Primary energy-dependent attenuation of polarization of secondary electrons emitted from Au/Fe(110)

We studied the Au thickness and the primary electron energy-dependence of polarization of secondary electrons emitted from Au thin film on an Fe(110) substrate. By fitting to the experimental data using the exponential function, we found that the magnetic information depth lambda(m) of the secondary electron polarization increases with primary electron energy E(p) from lambda(m) = 6 Angstrom at E(p) = 70 eV to lambda(m) = 26 Angstrom at E(p) = 4 keV. The accuracy of the fit degrades with higher E(p). We explain this behavior by considering the difference in secondary yields between Au and Fe.