Electric and Dielectric Properties of Nb-Doped CaCu3Ti4O12 Ceramics |
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| Authors: | Seong-Hyeon Hong Doh-Yeon Kim Hyun-Min Park Young-Min Kim |
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| Affiliation: | Department of Materials Science and Engineering and Nano Systems Institute-National Core Research Center, Seoul National University, Seoul 151-742, Korea; New Materials Evaluation Center, Korea Research Institute of Standards and Science, Taeduk Science Town, Taejon 305-600, Korea; Division of Electron Microscopic Research, Korea Basic Science Institute, Taejon 305-333, Korea |
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| Abstract: | Pure and Nb-substituted CaCu3Ti4− x Nb x O12+ x /2 (CCTO, x =0, 0.02, 0.1, 0.2, 0.4) ceramics were prepared by a conventional solid-state sintering, and their electric and dielectric properties were investigated using an impedance analyzer. A single-phase CCTO was obtained up to x =0.2 Nb substitution and the lattice parameter increased with Nb substitution concentration. While the grain size decreased with Nb substitution, the resistivity of the grain boundary decreased. The dielectric constant increased with Nb substitution, and the highest value of ∼420 000 was observed in the x =0.2 Nb-substituted specimen at 10 kHz. The obtained electric and dielectric properties in Nb-substituted CCTO were discussed in terms of the internal barrier layer capacitor model, particularly focusing on a ratio of thickness of the grain boundary region to grain size. |
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