Ion beam-induced magnetic patterning at the sub-0.1 mu m level

We present a method that allows magnetic patterning of a continuous magneti c film without significant modification of the surface roughness or of the film's optical indices. It involves ion irradiation of Co/Pt multilayers, u sing either a standard ion implantation technology combined with high resol ution masking, or a focussed ion beam. We fabricated arrays of lines or dot s whose magnetic properties differ on a sub-100 nm scale. We describe the i on collision physics on which the techniques are based, as well as some of the observed consequences on the micromagnetic properties of the arrays and on the ultimate resolution. Possible applications to high-density informat ion storage are briefly discussed. (C) Academie des sciences/Elsevier, Pari s.