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

• Published in: Journal of alloys and compounds 2022-04, Vol.899, p.163165, Article 163165
• Main Authors: Yuan, Ye, Sun, Buwei, Guo, Mengyao, Wu, Ming, Gao, Yangfei, Zhu, Xiaopei, Sun, Haonan, Zhao, Jiantuo, Liu, Yongbin, Gao, Jinghui, Liu, Qida, Lou, Xiaojie
• Format: Article
• Language: English
• Subjects: Antiferroelectric films; Antiferroelectricity; Calcium ions; Cooling; Dielectrics; Earth; Ferroelectric materials; Negative electrocaloric effect; PbZrO3; Phase transition; Phase transitions; Sol-gel processes; Thin films
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2021.163165

•Ca2+ and Sr2+ can increase the stability of antiferroelectric phase while Ba2+ decreases it.•An enhanced negative ECE of ΔT around − 10.6 K was obtained in the Pb0.9Sr0.1ZrO3 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 Pb0.9Sr0.1ZrO3 thin film, an enhanced negative electrocaloric effect (ECE) has been observed based on the Maxwell relation, with ΔT of around − 10.6 K under 450 kV/cm at room temperature, as compared with the pristine PbZrO3 thin film (with ΔT 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 PbZrO3 antiferroelectric thin films (Pb0.9A0.1ZrO3 (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 Pb0.9Sr0.1ZrO3 thin film exhibits an enhanced negative ECE with ΔT of around − 10.6 K under 450 kV/cm whereas the Pb0.9Ba0.1ZrO3 thin film shows a decreased negative ECE with ΔT of around − 2.5 K under 200 kV/cm, as compared with the pristine PbZrO3 thin films (with ΔT 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.