High Dielectric Permittivity Behavior in Cu-Doped CaTiO3

Authors


  • X. M. Chen—contributing editor

  • This work was supported by the Ministry of Science and Technology of China through a 973-Project under Grant No. 2009CB623303, NSF of China (50737001, and 50677029), and NSF of Beijing.

†Author to whom correspondence should be addressed. e-mail: linyh@mail.tsinghua.edu.cn

Abstract

Cu-doped CaTiO3-based polycrystalline ceramics have been prepared by the conventional solid-state sintering. Our results indicate that the dielectric constant can be enhanced greatly by increasing the Cu-doped content, which show weak frequency and temperature dependence. The fitted activation energy is almost same (∼0.10 eV) as the Cu-doped content is 0.4–0.6, which may be ascribed to the first ionization of the oxygen vacancies. The origin of the high dielectric permittivity observed in these Ca1−xCuxTiO3-based ceramics should be attributed to the interfacial polarization mechanism, and can be well described by the percolation theory with fc≈0.27 and s≈0.74.

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