Patterning magnetic films by ion beam irradiation

We have used ion beam irradiation through a silicon stencil mask to alter t he magnetic properties of Co/Pt multilayer and FePt chemically-ordered supe rlattice films. In both systems, ion irradiation disorders the as-grown fil ms which results in a reduction of the magnetic anisotropy. Regularly space d micrometer-sized regions of magnetically altered material have been produ ced over areas of a square millimeter. These magnetic structures have been observed by magnetic force microscopy. By stepping the mask during irradiat ion, features at twice the spatial frequency of the mask holes have been pr oduced. Such patterned magnetic films are of interest for application in hi gh-density magnetic recording. (C) 2000 American Institute of Physics. [S00 21- 8979(00)84908-7].