Mapping the spin-dependent electron reflectivity of Fe and Co ferromagnetic thin films

TL;DR

This study uses Spin Polarized Low Energy Electron Microscopy to analyze spin-dependent electron reflectivity in Fe/W(110) and Co/W(110) thin films, revealing high figure of merit values for potential spin polarimetry applications.

Contribution

It demonstrates a significant enhancement in spin polarimetry efficiency using low-energy electron reflectivity in Co/W(110) films, surpassing previous methods.

Findings

Maximum figure of merit observed at 2 eV in 5 monolayer Co/W(110)

Reflectivity and asymmetry depend on electron energy and film thickness

Potential for developing improved electron-spin-polarimeters

Abstract

Spin Polarized Low Energy Electron Microscopy is used as a spin dependent spectroscopic probe to study the spin dependent specular reflection of a polarized electron beam from two different magnetic thin film systems: Fe/W(110) and Co/W(110). The reflectivity and spin-dependent exchange-scattering asymmetry are studied as a function of electron kinetic energy and film thickness, as well as the time dependence. The largest value of the figure of merit for spin polarimetry is observed for a 5 monolayer thick film of Co/W(110) at an electron kinetic energy of 2eV. This value is 2 orders of magnitude higher than previously obtained with state of the art Mini-Mott polarimeter. We discuss implications of our results for the development of an electron-spin-polarimeter using the exchange-interaction at low energy.