Giant electrocaloric effect in thin film Pb Zr_0.95 Ti_0.05 O_3

TL;DR

This study demonstrates a giant electrocaloric effect in thin film PbZr0.95Ti0.05O3 near its Curie temperature, offering potential for efficient solid-state cooling and advancing understanding of electrocaloric phenomena.

Contribution

The paper reports a significantly larger electrocaloric effect in thin films compared to bulk materials, resolving previous controversies and suggesting new directions for material design.

Findings

Electrocaloric effect of 0.48 K V^-1 in thin films

Effect strongest near the ferroelectric Curie temperature of 222°C

Potential for outperforming traditional cooling technologies

Abstract

An applied electric field can reversibly change the temperature of an electrocaloric material under adiabatic conditions, and the effect is strongest near phase transitions. This phenomenon has been largely ignored because only small effects (0.003 K V^-1) have been seen in bulk samples such as Pb0.99Nb0.02(Zr0.75Sn0.20Ti0.05)0.98O3 and there is no consensus on macroscopic models. Here we demonstrate a giant electrocaloric effect (0.48 K V^-1) in 300 nm sol-gel PbZr0.95Ti0.05O3 films near the ferroelectric Curie temperature of 222oC. We also discuss a solid state device concept for electrical refrigeration that has the capacity to outperform Peltier or magnetocaloric coolers. Our results resolve the controversy surrounding macroscopic models of the electrocaloric effect and may inspire ab initio calculations of electrocaloric parameters and thus a targeted search for new materials.