Thermal conductivity and thermoelectric performance of Sr_xBa_1−xNb₂O₆ ceramics at high temperatures

The thermal conductivity of Sr_xBa_1−xNb₂O₆ ceramics increases with increasing temperature and exhibits a maximum around the Burns temperature. At the same temperature, the semiconductor–metallic transition occurs in the electron transport. This agreement indicates that the polarized regions have an effect on electrical and thermal transport. Sr_xBa_1−xNb₂O₆ ceramics have lower lattice thermal conductivities around the solid solution limitations because of the competing influences caused by increasing Sr content. The figure of merit ZT also exhibits larger values around the solid solution limitations and reaches the maximum of ∼0.2 at 1073 K in Sr_0.70Ba_0.30Nb₂O₆