Electrocaloric properties of 0.7Pb(Mg_1/3Nb_2/3)O₃–0.3PbTiO₃ ceramics with different grain sizes

Abstract

We have investigated the electrocaloric (EC) properties of the ceramic 0.7Pb(Mg_1/3Nb_2/3)O₃–0.3PbTiO₃. A variety of samples with different median grain sizes, i.e., 1.0, 2.2 and 4.0 μm, and relative densities of about 96% were prepared using atmospheric sintering at 1200^oC for 2, 8 and 16 h. The ceramic material with a median grain size of 2.2 μm exhibited the highest value for the EC temperature change, i.e., 1.27 K at 60 kV cm⁻¹, measured with a high-resolution calorimeter. This value is 25 and 19% higher than the value for the ceramics with the finer and the coarser grains, respectively.

Keywords:

• PMN-PT
• Electrocaloric effect
• Microstructure
• Grain size

Acknowledgements

The authors would like to thank B. Kmet, J. Cilenšek and B. Tratnik for their technical support. The Slovenian Research Agency is acknowledged for the financial support in the frame of the projects L2-6768, PR-06166 and programs P2-0105 and P1-0125.