Optimisation of SrBi2(Nb,Ta)<inf>2</inf>O<inf>9</inf>Aurivillius phase for lead-free electrocaloric cooling

Journal article


Axelsson, AK, Le Goupil, F, Valant, M and Alford, NMN (2018). Optimisation of SrBi2(Nb,Ta)<inf>2</inf>O<inf>9</inf>Aurivillius phase for lead-free electrocaloric cooling. Journal of the European Ceramic Society. 38 (16), pp. 5354-5358.
AuthorsAxelsson, AK, Le Goupil, F, Valant, M and Alford, NMN
Abstract

© 2018 Elsevier Ltd The influence of different substitutional mechanisms on the electrocaloric effect of a lead-free SrBi2(Nb0.2Ta0.8)2O9Aurivillius phase was studied for application in electrocaloric cooling systems. The A-site substitution with barium efficiently reduced the temperature of maximum permittivity from about 300 °C to 100 °C. The A-site substitution induced phenomena that are typical of strong relaxor ferroelectrics such as significant broadening of the permittivity peak and an increase in its frequency dispersion and with a depolarization temperature below room temperature. These features directly influenced the electrocaloric effect. A direct measurement system, based on a modified-differential scanning calorimeter, was used to analyze the EC effect of the dense (Sr0.5Ba0.5)Bi2(Nb0.2Ta0.8)2O9ceramics. In accordance with the relaxor characteristics, the EC effect was found to increase continuously over a broad temperature range above the room temperature. This was attributed to the alignment of field induced polar nanodomains. Directions for optimization towards a high-performing EC ceramic were identified.

Keywords0912 Materials Engineering; Materials
Year2018
JournalJournal of the European Ceramic Society
Journal citation38 (16), pp. 5354-5358
PublisherElseiver
ISSN0955-2219
Digital Object Identifier (DOI)doi:10.1016/j.jeurceramsoc.2018.07.044
Publication dates
Print30 Jul 2018
Publication process dates
Deposited11 Sep 2018
Accepted29 Jul 2018
Accepted author manuscript
License
CC BY-NC-ND 4.0
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Accepted author manuscript

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Electrocaloric effect in lead-free Aurivillius relaxor ferroelectric ceramics
Axelsson, AK, Le Goupil, F, Valant, M and Alford, MNM (2016). Electrocaloric effect in lead-free Aurivillius relaxor ferroelectric ceramics. Acta Materialia. 124, pp. 120 - 126.