Surface magnetic properties of Gd-doped EuO

Abstract 4f-photoelectrons emitted from ferromagnetic Gd-doped EuO are depolarized during the photoemission process. Measurements of the spin polarization at 20 K T T c show that the depolarization increases on approaching T c as expected from a mean-field model of the surface magnetization. Using this model the surface exchange constant is found to differ only slightly from its bulk value.