Fabrication of periodic arrangement of ferromagnetic nanoparticles as a potential application to future high density magnetic strage media

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In this study, we have examined a fabrication of periodically arranged ferromagnetic nanoprticles by using atomic, steps and lithography with polystyrene spheres for potential applications to future high density magnetic storage media. As a result, periodic arrangement of 4-nm-sized Feet nanoparticles was successfully produced by electron beam deposition onto an off-angle NaCl (001) substrate. Fabricated Feet nanoparticles were single crystalline with tetragonal L1o ordered structure just after the deposition at 673K.This fabrication temperature is more than 100K lower than that of previous reports. Magnetic coercivity decreased with decreasing the particle size of Feet, which can be explained by the thermal fluctuation of magnetic moments of very small Feet nanoparticles. Then we prepared Si(113) and SrTiO3(001) single crystal substrates with fine atomic steps. Deposition of noble metal elements like Au, Ag, Pd, Pt onto these step substrates resulted in formation of fine metal nanoparticles with high density, but periodic arrangement of nanoparticles along the step edges were not achieved in spite of the existence of periodic atomic steps on each substrate surfaces. Lithography technique ~ using periodic arrangement of polystyrene spheres lead to formation of Au and Pd nano-dot periodic arrays on MgO substrates. Our next step is to control the distribution of polystyrene spheres on the substrate