Microstructure and electrical properties of Nb‐doped SrTiO3‐BiFeO3 based lead‐free ceramics

Wang, Yuanyuan; Liu, Hongbo; Yan, Tingnan; Zhao, Jianwei; Guo, Shifeng; Sun, Rong; Lu, Zhilun; Wang, Dawei

Abstract

In this work, Nb-doped 0.75SrTiO3-0.25BiFeO3 (ST-BF) lead-free ceramics are designed and synthesized using a conventional solid-state reaction method. The influence of Nb doping on the microstructure, dielectric, and electrical properties are systematically investigated. With the increase of Nb concentration, the crystal structure of ST-BF remains pseudo-cubic as exhibited in the X-ray diffraction patterns. The grain size is found to increase from 0.33 to 6.23 μm, and then decrease to 1.88 μm by Nb doping, along with a clear heterogeneous core–shell microstructure. A relatively low dielectric loss (∼0.1, at 1 kHz) and a stable dielectric constant (∼700, at 1 kHz) are obtained for the 0.03 Nb-doped ST-BF composition at room temperature. Impedance spectroscopy analysis shows that Nb doping in ST-BF increases the total resistivity, forming an electrically conductive core and a nonconductive shell, with enhanced activation energy. The results may provide a feasible approach to develop novel ST-based lead-free dielectric ceramics for capacitor applications

• Journal Article Type: Article
• Acceptance Date: Oct 20, 2021
• Online Publication Date: Nov 3, 2021
• Publication Date: 2022-03
• Deposit Date: Nov 18, 2021
• Publicly Available Date: Nov 4, 2022
• Journal: Journal of the American Ceramic Society
• Print ISSN: 0002-7820
• Electronic ISSN: 1551-2916
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 105
• Issue: 3
• Pages: 2020-2028
• DOI: https://doi.org/10.1111/jace.18194
• Keywords: BiFeO3, core–shell microstructure, dielectric properties, impedance, SrTiO3
• Public URL: http://researchrepository.napier.ac.uk/Output/2822618