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)O-3-0.1PbTiO(3) 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 Delta T-EC/Delta E is obtained for the ceramic with 5.8-mu m 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 similar to 98% relative density and 3.6-mu m grains, the large EC temperature change (Delta T-EC) of 3.45 degrees 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. (C) 2015 Elsevier Ltd. All rights reserved.