Low-frequency dispersion of ZnO/Bi2O3 ceramics analyzing by universal power law

Recently, universal power law becomes widely used. In this paper, it was used to study the ZnO/Bi₂O₃ ceramics. Bi₂O₃ is the only additive of ZnO here in order to directly study the effect of Bi₂O₃ in ZnO. ZnO samples with different content of Bi₂O₃ were made by the traditional ceramic technique. Then the microstructure of the acid erosion surface was observed by polarized optical microscope, the dielectric properties of the samples, such as conductivity, permittivity and dielectric loss, were tested by Novocontrol Broadband-Frequency Dielectric Temperature Measuring Instrument, and the activation energy was calculated by Arrhenius relation. A strong Anomalous low-frequency dispersion phenomenon was found while investigating the dielectric properties of ZnO/Bi₂O₃ ceramics. The experimental results of the dielectric properties which are in the frequency range of 0.1 Hz ~ 10⁷ Hz and the temperature range of 173 K ~ 473 K were systematically analyzed by universal power law. The results show that the conductivity loss is the main factor in the low frequency, while the dielectric loss is dominant in the high frequency. The higher the temperature, the more similarity of the AC I-V characteristic to the DC ones, which means that omega_e can token the thermally simulated degree of electrons to the temperature, since the conductivity of the samples was generated mostly by thermally simulated electrons. The density ratio of zinc interstitials and oxygen vacancies decreased with the increase of Bi₂O₃ content fewer than 5 wt%, and then it will be oxygen vacancies from 5 wt % Bi₂O₃ content to 15 wt% that dominated the dielectric properties.