Microstructure and magnetic properties of FePt–TiC–C granular thin films for perpendicular recording

By using TiC as the segregate, FePt–TiC and FePt–TiC–C thin films were prepared by co-sputtering onto strongly (002)-textured MgO/NiTa underlayer on thermally-oxidized Si substrates. The TiC effects on the microstructure and magnetic properties of L10 ordered FePt and FePt–C thin films were studied. The TiC segregate can refine the grain size of L10 ordered FePt. Coercivities and the degree of L10 ordering were degraded with increasing TiC concentration. By properly tuning the composition of TiC and C, the granular microstructure with average grain size of 10.3 nm and standard deviation of 1.86 nm can be achieved with the coercivity of 1.4 T. The balance between microstructure and magnetic properties indicates that mixture addition as the segregates is promising.