High-resolution electron microscopy for incommensurate structure of K x RhO2 crystal
High-resolution electron microscopy for incommensurate structure of K x RhO2 crystal
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DOI：
10.1080/14786430903092401
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发表时间：
2009-10
影响因子：
1.6
通讯作者：
K. Yubuta;S. Shibasaki;I. Terasaki;T. Kajitani
中科院分区：
文献类型：
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作者：
K. Yubuta;S. Shibasaki;I. Terasaki;T. Kajitani
在用通量生长法合成的K0.49RhO2晶体中，局部观察到不相称的（3 + 2）维结构。用电子探针微分析仪在波色散光谱模式下测定了生长晶体的平均钾铑比为0.49。用透射电镜-能量色散光谱法测定了不匹配相的钾含量为0.25。具有两个调制矢量的不相称相位的卫星反射（a 0是γ-Na x coo2型结构的单元格），被成功地索引。高分辨率电子显微镜（HREM）图像显示在a-b平面上平行运行的深色条纹。暗条纹的间距和方向与卫星黑子的q向量有密切的关系。平行于[100]方向的电子束拍摄的HREM图像显示cdi2型RhO2层之间的平面团簇。这些簇对应于插入的钾离子。
An incommensurate, (3 + 2)-dimensional structure is locally observed in a K0.49RhO2 crystal synthesized by the flux growth method. The averaged potassium to rhodium ratio of the grown crystals was determined as 0.49 using an electron probe microanalyzer operated in the wave dispersive spectroscopy mode. The potassium content of the incommensurate phase was determined as 0.25 by the transmission electron microscopy–energy dispersive spectroscopy method. Satellite reflections of an incommensurate phase having two modulation vectors, and (a o is the unit cell for a γ-Na x CoO2-type structure), are indexed successfully. High-resolution electron microscopy (HREM) images show dark streaks running parallel in the a–b plane. The separations and directions of the dark streaks have a close relationship between the q -vector of satellite spots. A HREM image taken with the electron beam parallel to [100] direction shows planer clusters between CdI2-type RhO2 layers. These clusters correspond to the intercalated potassium ions.