SURFACTANT-INDUCED SUPPRESSION OF TWIN FORMATION DURING GROWTH OF FCCCO CU SUPERLATTICES ON CU(111)/

Cu/Co bilayers grown by molecular beam epitaxy on Cu(111) present a pe culiar defect: the Cu layers display a large fraction of fee twins, gi ving rise to a lack of lateral continuity in the film and causing dire ct ferromagnetic coupling in Co/Cu superlattices. We show how the form ation of twins in the epitaxial Cu layers can be suppressed by precove ring the clean Cu(111) surface with a monolayer of Pb that floats at t he surface of the growing film. The use of this surfactant results in a highly improved structural quality of Co/Cu superlattices.