FePt-C nanogranular films for perpendicular magnetic recording

We report the study of L10 ordered FePt-C nanogranular perpendicular anisotropy films and a media consisting of an 8 nm thick FePt-C hard magnetic layer covered with a 2 nm thick soft magnetic layer (CoFe and FePt-C). All the films were fabricated on oxidized Si substrates with a (100) textured polycrystalline MgO intermediate layer of 10 nm in thickness. Cosputtering of Fe, Pt, and C on the MgO layer results the formation of L10 ordered FePt nanogranular films with a strong c-axis texture and the average FePt particle size of about 5 nm with a narrow particle size distribution of 1.4 nm in standard deviation. Perpendicular coercivity is controllable between 7 and 12 kOe. The coercivity and the saturation field of the FePt-C granular films can be reduced by 55% and 38%, respectively, with the capping of thin soft magnetic layer. This study demonstrates that the FePt-C system accomplishes suitable nanogranular structures and magnetic properties for ultrahigh-density perpendicular recording media.