functional ceramics : dopant distribution control in rare earth-doped BaTiO3.
Advanced Functional Materials, 30 (6).
1905077.
ISSN 1616-301X
Abstract
Barium titanate is the dielectric material of choice in most multilayer ceramic capacitors (MLCCs) and thus in the production of ≈3 trillion devices every year, with an estimated global market of ≈$8330 million per year. Rare earth dopants are regularly used to reduce leakage currents and improve the MLCC lifetime. Simulations are used to investigate the ability of yttrium, dysprosium, and gadolinium to reduce leakage currents by trapping mobile oxygen defects. All the rare earths investigated trap oxygen vacancies, however, dopant pairs are more effective traps than isolated dopants. The number of trapping sites increases with the ion size of the dopant, suggesting that gadolinium should be more effective than dysprosium, which contradicts experimental data. Additional simulations on diffusion of rare earths through the lattice during sintering show that dysprosium diffuses significantly faster than the other rare earths considered. As a consequence, its greater ability to reduce oxygen migration is a combination of thermodynamics (a strong ability to trap oxygen vacancies) and kinetics (sufficient distribution of the rare earth in the lattice to intercept the migrating defects).
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
Keywords: | cation diffusion; defect distributions; free energy; kinetic control |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Materials Science and Engineering (Sheffield) |
Funding Information: | Funder Grant number ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL (EPSRC) EP/L017563/1 ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL (EPSRC) EP/P015565/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 29 Jan 2020 09:58 |
Last Modified: | 19 Oct 2021 12:46 |
Status: | Published |
Publisher: | Wiley |
Refereed: | Yes |
Identification Number: | 10.1002/adfm.201905077 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:155131 |
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