Dielectric properties and nonlinear I–V electrical behavior of (Li1+, Al3+) co-doped CaCu3Ti4O12 ceramics

Abstract

(Li1+, Al3+) co-doped CaCu3Ti4O12 ceramics (CaCu3−2xLixAlxTi4O12, x = 0.05, 0.1, 0.15) were prepared by a sol–gel method and were sintered at 1020–1080 °C for 8 h to improve the geometric microstructure, dielectric and nonlinear I–V electrical properties. Notably, very high dielectric constant of 1 × 105 with good dielectric-frequency as well as dielectric-temperature stability can be achieved in CaCu2.8Li0.1Al0.1Ti4O12 ceramic sintered at 1060 °C. The average grain sizes, resistivity and the non-Ohmic properties are also improved compared to pure CaCu3Ti4O12. These results indicate that (Li1+, Al3+) co-doping at the Cu2+ site can improve the dielectric properties of CaCu3Ti4O12, supporting the internal barrier layer capacitance effect of Schottky barriers at grain boundaries.