Effect of Rare-Earth Ions on Electrical Properties of BaTiO3 Ceramics

The effect of rare earth ions on dielectric permittivity, dielectric losses and microstructure of barium titanate ceramics doped with Ho, Er and Yb at the concentrations of 0.05 wt% to 1.0 wt% was investigated. The doped BaTiO3 were obtained by solid-state sintering reaction at a temperature of 1320°C in air atmosphere. The electrical properties were measured in the temperature interval from 30°C to 180°C at different frequencies. The results of electrical investigation showed that samples doped with a low additives concentration, with a spherical and large grains, have high dielectric constant value. εrat Curie temperature is 4250, 3828 and 3011 for 0.05 wt% Ho, Er and Yb respectively. By increasing dopant concentration and decreasing grain size, the dielectric permittivity value decreases. All investigated samples have low values of dielectric losses ranged from 0.01 to 0.09. Also, samples with a low concentration of additives follow Curie-Weiss‘s law. The Curie temperature of doped samples is slightly lower than Curie temperature of the undoped ceramics and it is 126-128 °C. The Curie constant $C$ for all examined samples increases with increasing dopant concentration, so that the highest values were measured for the samples doped with 1.0 wt% of the additive.