Johannes Gutenberg-Universität, Institut für Physik, 55099 Mainz, Germany.
Ultramicroscopy. 2013 Jul;130:63-9. doi: 10.1016/j.ultramic.2013.03.017. Epub 2013 Apr 8.
As Stern-Gerlach type spin filters do not work with electrons, spin analysis of electron beams is accomplished by spin-dependent scattering processes based on spin-orbit or exchange interaction. Existing polarimeters are single-channel devices characterized by an inherently low figure of merit (FoM) of typically 10⁻⁴-10⁻³. This single-channel approach is not compatible with parallel imaging microscopes and also not with modern electron spectrometers that acquire a certain energy and angular interval simultaneously. We present a novel type of polarimeter that can transport a full image by making use of k-parallel conservation in low-energy electron diffraction. We studied specular reflection from Ir (001) because this spin-filter crystal provides a high analyzing power combined with a "lifetime" in UHV of a full day. One good working point is centered at 39 eV scattering energy with a broad maximum of 5 eV usable width. A second one at about 10 eV shows a narrower profile but much higher FoM. A relativistic layer-KKR SPLEED calculation shows good agreement with measurements.
斯特恩-格拉赫型自旋滤波器不适用于电子，因此电子束的自旋分析是通过基于自旋轨道或交换相互作用的自旋相关散射过程来完成的。现有的偏振仪是单通道设备，其品质因数（FoM）固有地低，通常为 10⁻⁴-10⁻³。这种单通道方法与平行成像显微镜不兼容，也与同时获取特定能量和角度间隔的现代电子能谱仪不兼容。我们提出了一种新型的偏振仪，它可以通过利用低能电子衍射中的 k 平行守恒来传输全图像。我们研究了 Ir（001）的镜面反射，因为这种自旋滤波器晶体提供了高分析能力，同时在 UHV 中的“寿命”长达一整天。一个良好的工作点位于 39 eV 的散射能，具有 5 eV 的可用宽度的宽最大值。另一个约 10 eV 的工作点具有更窄的轮廓，但 FoM 高得多。相对论层-KKR SPLEED 计算与测量结果吻合良好。
