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Updated: May 24, 2026
07:01
Frequency Mixing Magnetic Detection Scanner for Imaging Magnetic Particles in Planar Samples
Published on: June 9, 2016
Long-time stability of a low-energy electron diffraction spin polarization analyzer for magnetic imaging
F Lofink1, S Hankemeier, R Frömter
1Institut für Angewandte Physik, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg, Germany. flofink@physik.uni-hamburg.de
The Review of Scientific Instruments
|March 3, 2012
Summary
The time stability of a low-energy electron diffraction (LEED) detector used in spin-SEM is investigated. Despite hydrogen adsorption, the detector
Area of Science:
- Materials Science and Surface Physics
- Electron Microscopy and Spectroscopy
Background:
- Scanning electron microscopy with spin polarization analysis (spin-SEM or SEMPA) requires stable polarization analyzers for accurate magnetic imaging.
- Low-energy electron diffraction (LEED) detectors, utilizing W(100) crystals, are employed in spin-SEM for spin analysis.
- The long-term stability of these LEED detectors under typical operating conditions, particularly concerning residual gas adsorption, is crucial for reliable measurements.
Purpose of the Study:
- To investigate the time stability of a LEED detector used as a polarization analyzer in spin-SEM.
- To quantify the impact of hydrogen adsorption on the performance and stability of the LEED detector.
- To determine the operational limits and duration of stable performance for the spin-SEM polarization analyzer.
Main Methods:
- Experimental investigation of a LEED detector based on W(100) crystal diffraction at 104.5 eV.
- Exposure of the detector to hydrogen from residual gas to simulate operational conditions.
- Monitoring of LEED beam angular shifts and intensity changes.
- Evaluation of the detector's quality factor, a measure of its efficiency in SEMPA applications.
Main Results:
- Hydrogen adsorption alters LEED scattering conditions, causing angular shifts and intensity variations of the diffracted beams.
- Despite these changes, the quality factor of the LEED detector remains nearly constant up to a hydrogen coverage of approximately 0.25.
- Stable working conditions for the polarization analyzer are maintained for approximately 1 hour under vacuum conditions of 10⁻¹⁰ mbar.
Conclusions:
- The LEED detector demonstrates sufficient time stability for practical spin-SEM applications, even with moderate hydrogen adsorption.
- The observed stability of the quality factor indicates robustness against environmental changes within the specified limits.
- The findings support the use of this LEED detector for reliable magnetic imaging in spin-SEM over extended periods.
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