Dielectric behavior and non-ohmic behavior of CCTO/SiO2 composites

In this study, the electrical behavior of CCTO/SiO2 composites have been analyzed. The ceramic composite was made of CaCu3Ti4O12 coated with SiO2 by sol-gel method. The composites were made of SiO2 concentration and sintered in different temperature. The effect of SiO2 concentration and sintering temperature on the microstructure and non-ohmic behavior of composites were investigated. The breakdown electrical field for composite of CCTO can improve from 1.96 KV/cm to 40 KV/cm by adding SiO2 due to the formation of a resistive layer in grainboundaries. The nonlinear coefficient of the sample is influenced by changing the Schottky barrier parameters to reach 3.8, which is predicted by conductivity behavior. It is believed that, the formation of the liquid phase caused the increase in diffusion which altered the conductivity of grainboundaries and affected the height and width of the potential barrier. The SEM pictures were conducted to illustrate the change in the microstructure of samples. The increase in the sintering temperature and emerge liquid phase results in grain growth.