Magnetic properties of Co/Pt multilayers deposited on patterned Si substrates

Arrays of Si dots 400 nm squares with a spacing of 100 nm and a height of 200 nm were patterned on silicon substrates by electron beam lithography and reactive ion etching, and a Co/Pt multilayer was sputter-deposited on these patterned silicon substrates. The magnetic film covers the top of the dots, the bottom of the grooves and to a much less extent the side-walls of the dots. The magnetic properties were studied by magnetic force microscopy (MFM). The Co/Pt multilayer exhibits perpendicular magnetic anisotropy and single-domain magnetic dots are obtained. Our results indicate that the width of the switching field distribution of the dots is not due to magnetostatic interactions but can be ascribed to a distribution of defects in the dots. A statistical analysis of MFM images shows that no significant direct coupling is mediated by the magnetic deposit on the side-walls of the dots.