The influence of extrinsic structural factors on the dielectric properties of CaCu3Ti3.90Cr0.10O12 ceramics

Abstract

Abstract In this study, CaCu3Ti3.90Cr0.10O12 was produced via a solid-state reaction method. The phase formation and crystal structure analyses indicate a body-centered cubic structure with the space group Im3. There were no observed secondary phases. A microstructural study revealed that, with the sintering time fixed at 3 h, the average grain size increases as the sintering temperature was raised from 1090 °C to 1110 °C. Interestingly, the dielectric permittivity of CaCu3Ti3.90Cr0.10O12 ceramics increases from 3.53×104 to 8.04×104 as the sintering temperature was increased. In addition, the loss tangent of the CaCu3Ti3.90Cr0.10O12 ceramic decreases from 0.086 to 0.043. Impedance spectroscopy reveals the construction of an internal barrier layer capacitor structure in CaCu3Ti3.90Cr0.10O12 ceramics. The presence of Cu+ and Ti3+ in the CaCu3Ti3.90Cr0.10O12 system is shown by X-ray photoelectron spectroscopy, indicating a charge compensation mechanism produced by the oxygen vacancy within the CaCu3Ti3.90Cr0.10O12 ceramics. Interfacial polarisation may be the most significant contributor to the high dielectric permittivity of these ceramics.