Effect of Ba2+ doping on microstructure and electric properties of calcium copper titanate (CaCu3Ti4O12) ceramics

The Ba 2+ doped ceramics of Ca 1−x Ba x Cu 3 Ti 4 O 12 (x = 0.005, 0.01, 0.03, 0.05 and 0.1) were sintered via conventional solid-state reaction at 1050 °C for 8 h in air. The microstructure and electric properties of Ba 2+ doping ceramics were investigated. The lattice parameters of Ca 1−x Ba x Cu 3 Ti 4 O 12 (CBCTO) ceramics decreased with the Ba 2+ doping, and Ba 1.31 Ti 8 O 16 as secondary phase was confirmed at x = 0.1. The doping of Ba 2+ resulted in uniformly distribution of small size grain (~4 μm). All the doped samples showed lower value of dielectric constant than CaCu 3 Ti 4 O 12 (CCTO), due to low resistivity of the grain boundary with the Ba 2+ doped samples. The nonlinear coefficient and breakdown field were significantly enhanced by Ba 2+ doping.