Theory of X-ray Absorption Magnetic Circular Dichroism and Resonant X-ray Emission Spectra for Mixed Valence Rare-earth Compounds in High Magnetic Fields

利用杂质安德森模型建立了混合价稀土化合物在强磁场下的x射线吸收磁性圆二色性理论，并对日本最新开发的脉冲强磁场法测得的x射线吸收磁性圆二色性实验数据进行了分析。我们首先利用YbInCu_4的Yb L_<2,3>边的电偶极跃迁分析了硬x射线XMCD谱的场依赖性，并考虑了一阶场致价跃迁，然后利用YbAgCu_4的电四极跃迁成功地确定了XMCD。最近，我们成功地分析了EuNi_2(Si_<0.18>Ge_<0.82>)_2的Eu M_<4,5>边缘的软x射线XMCD实验数据。最后对谐振x射线发射光谱（RXES）进行了计算，为今后在高磁场下的RXES实验做准备。

We constructed the theory of X-ray absorption magnetic circular dichroism (XMCD) of mixed-valence rare-earth compounds in high magnetic field with the impurity Anderson model, and analyzed experimental data of XMCD spectra measured by pulsed high magnetic field which was developed recently in Japan. We first analyzed the field dependence of hard X-ray XMCD spectra by electric dipole transition at the Yb L_<2,3>edges of YbInCu_4,taking into account the field-induced valence transition of the first order, and then succeeded in assigning the XMCD by the electric quadrupole transition for YbAgCu_4. More recently, we analyzed successfully the soft X-ray XMCD experimental data at the Eu M_<4,5>edges of EuNi_2(Si_<0.18>Ge_<0.82>)_2. Finally, we made some calculations of resonant X-ray emission spectroscopy (RXES), aiming at future RXES experiments in high magnetic fields.