Three dimensional nano-seeding assembly of ferromagnetic Fe/LaSrFeO ₄ nano-hetero dot array

Well-ordered ferromagnetic Fe nanodots/LaSrFeO ₄ nanocomposites have been fabricated by self-assembled crystal growth on La-SrTiO ₃ substrates having Fe nanoseed array fabricated by nanoimprint lithography (NIL). The Fe nanoseeds with spacing of 200 nm make possible the formation of perfectly arranged Fe/LaSrFeO ₄ nanocomposites; phase-separated Fe nanodots and the LaSrFeO ₄ matrix grew only on the nanoseeds and on the area except nanoseeds, respectively. A calculation based on a surface diffusion model has indicated that the nanoseed spacing required for the formation of the perfectly arranged nanocomposite is less than 400 nm. Magnetic force microscopy revealed an arrangement of isolated ferromagnetic domain corresponding to Fe nanodots grown on the Fe nanoseeds. The combination of self-assembled growth and NIL gives a route of the rational formation of high-density ferromagnetic memory devices.