STRUCTURE AND MAGNETIC-PROPERTIES OF CO/AL MULTILAYERED FILMS

We report on an investigation of Co/Al multilayered films (MLFs). The samples had periodic layered structures and had in-plane easy axes. Nonmagnetic CoAl compound was formed at the Co/Al interfaces. Co/Al MLFs had a perpendicular interface anisotropy. This interface anisotropy energy (Ks) was estimated to be 0.25 erg/cm2. Taking account the volume contribution of Co layers, it was suggested that perpendicular magnetism would appear when the remaining unmixed Co layer thickness was under 6 Å. However, this surface anisotropy energy vanished when the Co layers were thinner than 9 Å. In Co/Al MLFs with thin Co layers, the island growth of Co on the initial stage was considered to be the reason for Ks=0.