Abstract
The spin polarization of electrons field emitted from single-crystal iron surfaces was observed to be (+25±5)% for emission along [100], (+25±5)% along [111], and (-5±10)% along [110] (the polarization is positive for majority-spin electrons). These results correlate qualitatively with expectations from the bulk band model. However, quantitative calculations with bulk wave functions gave strongly parameter-dependent results. For meaningful calculations the effect of the surface on the wave functions must be included.