Electrical responses and dielectric properties of (Zn2+ + F−) co–doped CaCu3Ti4O12 ceramics

Abstract

The effects of Zn2+ and F− ions on the ceramic microstructure, electrical properties, and colossal dielectric response of CaCu3Ti4O12 were investigated. The dopants influenced the microstructure of the CaCu3Ti4O12. The replacement of Zn2+ and F− ions reduced the low–frequency loss tangent while retaining the high dielectric constant of CaCu3Ti4O12. In co–doped ceramics, the high dielectric permittivity of around 5.76 – 7.59 × 104 and low loss tangent of 0.082 – 0.085 can be attained. The decrease in the loss tangent of the co–doped ceramic samples is commensurate with the significant increase in the grain boundary (GB) resistance and breakdown electric field. The Cu+ and Ti3+ ions in CaCu3Ti4O12 were identified using X–ray photoelectron spectroscopy and were found to be decreased by co–doping with Zn2+ and F−. The presence of these ions may play a crucial role in the semiconducting grains. The substitution of Zn2+ and F− ions can increase the electrostatic potential barriers at the GBs, resulting in improved GB resistance.