Influence of Grain Growth on Electric Properties of Er-Doped BaTiO3

This paper investigated the effect of grain growth on the electrical characteristics of Er-doped BaTiO3 ceramics. The concentrations of Er2O3 ranged from 0.01 to 1.0 at% Er. For the samples doped with a low concentration of additives and sintered at 1320°C, a uniform microstructure with an average grain size of 1 - 5 °m is characteristic. In Er-BaTiO3 ceramics sintered at a higher temperature, in samples doped with a higher concentration of dopants, the appearance of secondary abnormal grains with a domain structure was observed. Higher values of the dielectric constant were obtained for samples with a lower concentration of dopants (0.01 and 0.1 at% Er) sintered at 1380°C. For samples with an Er content above 0.5 at%, the lower value of the dielectric constant is due to secondary abnormal grain growth and the presence of a non-ferroelectric phase rich in Er. Very low values of dielectric losses (from 0.006 to 0.02) are characteristic of all tested samples. Electrical resistivity decreases with increasing additive concentration up to 0.5 at%, while it increases above 0.5 at% of Er.