Coherent fcc stacking in epitaxial Co/Cu superlattices

Abstract
A series of epitaxial Co/Cu superlattices has been grown on GaAs(110) substrates by molecular-beam epitaxy. Detailed analysis of x-ray diffuse scattering scans along Co (101¯l) reveals metastable fcc stacking of Co, with stacking coherence extending across Co layers at thicknesses below 20 Å, while coherent interfaces are obtained at Co thickness up to 40 Å. We discuss possible mechanisms for stabilizing the stacking sequence.