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Title: Design and performance of a spin-polarized electron energy loss spectrometer with high momentum resolution

Abstract

We describe a new “complete” spin-polarized electron energy loss spectrometer comprising a spin-polarized primary electron source, an imaging electron analyzer, and a spin analyzer of the “spin-polarizing mirror” type. Unlike previous instruments, we have a high momentum resolution of less than 0.04 Å{sup −1}, at an energy resolution of 90-130 meV. Unlike all previous studies which reported rather broad featureless data in both energy and angle dependence, we find richly structured spectra depending sensitively on small changes of the primary energy, the kinetic energy after scattering, and of the angle of incidence. The key factor is the momentum resolution.

Authors:
;  [1]
  1. Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany)
Publication Date:
OSTI Identifier:
22597651
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 87; Journal Issue: 8; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; DESIGN; ELECTRON SOURCES; ELECTRONS; ENERGY LOSSES; ENERGY RESOLUTION; IMAGES; INCIDENCE ANGLE; KINETIC ENERGY; MEV RANGE; MIRRORS; PERFORMANCE; SCATTERING; SPECTRA; SPECTROMETERS; SPIN; SPIN ORIENTATION

Citation Formats

Vasilyev, D., and Kirschner, J.. Design and performance of a spin-polarized electron energy loss spectrometer with high momentum resolution. United States: N. p., 2016. Web. doi:10.1063/1.4961471.
Vasilyev, D., & Kirschner, J.. Design and performance of a spin-polarized electron energy loss spectrometer with high momentum resolution. United States. doi:10.1063/1.4961471.
Vasilyev, D., and Kirschner, J.. 2016. "Design and performance of a spin-polarized electron energy loss spectrometer with high momentum resolution". United States. doi:10.1063/1.4961471.
@article{osti_22597651,
title = {Design and performance of a spin-polarized electron energy loss spectrometer with high momentum resolution},
author = {Vasilyev, D. and Kirschner, J.},
abstractNote = {We describe a new “complete” spin-polarized electron energy loss spectrometer comprising a spin-polarized primary electron source, an imaging electron analyzer, and a spin analyzer of the “spin-polarizing mirror” type. Unlike previous instruments, we have a high momentum resolution of less than 0.04 Å{sup −1}, at an energy resolution of 90-130 meV. Unlike all previous studies which reported rather broad featureless data in both energy and angle dependence, we find richly structured spectra depending sensitively on small changes of the primary energy, the kinetic energy after scattering, and of the angle of incidence. The key factor is the momentum resolution.},
doi = {10.1063/1.4961471},
journal = {Review of Scientific Instruments},
number = 8,
volume = 87,
place = {United States},
year = 2016,
month = 8
}
  • Based on 143 deg. electrostatic deflectors we have realized a new spectrometer for electron energy loss spectroscopy which is particularly suitable for studies on surface spin waves and other low energy electronic energy losses. Contrary to previous designs high resolution is maintained even for diffuse inelastic scattering due to a specific management of the angular aberrations in combination with an angle aperture. The performance of the instrument is demonstrated with high resolution energy loss spectra of surface spin waves on a cobalt film deposited on the Cu(100) surface.
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  • We discuss the spin excitations of a simple model of an ultrathin ferromagnetic film, in which the magnetic moment bearing electrons are itinerant in character. The one-band Hubbard model, treated in mean-field theory, forms the basis of the discussion. The spin excitations are treated by means of the random-phase approximation. We find spin-wave modes of standing wave character, and a spectrum of Stoner excitations influenced strongly by size effects. While the dispersion relations of the standing spin-wave modes appear as expected from a localized-spin model, there are substantive differences between the itinerant- and localized-spin cases. An example is the numbermore » of spin-wave modes evident in the appropriate spectral density functions, for each wave vector. We use a previously developed formalism of spin-polarized electron-energy-loss scattering (SPEELS) to compute SPEELS spectra for our model film. In addition to a broad feature with origin in Stoner excitations, we find clear and relatively intense spin-wave loss peaks.« less