PERPENDICULAR MAGNETIC-ANISOTROPY AND STRUCTURES OF EPITAXIAL CO AG AND CO AU METALLIC SUPERLATTICES

The magnetic anisotropy and structures of Co/Ag and Co/Au metallic superlattices (SLs) grown by molecular-beam epitaxy were studied. In the Co/Ag SLs, the total magnetic anisotropy energy K(eff) was larger for the flatter Co/Ag interfaces and for the smaller strains of the Ag buffer layers. Particularly at 5 K, the perpendicular magnetic anisotropy was observed in the Co/Ag SLs with the nominal Co layer thickness t being 1 monolayer, and was strongly temperature dependent. The dependence of K(eff) . t on t was linear both at 5 and 300 K. The difference of the magnetic anisotropy in the Co/Ag and the Co/Au SLs was discussed in terms of structural characteristics. The origin of the perpendicular magnetic anisotropy was suggested to be the Neel-type surface anisotropy in the Co/Ag SLs and to be mainly the magnetoelastic anisotropy in the Co/Au SLs.