Effects of Sm_2O_3 Doping on Structure and Electric Characteristics of BaTiO_3 Ceramics

BaTiO3 ceramics doped with Sm2O3(the additive contents were 0.001, 0.002, 0.003, 0.005, 0.007 mol respectively) were prepared by the sol-gel method. The effects of Sm2O3 doping on the structure and electric characteristics of BaTiO3 ceramics were studied. The results showed that the structure of the crystal was tetragonal, and with the increasing of Sm2O3 content, the grain size became smaller, which illustrated that Sm2O3 doping could prohibit the growing of the grain. The resistivity of BaTiO3 ceramics doped with Sm2O3 decreased obviously, when Sm2O3 content was 0.001mol, the resistivity was the smallest, which changed from 4.3×109Ω·m to 6.536×103Ω·m. The grain resistance of BaTiO3 ceramics doped with Sm2O3 exhibited NTC, but the grain boundary resistance showed PTC, and the grain boundary resistance was larger than the grain resistance, so the PTC effect originated from the grain boundary.