Dielectric properties and high-temperature dielectric relaxation of tungsten-bronze structure ceramics Ba2GdFeNbTa3O15
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Ba2GdFeNbTa3O15 was synthesized by a standard solid-state technique, which adopts a tetragonal filled tungsten bronze structure and exhibits paraelectric nature at room temperature. The dielectric temperature coefficient of Ba2GdFeNbTa3O15 at 1 MHz is 147 ppm °C . −1 AC impedance plots were used as tools to analyze the electrical behavior of the sample as a function of frequency at different temperatures. The conduction is a thermally activated process with activation energy ~1.30 eV. The frequency-dependent maxima in the imaginary part of impedance are found to obey an Arrhenius law with activation energy ~1.34 eV. Such a value of activation energy suggests the existence of a relaxation mechanism (a conductive process), which may be interpreted by an ion hopping between neighboring sites within the crystalline lattice.
KeywordsDielectric Relaxation Relaxation Frequency Dielectric Anomaly Debye Relaxation Precision Impedance Analyzer
This work was supported by Natural Science Foundation of China (Nos. 50962004, 51002036), Natural Science Foundation of Guangxi (Nos. 0832003Z, 0832001, C013002), ICDD Grant-in-Aid Program, and Programs for New Century Excellent Talents in Guangxi (No. 2006202). This work was also sponsored by Guangxi Key Lab for the Advanced Materials and New Processing Technology (0842003).
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