标题：Huge low-frequency dielectric response of (Nb,In)-doped TiO2ceramics
作者：Wu, Y.Q. ;Zhao, X. ;Zhang, J.L. ;Su, W.B. ;Liu, J.
作者机构：[Wu, Y.Q. ;Zhao, X. ;Zhang, J.L. ;Su, W.B. ;Liu, J. ] School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan; 250100 更多
来源：Applied Physics Letters
摘要：The (Nb,In)-doped TiO2ceramics have drawn considerable attention as a type of promising giant-permittivity dielectric materials in recent years. However, a significant controversy concerning the giant dielectric mechanism currently exists, and clarifying it is vitally important from both scientific and technological viewpoints. This letter reports the results of a systematical comparison study, where two kinds of (Nb,In)-doped TiO2ceramics with a substantial difference in dielectric loss are used. Dielectric properties and complex impedance are investigated over a broad frequency band of 3 mHz-110 MHz. A huge low-frequency dielectric response in addition to the giant dielectric relaxation appearing above 1 MHz is observed for both kinds of (Nb,In)-doped TiO2ceramics in dielectric dispersion. The huge dielectric response observed in the low frequency range can be ascribed to a non-ohmic electrode-contact, and the dielectric relaxation appearing above 1 MHz can be attributed to an internal barrier layer capacitance effect. An electrical equivalent circuit model suggested can well describe the observed dielectric properties and electrical behaviors.
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