Improved electrical performance of MgO-modified CaCu3Ti4O12 ceramics

Abstract

Colossal permittivity material CaCu3Ti4O12 (CCTO) ceramics modified by MgO with the mass fraction of 0%, 0.5%, 1%, and 2% were synthesized using a sol-gel method followed by a conventional ceramic preparation process. The scanning electron microscope exhibits that all CCTO ceramics possess the high densities and large grain size. The results of dielectric measurement show that all the samples possess giant dielectric properties. The colossal dielectric constant of CCTO ceramics increases firstly and then decreases with the increase of mass fraction from 0% to 2% at room temperature, while the value of dielectric loss is opposite. Specifically, the sample with the mass fraction of 1% shows the highest density, largest grains and most obvious grain boundaries. 1% sample also shows better electrical properties with giant dielectric constant (~6.59 × 104 at 1 kHz) and low dielectric loss (~0.06 at 1 kHz) at room temperature. In addition, the optimal sample with the mass fraction of 1% shows a more stable dielectric constant from 20 °C to 200 °C. The electrical properties of the CCTO ceramics have achieved good performance by the addition of MgO.