Surface magnetization and hydrogen chemisorption on Gd: A spin-polarized photoemission study

Abstract

The spin polarization of photoelectrons emitted from polycrystalline Gd decreases linearly with temperature between 20 and 300 K. Submonolayer coverages of hydrogen, chemisorbed at 20 K, drastically reduce the observed spin polarization. This indicates a very short probing depth of spin-polarized photoemission, which arises from strong spin-exchange scattering. Hydrogen chemisorption is found to induce a canted or disordered spin structure at the Gd surface with a much lower ordering temperature than that of the clean Gd surface.