Domain structure of magnetic layers deposited on patterned silicon

Arrays of Si square dots down to 200 nm in size were patterned on silicon s ubstrates, and thin films of different magnetic materials were sputter depo sited on these patterned substrates. The magnetic film covers the top of th e dots, the bottom of the grooves and to much less extent the sidewalls of the dots. Single domain magnetic dots were obtained for Co/NiO bilayers and Co/Pt multilayers, without significant direct coupling mediated by the mag netic deposit on the sidewalls of the dots. Our results indicate that, in t hese arrays, the magnetic pinning forces are stronger than the estimated va lue of the largest demagnetizing magnetostatic field on each individual dot . As a result, any magnetic configuration could in principle be stored in s uch arrays. This approach seems therefore very promising for the preparatio n of magnetic storage media with ultrahigh density. (C) 1999 American Insti tute of Physics. [S0003-6951(99)01342-X].