Microstructure and electrical properties of MnO2 modified (Ca0.4Sr0.6)Bi4Ti4O15 high Tc aurivillius ceramics

• Published in: Ceramics international Vol. 47; no. 5; pp. 6860 - 6866
• Main Authors: Mitharwal, Chhavi, Mishra, Sakshi, Paliwal, Garima, Mittal, Sakshi, Mitra, Supratim
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2021
• Subjects: Electrical conductivity; Electrical properties; Functional applications; Layered ferroelectrics; Microstructure; Electrical conductivity; Electrical properties; Microstructure; Functional applications; Layered ferroelectrics
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2020.11.030

We have investigated the electrical behaviour of MnO2 modified (x = 0.00, 0.04, 0.08, 0.12 mol) (Ca0.4Sr0.6)Bi4Ti4O15 (CSBT-xMn) ceramics prepared using a conventional solid-state reaction method. The structural analysis confirmed no considerable changes in the crystal structure. However, an improvement in relative density along with dense microstructure was observed due to Mn addition. A temperature-dependent dielectric study showed a significantly low dissipation factor (<0.05) that remained constant up to ~600 °C for x = 0.04. A reasonable relative permittivity (782–1268) was also observed in the frequency range for the same composition. Curie-temperature (TC) for all the composition varied negligibly with Mn content which is found to be beneficial for high-temperature applications. In addition, a significant reduction in the DC conductivity was also observed owing to the formation of defects for a small concentration of Mn. The formation of defect complex between Mn3+Ti’ and oxygen vacancy (VO••) for x = 0.04 reduced the DC conductivity to 10−6 (Ω-cm)−1 even at TC (600 °C). From the impedance study, a very high insulating behavior was observed for a small concentration of Mn (x = 0.04). Therefore, the study showed that (Ca0.4Sr0.6)Bi4Ti4O15 with x = 0.04 could be an appropriate choice of composition for a high-temperature electromechanical application.