Improved dielectric properties in CaCu3Ti4O12 ceramics modified by TiO2

The fabrication of TiO2 modified CaCu3Ti4O12 (w = 0, 0.01, 0.1, 2%) ceramics were obtained by a sol–gel process. The influence of TiO2 amount on the microstructures and dielectric properties was studied. The results indicate that TiO2 modified CaCu3Ti4O12 ceramics exhibits higher density, more obvious grain boundaries, and larger grains, and show improved dielectric properties, including colossal permittivity (~ 104) and comparably low dielectric loss (~ 0.1–2.3) at room temperature over the frequency range from 100 Hz to 1 MHz. The colossal permittivity could be explained by an internal boundary layer capacitance effect. CaCu3Ti4O12 modified with w = 0.01% TiO2 shows improved dielectric constant (~ 6.81 × 104) and low dielectric loss (~ 0.12) at room temperature and 1 kHz, and it also exhibits good performance over a broad temperature from 20 to 200 °C. The results show that TiO2 modification can make an improvement in both microstructures and dielectric properties for CaCu3Ti4O12.