Magnetic lithography using a flexible master: A method for instantaneous magnetic recording on media surfaces with flatness imperfections

Abstract

A method for instantaneous parallel recording on magnetic media using a flexible master has been developed. Magnetic lithography (qualitatively analogous to optical lithography) transfers information from a patterned magnetic mask (analog of optical photomask) to magnetic media (analog of photoresist). The mask consists of patterned soft magnetic material (FeNiCo, FeCo) on a flexible polyethylene tetraphthalate (PET) substrate. When uniformly magnetized media is brought into intimate contact with the magnetic mask, an externally applied magnetic field selectively changes the magnetic orientation in the areas not covered with the soft magnetic material. Imperfect flatness or the presence of particular contaminants can result in local loss of intimate contact between the master and media, resulting in loss of resolution of submicron features in the transferred magnetic pattern. A flexible master, held against the media via an applied pressure, offers superior compliance to imperfections, even at relatively small applied pressures. We fabricated samples of submicron patterned FeCo and FeNiCo magnetic masks, and successfully transferred patterns to hard disk CrPtCo-based magnetic media. The details of the method, including fabrication of the magnetic mask on flexible PET substrates, physics of the magnetic lithography pattern transfer, and magnetic force microscopy images of the magnetic transition patterns are reported.