Near room-temperature large negative electrocaloric effect accompanied by giant thermal switching ratio in Zr-rich lead zirconate titanate.

Materials with electrocaloric effect (ECE) and/or thermal switching ratio λ are desirable for developing various heat management devices, but developing high-performance candidates, especially those that simultaneously possess large near room-temperature ECE and λ is actually absent. The Zr-rich PbZr_1−xTi_xO₃ (PZT) displays a composition-induced antiferroelectric-ferroelectric (AFE-FE) phase boundary, where an unusual negative ECE is expected. Meanwhile, the electric field-sensitive dipole orientation during the AFE-FE phase transition can be employed to modulate λ. In this work, the Zr-rich PZT with coexisting AFE and FE phases was developed and the AFE-FE phase transition temperature is tuned toward room temperature by changing the Ti content to achieve large negative ECE and λ. A large adiabatic temperature change ΔT of −3.3 K accompanied by a giant λ of 1.84 near 60 °C is captured in optimal PbZr_0.95Ti_0.05O₃ ceramics, demonstrating a prominent application prospect in solid-state refrigeration. [ABSTRACT FROM AUTHOR]