Spin-polarized scanning tunneling microscopy in field emission mode

Image-potential states in front of the Fe(110) surface have been investigated by spin-polarized scanning tunneling spectroscopy. For the n=1 state energetic splittings of up to 25meV are observed in the spectroscopic data measured above oppositely magnetized surface areas. The technique offers the possibility to access the spin dependence of image-potential states on a local scale. These states can be used as a sensitive probe of surface magnetism, allowing high resolution magnetic imaging at tip-sample distances larger than in normal tunneling experiments, thereby reducing the probability of accidental tip-surface collisions.