MOLECULAR-BEAM EPITAXIAL-GROWTH AND MAGNETIC-PROPERTIES OF CO-PT SUPERLATTICES ORIENTED ALONG THE [001], [110] AND [111] AXES OF PT

The magnetic and structural properties of epitaxial Co/Pt superlattices, oriented along the [001], [110] and [111] directions of Pt, are presented. We find that the magnetic properties of the superlattices are reproducible and distinctly different for the different orientations. For structures with 3.2 angstrom Co/16.7 angstrom Pt, the easy axis of magnetization is perpendicular to the film plane for growth along Pt[111] but in the film plane for growth along [001]. The [110] oriented superlattices have intermediate behaviour. X-ray and TEM analysis of the superlattices reveals significant differences in interface quality and defect structure for the different orientations. These effects may play a more important role in the origin of magnetic anisotropy than previously assumed.