Dielectric behavior of Bi2/3Cu3Ti4O12 ceramic and thick films |
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Authors: | D Szwagierczak |
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Affiliation: | (1) Cracow Division, Institute of Electron Technology, Zabłocie 39, 30-701 Kraków, Poland |
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Abstract: | The paper reports on synthesis, sintering and microstructure of Bi2/3Cu3Ti4O12, a lead-free, high-permittivity material with internal barrier layer capacitor behavior. Complex impedance and capacitance
of the ceramic and thick films were studied as a function of frequency (10 Hz–2 MHz) and temperature (−170 to 400°C). Dc electrical
conductivity of the samples was measured in the temperature range 20–400°C. Broad and high maxima of dielectric permittivity
versus temperature plots were observed reaching 60,000 for ceramic and 5,000 for thick films. The maxima decrease and shift
to higher temperatures with increasing frequency. Two arcs ascribed to grains and grain boundaries were found in the plots
of imaginary part versus real part of impedance. Analysis of the impedance spectra indicates that Bi2/3Cu3Ti4O12 ceramic could be regarded as electrically heterogeneous system composed of semiconducting grains and less conducting grain
boundaries. The developed thick film capacitors with dielectric layers based on Bi2/3Cu3Ti4O12 exhibit dense microstructure, good cooperation with Ag electrodes, high permittivity up to 5,000 and relatively low temperature
coefficient of capacitance in the temperature range 100–300°C. Broad maxima in the dielectric permittivity versus temperature
curves may be attributed to Maxwell–Wagner relaxation. |
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Keywords: | Bi2/3Cu3Ti4O12 ceramic Thick films Dielectric response Internal barrier layer capacitor |
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