Origin of the Large Negative Electrocaloric Effect in Antiferroelectric PbZrO3

TL;DR

This study investigates the electrocaloric effect in PbZrO3, revealing large negative and positive effects near phase transition, driven by antiferroelectric-ferroelectric switching rather than dipole destabilization.

Contribution

It demonstrates that the large negative electrocaloric effect in PbZrO3 originates from phase switching, providing new insight into electrocaloric mechanisms in antiferroelectrics.

Findings

Large electrocaloric effects of -3.5 K to +5.5 K measured.

Negative effect caused by antiferroelectric-ferroelectric switching.

Contrasts with previous dipole destabilization explanation.

Abstract

We have studied the electrocaloric response of the archetypal antiferroelectric PbZrO3 as a function of voltage and temperature in the vicinity of its antiferroelectric-paraelectric phase transition. Large electrocaloric effects of opposite signs, ranging from an electro-cooling of -3.5 K to an electro-heating of +5.5 K, were directly measured with an infrared camera. We show by calorimetric and electromechanical measurements that the large negative electrocaloric effect comes from an endothermic antiferroelectric-ferroelectric switching, in contrast to dipole destabilization of the antiparallel lattice, previously proposed as an explanation for the negative electrocaloric effect of antiferroelectrics.