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Determination of electrical properties of degraded mixed ionic conductors: Impedance studies with applied dc voltage

Bayer, T. J. M. and Carter, J. J. and Wang, Jian-Jun and Klein, Andreas and Chen, Long-Qing and Randall, C. A. (2017):
Determination of electrical properties of degraded mixed ionic conductors: Impedance studies with applied dc voltage.
In: Journal of Applied Physics, 122 (24), p. 244101, ISSN 0021-8979,
DOI: 10.1063/1.5006062,
[Online-Edition: https://doi.org/10.1063/1.5006062],
[Article]

Abstract

Under electrical bias, mixed ionic conductors such as SrTiO3 are characterized by oxygen vacancy migration which leads to resistance degradation. The defect chemistry to describe the relationship between conductivity and oxygen vacancies is usually obtained by high temperature conductivity data or quenching experiments. These techniques can investigate the equilibrated state only. Here, we introduce a new approach using in-situ impedance studies with applied dc voltage to analyze the temperature dependent electrical properties of degraded SrTiO3 single crystals. This procedure is most beneficial since it includes electric field driven effects. The benefits of the approach are highlighted by comparing acceptor doped and undoped SrTiO3. This approach allows the determination of the temperature activation of both anodic and cathodic conductivity of Fe-doped SrTiO3 in the degraded state. The anodic activation energy matches well with the published results, while the activation energy of the degraded cathode region reported here is not in agreement with earlier assumptions. The specific discrepancies of the experimental data and the published defect chemistry are discussed, and a defect chemistry model that includes the strong temperature dependence of the electron conductivity in the cathode region is proposed.

Item Type: Article
Erschienen: 2017
Creators: Bayer, T. J. M. and Carter, J. J. and Wang, Jian-Jun and Klein, Andreas and Chen, Long-Qing and Randall, C. A.
Title: Determination of electrical properties of degraded mixed ionic conductors: Impedance studies with applied dc voltage
Language: English
Abstract:

Under electrical bias, mixed ionic conductors such as SrTiO3 are characterized by oxygen vacancy migration which leads to resistance degradation. The defect chemistry to describe the relationship between conductivity and oxygen vacancies is usually obtained by high temperature conductivity data or quenching experiments. These techniques can investigate the equilibrated state only. Here, we introduce a new approach using in-situ impedance studies with applied dc voltage to analyze the temperature dependent electrical properties of degraded SrTiO3 single crystals. This procedure is most beneficial since it includes electric field driven effects. The benefits of the approach are highlighted by comparing acceptor doped and undoped SrTiO3. This approach allows the determination of the temperature activation of both anodic and cathodic conductivity of Fe-doped SrTiO3 in the degraded state. The anodic activation energy matches well with the published results, while the activation energy of the degraded cathode region reported here is not in agreement with earlier assumptions. The specific discrepancies of the experimental data and the published defect chemistry are discussed, and a defect chemistry model that includes the strong temperature dependence of the electron conductivity in the cathode region is proposed.

Journal or Publication Title: Journal of Applied Physics
Volume: 122
Number: 24
Divisions: 11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Surface Science
11 Department of Materials and Earth Sciences
Date Deposited: 27 Dec 2017 11:37
DOI: 10.1063/1.5006062
Official URL: https://doi.org/10.1063/1.5006062
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