Modulated crystal structure and spin/hole arrangement in the chain compound CaxCuO2 (x = 0.8240)
Modulated crystal structure and spin/hole arrangement in the chain compound CaxCuO2 (x = 0.8240)
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链状化合物 CaxCuO2 (x = 0.8240) 中的调制晶体结构和自旋/空穴排列
DOI：
10.1143/jpsj.71.782
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发表时间：
2002
影响因子：
1.7
通讯作者：
E. Takayama
中科院分区：
文献类型：
--
作者：
M. Isobe;K. Kimoto;E. Takayama
用调制结构分析技术对X射线衍射数据进行Rietveld修正，研究了CaxCuO2(x=0.8240)的晶体结构。利用得到的铜氧原子间距离，通过键价和计算确定了空穴分布。结果表明，链上每隔三个铜位就有一个空穴占据。此外，还发现无空位的铜-氧-铜键合角小于90°。这表明最近邻磁相互作用J1是铁磁性的，其大小与次近邻反铁磁相互作用J2相当。基于得到的空穴分布和自旋之间磁相互作用的符号，我们提出了一种可能的链中自旋/空穴排列模型，该模型包含了链中大部分部分的\(\cdots\uparrow\bigcirc\downarrow\downarrow\bigcirc\uparrow\cdots\)主序列。
The crystal structure of Ca x CuO 2 ( x =0.8240) has been studied by the Rietveld refinement of X-ray diffraction data using a modulated-structure analysis technique. Hole distribution was determined by bond-valence sum calculation using the obtained Cu–O inter-atomic distances. The results revealed that every third Cu site along a chain tends to be occupied by a hole. Furthermore, it was found that the Cu–O–Cu bond-angles for hole-unoccupied Cu sites are smaller than 90°. This suggests that the nearest-neighbor magnetic interaction J 1 is ferromagnetic and its magnitude is comparable to the next nearest-neighbor antiferromagnetic interaction J 2 . Based on the obtained hole distribution and the signs of the magnetic interactions between spins, we proposed a possible spin/hole arrangement model in the chain, which includes a main sequence of \(\cdots\uparrow\bigcirc\downarrow\downarrow\bigcirc\uparrow\cdots\) in most parts of the chain.