Kutnyakhov, D., Lushchyk, P., Fognini, A., Perriard, D., Kolbe, M., Medjanik, K., Fedchenko, E., Nepijko, S. A., Elmers, H. J., Salvatella, G., Stieger, C., Gort, R., Bähler, T., Michlmayer, T., Acremann, Y., Vaterlaus, A., Giebels, F., Gollisch, H., Feder, R., Tusche, C., Krasyuk, A., Kirschner, J., Schönhense, G.
Imaging spin filter for electrons based on specular reflection from iridium(001)
Ultramicroscopy 130, pp 63-69 (2013)
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 39eV scattering energy with a broad maximum o f 5eV usable width. A second one at about 10eV shows a narrower profile but much higher FoM. A relativistic layer-KKR SPLEED calculation shows good agreement with measurements.