Large electrocaloric effect and wide working area in the transition from ferroelectric to nanodomains

A large adiabatic temperature change along with a wide operating temperature region is usually required for the electrocaloric materials to fulfill their refrigeration function. In general, doping foreign ions into BaTiO 3 is the frequently utilized strategy in order to obtain excellent electrocaloric materials for the practical application. In the current paper, BaTiO 3 lead‐free ferroelectric ceramics were doped by Ca 2+ and Sn 4+ simultaneously in order to generate a coexistence state at room temperature, where ferroelectric domains and nanodomains exit. As a result, a large polarization and a wide operating temperature range were finally induced. It is found that Ba 0.9 Ca 0.1 Ti 0.85 Sn 0.15 O 3 has a maximum adiabatic temperature change of 0.85 K and an excellent working temperature region (65 K, ∆ T > 90% T max ) was achieved under an electric field of 50 kV/cm. The above phenomenon indicates that the modified BaTiO 3 ceramics can be a good potential electrocaloric material in the state of cross‐existence of ferroelectric domains and nanodomains.