Grain Size Effect on Dielectric Properties of Ba(Zr,Ti)O3 Ceramics

We demonstrated the size effect on the dielectric properties of BaZrxTi1-xO3 (x = 0.2 and 0.25) ceramics that showed relaxor behavior. Fine-grained BaZrxTi1-xO3 ceramics with micrometer- and nanometer-sized grains were fabricated by the two-step sintering method and aerosol deposition (AD) method, respectively. From the dielectric measurement, the permittivity of the BaZrxTi1-xO3 ceramics markedly decreased with decreasing grain size below 3 µm. The permittivity of the BaZrxTi1-xO3 nanograined ceramics decreased with increasing Zr content and was much smaller than the permittivity of the BaTiO3 nanograined ceramics. These results indicated that the BaZrxTi1-xO3 ceramics were more susceptible to the grain size effect than the pure BaTiO3 ceramics. The dielectric responses to temperature and frequency suggested that the volume fraction of polar nanoregions decreased and the relaxor characteristics increased with decreasing grain size in BaZrxTi1-xO3 ceramics.