title: The effect of grain boundary on the energy storage properties of (Ba0.4Sr0.6M)TiO3 paraelectric ceramics by varying grain sizes.
abstract: (Ba0.4Sr0.6)TiO3 (BST) ceramics with various grain sizes (0.3-3.4 μm) were synthesized by the oxalate coprecipitation method and prepared by plasma activated sintering and conventional solid-state sintering process. The effect of grain boundary on the energy storage properties and the dielectric relaxation characteristics of BST paraelectric ceramics (Curie point ≈ -67°C) with various grain sizes were investigated. The dielectric breakdown strength (simplified as BDS) is obviously improved and then deteriorated with decreasing grain size, accounting for the energy density variation. The enhancement of interfacial polarization at grain boundary layers has a negative effect on the BDS, leading to the decreased values for samples with grain size smaller than 0.7 μm. In addition, the insulation effect of grain boundary barriers was discussed based on the complex impedance spectroscopy analysis, which was found to play a dominant role in controlling the BDS with coarser grain size. Among them, the sharply decreased BDS for BST with grain size of 1.8 μm was believed to be attributed to the combination of lower grain boundary density and higher interfacial polarization, due to the significant increase of oxygen vacancies at higher sintering temperature.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Song
authors.forename: Hanxing
authors.initials: H
authors.lastname: Liu
authors.forename: Hua
authors.initials: H
authors.lastname: Hao
authors.forename: Shujun
authors.initials: S
authors.lastname: Zhang
authors.forename: Minghe
authors.initials: M
authors.lastname: Cao
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Yao
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.forename: Yatong
authors.initials: Y
authors.lastname: Shi
authors.forename: Biyang
authors.initials: B
authors.lastname: Hu