Equiatomic FePt and CoPt alloy thin films have received significant attention as possible magneto-optic recording media owing mainly to the existence of ordered intermetallic magnetic phases with exceptional magnetic properties. In the search for perpendicular magnetic recording media with high anisotropy, high coercivity and low media noise, these alloys have shown promising characteristics. High magnetic recording density with low media noise imposes the need of a material, which consisting of magnetically isolated grains with size below 10nm. The magnetic isolation of the grains can be controlled basically by the amount of additional element in the system, which determines the interparticle separation and therefore the interparticle interactions. Most of the study on these systems is followed by annealing [001] oriented multiplayer precursors and obtaining the magnetic properties superior to those of the as-deposited films , Although this process resulting in films with desired magnetic properties, it is observed to be somewhat complicated, involving both multiplayer deposition and postdeposition annealing. Moreover, this method has disadvantages as a manufacturing process because such a high temperature postdeposition annealing can cause irreversible changes in substrates for magnetic media and enhances particle growth rapidly.
So, in this work, we presents a further simplification process, direct synthesis of c-axis oriented ordered FePt:C by cosputtering both C and Fe with Pt chips at temperatures from 300℃ to 600℃. The samples of $(FePt)_{1-x}C_x$ is prepared at different substrate temperatures using sputtering technique onto a heated single crystal [100] MgO substrates. The room temperature magnetic and structural properties of the $(FePt)_{1-x}C_x$ system are studied by VSM, MOMM and Xrd, TEM, SEM respectively. The magnetic coercivity is observed to decrease with C addition after having a maximum (9kOe) value for 20% C addition. The mean particle size, obtained from TEM microstructure and calculated from the corresponding histogram, decreases with increasing C content in $(FePt)_{1-x}C_x$ films. Structural evidence establishing the formation of ordering phases with varying degrees of chemical order will be presented and correlated directly with the resulting magnetic properties in more details.
