Impact of annealing on electrocaloric response in Lanthanum-modified lead zirconate titanate ceramic

• Published in: Journal of alloys and compounds Vol. 907; p. 164517
• Main Authors: Asbani, B., Dellis, J.-L., Lahmar, A., Amjoud, M., Gagou, Y., Mezzane, D., Kutnjak, Z., Pirc, R., El Marssi, M., Luk’yanchuk, I., Rožič, B.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 25-06-2022; Elsevier BV; Elsevier
• Subjects: Annealing; Ceramics; Condensed Matter; Dielectric; Electric fields; Electrocaloric; Ferroelectric; Ferroelectric materials; Ferroelectricity; Ferroelectrics; Lanthanum; Lead lanthanum zirconate titanate; Lead zirconate titanates; Perovskites; Phase diagrams; Physics; Relaxors; Responsivity; Ferroelectric; Electrocaloric; Lanthanum; Dielectric; Responsivity
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2022.164517

Over the past decades, there has been significant interest in new cooling technology based on the large electrocaloric effect observed in polymeric and inorganic ferroelectric materials. We report a dramatic impact of annealing on the electrocaloric effect observed by direct measurements in Pb0.88La0.12(Zr0.65Ti0.35)0.97O3 bulk ceramics (12/65/35 PLZT). In addition, the EC response was measured deep in a relaxor part of the PLZT composition phase diagram. After additional one-hour sample annealing at 600 °C, the EC response increased by about six times. Electrocaloric results confirm the existence of the significant electrocaloric response with the EC temperature change (ΔTEC) of 4.5 K at 360 K and 90 kV/cm in an annealed sample. This value exceeds previously obtained maximum ΔTEC values at the same field in perovskite relaxor ferroelectrics such as Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) and 8/65/35 PLZT ceramics. The electrocaloric responsivity ΔT/ΔE = 5.09 × 10−7 Km/V determined at 360 K is among the highest observed in bulk perovskite ferroelectrics at a relatively high electric field of 90 kV/cm.
•Relaxor ferroelectrics exhibit mostly an electrocaloric effect (ECE) of about 3 K.•The stress field makes the ferroelectric state more supercritical with smaller ECE.•The annealing enhances the ECE in 12/65/35 PLZT ceramics by about six times.•ECE of 4.5 K exceeds previously obtained values in bulk relaxor ferroelectrics.•The ECE responsivity is the highest observed at a relatively high electric field.