Interface Magnetism and Possible Quantum Well Oscillations in Ultrathin Co/Cu Films Observed by Magnetization Induced Second Harmonic Generation

fcc Co on Cu(001) and multilayers of Cu/Co/Cu(001) are studied by magnetization induced SHG (MSHG) in combination with linear Kerr measurements, for thicknesses between 1 and 20 monolayers (ML). Interface sensitivity of MSHG is demonstrated by its Co thickness dependency. Aside from a weak modulation, the MSHG signal from Co/Cu is nearly constant for thicknesses between 6 and 20 ML. Very strong oscillations in the MSHG signal are found for the Cu/Co/Cu system as a function of the thickness of the Cu coverlayer, which are possibly related to quantum well states in these thin Cu films.