RMnO₃（R = 镧、镨、钕、钙、锶）和(La, Sr)₂NiO₄的结构特性与电荷有序状态
Structural properties and charge ordered states in RMnO3 (R=La, Pr, Nd, Ca, Sr) and (La, Sr)2NiO4.
作者信息
Li J Q, Chen H Y, Zhang H R, Yu H C, Shi Y G, Liu L B, Tian H F, Zhu Y, Tranquada J M
机构信息
Beijing Laboratory of Electron Microscopy, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
出版信息
Micron. 2004;35(6):419-24. doi: 10.1016/j.micron.2004.01.006.
Structural distortions arising from the condensations of two essential kinds of phonon modes: the triply degenerate rotational modes (phix, phiy, phiz) of MnO(6) and the doubly degenerate Jahn-Teller active modes (Q1, Q2) have been systematically investigated in the perovskite manganites. Microstructural features associated with certain types of distortions have been observed by transmission electron microscopy (TEM). In RMnO(3) and La(Sr)(2)NiO(4), we characterize the local structure, charge ordered states and orbital ordering by means of low-temperature TEM. We present direct evidence that the stripe modulation in La(Sr)(2)NiO(4) is indeed one-dimensional within each NiO(2) plane. Several typical kinds of defect structures, including antiphase boundaries and the 90 degrees -twin domains, appear commonly in the charge-ordered states.
在钙钛矿锰氧化物中，系统地研究了由两种基本声子模式凝聚引起的结构畸变：MnO(6)的三重简并旋转模式（phix、phiy、phiz）和双重简并的 Jahn-Teller 活性模式（Q1、Q2）。通过透射电子显微镜（TEM）观察到了与某些畸变类型相关的微观结构特征。在RMnO(3)和La(Sr)(2)NiO(4)中，我们借助低温TEM表征了局部结构、电荷有序态和轨道有序。我们提供了直接证据，证明La(Sr)(2)NiO(4)中的条纹调制在每个NiO(2)平面内确实是一维的。几种典型的缺陷结构，包括反相边界和90度孪晶畴，在电荷有序态中普遍出现。
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