University of Oulu

M. Tyunina, "Conductivity in Ferroelectric Barium Titanate: Electrons Versus Oxygen Vacancies," in IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 68, no. 2, pp. 296-302, Feb. 2021, doi: 10.1109/TUFFC.2020.2978901

Conductivity in ferroelectric barium titanate : electrons versus oxygen vacancies

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Author: Tyunina, M.1
Organizations: 1Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, P. O. Box 4500, FI-90014 Oulu, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 1.2 MB)
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Language: English
Published: Institute of Electrical and Electronics Engineers, 2021
Publish Date: 2021-04-28


Mobile oxygen vacancies are increasingly widely believed to be responsible for electrical conductivity in perovskite oxide ferroelectrics. Here, this hypothesis is debated. The small-signal conductivity is investigated in oxygen-deficient films of barium titanate, where oxygen vacancies are epitaxially clamped and immobile. The observed behavior of conductivity as a function of temperature and frequency evidences pure electronic processes. Importantly, it is shown that these processes mimic motion of oxygen vacancies, which are immobile. It is also demonstrated that under the applied dc electric field, the electronic processes lead to such effects as coloration and degradation, which before were plausibly ascribed to migration of oxygen vacancies. Finally, it is concluded that the hypothesis of mobile oxygen vacancies is misleading.

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Series: IEEE transactions on ultrasonics, ferroelectrics and frequency control
ISSN: 0885-3010
ISSN-E: 0885-3010
ISSN-L: 0885-3010
Volume: 68
Issue: 2
Pages: 296 - 302
DOI: 10.1109/TUFFC.2020.2978901
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
213 Electronic, automation and communications engineering, electronics
Funding: This work was supported by the Czech Science Foundation (Grant No. 19-09671S) and the European Structural and Investment Funds and the Ministry of Education, Youth and Sports of the Czech Republic through Programme “Research, Development and Education” (Project No. SOLID21 - CZ.02.1.01/0.0/0.0/16_019/0000760).
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