Microstructure-dependent giant dielectric response in CaCu3Ti4O12 ceramics

CaCu3Ti4O12 ceramics were prepared at the sintering temperatures ranged from 1025 to 1125 °C, and the dielectric characteristics were evaluated together with the microstructures. The giant dielectric constant with the maximum of 53,120 was obtained in CaCu3Ti4O12 ceramics at room temperature and 10 kHz, and strong processing and microstructure dependence of dielectric characteristics of the present ceramics was determined. The precipitation of the dispersed Cu-rich secondary phases of CuO and/or Cu2O and their network structure provided the extrinsic origins of the enhanced giant dielectric response, and the present findings would offer the greater potential for enhancing the giant dielectric constant and controlling the dielectric loss in CaCu3Ti4O12 ceramics by optimizing the microstructures.