The effect of CoPt3 sublayer on the formation of fct-L10 FePt nanoparticles in direct synthesis method

Abstract The smaller the size of magnetic nanoparticles is, the less their coercivity will be. The magnetic coercivity of FePt nanoparticles, in the compound ordered phase, known as fct-L1 0 FePt, is up to the order of tesla; however, the temperature of 600 °C, required for the formation of this phase, increases the size of FePt nanoparticles. In this research, fct-L1 0 FePt nanoparticles were fabricated using the direct synthesis method by Co-sputtering system. The presence of a CoPt 3 sublayer resulted in the formation of a fct-L1 0 phase of FePt nanoparticles at 400 °C with a uniform surface distribution and mean size and standard deviation of 11 nm and 1.5 nm, respectively. The same as the other results of FePt/CoPt 3 , magnetic coercivity of fct-L1 0 FePt nanoparticles, with the mentioned size, reached to 3.0 kOe at room temperature, because of the presence of the CoPt 3 sublayer.