Magnetic nanostructures fabricated by the atomic force microscopy nano-lithography technique

A local oxidation technique using atomic force microscopy (AFM) was performed in order to modify magnetic domain structures in ferromagnetic nanostructures. Co-based nanostructures with a rectangular shape were fabricated by using electron beam lithography followed by AFM nano-oxidation. After fabricating a Co-oxide nanowire across a Co nanodot by AFM nano-oxidation, a domain structure of the dot observed before the nano-oxidation was divided into two parts of the domain. AFM nano-oxidation for a higher aspect ratio of height/width of the fabricated nanostructures was also investigated. By applying a dc bias between an Al 2 O 3 /Ni double layer film and the AFM tip, the Ni layer was locally oxidized through the capped Al 2 O 3 insulating layer. The nanowires of oxide obtained on the Al 2 O 3 /Ni double layer film were thicker and had a higher aspect ratio of height/width than those obtained on a Ni single layer film.