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The structural and the magnetic properties of (111)Pt/Co/Ag, Pt/Co, and Ag/Co/Pt superlattices (SLs) were studied. The samples were grown at 373 K on Ag buffer layers preformed on 7×7-(111)Si substrates by molecular-beam epitaxy. Reflection high-energy electron diffraction indicated 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 Keff of a Pt/Co/Ag SL was similar to K̄eff, an average of Keff values of a Pt/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 system 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 Keff value.

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We studied epitaxial growth and structures of Al/Ag superlattices prepared using molecular beam epitaxy. Samples were grown at temperatures of 20, 50, 70 and 100°C, at a growth rate of 0.1 monolayers per second, on 50-nm-thick (100) Ag buffer layers preformed on (100) MgO substrates. In situ reflection high-energy electron diffraction (RHEED) during growth and ex situ X-ray diffraction were performed to analyze the growth behavior and the structures. In all samples, (100) epitaxial growth was confirmed at early stages. Moreover, RHEED intensity oscillations were observed when Al layers were grown on Ag buffer layers. However, (111)-grown domains subsequently appeared and gradually became dominant upon prolonged growth. After sixty Al/Ag bilayer depositions, all surface areas were occupied by (111)-grown domains. Persistence of (100) epitaxial growth was strongly temperature dependent; (100) growth persisted during a few tens of bilayer depositions at 50°C, while at 20 and 70°C the growth orientation changed to (111) much faster. Other features, including the structures, are also described.