Abstract: BaTi_1-xSn_xO₃(x=0.02, 0.10, 0.15, 0.25) ceramics were synthesized by the traditional solid state reaction method. XRD spectrum shows that all sample is tetragonal phase. With the increase of Sn⁴⁺/Ti⁴⁺ molar ratio, Curie temperature of all compositions will drop a little. When x value range 0.02 to 0.15, the impedance spectrum analysis shows that the sample resistance may be mainly ascribed to grain boundary. While for composition of x=0.25, the response from grain can not be ignored. Through analyzing the dielectric spectrum and impedance spectroscopy, the values of activation energy calculated from conduction were lower than that calculated from impedance measurements. The results suggest that the relaxation process of BaTi_1-xSn_xO₃ ceramics is dominated by a dipolar conduction. The conduction mechanism can be explained by thermal dynamic process of oxygen vacancy.

Key words: high-temperature dielectric relaxation, impedance, conduction mechanism