Fabrication of patterned media using self-assembled masks and simulations of probe recording

Summary form only given We have successfully patterned multilayer Pt/Co thin films using the process of Self Assembled Nanosphere Lithography. A layer of polystyrene nanospheres held in a liquid suspension is spun onto a hydrophilic substrate (chemically etched Si) where they self-assemble to form a mask. A Pt/Co multilayer thin film is deposited through the mask and a pattern is produced by lift-off. The size and shape of the resulting. thin film islands depend upon the structure of the nanosphere mask and the diameter of the nanospheres used. In the case of a monolayer, a hexagonal pattern of triangular structures is produced, where 200nm nanospheres were used to produce 40nm islands. Double layers of nanospheres have been used to produce a regular hexagonal array in which the islands are smaller but the separation is determined by the diameter of the nanospheres. The continuous and patterned films have been simulated using OOMMF, obtaining good agreement with experimental magnetometry. The simulation has been extended to demonstrate the feasibility of scanned probe recording using a pattern obtained directly from an SEM image of the experimental material and a realistic tip field produced using the method of triangular charge sheets introduced by Hill (1995).