Low temperature L10 ordering of FePt films fabricated on SiO2/Si substrates

The transition temperature for the A1 to L10 phase transition of magnetron sputter deposited FePt films in the thickness range between 35 and 130 nm is investigated. Large ordering factors up to S = 0.93 are observed either for a deposition at T = 350°C or a post-deposition annealing at 400°C. These low ordering temperatures are explained by a defect enhanced atomic site exchanges induced by the impact of energetic ions. Due to the use of amorphous substrates no preferential grain orientation and thus only a weak magnetic anisotropy could be achieved.