Crystallography, morphology, and magnetic properties of Fe nanostructures on faceted {alpha}-Al{sub 2}O{sub 3} m plane

The properties of iron nanostructures prepared by shallow incidence molecular beam epitaxy on faceted {alpha}-Al{sub 2}O{sub 3} (1010) (m plane) are described. Depending on the angle of deposition with regard to the sapphire surface, the morphology of the structures reaches from pearl-necklet-like strung nanodrops to laced nanowires. Crystallographic measurements reveal at least four epitaxial close to (211)-oriented twins. Magnetization measurements performed at room temperature in a vibrating sample magnetometer and magneto-optical Kerr rotation measurements reveal an easy axis of magnetization close to the facet ridges. Still, the shape of the hysteresis loops depends strongly on the morphology of the samples. The magnetization reversal process can be described by the formation of a magnetic vortex structure.