Processing of lanthanum doped CaCu3Ti4O12 electroceramics in molten eutectic mixture for low loss high dielectric materials

• Main Author: Arindam Sen
• Format: Article
• Language: English
• Published: University of Novi Sad 2020-09-01
• Series: Processing and Application of Ceramics
• Subjects: cacu3ti4o12 ceramics; dielectric properties; microstructure; perovskites; sintering
• Online Access: http://www.tf.uns.ac.rs/publikacije/PAC/pdf/PAC%2049%2009.pdf

Giant dielectric material CaCu3Ti4O12 (CCTO) has found widespread applications, but associated high dielectric loss is still a major concern. The decreasing of dielectric tangent loss (tan δ) via rare earth element doping has been proven to be effective strategy, but in most cases it involves complex and time consuming processing. In the present paper, a fast and facile process is reported for the synthesis of lanthanum doped CCTO powders (Ca1-xLaxCu3Ti4O12 where x = 0.0, 0.05 and 0.1) using molten eutectic mixture as the reaction medium. The obtained powders were pressed and finally sintered at 1050 °C. La3+ substitution at Ca2+ site results in remarkable reduction in dielectric loss (tan δ < 0.03) at room temperature compared to the parent CCTO. The increased grain boundary resistance (Rgb) estimated from room temperature complex impedance plane plot (Z∗) for the doped ceramics is proposed to be the major cause for higher thermal stability of dielectric constant (εr) and remarkable reduction in tan δ at room temperature. Furthermore, the frequency and temperature stability of εr and tan δ over wide ranges make the doped CCTO a promising candidate for high temperature ceramic capacitor application.