Large enhancement of the electrocaloric effect in PLZT ceramics prepared by hot-pressing

Guangzu Zhang,Baoyan Fan,Zhibiao Chen,Mo Chen,Jianguo Liu,Shenglin Jiang,Yike Zeng,Pin Liu,Meng Shen,Qing Wang

doi:10.1063/1.4950844

Abstract

In this contribution, we demonstrate the optimization of the microstructures of the Pb0.85La0.1(Zr0.65Ti0.35)O3 (PLZT) relaxor ferroelectric ceramics and subsequent enhancements in their polarization and electrical resistivity by using a hot-pressing process. The resulting superior breakdown strength of hot-pressed PLZT enables the application of high electric field to induce a giant electrocaloric effect, in which the adiabatic change of temperature (ΔT) and the isothermal change of entropy (ΔS) are around 2 times greater than those of the samples prepared by the conventional sintering approach using muffle furnace. Moreover, the addition of extra PbO to make up the loss of Pb in the high-temperature sintering leads to the further improvements in the phase composition and electrical properties of PLZT, due to inhibition of the pyrochlore phase formation. The relationship among the sintering conditions, the content of excess PbO, and the microstructure as well as the electrical characteristics of PLZT have been investigated in a systematic manner. This work provides a facile approach to enhanced electrocaloric effect in bulk ceramics.

Highlights

We demonstrate the optimization of the microstructures of the Pb0.85La0.1(Zr0.65Ti0.35)O3 (PLZT) relaxor ferroelectric ceramics and subsequent enhancements in their polarization and electrical resistivity by using a hot-pressing process
The resulting superior breakdown strength of hot-pressed PLZT enables the application of high electric field to induce a giant electrocaloric effect, in which the adiabatic change of temperature (∆T) and the isothermal change of entropy (∆S) are around 2 times greater than those of the samples prepared by the conventional sintering approach using muffle furnace
We demonstrated that the phase composition and electrical properties of PLZT can be further optimized by adding an appropriate content of excess PbO

Summary

Introduction

We demonstrate the optimization of the microstructures of the Pb0.85La0.1(Zr0.65Ti0.35)O3 (PLZT) relaxor ferroelectric ceramics and subsequent enhancements in their polarization and electrical resistivity by using a hot-pressing process. The resulting superior breakdown strength of hot-pressed PLZT enables the application of high electric field to induce a giant electrocaloric effect, in which the adiabatic change of temperature (∆T) and the isothermal change of entropy (∆S) are around 2 times greater than those of the samples prepared by the conventional sintering approach using muffle furnace.

Results

Conclusion