TU Darmstadt / ULB / TUbiblio

Tailoring the electrocaloric effect by internal bias fields and field protocols

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

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.

Item Type: Article
Erschienen: 2018
Creators: Ma, Yangbin and Xu, Bai-Xiang and Albe, Karsten and Grünebohm, Anna
Title: Tailoring the electrocaloric effect by internal bias fields and field protocols
Language: English
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.

Journal or Publication Title: Physical Review Applied
Volume: 10
Number: 2
Publisher: AMER PHYSICAL SOC
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 > Materials Modelling
Date Deposited: 26 Nov 2018 06:10
DOI: 10.1103/PhysRevApplied.10.024048
Funders: 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.
Export:

Optionen (nur für Redakteure)

View Item View Item