High resolution magnetic patterning using focused ion beam irradiation

We show how Focused Ion Beam irradiation can be used to modify the magnetic properties of a thin Co/Pt layer at a nanometric length-scale. The control of the injected ion dose enables the adjustment of the coercive field and the Curie temperature of the layer on localized parts of the sample. The me chanism induced during irradiation is identified as a collisional mixing pr ocess which incorporates some Pt into the Co layer thus lowering the Curie temperature. The ultimate resolution of this magnetic patterning technique is discussed.