Giant dielectric, low loss tangent and non-ohmics properties of CaCu3Ti4.7O12 ceramics prepared by polymer pyrolysis method

In this work, CaCu3Ti4.7O12 (CCT4.7O) powder was prepared by polymer pyrolysis method. The influence of phase composition and microstructure were characterized using X ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the TiO2 secondary phase has a remarkable on the microstructure, dielectric loss tangent (tan and dielectric constant () of CCT4.7O ceramics, respectively. Interestingly, low loss tangent of ~0.03 and giant dielectric constant of 31,908 with temperature coefficients less than ±15% in the temperature range of −50–90 oC are observed in a ceramic sintered at 1060 oC for 10h (CCT4.7O-2). Both of ceramics sintered at 1060 oC for 6h (CCT4.7O-1) and 10 h (CCT4.7O-2) display a non linear current voltage with the non-linear coefficient () and breakdown field (Eb) values of 6.4, 5.6 and 1554, 1020, respectively. The dielectric constant, electrical response of grain boundaries, and related nonlinear currentvoltage behavior are found to be associated with the microstructure of CCT4.7O ceramics.