Dielectric properties of Ni and Nb doped CaCu3Ti4O12 ceramics

Abstract

Abstract CaCu2.8Nb0.2Ti4-xNixO12 (x=0.1, 0.2, 0.3) and CaCu3Ti4O12 ceramics were successfully fabricated through the solid-state reaction method. All the samples were methodically examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), impedance and dielectric properties measurements. XRD analyses verified the constitution of a cubic perovskite structure with Im-3 space group. The average grain size of CaCu3Ti4O12 ceramics reduced with Ni and Nb ions doping, especially decreased significantly with the increase of Ni content. Compared with un-doped CaCu3Ti4O12, Ni and Nb ions doped CaCu3Ti4O12 ceramics presented greatly enhanced dielectric constant range from 102 Hz to 106 Hz, illustrating the Ni and Nb ions have great influence on improving the dielectric constant. The CaCu2.8Nb0.2Ti3.8Ni0.2O12 sample achieves the highest dielectric constant, possesses the lowest dielectric loss and acquires the largest grain boundary resistance in the doped samples. Therefore, it has optimal dielectric performance.