A Monte Carlo study of the spin polarization of secondary electrons

Abstract

A spin‐involved Monte Carlo simulation model is developed to study the mechanism of the spin polarization of secondary electrons. The spin‐dependent mean free path asymmetry and the Stoner excitation are considered in modeling electron inelastic scattering, and the spin‐dependent excitation mechanism of cascade electrons is introduced according to the spin density of the state of a magnetism sample. The simulation has been performed for Ni and Fe. The simulated results, including secondary electron yields, secondary electron energy spectrum, and spin polarization of secondary electrons, are in good agreement with experimental results. According to the present simulation results, it is concluded that the high spin polarization of secondary electrons less than approximately 5 eV is inherently related to the cascade production process of secondary electrons; a more obvious effect of Stoner excitation is found for Ni but not for Fe because of the lack of unoccupied 3d states for spin‐majority electrons above the Fermi level for Ni. We have further studied the case that an unpolarized thin layer exists on Fe surface; the results show that the spin polarization of secondary electrons can be greatly affected at low primary energies. Copyright © 2012 John Wiley & Sons, Ltd.