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Significantly reduced conductivity in strontium titanate-based lead-free ceramics by excess bismuth

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


Yuanyuan Wang

Hongbo Liu

Tingnan Yan

Jianwei Zhao

Junjie Li

Shifeng Guo

Shikuan Sun

Rong Sun

Zhilun Lu

Dawei Wang


Lead-free dielectric ceramics 0.75SrTiO3-0.25BiFeO3 (ST-BF) with an extra amount of bismuth (Bi) are synthesized by the conventional solid-state reaction method. The crystal structures of ST-BF retain pseudo-cubic phase as Bi content increases. The grain size is found to significantly increase from 1.8 to 4.9 µm and then fall to 3.3 µm in the presence of excess Bi, exhibiting a distinct heterogeneous core–shell microstructure. Impedance spectroscopy data indicates that with increasing excess Bi content to 2 mol%, the shell resistivity increases significantly to ∼ 9 MΩ cm with the largest volume fraction of the shell/core area, and both the core and shell activation energies are increased, resulting in reduced dielectric loss of ∼ 0.08 at 1 kHz and high breakdown strength of ∼ 140 kV cm−1. This work provides a potential strategy for further improvement of ST-BF for capacitor applications.

Journal Article Type Article
Acceptance Date Dec 4, 2021
Online Publication Date Dec 9, 2021
Publication Date 2022-02
Deposit Date Dec 29, 2021
Publicly Available Date Dec 10, 2022
Journal Materials Letters
Print ISSN 0167-577X
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 309
Article Number 131453
Keywords SrTiO3, BiFeO3, Core–shell microstructure, Impedance, Dielectric properties
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