QUANTUM-WELL STATES AND SHORT-PERIOD OSCILLATIONS OF THE DENSITY-OF-STATES AT THE FERMI-LEVEL IN CU FILMS GROWN ON FCC CO(100)

Quantum well states are observed around the ''neck'' of the Fermi surf ace in Cu films grown on magnetic fee Co(100) substrates, using high-r esolution angle-resolved photoemission. The observation is only possib le with an abrupt, nonreacted Cu/Co interface, which is produced by lo w temperature deposition of the first Cu layer. The analysis of the sp ectra gives a periodic crossing of the Fermi level of similar to 2.6 a tomic layers, the same short magnetic coupling period obtained in Co/C u/Co trilayers, and also the same value predicted by the theory. This is a strong confirmation of the role of quantum well states as mediato rs of magnetic coupling in superlattices.