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Tailoring the electrocaloric effect by internal bias fields and field protocols

Ma, Yangbin ; Xu, Bai-Xiang ; Albe, Karsten ; Grünebohm, Anna :
Tailoring the electrocaloric effect by internal bias fields and field protocols.
In: Physical Review Applied, 10 (2) 024048. ISSN 2331-7019
[Artikel] , (2018)

Kurzbeschreibung (Abstract)

Defect dipoles, strain gradients, and the electric boundary conditions at interfaces and surfaces often impose internal bias fields in acceptor-doped ferroelectrics, ferroelectric films, nanocomposites, and multilayers. In this work, we study the impact of internal bias fields on the electrocaloric effect (ECE), utilizing an analytical model and ab-initio-based molecular-dynamics simulations. We reveal the complex dependency of the ECE on field protocol and the relative strength of internal and external fields. The internal fields may even reverse the sign of the response (inverse or negative ECE). We explore the transition between conventional and inverse ECE and discuss reversible and irreversible contributions to the field-induced specific entropy change. Most importantly, we predict design routes to optimize the cooling and heating response for small external fields by the combination of internal field strengths and the field-loading protocol.

Typ des Eintrags: Artikel
Erschienen: 2018
Autor(en): Ma, Yangbin ; Xu, Bai-Xiang ; Albe, Karsten ; Grünebohm, Anna
Titel: Tailoring the electrocaloric effect by internal bias fields and field protocols
Sprache: Englisch
Kurzbeschreibung (Abstract):

Defect dipoles, strain gradients, and the electric boundary conditions at interfaces and surfaces often impose internal bias fields in acceptor-doped ferroelectrics, ferroelectric films, nanocomposites, and multilayers. In this work, we study the impact of internal bias fields on the electrocaloric effect (ECE), utilizing an analytical model and ab-initio-based molecular-dynamics simulations. We reveal the complex dependency of the ECE on field protocol and the relative strength of internal and external fields. The internal fields may even reverse the sign of the response (inverse or negative ECE). We explore the transition between conventional and inverse ECE and discuss reversible and irreversible contributions to the field-induced specific entropy change. Most importantly, we predict design routes to optimize the cooling and heating response for small external fields by the combination of internal field strengths and the field-loading protocol.

Titel der Zeitschrift, Zeitung oder Schriftenreihe: Physical Review Applied
Band: 10
(Heft-)Nummer: 2
Verlag: AMER PHYSICAL SOC
Fachbereich(e)/-gebiet(e): 11 Fachbereich Material- und Geowissenschaften
11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft
11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Mechanik Funktionaler Materialien
11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Materialmodellierung
Hinterlegungsdatum: 26 Nov 2018 06:10
DOI: 10.1103/PhysRevApplied.10.024048
Sponsoren: Funding from the Deutsche Forschungsgemeinschaft (DFG) SPP 1599 B3 (Grants No. XU 121/1-2 and No. AL 578/16-2) and A11/B2 (Grant No. GR 4792/1-2) is acknowledged., Additionally, we are grateful to the Lichtenberg-High Performance Computer at TU Darmstadt and the Center for Computational Science and Simulation (CCSS) at University of Duisburg-Essen for the use of their computational resources.
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