Spin dependent electron transmission through ferromagnetic thin films

Abstract

Spin-polarized electron spectroscopies are used to probe the nature of magnetism in surfaces and thin films. Strong inelastic scattering of the electron from particle-hole and collective excitations results in short mean free paths that can be spin dependent. A quantitative understanding of the spin dependence of the inelastic mean free path is critical to the interpretation of results from spin-polarized electron spectroscopies such as spin-polarized low energy electron diffraction, spin-polarized electron energy loss spectroscopy, and spin-polarized photoemission. Substantial spin asymmetry of the photocurrent has been observed and interpreted as being due to the spin-dependence of the photoelectron inelastic mean free path. We have examined such spin dependent behavior of electrons transmitted though magnetic films with higher kinetic energy in order to reduce complications due to spin-flip scattering, which are more prevalent at lower kinetic energy. We present clear evidence of a spin filter effect for the Ag 3d photoelectrons through a ferromagnetic Fe film at 720 eV (kinetic energy).