Study of magnetic circular dichroism in hard x-ray emission spectroscopy in the alloys of transitional elements and rare-earth

通过二阶光激发过程发射的X射线的能谱提供了关于所选元素的相当有价值的信息，它直接反映了电子的基态和激发态。这种非弹性散射X射线的光谱被称为X射线发射光谱(XES)。本项目的目标是发展与自旋相关的磁性圆二色谱(MCD-XES)的方法学及其在过渡金属和稀土中的应用。本研究最显著的成果是获得了非常精确的MCD-XES谱，并将结果与理论计算进行了定量检验，这首次使MCD效应的起源得到了适当的解释，并发表在《物理评论》上。为了在Spring-8建立XES束线，与东北大学课题组合作，进行了测量装置和各种测试实验。建立了包括MCD-XES在内的XES的测量和分析方法。其中，“寿命展宽-抑制/自由XANES”的发展尤为重要，它支持了MCD-XES应用的广泛发展。

Energy spectra of the X-ray emitted via the second order photo-excitation process give quite valuable information on a selected element which directly reflects ground states and excited states of electrons. This type of spectroscopy for inelastic scattering x-rays is named X-ray Emission Spectroscopy (XES).The objective of the present project is to develop the methodology of the spin-dependent magnetic circular dichroism XES (MCD-XES) and the application to transition metals and rare earths.The most remarkable achievement of the present study is that very precise MCD-XES spectra were obtained and the results were quantitatively examined comparing with the theoretical calculations, which for the first time enabled an appropriate interpretation of the origins of the MCD effect and was published in Physical Review.In order to construct the XES beam line at SPring-8, the measuring apparatus and various testing experiments were made by the cooperation with the group of Tohoku University. And the methodologies of the measurements and the analyses for the XES including MCD-XES have been established. Among them, the development of "Lifetime-broadening-suppressed/free XANES" is especially important, which supports the wide development of the applications of MCD-XES.