Magnetic properties of granular CoCrPt:SiO₂ recording media deposited on GaSb nanocones

Investigation of the magnetization reversal in arrays of magnetic nanostructures is relevant for both fundamental understanding as well as application for magnetic data storage. We present a study of the magnetization reversal in granular CoCrPt:SiO₂ recording media with weakly interacting magnetic grains grown onto prestructured templates fabricated by ion irradiation of GaSb. By tuning the irradiation conditions assemblies of nanocones of different size and periodicity were prepared. Columnar CoCrPt grains with their c-axis normal to the surface of the cones were formed as evidenced by HR-TEM. The spread of the c-axis of these grains results in a tilted easy magnetization axis with respect to the substrate normal. Investigation of the integral magnetic properties by vector-VSM reveals a decrease of the remanence with increasing cone size. The magnetic domain patterns observed by MFM suggest that the CoCrPt behaves as a single-domain cap structure on the cones.