Neutron diffraction study of long-range antiferromagnetic order and crystal structure of uranium (III) tri-iodide
Neutron diffraction study of long-range antiferromagnetic order and crystal structure of uranium (III) tri-iodide
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三碘化铀长程反铁磁序及晶体结构的中子衍射研究
DOI：
10.1088/0022-3719/14/13/009
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
W. Szczepaniak
中科院分区：
文献类型：
--
作者：
A. Murasik;P. Fischer;W. Szczepaniak
在1.3 ~ 293K的温度范围内对多晶UI3进行了中子衍射实验，以澄清之前测量中观察到的异常。目前的中子结果证明在TN=(2.8+或0.1)K以下的UI3中存在三维远程反铁磁序。磁性结构对应于k向量（1/2,1/2,1/2），并且U3+的磁矩方向平行于a。与MnO相似，相邻铁磁层（111）的U磁矩方向相反。在1.3K时，U3+ (5f3, 4I9.2)的有序饱和矩mu U=(1.98+或0.05)mu B表明晶体场明显减小。在温度高于TN时，观察到明显的反铁磁性短程有序。在293和4.2K时，用剖面法对UI3的PuBr3结构参数进行了细化。
Neutron diffraction experiments were performed on polycrystalline UI3 in the temperature range from 1.3 to 293K in order to clarify anomalies which were observed in previous measurements. The present neutron results prove the existence of three-dimensional long-range antiferromagnetic order in UI3 below TN=(2.8+or-0.1)K. The magnetic structure corresponds to k vector (1/2,1/2,1/2), and the magnetic moments of U3+ are oriented parallel to a. Similarly to MnO the U moments of adjacent ferromagnetic (111) layers are aligned in opposite directions. The ordered saturation moment mu U=(1.98+or-0.05) mu B of U3+ (5f3, 4I9.2) at 1.3K indicates a substantial crystal-field reduction. Considerable antiferromagnetic short-range order is observed at temperatures above TN. The parameters of the PuBr3 structure of UI3 were refined by means of the profile method both at 293 and 4.2K.