SPIN-DEPENDENT ELECTRON ATTENUATION LENGTHS AND INFLUENCE ON SPECTROSCOPIC DATA

Inverse photoemission from W(110) becomes spin dependent when the surf ace is covered with ultrathin ferromagnetic iron films. The spin asymm etry is not intrinsic to the tungsten electronic structure but is caus ed by spin-dependent electron attenuation within the ferromagnetic ove rlayer. The ratio of 1.7 +/- 0.3 between the spin-down and spin-up att enuation lengths for an electron energy of 12.6 eV above the Fermi lev el can be explained within a simple model by inelastic scattering. The influence of spin-dependent attenuation lengths on experimental data from electron spectroscopy is discussed and demonstrated by simulation s. The observed electron spin polarization or spin asymmetry is strong ly affected, while the energetic positions of features in spin-up and spin-down spectra are not.