MOLECULAR-BEAM-EPITAXIAL GROWTH AND MAGNETIC-PROPERTIES OF (111)PT CO/AG, PT/CO, AND AG/CO/PT SUPERLATTICES/

The structural and the magnetic properties of (111)Pt/Co/Ag, Pt/Co, an d Ag/Co/Pt superlattices (SLs) were studied. The samples were grown at 373 K on Ag buffer layers preformed on 7 x 7-(111)Si substrates by mo lecular-beam epitaxy. Reflection high-energy electron diffraction indi cated that in-plane lattice constants of Co, Pt, and Ag layers changed continuously during layer growth in Pt/Co/Ag SLs with thin Co layers and Pt/Co SLs. The effective magnetic anisotropy energy K(eff) of a Pt /Co/Ag SL was similar to KBAR(eff), an average of K(eff) values of a P t/Co and an Ag/Co SL with the same Co layer thicknesses. This suggests that the origins of perpendicular magnetic anisotropy in the Pt/Co sy stem are different from those in the Au/Co system investigated earlier , in which the difference between the Au/Co and Au/Co/Ag SLs is small in K(eff) value.