Significantly improved non-Ohmic and giant dielectric properties of CaCu_3-xZn_xTi₄O₁₂ ceramics by enhancing grain boundary response

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• 作者：Jakkree Boonlakhorn^a ; Pinit Kidkhunthod^b ; Bundit Putasaeng^c ; Prasit Thongbai^a ; ^{pthongbai@kku.ac.th}
• 关键词：CaCu3Ti4O12 ; Impedance spectroscopy ; Electrical properties ; Loss tangent ; Dielectric permittivity
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：1 February 2017
• 年：2017
• 卷：43
• 期：2
• 页码：2705-2711
• 全文大小：1483 K
• 卷排序：43

文摘

The high permittivity of CaCu3Ti4O12 ceramics has attracted considerable attention in recent years due to their potential applications in electronic devices. However, their dielectric loss tangents are still too large. Here, we report of achieving a greatly decreased loss tangent with retaining high permittivity in Zn-doped CaCu3Ti4O12 (x=0–0.10) ceramics prepared using a modified sol–gel method. The influences of Zn2+ doping on the microstructure, giant dielectric response, and non–Ohmic properties as well as microscopic effects on the electrical properties of grain and grain boundary were systematically studied. In addition to their dielectric properties, their non–Ohmic properties were remarkable improved. Very–low loss tangents (tanδ~0.016–0.017) and high permittivities (ε′~6500–7700) at 1 kHz were successfully achieved in CaCu3-xZnxTi4O12 ceramics with x=0.05–0.10. Substitution of Zn2+ ions into Cu2+ sites caused an increase in the total resistance, which was governed by the grain boundary resistance. The potential barrier height of CaCu3Ti4O12 ceramics was significantly increased by Zn2+ dopant ions. The reduced apparent tanδ and improved nonlinear electrical properties were primary attributed to the modified grain boundary response as a result of Zn2+ doping.