Magnetic states of granular layered CoFe-Al/sub 2/O/sub 3/ system

The granular layered magnetic system Co/sub 80/Fe/sub 20/(t)/Al/sub 2/O/sub 3/ (3 nm), where the Co/sub 80/Fe/sub 20/ layers of nominal thickness t form separate, almost spherical magnetic granules of typical diameter 2-3 nm between the Al/sub 2/O/sub 3/ spacers, was studied. We discuss measurements of the dc and ac magnetic susceptibility /spl chi/ for 1 nm