Resonant magnetic reflection coefficients at the Fe 2 p edge obtained with linearly and circularly polarized soft x rays
Resonant magnetic reflection coefficients at the Fe 2 p edge obtained with linearly and circularly polarized soft x rays
复制标题
使用线偏振和圆偏振软 X 射线获得的 Fe 2 p 边缘处的共振磁反射系数
DOI：
10.1103/physrevb.66.184404
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发表时间：
2002
影响因子：
3.7
通讯作者：
P. Oppeneer
中科院分区：
文献类型：
--
作者：
H. Mertins;D. Abramsohn;A. Gaupp;F. Schäfers;W. Gudat;O. Zaharko;H. Grimmer;P. Oppeneer
本文系统地研究了圆偏振和线偏振辐射在磁性材料上的镜面反射率。在基于完全反射矩阵和Stokes参数形式主义的框架内，反射率被建模为入射光的偏振状态的函数，用于纵向和横向磁化。通过极化软x射线在铁磁Fe/C多层膜上的$\mathrm{Fe}\ensuremath{-} 2 p $吸收边的共振磁反射实验，确定了反射系数和它们各自的磁贡献。利用可调波荡器辐射的绝对反射率的圆或线偏振，光子能量，入射角，和磁场方向的程度的函数进行了研究。正如所预测的发达的形式主义的相应的磁不对称性参数依赖于非线性的偏振度在大角度的入射由于样品的偏振功率的影响。在使用圆偏振光的纵向几何结构中，磁贡献与光学常数的磁贡献直接相关，光学常数已通过对相同透射样品的法拉第测量独立地确定。
A systematic study of the specular reflectivity using circularly and linearly polarized radiation on magnetic materials is presented. Within a frame work based on the complete reflection matrix and the Stokes parameter formalism, the reflectance is modeled as a function of the polarization state of the incoming light for the longitudinal and the transversal magnetization. The nonmagnetic reflection coefficients and their individual magnetic contributions are determined from resonant magnetic reflectivity experiments of polarized soft x rays across the $\mathrm{Fe}\ensuremath{-}2p$ absorption edge on a ferromagnetic Fe/C multilayer. Exploiting tunable undulator radiation the absolute reflectance is investigated as a function of the degree of circular or linear polarization, photon energy, angle of incidence, and magnetic-field direction. As predicted by the developed formalism the corresponding magnetic asymmetry parameters depend nonlinearly on the degree of polarization at large angles of incidence due to the influence of the polarizing power of the sample. In the longitudinal geometry using circularly polarized light, the magnetic contribution is directly related to the magnetic contribution of the optical constants, which have independently been determined by Faraday measurements on an identical transmission sample.