L1₀-ordered high coercivity (FePt)AgC granular thin films for perpendicular recording

We report (FePt)AgC granular thin films for potential applications to ultrahigh density perpendicular recording media, that were processed by co-sputtering FePt, Ag, and C targets on MgO underlayer deposited on thermally oxidized Si substrates. (FePt)_1-xAg_xyvol%C (0<x<0.2, 0<y<50) films were fabricated on oxidized silicon substrates with a 10 nm MgO interlayer at 450^oC. We found that the Ag additions improved the L1₀ ordering and the granular structure of the FePtC films with the perpendicular coercivity ranging from 26 to 37 kOe for the particle size of 58 nm. The (FePt)_0.9Ag_0.150vol%C film showed the optimal magnetic properties as well as an appropriate granular morphology for recording media, i.e., average grain size of D_av=6.1 nm with the standard deviation of 1.8 nm.