Structural and magnetic study of Fe stripes and boxes patterned by the atomic saw method

The Atomic Saw method has been successfully used to cut a Fe thin film, epitaxially grown onto a (001) MgO substrate, into stripes (widths ranging from 1μm to 100 nm) and boxes (lateral sizes ranging from 1 μm to 3 μm). A structural analysis of these magnetic structures by atomic force microscopy has shown that their geometries are controlled by the plastic strain. A magnetooptical study of the Fe stripes has revealed a surprising uniaxial magnetic anisotropy with an in-plane easy axis perpendicular to the stripes. This strong anisotropy can be explained by an anisotropic relaxation of the misfit between the starting Fe film and the MgO substrate, induced by the cutting into stripes. Magnetooptical experiments on boxes have revealed that the initial cubic symmetry is recovered since, in this case, the relaxation is similar in perpendicular directions. They have also proved that their magnetization reversal is governed by nucleation phenomena.