Magnetic and structural properties of Co/Pt multilayers

Abstract

The magnetic properties of Co/Pt multilayers, in particular anisotropy and coercivity, are very sensitive to the Co layer thickness and less dependent on the Pt layer thickness. Such dependence is illustrated and discussed for e-beam evaporated Co/Pt multilayers of various Co and Pt thicknesses. It is shown that the largest perpendicular anisotropy occurs for Co layer thickness of 1-2 monolayers. The magnetic anisotropy of Co/Pt multilayers also strongly depends on the crystallographic orientation. The largest perpendicular magnetic anisotropy was obtained for Co/Pt multilayers with Pt(111) parallel to the film plane. This was demonstrated in both evaporated and sputtered polycrystalline multilayers, as well as in molecular beam epitaxy (MBE) grown Co/Pt(111) superlattices. By contrast, MBE grown 3.7 Å Co/16.8 Å Pt(100) multilayers show in-plane anisotropy, and 3.7 Å Co/16.8 Å Pt(110) multilayers exhibit very strong anisotropy within the film plane. These observations suggest that the magneto-crystalline anisotropy plays a key role in the magnetic anisotropy of these structures. Significantly enhanced effective magnetization was observed for Co/Pt multilayers with ultrathin Co layer. © 1991.