Secondary electrons from Gd(0001) films grown on W(110) show spin pola
rization values of 28-34% in the energy range 1.5-7 eV at 150 K. No in
dication of a polarization enhancement is found. Below 1.5 eV the pola
rization drops to 20%, which is attributed to the presence of the 4f8
states just above the vacuum level.