Dielectric constant versus voltage and non-Ohmic characteristics of Bi_2/3Cu₃Ti₄O₁₂ ceramics prepared by different methods

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• 作者：Longhai Yang ; Xiaolian Chao ^{chaoxl@snnu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Zhao Yang ; Nan Zhao ; Lingling Wei ; Zupei Yang ; ^{yangzp@snnu.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：C. Dielectric properties ; Bi2/3Cu3Ti4O12 ; Impedance spectroscopy ; Non-Ohmic properties
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：1 February 2016
• 年：2016
• 卷：42
• 期：2
• 页码：2526-2533
• 全文大小：2142 K

文摘

Bi_2/3Cu₃Ti₄O₁₂ (BCTO) ceramics were successfully prepared by traditional solid-state reaction method (BCTO-SS) and sol–gel method (BCTO-SG). Pure perovskite phase and dense structure were obtained in BCTO ceramics prepared by both methods. BCTO-SG ceramics showed a large dielectric constant of ~1.1×10⁴ while BCTO-SS ceramics exhibited a low dielectric constant of ~3200. At 100 kHz, the dielectric constant of BCTO-SS ceramics decreased with applied voltage increasing, while the dielectric constant of BCTO-SG ceramics increased with applied voltage increasing. Further study of the relationship between dielectric constant and voltage suggested BCTO-SG ceramics had larger defect concentration than BCTO-SS ceramics. The investigation of complex impedance indicated that the electrical properties of grain boundaries for all BCTO ceramics were evidently affected by applied voltages and the electrical properties of grains were independent of applied voltages. In addition, the non-Ohmic properties of BCTO ceramics were studied in detail. The non-linear coefficients of BCTO-SS and BCTO-SG ceramics were 1.65 and 1.01, respectively. The breakdown electric fields of BCTO-SS and BCTO-SG ceramics were found to be 1.21 and 0.48 kV/cm, respectively. The potential barrier heights of BCTO-SS and BCTO-SG ceramics were calculated to be 0.549 and 0.485 eV, indicating that the potential barriers at the grain boundaries for BCTO-SS and BCTO-SG ceramics are the Schottky-type barrier.