Exchange split quantum well states of a noble metal film on a magnetic substrate

By spin resolved photoemission we have detected exchange-split spin-polarized electronic states in a nonmagnetic material deposited on a magnetic substrate. Epitaxial Cu overlayers on fcc Co(100) exhibit sp symmetry electronic states which are spin polarized by the confining magnetic interface. These spin-polarized states can be observed up to a film thickness of at least 10 atomic layers. The spectral polarization and intensity at the Fermi level display a periodicity correlated with the oscillations of the long range coupling between magnetic films separated by Cu(100) layers.