Abnormal dielectric behaviors in Mn-doped CaCu3Ti4O12 ceramics and their response mechanism |
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| Authors: | Yuan-Hua Lin Wei Deng Wei Xu Yong Liu Dongliang Chen Xiaoli Zhang Ce-Wen Nan |
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| Affiliation: | 1. State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, PR China;2. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, PR China;3. Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, PR China;4. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, PR China |
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| Abstract: | Mn-doped CaCu3Ti4O12 (CCTO) polycrystalline ceramics have been prepared by the conventional solid state sintering. Our results indicate that 10% Mn doping can decrease the dielectric permittivity in CaCu3Ti4O12 by about 2 orders of magnitude (from 104 to 102). The grain and grain boundary activation energies show an obvious increase from 0.054 eV to 0.256 eV, and decrease from 0.724 eV to 0.258 eV with increasing the Mn doping concentration, respectively, which may be caused by the variation of Cu and Ti valence states in the CCTO samples evidenced by the X-ray absorption spectra. The similar grain and grain boundary activation energies result in invalidation of the internal boundary layer capacitance effect for the 10% Mn-doped CCTO sample, and thus result in the dramatic decrease of dielectric permittivity. |
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| Keywords: | CaCu3Ti4O12 High dielectric Activation energy |
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