Li, L., Walkley, B. orcid.org/0000-0003-1069-1362, Reaney, I.M. orcid.org/0000-0003-3893-6544 et al. (1 more author) (2021) The influence of Fe2O3 reagent grade purity on the electrical properties of ‘undoped’ LaFeO3 ceramics: a cautionary reminder. Journal of the European Ceramic Society, 41 (7). pp. 4189-4198. ISSN 0955-2219
Abstract
Low levels of impurities can have a dramatic influence on the electrical properties of metal oxides. Here, we use a combination of impedance spectroscopy and Seebeck coefficient measurements to show the defect chemistry and p-type conduction mechanism in undoped LaFeO3(LF) ceramics is significantly influenced by impurities in Fe2O3 reagents. A low but significant concentration of impurities associated with 99.9% Fe2O3 reagent is sufficient to compete against the intrinsic Schottky disorder responsible for the p-type behaviour normally observed for undoped LF ceramics. This produces electrically heterogeneous grain (bulk) responses that are strongly dependent on the processing conditions. To achieve electrically homogeneous bulk responses requires adjustment of the oxygen content by annealing in a reducing atmosphere (n-type) or via doping with a significant level of acceptors (mixed ionic/ p-type electronic). These results illustrate the importance of using high purity reagents when studying the electrical properties of ferrite-based perovskites.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021 Elsevier. This is an author produced version of a paper subsequently published in Journal of the European Ceramic Society. Uploaded in accordance with the publisher's self-archiving policy. Article available under the terms of the CC-BY-NC-ND licence (https://creativecommons.org/licenses/by-nc-nd/4.0/). |
Keywords: | lanthanum ferrite; Impedance; conduction mechanism; electrical microstructure; impurity |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Chemical and Biological Engineering (Sheffield) 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 EP/L017563/1 ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL EP/L027348/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 25 Feb 2021 12:38 |
Last Modified: | 18 Feb 2022 01:38 |
Status: | Published |
Publisher: | Elsevier BV |
Refereed: | Yes |
Identification Number: | 10.1016/j.jeurceramsoc.2021.02.019 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:171573 |
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