Spin-Polarized Eels on Ultrathin FCC Co Layers on CU(100)

The magnetism and the electronic structure of fcc Co films epitaxially grown on Cu(100) was investigated by spin polarized electron energy loss spectroscopy. Films above 2 atomic layers thickness show ferromagnetic order above room temperature with the magnetization in the plane. An exchange splitting of 0.8 eV and a Stoner gap of 300 meV is found. Films thinner than 1.6 layers do not show remanent magnetization above 80 K. No evidence for enhanced moments in monolayer films is found.