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

摘要

An applied electric field can reversibly change the temperature of anelectrocaloric material under adiabatic conditions, and the effect is strongestnear phase transitions. This phenomenon has been largely ignored because onlysmall effects (0.003 K V^-1) have been seen in bulk samples such asPb0.99Nb0.02(Zr0.75Sn0.20Ti0.05)0.98O3 and there is no consensus on macroscopicmodels. Here we demonstrate a giant electrocaloric effect (0.48 K V^-1) in 300nm sol-gel PbZr0.95Ti0.05O3 films near the ferroelectric Curie temperature of222oC. We also discuss a solid state device concept for electricalrefrigeration that has the capacity to outperform Peltier or magnetocaloriccoolers. Our results resolve the controversy surrounding macroscopic models ofthe electrocaloric effect and may inspire ab initio calculations ofelectrocaloric parameters and thus a targeted search for new materials.