Enhanced electrocaloric effect in lead-free NBT-based ceramics

Improvement of the electrocaloric (EC) effect was investigated in the lead-free (Na,Bi)TiO3 (NBT)-based ferroelectric ceramics fabricated by a Sol-Gel flame synthetic approach. It is found that the NBT-based samples with the compositions located at the morphotropic phase boundary exhibit superior EC entropy change (ΔS) and temperature change (ΔT). The highest ΔS of 2.20 J kg−1 K−1, ΔT of 1.50 K and the EC coefficient (ΔT/ΔE) of 0.030 K cm kV−1 are obtained in the 0.94NBT-0.06BaTiO3 ceramic. The ΔT/ΔE value of the 0.94NBT-0.06BaTiO3 ceramic is significantly higher than that of lead-free ferroelectric materials reported so far and is comparable to the values of the lead-containing materials.