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Magnetism of Uranium compound under Pressure studied by the X-ray Magnetic Diffraction

X射线磁衍射研究加压下铀化合物的磁性

基本信息

批准号：
11440114
负责人：
ITO Masahisa
金额：
$ 10.18万
依托单位：
Gunma University (2001)Himeji Institute of Technology (1999-2000)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11440114/
关键词：
X-ray magnetic diffraction X-ray magnetic scattering synchrotron radiation ferromagnet high pressure uranium spin magnetic moment orbital magnetic moment フェリ磁性体磁気形状因子超伝導磁石

项目摘要

We have developed an experimental system of X-ray magnetic diffraction under multiple extreme condition (low temperature(4.2K)・high magnetic field(6T)・high pressure(20GPa)) on BL39XU at the SPring-8, by utilizing a super-conducting magnet and a diamond-anvil cell. We have developed a new method of X-ray magnetic diffraction by switching helicity of synchrotron radiation utilizing a phase plate.In the first experiment of X-ray magnetic diffraction with a super-conducting magnet we could enclosed a very small crystal of UTe (〜200 μm in size) in the anvil cell, which was installed to the magnet. We succeeded in measuring the lattice constant of UTe at 4.2K under ambient pressure. However, in this experiment, leak magnetic field from the magnet turned out to alter the electron-beam orbit in the storage ring and change the intensity of synchrotron radiation in the configuration of the magnetic field direction perpendicular to the synchrotron beam. So this configuration was prohibited, and the LS separation by the X-ray magnetic diffraction could not be performed. We tried the X-ray MCD (magnetic circular dichroizm) measurement of Fe and Ni under pressure, which could be made only in the parallel configuration. For Ni, the observed curve of MCD signal vs. pressure was reproduced well by the curve of the orbital moment vs. pressure by the band calculation. This result suggested that the MCD signal is strongly correlated with the orbital moments.

我们利用超导磁体和金刚石压砧装置，在SPring-8上研制了一套BL 39 XU多极端条件（低温（4.2K）、强磁场（6 T）、高压（20 GPa））下的X射线磁衍射实验系统。我们发展了一种利用相位板切换同步辐射螺旋度的X射线磁衍射新方法，在第一次超导磁体X射线磁衍射实验中，我们将一个尺寸为~ 200 μm的UTe晶体装入安装在磁体上的压砧室中。我们成功地在常压下测量了4.2K下UTe的晶格常数。然而，在这个实验中，从磁铁泄漏磁场原来改变电子束在储存环的轨道和改变的磁场方向垂直于同步辐射束的配置的同步辐射的强度。因此，该配置被禁止，并且不能进行通过X射线磁衍射的LS分离。我们尝试了在压力下对Fe和Ni进行X射线MCD（磁性圆二色性）测量，这种测量只能在平行结构中进行。对于Ni，通过能带计算得到的轨道矩-压力曲线很好地再现了观测到的MCD信号-压力曲线。这一结果表明，MCD信号与轨道矩密切相关。