Giant electrocaloric effect in lead-free Ba0.94Ca0.06Ti1-xSnxO3 ceramics with tunable Curie temperature

Electrocaloric effect in lead-free Ba0.94Ca0.06Ti1-xSnxO3 ceramics is studied using an indirect method. The Ba(0.94)Ca(0.06)Ti(0.87)5Sn(0.125)O(3) ceramic located near a multi-phase point shows best electrocaloric performance, which provides further experimental evidence for optimizing electrocaloric properties through constructing multiphase coexistence. Giant electrocaloric efficiency (similar to 0.4K mm/kV) is achieved in this ceramic at about room temperature at a low electric field of 6 kV/cm. While large electrocaloric temperature (similar to 0.63 K) is obtained by further enhancing electric field (20 kV/cm), a decrease in electrocaloric efficiency (0.32K mm/kV) is simultaneously observed, which is attributed to phase transition from first-order to more diffusive second-order under higher electric field. (C) 2015 AIP Publishing LLC.