| Original Articles |
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Investigation of the Size Effect on the Giant Dielectric Constant of CaCu3Ti4O12 Ceramic |
| CHEN Kai;LI Wei;LIU Yun-Fei;BAO Peng;LU Xiao-Mei;ZHU Jin-Song |
| National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 |
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| Cite this article: |
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CHEN Kai, LI Wei, LIU Yun-Fei et al 2004 Chin. Phys. Lett. 21 1815-1818 |
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Abstract Cubic perovskite-related ceramic CaCu3Ti4O12 has a very high dielectric constant larger than 10000 in the kilohertz frequency region. It is almost constant in the 100--600K region. The ceramic compounds were prepared by conventional solid-state reaction at different sintering temperatures 1040°C(C04),1060°C(C06), 1080°C(C08), and 1100°C(C10). Impedance spectroscopy on CaCusTi4O12 ceramics demonstrates that they are electrically heterogeneous and consist of semi-conducting grains with insulating grain boundaries. It is shown that C06 is the most suitable one for device applications. Surface observation and analysis of the grain-boundary-grained structure were carried out by using scanning electron microscopy, which confirms that the samples have clearly different crystal grain sizes and C06 has a larger grain size of about 20μm. Compared to the dielectric relaxation spectroscopy, the mechanical relaxation spectroscopy on C06 was performed and a mechanical loss peak was found, which was attributed to the thermally activated behaviour being immanent in the grains.
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| Keywords:
77.84.Dy
77.22.Ch
62.40.+i
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Published: 01 September 2004
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| PACS: |
77.84.Dy
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77.22.Ch
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(Permittivity (dielectric function))
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62.40.+i
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(Anelasticity, internal friction, stress relaxation, and mechanical resonances)
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