Unveiling a giant electrocaloric effect at low electric fields through continuous phase transition design

Abstract

The reported electrocaloric (EC) effect in ferroelectrics is poised for application in the next generation of solid-state refrigeration technology, exhibiting substantial developmental potential. This study introduces a novel and efficient EC effect strategy in (1–x)Pb(Lu_1/2Nb_1/2)O₃-xPbTiO₃ (PLN-xPT) ceramics for low electric-field-driven devices. Phase-field simulations provide fundamental insights into thermally induced continuous phase transitions, guiding subsequent experimental investigations. A comprehensive composition/temperature-driven phase evolution diagram is constructed, elucidating the sequential transformation from ferroelectric (FE) to antiferroelectric (AFE) and finally to paraelectric (PE) phases for x=0.10−0.18 components. Direct measurements of EC performance highlight x=0.16 as an outstanding performer, exhibiting remarkable properties, including an adiabatic temperature change (ΔT) of 3.03 ​K, EC strength (ΔT/ΔE) of 0.08 ​K ​cm kV⁻¹, and a temperature span (T_span) of 31 ​°C. The superior EC effect performance is attributed to the temperature-induced FE to AFE transition at low electric fields and diffusion phase transition behavior contributing to the wide T_span. This work provides valuable insights into developing high-performance EC effect across broad temperature ranges through the strategic design of continuous phase transitions, offering a simplified and economical approach for advancing ecofriendly and efficient solid-state cooling technologies.