Antiferroelectric-ferroelectric phase transition and negative electrocaloric effect in alkaline-earth element doped PbZrO3 thin films.

• Ca2+ and Sr2+ can increase the stability of antiferroelectric phase while Ba2+ decreases it. • An enhanced negative ECE of Δ T around − 10.6 K was obtained in the Pb 0.9 Sr 0.1 ZrO 3 thin film at room temperature. • The modification of antiferroelectric-ferroelectric phase transition is an effective strategy to enhance the negative electrocaloric effect in antiferroelectric thin films. In the Pb 0.9 Sr 0.1 ZrO 3 thin film, an enhanced negative electrocaloric effect (ECE) has been observed based on the Maxwell relation, with Δ T of around − 10.6 K under 450 kV/cm at room temperature, as compared with the pristine PbZrO 3 thin film (with Δ T of around −7.3 K under 300 kV/cm at 361 K), as shown in the figure. Our work demonstrates that modifying antiferroelectric-ferroelectric phase transition is an effective way to enhance the negative ECE in antiferroelectric thin films. [Display omitted] Electrocaloric effect (ECE) in dielectric materials has attracted much attention due to its promising applications in solid-state cooling devices. In this work, alkaline-earth doped PbZrO 3 antiferroelectric thin films (Pb 0.9 A 0.1 ZrO 3 (A=Ca, Sr, and Ba)) were deposited by a sol-gel method and its antiferroelectric-ferroelectric phase competition as well as the negative ECE were studied. It is found that Ca2+ and Sr2+ expand the antiferroelectric phase region while Ba2+ reduces it, due to the different ion radii of these alkaline-earth elements. As a result, the Pb 0.9 Sr 0.1 ZrO 3 thin film exhibits an enhanced negative ECE with Δ T of around − 10.6 K under 450 kV/cm whereas the Pb 0.9 Ba 0.1 ZrO 3 thin film shows a decreased negative ECE with Δ T of around − 2.5 K under 200 kV/cm, as compared with the pristine PbZrO 3 thin films (with Δ T of around −7.3 K under 300 kV/cm). This work provides an effective method to enhance the negative ECE of antiferroelectrics in electrical cooling applications by adjusting their antiferroelectric to ferroelectric phase transition. [ABSTRACT FROM AUTHOR]