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Optimized electrocaloric effect by field reversal: Analytical model

Ma, Yang-Bin and Novak, Nikola and Albe, Karsten and Xu, Bai-Xiang (2016):
Optimized electrocaloric effect by field reversal: Analytical model.
In: Applied Physics Letters, American Institute of Physics Publishing, pp. 1-5, 109, (202906), ISSN 0003-6951, [Online-Edition: http://dx.doi.org/10.1063/1.4968006],
[Article]

Abstract

Applying a negative field on a positively poled ferroelectric sample can enhance the electrocaloric cooling and is a promising method to optimize the electrocaloric cycle. Experimental measurements show that the maximal cooling is not obtained, when the electric field is removed, but reversed to a value corresponding to the shoulder of the P-E loop. This phenomenon cannot be explained if a constant total entropy is assumed under adiabatic conditions. Thus, a direct analysis of entropy changes based on work loss is proposed in this work, which takes the entropy contribution of the irreversible process into account. The optimal reversed field determined by this approach agrees with the experimental observations. This study signifies the importance of considering irreversible process in the electrocaloric cycles.

Item Type: Article
Erschienen: 2016
Creators: Ma, Yang-Bin and Novak, Nikola and Albe, Karsten and Xu, Bai-Xiang
Title: Optimized electrocaloric effect by field reversal: Analytical model
Language: English
Abstract:

Applying a negative field on a positively poled ferroelectric sample can enhance the electrocaloric cooling and is a promising method to optimize the electrocaloric cycle. Experimental measurements show that the maximal cooling is not obtained, when the electric field is removed, but reversed to a value corresponding to the shoulder of the P-E loop. This phenomenon cannot be explained if a constant total entropy is assumed under adiabatic conditions. Thus, a direct analysis of entropy changes based on work loss is proposed in this work, which takes the entropy contribution of the irreversible process into account. The optimal reversed field determined by this approach agrees with the experimental observations. This study signifies the importance of considering irreversible process in the electrocaloric cycles.

Journal or Publication Title: Applied Physics Letters
Volume: 109
Number: 202906
Publisher: American Institute of Physics Publishing
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Mechanics of functional Materials
11 Department of Materials and Earth Sciences > Material Science > Nonmetallic-Inorganic Materials
Date Deposited: 18 Nov 2016 06:27
Official URL: http://dx.doi.org/10.1063/1.4968006
Identification Number: doi:10.1063/1.4968006
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