Molecular-dynamics investigation of the surface characteristics of Fe-Cu magnetic thin-film layers

Abstract

Using molecular dynamics simulation, the structural characteristics of Fe and Cu thin films grown on Cu and Fe(001) substrates, respectively, were investigated with respect to the incident energy of adatoms and substrate temperature. In the case of Cu on Fe(001), no surface alloying at the interface was observed in the early stage of thin-film deposition, and growth generally followed the layer-by-layer growth mode. For Fe on a Cu(001) surface, a mixture confined to a single atomic layer at the Cu(001) surface was found to form at room temperature while films showed island growth. The steering effect due to atomic attraction was also observed at low incident energy, resulting in a rougher surface. Fe/Cu(001) growth changed to a layer-by-layer mode for an incident energy of 6 eV. The different aspects of surface morphology between Fe/Cu(001) and Cu/Fe(001) systems were explained in terms of surface free energy and impact cascade diffusion.