The domain contribution to the aging characteristics of BaTiO3 (BTO) ceramics in a DC electric field was quantitatively investigated using microwave dielectric spectroscopy. The BTO aging effect was related to its domain size (DS): The reduction in the apparent permittivity by the DC electric field, Δϵ, increased with decreasing BTO DS. Inspection of the microwave dielectric spectra revealed that dipole polarization governed the overall aging effect regardless of the BTO DS, and that the ionic and electronic polarizations contributions were small. Substitutional loading of acceptor Mg2+ into the Ti4+ site decreased the BTO's DS because defect pairs consisting of MgTi′′ and its counterpart VO - acted as nucleation sites for new domain walls. Magnesium-loaded BTO (Mg-BTO) had smaller Δϵ values (attributed to dipole polarization) than BTO for similar DS. The MgTi′′-VO - defect complex effectively clamped the domain walls, thereby suppressing domain wall migration in the presence of an electric field. The measured permittivity decrease under a DC field was 423 for BTO but 246 for Mg-BTO with a similar DS, corresponding to a 41.8% improvement.
ASJC Scopus subject areas
- Physics and Astronomy(all)