SiO2–Ti0.98In0.01Nb0.01O2 composite ceramics with low dielectric loss, high dielectric permittivity and an enhanced breakdown electric field

Abstract

SiO₂–Ti_0.98In_0.01Nb_0.01O₂ (SiO₂–TINO) composite ceramics were synthesized by solid-state sintering methods. The dielectric loss can be lowered and the breakdown electric field can be greatly enhanced by doping 2 mol% SiO₂ into TINO ceramics, while preserving the relatively high dielectric permittivity (∼30 000). The microstructure and electrical response of SiO₂–TINO composite ceramics were studied to investigate the reasons for these good dielectric properties. The lower dielectric loss and enhanced breakdown electric field were attributed to the embedding of SiO₂ in the TINO grain boundaries, which induced a drop in the potential and a blocking effect around the grain boundaries for the 2 mol% SiO₂–TINO composite ceramic. The results provide a way to lower the dielectric loss and enhance the breakdown voltage by tuning the grain boundary.