Improved dielectric properties of BaTiO3-added CaCu3Ti4O12 polycrystalline ceramics

• Published in: Electronic materials letters 2013, 9(3), , pp.325-330
• Main Authors: Kim, Hui Eun, Choi, Soon-Mi, Lee, Sung-Yun, Hong, Youn-Woo, Yoo, Sang-Im
• Format: Article
• Language: English
• Subjects: Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed Matter Physics; Dielectric loss; Dielectric properties; Electric potential; Grain boundaries; Leakage current; Materials Science; Nanotechnology; Nanotechnology and Microengineering; Optical and Electronic Materials; Reduction; Voltage; 전자/정보통신공학
• ISSN: 1738-8090; 2093-6788
• DOI: 10.1007/s13391-013-2202-7

The effects of the BaTiO 3 (BTO) additive on the electrical properties of CaCu 3 Ti 4 O 12 (CCTO) polycrystalline ceramics were systematically investigated. Various amounts of BTO powder up to 15 mol. % were added to CCTO powder. Each batch was ball-milled, pressed into pellets, and finally sintered at 1060°C for 12 h in air. Compared with pure CCTO sample ( ɛ r ∼ 52,000 and tan δ ∼ 0.38 at 100 kHz), BTO-added CCTO samples commonly showed significantly reduced dielectric losses although their dielectric constants were decreased approximately by one order of magnitude (for instance, ɛ r ∼ 4,075 and tan δ ∼ 0.02 at 100 kHz for 5 mol. % BTO-added CCTO sample). In addition, the breakdown voltages of BTO-added CCTO samples were much higher than that of pure CCTO sample, and thus the leakage currents were greatly reduced at the applied voltage above ∼ 10 V. A large reduction in the dielectric losses and leakage currents is attributed to the secondary phases segregated at the CCTO grain boundary which are composed of CaTiO 3 , Ba 4 Ti 12 O 27 , and unreacted BTO.