High thermal stability of RF dielectric properties of BiVO4 matrix with added ZnO
| Autor: | D. X. Gouveia, G. S. Batista, Dang-xia Zhou, An.V. Trukhanov, D. C. Souza, L.V. Panina, S.V. Trukhanov, R. G. M. Oliveira, Antonio Sergio Bezerra Sombra, Charanjeet Singh, J. E. V. de Morais, Marcelo Antônio Santos Da Silva |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
Constant phase element Analytical chemistry Dielectric Activation energy Condensed Matter Physics Capacitance Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials chemistry.chemical_compound chemistry visual_art Bismuth vanadate visual_art.visual_art_medium Grain boundary Ceramic Electrical and Electronic Engineering Temperature coefficient |
| Zdroj: | Journal of Materials Science: Materials in Electronics. 31:13078-13087 |
| ISSN: | 1573-482X 0957-4522 |
| DOI: | 10.1007/s10854-020-03858-x |
| Popis: | In this work, a complex impedance spectroscopy study of bismuth vanadate (BiVO4) ceramics with different additions of ZnO (25, 50, and 75 wt %) was performed. BiVO4 (BVO) was synthesized by the reaction method in solid-state and calcined at 500 °C and BVO–ZnO composites were moulded in sintered ceramic pellets at 700 °C. X-ray diffraction (XRD) was used to analyse the crystal structure of BVO and the BVO–ZnO composites; none spurious phase was observed during the synthesis. Analysis by complex impedance spectroscopy (CIS) showed that increasing the concentration of ZnO reveals increased activation energy due to thermo-activated charge transfer for the sample with 25 wt % ZnO. At room temperature, the increase in the ZnO concentration in the BVO matrix maintained a high value for the dielectric constant (e), in the order of 104 at a frequency of 1 Hz. Average normalized change (ANC) was used to identify the temperature at which the available density of trapped charge states vanishes in each sample. The temperature coefficient of capacitance was positive for BVO and negative for composites. The adjustment through the equivalent circuit presented excellent electrical response for the composites, and identified an association with three resistors, each in parallel a constant phase element, showing the influence of grain and grain boundary on the process of thermo-active conduction. |
| Databáze: | OpenAIRE |
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