Buffer Layers for Highly Ordered L1 FePt-Oxide Thin Film Granular Media at Reduced Processing Temperature

In this work, we present an experimental technique for obtaining highly ordered L1 FePt-oxide thin film media at moderate deposition temperatures. In most previous studies, a FePt-Oxide layer is directly deposited on a (001) textured MgO layer. By introducing a buffer layer in between the FePt-oxide layer and the MgO underlayer, we are able to substantially enhance the L1 ordering of the FePt-oxide layer while lowering the deposition temperature to 400 C. The buffer layer also yields a significantly enhanced (001) texture of the formed L1 FePt structure. With the order parameter near unity, the coercivity of the resulting granular L1 FePt-oxide film exceeds 20 kOe with an average grain size about 8 nm. With the buffer layer technique, 18kOe coercivity has also been achieved for L1 FePt-oxide film at a grain size of about 4.5 nm. In this work, the detailed material composition choice of the buffer layers and the corresponding results are presented.