Colossal dielectric permittivity and electrical properties of the grain boundary of Ca_1∿x/2Yb_xCu_{3∿span style='font-style: italic'>y}Mg_yTi₄O₁₂ (x=0.05, y=0.05 and 0.30)

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• 作者：Jakkree Boonlakhorn^a ; Pinit Kidkhunthod^b ; Prasit Thongbai^c ; ^{pthongbai@kku.ac.th" class="auth_mail" title="E-mail the corresponding author} ; Santi Maensiri^d
• 关键词：Loss tangent ; Colossal dielectric ; CaCu3Ti4O12 ; Impedance spectroscopy ; Co-doping
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：15 May 2016
• 年：2016
• 卷：42
• 期：7
• 页码：8467-8472
• 全文大小：2021 K

文摘

Dielectric properties of Ca_1−3x/2Yb_xCu_3−yMg_yTi₄O₁₂ (x=0.05, y=0.05 and 0.30) prepared using a modified sol–gel method and sintered at 1070 °C for 4 h were investigated. The mean grain sizes of the CaCu₃Ti₄O₁₂ and co-doped Ca_0.925Yb_0.05Cu_3−yMg_yTi₄O₁₂ (y=0.05 and 0.30) ceramics were ≈15.86, ≈3.37, and ≈2.32 μm, respectively. Interestingly, the dielectric properties can be effectively improved by co-doping with Yb³⁺ and Mg²⁺ ions to simultaneously control the microstructure and properties of grain boundaries, respectively. These properties were improved over those of single-doped and un-doped CaCu₃Ti₄O₁₂ ceramics. A highly frequency−independent colossal dielectric permittivity (≈10⁴) in the range of 10²–10⁶ Hz with very low loss tangent values of 0.018–0.028 at 1 kHz were successfully achieved in the co-doped Ca_0.925Yb_0.05Cu_3−yMg_yTi₄O₁₂ ceramics. Furthermore, the temperature stability of the colossal dielectric response of Ca_1−3x/2Yb_xCu_3−yMg_yTi₄O₁₂ was also improved to values of less than ±15% in the temperature range from −70 to 100 °C.