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

Abstract

The effect of adding 0.05 to 16.2 mol.% CeO2 on the dielectric properties and loss tangent of sintered BaTiO3 was investigated at different temperatures. The permittivity increased with CeO2 additions up to 0.5 mol%, then decreased with increasing concentrations. In the samples doped with 5.6 and 16.2 mol.% CeO2 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 CeO2 (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 BaTiO3 and 0.0120 for samples containing 16.2 mol.% CeO2. 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.% CeO2(c/a=1.001249). Shrinking of the c axis reached its maximum at 16.2 mol.% CeO2 (c/a=0.994341).