LAUSR

Abstract The high permittivity of CaCu 3 Ti 4 O 12 ceramics has attracted considerable attention in recent years due to their potential applications in electronic devices. However, their dielectric loss tangents are still too large. Here, we report of achieving a greatly decreased loss tangent with retaining high permittivity in Zn-doped CaCu 3 Ti 4 O 12 ( x =0–0.10) ceramics prepared using a modified sol–gel method. The influences of Zn 2+ doping on the microstructure, giant dielectric response, and non–Ohmic properties as well as microscopic effects on the electrical properties of grain and grain boundary were systematically studied. In addition to their dielectric properties, their non–Ohmic properties were remarkable improved. Very–low loss tangents (tanδ~0.016–0.017) and high permittivities (e′~6500–7700) at 1 kHz were successfully achieved in CaCu 3 -x Zn x Ti 4 O 12 ceramics with x =0.05–0.10. Substitution of Zn 2+ ions into Cu 2+ sites caused an increase in the total resistance, which was governed by the grain boundary resistance. The potential barrier height of CaCu 3 Ti 4 O 12 ceramics was significantly increased by Zn 2+ dopant ions. The reduced apparent tanδ and improved nonlinear electrical properties were primary attributed to the modified grain boundary response as a result of Zn 2+ doping.