Effect of cerium oxide (CeO2) additives on the dielectric properties of BaTiO3ceramics

The effect of adding 0.05 to 16.2 mol.% CeO 2 on the dielectric properties and loss tangent of sintered BaTiO 3 was investigated at different temperatures. The permittivity increased with CeO 2 additions up to 0.5 mol%, then decreased with increasing concentrations. In the samples doped with 5.6 and 16.2 mol.% CeO 2 the curves show a slight increase in the permittivity with temperature, without any significant tendency to a peak value, down to room temperature. Smaller additions of CeO 2 (0.05 to 2 mol.%) lower the Curie temperature to 92 degrees C. The loss tangent maximum (tan delta ) max at the Curie temperature was less than 0.035 for pure BaTiO 3 and 0.0120 for samples containing 16.2 mol.% CeO 2 . X-ray measurement shows that the lattice parameters change with the concentration of additive, the a axis expanded while the c axis shrank, approaching a cubic structure at room temperature for 5.6 mol.% CeO 2 (c/a=1.001249). Shrinking of the c axis reached its maximum at 16.2 mol.% CeO 2 (c/a=0.994341).