材料科学
介电谱
杂质
方向错误
晶界强化
微晶
电子背散射衍射
凝聚态物理
电导率
空间电荷
晶界
分析化学(期刊)
电化学
化学物理
电子
复合材料
冶金
微观结构
电极
物理化学
化学
物理
量子力学
有机化学
色谱法
作者
Xin Xu,Christopher Carr,Xinqi Chen,Benjamin D. Myers,Ruiyun Huang,Weizi Yuan,Sihyuk Choi,Dezhi Yi,Charudatta Phatak,Sossina M. Haile
标识
DOI:10.1002/aenm.202003309
摘要
Abstract Typical models of polycrystalline ionic materials treat the grain boundary properties as single valued, without consideration of the full range of values that define the macroscopically measured average. Here a unique experimental platform suitable for local multimodal characterization of individual grain boundaries in bicrystal fibers is reported. A variation of three orders of magnitude in the grain boundary conductivity of ceria is observed, as measured across six individual bicrystals by both alternating current impedance spectroscopy and direct current (D.C.) linear sweep voltammetry. Nonlinear behavior of the D.C. measurements is consistent with resistance due to a space charge effect. Time‐of‐flight secondary ion beam spectroscopy reveals a correlation between grain boundary resistance and the concentration of impurities Si, Al, and Ca segregated at the grain boundaries, although the bulk concentrations of these impurities are negligible. Electron backscatter diffraction analysis of the crystal orientations suggests a correlation between the misorientation across the grain boundaries and grain boundary resistance. These correlations point towards a grain boundary resistance that arises from impurity‐generated space charge effects and variations in impurity concentration and hence resistivity driven by the energetics of impurity segregation to grain boundaries of differing surface energies.
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