Tailoring electrocaloric properties of Ba1-xSrxSnyTi1-yO3 ceramics by compositional modification

This paper presents compositional modifications on lead-free material system based on barium titanate to optimize its electrocaloric (EC) properties. By addition of strontium and tin we prepared solid solutions of Ba1-xSrxSnyTi1-yO3 (BSSnT-100∙x-100∙y) which allow for shifting of maximum EC effect to room temperature as well as broadening the temperature range of high EC temperature changes ΔTEC. Bulk ceramic samples of BSSnT were prepared by solid-state reaction route and the influence of Sn:Sr ratio on dielectric and ferroelectric properties was investigated. The EC temperature change was measured directly using resistance welded thermocouple wires. Most promising results could be achieved for BSSnT-18-6.5, which showed a maximum ΔTEC of 0.49 K around 30 °C with ΔTEC > 0.3 K in the temperature range from 10 °C to 50 °C under a comparatively low electric field change of 2 V μm-1.