Topmost layer magnetization of ultrathin Cr films on Fe(100) from proton-induced spin-polarized electron emission

The magnetic ordering of the topmost surface layer of ultrathin Cr films grown on Fe(100) is studied via spin-polarized electron emission, excited by fast protons grazingly scattered from the film surface. We find that most electrons originate from the topmost layer. Based on simple assumptions we are able to deduce the layer-dependent magnetic moments from the observed spin polarization of electrons. We demonstrate that our method has a clearly smaller probing depth than conventional spin-polarized electron spectroscopies.