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畴是所有铁性材料的一个共同本质特性,畴及畴界的结构极大影响着材料性能。本文应用高分辨透射电子显微学和定量电子显微学,在原子尺度定量研究了钙钛矿菱面体结构多铁性薄膜BiFeO3的109°畴界的精细结构,包括畴界附近阳离子位移及局部铁电极化分布。结果表明:正是由于畴界附近原子发生微小位移,导致材料能带的变化,带隙减小,从而在绝缘BiFeO3中产生独特的导电性能。这不仅为研究铁电极化反转和磁电效应等科学问题提供关键的定量结构信息,同时也促进相关材料的设计和性能优化。
Domain is a common essential property of all iron materials. The structure of domain and domain boundary greatly influences the material properties. In this paper, high-resolution transmission electron microscopy and quantitative electron microscopy were used to quantitatively study the fine structure of the 109 ° domains of the perovskite-structured polyferroic thin film BiFeO3 at the atomic scale, including the cation displacement near the domain boundaries and the local Ferroelectric polarization distribution. The results show that it is due to the small displacement of the atoms in the vicinity of the domain boundary, which leads to the change of the band gap of the material and the decrease of the band gap, thus resulting in a unique conductivity in the insulated BiFeO3. This not only provides key quantitative structural information for studying the ferroelectric polarization reversal and magnetoelectric effect, but also promotes the design and performance optimization of related materials.