Abstract: 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 BaTiO_3 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.

Key words: BaTiO₃, Sm₂O₃ dopant, electric characteristics, sol-gel