Resonant and non-resonant magnetic scatterings with circularly polarized X-rays: magnetic scattering factor and electron density of gadolinium iron garnet
Resonant and non-resonant magnetic scatterings with circularly polarized X-rays: magnetic scattering factor and electron density of gadolinium iron garnet
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圆偏振 X 射线的共振和非共振磁散射：钆铁石榴石的磁散射因子和电子密度
DOI：
10.1107/s2053273317003588
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Maki Okube and Satoshi Sasaki
中科院分区：
文献类型：
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作者：
Yo Sasaki;Maki Okube and Satoshi Sasaki
利用圆偏振X射线对共振磁散射进行了理论和实验研究。右和左手极化散射振幅之间的不对称比率的偏振依赖性揭示了共振和非共振磁散射可以同时观察到。在这项研究中，同步辐射X射线强度的实验进行了钆铁石榴石（GdIG）在前边缘的铁K吸收边。由于Fe ~（3+）在Fe_2（24 d）位的共振磁响应，圆极化的非对称性比呈现三个峰。这些磁响应是反平行的，并具有明显更高的分辨率比色散X射线磁性圆二色性在前边缘区域，这可以主要归因于电偶极跃迁从1 s到t2能级的3d轨道在四面体对称在一个不稳定的状态淬火在较高的温度。由非对称比估算了共振磁散射因子f′m。使用能量为E = 7.1085 keV的圆偏振X射线之间的强度差进行傅立叶分析。 在这个能级上，可以清楚地观察到磁电子密度的特征分布。这种分布被解释为Gd和Fe离子在GdIG中的自旋排列。还观察到的是存在的杂化的磁性电子轨道，以及共振磁性Fe 3+。该方法在晶体结构分析中具有广泛的应用前景。
Theoretical and experimental studies on resonant magnetic scattering have been carried out using circularly polarized X-rays. Polarization dependence of the asymmetric ratio between right- and left-handed polarized scattering amplitudes has revealed that resonant and non-resonant magnetic scatterings can be observed simultaneously. In this study, synchrotron X-ray intensity experiments were conducted on Gd iron garnet (GdIG) at the pre-edge of the Fe K absorption edge. The asymmetric ratio between circular polarizations exhibited three peaks due to the resonant magnetic responses of Fe3+ in the Fe2 (24d) site. These magnetic responses are antiparallel and have apparently higher resolution than dispersive X-ray magnetic circular dichroism at the pre-edge region; this can be mainly attributed to electric dipole transitions from 1s to t2 energy levels of the 3d orbitals in the tetrahedral symmetry in an unstable state quenched at higher temperature. Resonant magnetic scattering factors f′m were estimated from the asymmetric ratios. Fourier analysis was conducted using the intensity differences among circularly polarized X-rays at an energy of E = 7.1085 keV. At this energy level, the characteristic distribution of magnetic electron density was clearly observed. This distribution was interpreted as a spin arrangement of Gd and Fe ions in GdIG. Also observed was the presence of hybridization of the magnetic electron orbitals as well as of the resonant magnetic Fe3+. The proposed method has the potential to be widely used in crystal structure analysis.