Ion Beam Stabilization of FePt Nanoparticle Arrays for Magnetic Storage Media

摘要

We describe the use of ion beam induced crosslinking to harden the organic matrix material of self-assembled arrays of monodisperse (4 nm) FePt nanoparticles, providing Diamondlike Carbon barriers to inhibit agglomeration of the nanoparticles under heat treatment. Such stabilization is necessary for the particles to survive the less than 500 degrees C annealing required for growth of the fat L1o phase of FePt, whose magnetic anistropy is necessary for application of such arrays for high density perpendicular recording. Selective area irradiation of continuous nanoparticle coatings, using ion beams patterned over a full disk by stencil mask or with ion projection optics, followed by dissolution of the unexposed coating, is proposed as a means of fabricating extended bit patterns consisting of isolated 'islands' of FePt nanoparticles, with characteristic dimensions of tens of nanometers.