Inhomogeneous electric-field–induced negative/positive electrocaloric effects in ferroelectric nanoparticles

¹ Hunan Provincial Key Laboratory of Health Maintenance for Mechanical Equipment, Hunan University of Science and Technology - Hunan Xiangtan 411201, China
² School of Materials and Engineering, Hunan University of Science and Technology - Hunan Xiangtan 411201, China
³ School of Materials and Engineering, Xiangtan University - Hunan Xiangtan 411105, China
⁴ China Three Gorges Corporation - Chengdu, Sichuan 610041, China

^(a) lfliu1@hnust.cn (corresponding author)
^(b) bli@xtu.edu.cn

Received: 27 February 2017
Accepted: 4 April 2017

Abstract

The electrocaloric effect in PbTiO₃ ferroelectric nanoparticles has been studied using Landau-Ginzburg-Devonshire theory to determine the optimal electric field to induce large adiabatic temperature changes. The calculation results show that a large positive or negative adiabatic temperature change could be induced using an inhomogeneous electric field. The electrically induced negative adiabatic temperature change becomes positive as the strength of the electric field is increased. This transformation of the adiabatic temperature change is attributed to domain switching owing to the applied electric field. These results may provide an explanation for transformations from a negative to a positive electrocaloric effect in ferroelectrics.