Type–I pseudo–first–order phase transition induced electrocaloric effect in lead–free Bi0.5Na0.5TiO3–0.06BaTiO3 ceramics

In this study, the electrocaloric effect (ECE) of Bi0.5Na0.5TiO3–0.06BaTiO3 (BNT–0.06BT) ceramic has been directly measured using a home-made adiabatic calorimeter. The maximum adiabatic temperature change (ΔT) approaches 0.86 K under an electric field of 5 kV/mm at 110 °C, which provides experimental evidence for optimizing the ECE near the type–I pseudo–first–order phase transition (PFOPT). Most importantly, a considerable ΔT value can be maintained over a wide temperature range well above the temperature of the PFOPT under a high electric field. In addition, ΔT is closely related to the structural transition and electric field strength. This work provides a guideline to investigate the high ECE in BNT–based ferroelectric ceramics for applications in cooling technologies.