Magnetic properties of epitaxial Co nanodisk arrays packed on atomically smooth and vicinal Si substrates

Arrays of circular nanodisks have been formed from epitaxial Co films deposited on atomically smooth and vicinal Si(111) single crystals by using a focused Ga⁺ ion beam. The surface roughness has been determined by scanning tunneling microscopy. The coercive force and the processes of magnetization reversal in films and arrays of epitaxial Co nanodisks have been studied. It has been shown that the coercive force of the Co nanodisk arrays on the atomically smooth Si(111) surface is larger and that on the vicinal Si(111) surface is smaller than that in the epitaxial films. The studies of the magnetic structure of the nanodisks by magnetic-force microscopy in combination with the micromagnetic simulation have shown that the processes of magnetization reversal in the nanodisks on the atomically smooth substrates occur through the vortex-like states and, on the vicinal substrates, through the C-type state.