Large electrocaloric effect in grain-size-engineered 0.9Pb(Mg1/3Nb2/3)O3–0.1PbTiO3

It is shown that a substantial enhancement of the electrocaloric (EC) effect can be achieved with a properly engineered, ceramic microstructure. In particular, a significant impact of the grain size on the EC effect in 0.9Pb(Mg1/3Nb2/3)O3–0.1PbTiO3 ceramics is demonstrated. The single-phase perovskite ceramics with grain sizes ranging from 2.8 to 9.4 mm were prepared. The largest EC coefficient ΔTEC/ΔE is obtained for the ceramic with 5.8-μm grains, as a consequence of its larger saturation polarization.The EC response is limited by the breakdown strength of the material, which is higher than 160 kV cm−1 for the fine-grained ceramics. For the material with a ∼98% relative density and 3.6-μm grains, the large EC temperature change (ΔTEC) of 3.45 °C is achieved. This value is the highest reported so far for Pb-based perovskites and is comparable to best results obtained by multi-critical-point enhancement.