DEPENDENCE OF DOMAIN STRUCTURES ON Au THICKNESS IN Co/Au MULTILAYER FILMS

The magnetic force images and surface topography images of sputtered Co/Au multilayer films in remnant state were measured by magnetic force microscopy. From the surface magnetic structures shown in the magnetic force images it can be seen that the domain pattern and size vary with the increase of the thickness t of the non-ferromagnetic Au layer remarkably. With the measurements of the effective perpendicular anisotropy K_u and the domain period d, it was found that there are similar trends of d and K_u as functions of t. The variations of the domain pattern and size were qualitatively interpreted in terms of magnetic domain theory. the theoretical relations of d and the domain wall energy \sigma_w vs t were calculated. As t=8.5 AL(1 AL=0.235 nm), the largest \sigma_w is 11 mJ/m².