Magnetic anisotropy and structural characterization of Co/Pt superlattices grown along selected orientations by molecular-beam epitaxy

In this paper we report the molecular-beam epitaxial growth of Co/Pt superlattices on epitaxial Ag films on GaAs substrates. The growth axis of the superlattice was selected by seeded epitaxy to be along either the [001], [110], or [111] axis of Pt. The magnetic properties of the superlattices depend on the orientation of the growth axis. In situ x-ray photoelectron diffraction studies of the Co-Pt interfaces during their formation reveals that they are not atomically abrupt for any of the orientations. We conclude that models for magnetic anisotropy of Co/Pt superlattices should be based on a combination of magnetocrystalline anisotropy and strain in compositionally mixed interfaces.