Dielectric spectroscopy on Bi3Zn2Sb3O14 ceramic: an approach based on the complex impedance
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Data
2003-12-01
Autores
Nobre, MAL
Lanfredi, S.
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Elsevier B.V.
Resumo
The dielectric properties and loss of Bi1.5ZnSb1.5O7 a poor-semiconducting ceramic were investigated by impedance spectroscopy, in the frequency range from 5 Hz to 13 MHz. Electric measurements were performed from 100 to 700 degreesC. Pyrochlore type phase was synthesized by the polymeric precursor method. Dense ceramic with 97% of the theoretical density was prepared by sintering via constant heating rate. The dielectric permittivity dependence as a function of frequency and temperature showed a strong dispersion at frequency lower than 10 kHz. The losses (tan delta) exhibit slight dependence with the frequency at low temperatures presenting a strong increase at temperatures higher than 400 degreesC. A decrease of the loss magnitude occurs with increasing frequency. Relaxation times were extracted using the dielectric functions Z(omega) and M(omega). The plots of the relaxation times tau(Z'), and tau(M) as a function of temperature follow the Arrhenius law, where a single slope is observed with activation energy values equal to 1.38 and 1.37 eV, respectively. (C) 2003 Elsevier Ltd. All rights reserved.
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ceramics, electronic materials, chemical synthesis, dielectric properties, electrical properties
Como citar
Journal of Physics and Chemistry of Solids. Oxford: Pergamon-Elsevier B.V., v. 64, n. 12, p. 2457-2464, 2003.