Periodic magnetic anisotropy in ultrathin ferromagnetic films on faceted surfaces
Résumé
Since faceted surfaces lower the dimensionality of the surface, they are an ideal template to nanostructure magnetic stripes. In particular, it is possible to obtain an alternatively in- and out-of-plane magnetization in thin films deposited on periodically faceted surfaces. The periodicity of the surface can be replicated in the magnetization by the magnetoelastic anisotropy. The effect is particularly relevant for a film thickness close to the spin reorientation transition. In these conditions, the divergence of the magnetoelastic anisotropy near the facet edges forces in- plane magnetization regions in the faceted surface, while unfaceted surfaces corresponding to single facets present an out-of-plane easy axis. The magnetic anisotropy can thus be controlled at a nanometer scale by using a faceted substrate.