Enhanced Electrocaloric Effect of Lead Scandium Tantalate by Zirconium Doping.

Abstract

The electrocaloric effect (ECE) is a novel technology that offers high efficiency and environmental friendliness, making it suitable for solid-state refrigeration applications. Among the extensively studied ECE materials, lead scandium tantalate (PST) stands out for its excellent performance. However, its applications are restricted by its narrow working temperature range. To overcome this limitation, we explore the enhancement of the ECE through zirconium ion doping. We synthesized PbSc0.5-0.5xTa0.5-0.5xZrxO3 samples (x = 0, 0.025, 0.05, 0.075). The introduction of zirconium ions led to an increase in the Curie temperature from 28.9 °C (x = 0) to 55.5 °C (x = 0.075). Additionally, the relaxation factor γ of the ceramics increased from 1.40 (x = 0) to 1.59 (x = 0.075). The temperature span (Tspan) exhibited a rising trend with increasing x, reaching 10.9 K at x = 0.075. The maximum temperature change (ΔTmax) was observed at x = 0.025, with a value of 1.94 K. X-ray diffraction (XRD) patterns revealed that zirconium ion doping influenced the B-site ordering degree, thereby regulating the ECE. To further validate the results, we employed direct measurements and thermodynamic calculations. Overall, the regulation of ionic ordering through zirconium doping effectively enhances the ECE performance. These findings contribute to the development of advanced materials for solid-state refrigeration technologies.