Effects of oxygen vacancies and grain sizes on the dielectric response of BaTiO_3

摘要

The effects of grain size and oxygen vacancies on the dielectric responses of BaTiO_3 ceramics were investigated using wideband dielectric spectroscopy. Both dipole and ionic polarizations were enhanced by the reduction in grain size down to 2.5 μm. The annealing in low oxygen partial pressure markedly suppressed the dipole polarization possibly due to the domain-wall clamping by oxygen vacancies. To explain the dielectric response of BaTiO_3 ceramics, a complex structure including gradient lattice strain layers (GLSL) were proposed as a model of 90° domain structure.