By probing the magnetization profile of high-quality molecular-beam-epitaxy-grown Co/Cu(111) superlattices with spin-polarized neutron reflectivity (SPNR), we have observed a coherent antiferromagnetic spin structure and confirm that this coupling behavior sensitively depends on the Cu spacer thicknesses. We present magneto-optical Kerr-effect data from which the period of the exchange coupling can be determined to be about 9 Å, consistent with theory and the SPNR data. With these results we confirm the existence of an oscillatory exchange coupling in this controversial system.

• Received 7 April 1993

DOI:https://doi.org/10.1103/PhysRevB.47.15334