Lead-free (Ba,Sr)(Sn,Ti)O3 multilayer ceramic components for electrocaloric application

Abstract

In this paper, we report on multilayer ceramic components based on $B{a}_{0.82}S{r}_{0.18}S{n}_{0.065}T{i}_{0.935}{O}_3$ (BSSnT) with $\text{MgO}$ addition or $\text{Ca}$ modification for electrocaloric (EC) cooling applications. The influence of sintering parameters on grain size, dielectric and EC properties are investigated. In components with $\text{MgO}$ addition we could increase grain size from 0.4 µm to 4.6 µm by adapting sintering parameters. With increasing grain size dielectric strength is reduced, thus limiting EC properties. In BSSnT components modified with $\text{Ca}$, grain size was increased from 1.7 µm to 6.6 µm, resulting in an increase of EC temperature change from 0.76 K to 0.94 K under an electric field change of 14 V µm⁻¹. Simultaneously, dielectric strength decreases from 31.6 V µm⁻¹ to 21.5 V µm⁻¹. Therefore, the optimal grain size represents a compromise between a moderate EC effect and a moderate dielectric strength, since both properties show an opposite dependence on grain size.