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Large Dielectric Constant And Maxwell-Wagner Relaxation In Bi2/3cu3ti4o12, Jianjun Liu, Chun-Gang Duan, Wei-Guo Yin, Wai-Ning Mei, Robert W. Smith, John R. Hardy
Large Dielectric Constant And Maxwell-Wagner Relaxation In Bi2/3cu3ti4o12, Jianjun Liu, Chun-Gang Duan, Wei-Guo Yin, Wai-Ning Mei, Robert W. Smith, John R. Hardy
Physics Faculty Publications
We studied frequency and temperature dependences of impedance, electric modulus, and dielectric permittivity of Bi2/3Cu3Ti4O12 in the ranges of 10−1–106 Hz and −150–200 °C, respectively. We first observed two electrical responses in the impedance and modulus formalisms. Then we detected a Debye-like relaxation in the permittivity formalism. Most interestingly, we found that the large dielectric constant of Bi2/3Cu3Ti4O12 is independent of the temperature and frequency below 150°C. The results are interpreted in terms of a two-layer model with conducting grains partitioned from each other by poorly conducting grain boundaries. Using this model, we attributed the two electrical responses in impedance …
Dielectric Permittivity And Electric Modulus In Bi2ti4o11, Jianjun Liu, Chun-Gang Duan, Wei-Guo Yin, Wai-Ning Mei, Robert W. Smith, John R. Hardy
Dielectric Permittivity And Electric Modulus In Bi2ti4o11, Jianjun Liu, Chun-Gang Duan, Wei-Guo Yin, Wai-Ning Mei, Robert W. Smith, John R. Hardy
Physics Faculty Publications
Frequency and temperature dependences of dielectric permittivity and electric modulus of pure and Ba-doped Bi2Ti4O11 were studied in the ranges of 1021–106 Hz and 2150–350 °C, respectively. We found that the antiferroelectric phase transition temperature of Bi2Ti4O11 decreases with Ba doping. In the permittivity studies, we also observed dielectric relaxation peaks shift to higher temperature with increasing frequency. Furthermore, in the electric modulus formalism, conducting peaks were uncovered above 150 °C in addition to the dielectric relaxation peak. We discussed the mechanisms for the dielectric relaxation and conduction processes based on TiO6 octahedra distortion and a space-charge model.