Transfer of spin polarization in ion-surface scattering

Low-energy ion beams impinging under grazing incidence on surfaces interact inherently with the topmost surface layer(s). The method of electron capture spectroscopy in which the degree of polarization of the light emitted by the neutralized projectiles is analyzed has been used to investigate spin polarization effects at Ni(1 1 0) and Fe(1 1 0) surfaces. The results hint at strong spin filtering mechanisms. With multiply charged instead of singly charged ion beams one may obtain access to short range spin ordering at the surface. Progress in the development of this new, so-called multiple electron capture spectroscopy technique is discussed and first results for He2+ ions interacting with a Ni(1 1 0) surface are presented.