Long-time stability of a low-energy electron diffraction spin polarization analyzer for magnetic imaging.

The time stability of a polarization analyzer that is used for imaging of magnetic structures in a scanning electron microscope with spin polarization analysis (spin-SEM or SEMPA) is investigated. The detector is based on the diffraction of low-energy electrons at a W(100) crystal at 104.5 eV (LEED detector). Due to the adsorption of hydrogen from residual gas, a change of the scattering conditions is found that causes an angular shift of the LEED beams as well as changes of intensity. The quality factor, which describes the efficiency of the detector in SEMPA application, however, is found to be almost constant up to a hydrogen coverage of θ ≈ 0.25. This gives stable working conditions within roughly 1 h at vacuum conditions of 10(-10) mbar.

Size dependence of L2,3 branching ratio and 2p core-hole screening in x-ray absorption of metal clusters.

Resonant 2p x-ray absorption spectra of size-selected transition metal ions and clusters consisting of 1