Effect of SiO2 on dielectric properties of core-shell Sr and Tm co-doped BaTiO3@SiO2 ceramics

Abstract Sr and Tm co-doped Ba 0.7 Sr 0.3 Ti 0.9925 Tm 0.01 O 3 (BST) and core-shell structured BST@SiO 2 ceramics were prepared by sol-gel method and conventional sintering. Along with the obvious perovskite phases in the BST and BST@SiO 2 powders, a new phase, Ba 2 TiSi 2 O 8 , was confirmed in the sintered BST@SiO 2 bulk by XRD analysis. TEM analysis revealed that the BST powders were coated with an amorphous SiO 2 film, while SEM analysis indicated that the SiO 2 film plays a role in grain size reduction. The dielectric losses of BST@SiO 2 ceramics reduced effectively compared to that of BST. In addition, the Curie peak of the BST@1%SiO 2 ceramic significantly broadened and the Curie temperature shifted toward lower temperatures; this provides a new approach to improving the dielectric properties of BaTiO 3 ceramics.