Magnetically split sp -derived states in fcc-like Fe/Cu(001)

The spin dependence of sp-derived bulk and surface states of fcc-like Fe films on Cu(001) has been studied by spin-resolved inverse photoemission. The exchange splitting of a crystal-induced surface state at X̄ is determined as 0.9 eV. A transition between sp bulklike states about halfway between Γ and X̄ shows a spin splitting of 0.4 eV. The first result is unique proof of a magnetically live surface layer. The latter shows that ferromagnetic order is not restricted to the topmost layer, but the size of the splitting indicates that the magnetic moment of the sublayers is reduced compared with the surface.