Effects of praseodymium substitution on electrical properties of CaCu<sub>3sub>Ti<sub>4sub>O<sub>12sub> ceramics

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• 作者：Alok Kumar Rai ; Jihyeon Gim ; Eui-chol Shin ; Hyun-Ho Seo ; Vinod Mathew ; K.D. M ; al ; Om Parkash ; Jong-Sook Lee ; Jaekook Kim
• 关键词：B. Grain size ; C. Electrical properties ; C. Dielectric properties ; D. Perovskites
• 刊名：Ceramics International
• 出版年：January, 2014
• 年：2014
• 卷：40
• 期：1_part_PA
• 页码：181-189
• 全文大小：1450 K

文摘

Effect of praseodymium (Pr<sup>3+sup>) substitution at Ca<sup>2+sup> site in calcium copper titanate, CaCu<sub>3sub>Ti<sub>4sub>O<sub>12sub> (CCTO), has been investigated. Compositions with x=0.10 and 0.20 were synthesized in the system Ca<sub>(1鈭?x/2)sub>Pr<sub>xsub>Cu<sub>3sub>Ti<sub>4sub>O<sub>12sub> by chemical route. Crystal structure is remained cubic. X-ray diffraction and field-emission scanning electron macrographs indicate the presence of secondary phases such as CaTiO<sub>3sub> and CuO. X-ray photoelectron spectroscopy suggests the substitution of Ca<sup>2+sup> by Pr<sup>3+sup>/Pr<sup>4+sup>. Low temperature admittance spectroscopy identified two deep trapping levels at 0.098 and 0.073 eV for x=0.20 and 0.078 and 0.060 eV for x=0.10. High temperature impedance spectroscopy shows that the grain boundary potential is 0.40 eV and 0.48 eV for x=0.20 and x=0.10 samples respectively. Pr<sup>3+sup> doping decreases dielectric loss in the bulk at low temperature but increases the dc leakage due to the lower value of grain boundary potential.