Colloidal domain lithography for regularly arranged artificial magnetic out-of-planemonodomains in Au/Co/Au layers

Abstract

Regularly arranged magnetic out-of-plane patterns in continuous and flat films arepromising for applications in data storage technology (bit patterned media) or transport ofindividual magnetic particles. Whereas topographic magnetic structures are fabricated bystandard lithographical techniques, the fabrication of regularly arranged artificialdomains in topographically flat films is difficult, since the free energy minimizationdetermines the existence, shape, and regularity of domains. Here we show that keVHe + ion bombardment of Au/Co/Au layer systems through a colloidal mask of hexagonallyarranged spherical polystyrene beads enables magnetic patterning of regularly arrangedcylindrical magnetic monodomains with out-of-plane magnetization embedded in aferromagnetic matrix with easy-plane anisotropy. This colloidal domain lithography createsartificial domains via periodic lateral anisotropy variations induced by periodic defectdensity modulations. Magnetization reversal of the layer system observed by magneticforce microscopy shows individual disc switching indicating monodomain states.