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Long term stability of electrocaloric response in barium zirconate titanate

Weyland, Florian and Eisele, Thorsten and Steiner, Sebastian and Frömling, Till and Rossetti Jr., George A. and Rödel, Jürgen and Novak, Nikola (2018):
Long term stability of electrocaloric response in barium zirconate titanate.
In: Journal of the European Ceramic Society, Elsevier Science Ltd, England, pp. 551-556, 38, ISSN 09552219, DOI: 10.1016/j.jeurceramsoc.2017.09.018, [Online-Edition: http://dx.doi.org/10.1016/j.jeurceramsoc.2017.09.018],
[Article]

Abstract

The stability of the electrocaloric effect under electric field cycling is an important consideration in the development of solid-state cooling devices. Here we report measurements carried out on Ba(Zr0.2Ti0.8)O3 ceramics which reveal that the adiabatic temperature change, polarization-electricfield hysteresis loops and dielectric permittivity/loss show stable behavior up to 10^5 cycles. We further demonstrate that the loss in electrocaloric response observed after 10^5 cycles is associated with the migration of oxygen vacancies. As a result, the electrical properties of the material are changed leading to an increase in leakage current and Joule heating. Reversing the polarity of the electric field after every 10^5 cycles changes the migration direction of oxygen vacancies, thereby preventing charge accumulation at grain boundaries and electrodes. By doing so, the electrocaloric stability is improved and the adiabatic temperature remains constant even after 10^6 cycles, much higher than achieved in commercially available barium titanate ceramics.

Item Type: Article
Erschienen: 2018
Creators: Weyland, Florian and Eisele, Thorsten and Steiner, Sebastian and Frömling, Till and Rossetti Jr., George A. and Rödel, Jürgen and Novak, Nikola
Title: Long term stability of electrocaloric response in barium zirconate titanate
Language: English
Abstract:

The stability of the electrocaloric effect under electric field cycling is an important consideration in the development of solid-state cooling devices. Here we report measurements carried out on Ba(Zr0.2Ti0.8)O3 ceramics which reveal that the adiabatic temperature change, polarization-electricfield hysteresis loops and dielectric permittivity/loss show stable behavior up to 10^5 cycles. We further demonstrate that the loss in electrocaloric response observed after 10^5 cycles is associated with the migration of oxygen vacancies. As a result, the electrical properties of the material are changed leading to an increase in leakage current and Joule heating. Reversing the polarity of the electric field after every 10^5 cycles changes the migration direction of oxygen vacancies, thereby preventing charge accumulation at grain boundaries and electrodes. By doing so, the electrocaloric stability is improved and the adiabatic temperature remains constant even after 10^6 cycles, much higher than achieved in commercially available barium titanate ceramics.

Journal or Publication Title: Journal of the European Ceramic Society
Volume: 38
Publisher: Elsevier Science Ltd, England
Uncontrolled Keywords: Electrocaloric e ff ect Ferroelectric Resistance degradation Fatigue Lead-free
Divisions: 11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Nonmetallic-Inorganic Materials
11 Department of Materials and Earth Sciences
Date Deposited: 01 Dec 2017 14:29
DOI: 10.1016/j.jeurceramsoc.2017.09.018
Official URL: http://dx.doi.org/10.1016/j.jeurceramsoc.2017.09.018
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