Dielectric properties, nonlinear electrical response and microstructural evolution of CaCu3Ti4-xSnxO12 ceramics prepared by a double ball-milling process

Abstract

Recently, the dielectric properties and nonlinearity of the current-voltage (I–V) characteristics of CaCu3Ti4O12 (CCTO) ceramics, which can be controlled mainly by their microstructures, have been widely studied. The microstructure of CCTO ceramics has a great effect on both the dielectric properties and nonlinear current-voltage characteristics. In this work, the microstructure, dielectric response, and nonlinear I–V properties of CaCu3Ti4-xSnxO12 ceramics that were prepared by a double ball-milling process were studied. The crystal structures and microstructures were methodologically investigated. The dielectric permittivity of the CCTO ceramics at 1 kHz increased from ~3.90 × 104 to ~5.30 × 104-6.51 × 104 by doping with Sn4+ ions, while the dielectric loss decreased significantly. The nonlinear I–V properties of the CaCu3Ti4-xSnxO12 ceramics significantly improved as x increased. The improved dielectric and nonlinear I–V properties were mainly associated with the substantially enhanced grain boundary response.