The effect of thulium oxide (Tm2O3) doping on the electrical properties of barium titanate (BaTiO3) ceramics was investigated in terms of the crystallinity and core-shell structure. The electrical properties of the Tm2O3 doped BaTiO3 were evaluated by measurements of the dielectric constant and temperature coefficient of capacitance (TCC) in addition to insulation resistance (IR). The dielectric constant and the IR of an undoped dielectric specimen were about 30% and 20%, respectively, lower than the values of a 1 mol% Tm2O3 doped specimen which met the reliability test condition in the range from -55 to 125 oC. The addition of Tm2O3 in BaTiO3 contributed to the enhanced electrical properties; however, an excessive addition had bad effects on the characteristics of BaTiO3 due to the formation of a second phase and the expansion of the shell region. This could be explained by the fact that the improved dielectric properties and IR according to the appropriate doping of Tm2O3, were revealed by an increase of the crystallinity and the reinforcement of the core-shell structure in BaTiO3.

Keywords: BaTiO3, Thulium, Electrical properties, Crystallinity, Core-shell structure.