Facultatea de Fizică
Universitatea "Al.I.Cuza" Iaşi
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| Titlu: Description of Maxwell-Wagner dielectric dispersion by equivalent circuits in impedance spectroscopy characterization |
| Autori: Geanina Apachitei1, Lavinia-Petronela Churecheriu 1 |
| Afiliere: 1Department of Physics, Faculty of Physics, Univ. “Al. I. Cuza”, Iasi, Romania |
| Abstract: The impedance spectroscopy tool is a very important technique for the characterization of discrete materials (polycrystalline, with solid-solid, solid-liquid interfaces, nanostructured materials). These materials have complex electrical properties at local scale, needing advance experimental method for investigation and a detailed correlation with the microstructural characteristics. At interfaces a strong variation of physical properties takes place (crystallographic, mechanic, compositional and electric), following by a distribution of heterogeneous polarization charges. The interfaces are uniformly polarized by the electric field and they have large contribution to total polarization of the system, especially at low frequency. The impedance spectroscopy is based on determination of complex impedance in a large frequency range and studying the response using equivalent circuits. The electrical heterogeneity regions (different permittivity and conduction) give multiple components in complex diagram, while homogeneous electrical regions have a singular semicircle in the Cole-Cole plot. In the present paper, a method for analyzing experimental the dielectric dispersion observed in heterogeneous materials was developed by designed and build different circuits in order to modeling complex response of ceramics systems. The heterogeneity of specimen can be represented by an equivalent circuit composed by a combination of paralel and series conections of two rezistances and two capacitances (two-layer model). The circuits were analized for frequencies from 10 Hz to 2 MHz using the impedance spectroscopy method. The loss tangent was represented as a function of frequency. |
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