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.

我们在SPring-8的BL39XU上开发了多种极端条件（低温（4.2K）·高磁场（6T）·高压（20GPa））下的X射线磁衍射实验系统，利用超我们开发了一种利用相位板切换同步辐射螺旋性的 X 射线磁衍射新方法。在 X 射线磁衍射实验中。通过超导磁体衍射，我们可以将非常小的 UTe 晶体（尺寸约为 200 μm）封装在安装在磁体上的砧座中，我们成功地在环境压力下测量了 4.2K 的 UTe 晶格常数。然而，在这个实验中，来自磁体的漏磁场结果改变了存储环中的电子束轨道，并改变了垂直于磁场方向的同步加速器辐射的强度。因此，这种配置被禁止，并且无法通过X射线磁衍射进行LS分离，我们尝试了只能在压力下进行Fe和Ni的X射线MCD（磁圆二色性）测量。对于Ni，通过能带计算得到的轨道力矩与压力的曲线很好地再现了观察到的MCD信号与压力的关系曲线，该结果表明MCD信号与轨道力矩相关。