Magnetic properties, nanostructure and ordering kinetics of feptcu thin films

In this study, the (FePt)_100-xCu_x (x=0, 4.6, 6.7, 8.8, 10.9) (FePtCu) alloy films were prepared by cosputtering. The effects of Cu addition content and heat treatment on the nanostructure and magnetic properties of the polycrystalline (FePt)_100-xCu_x films are reported. The experimental results show that the ordering temperature of the (FePt)_100-xCu_x (x=6.7) films reduced to 320°C, which is much lower than that of the FePt alloy. After heat treatment at 600°C for 1 hour, the (FePt)_100-xCu_x (x=6.7) film shows a coercive force of 15 kOe and the magnetization of 576 emu/cc. The magnetic properties of the FePtCu films can be adjusted by varying the Cu content in the films. The enhancement of the magnetic properties of the FePtCu films mainly resulted from the formation of the order L10 phase. DSC traces of as-deposited disorder films at different heating rates, to evaluate the crystallization of the order phase, showed that the addition of Cu atoms reduced the activation energy of ordering from 217 kJ/mol to 87 kJ/mol for the (FePt)_100-xCu_x films (x= 0 and 6.7, respectively). The reduction of the ordering temperature and corresponding activation energy might due to the solid solution of the Cu atoms in the FePt films.