Low-temperature ordering of L1 FePt by PtMn underlayer

The ordering temperature of FePt films grown on PtMn underlayers was reduced due to phase transformation of the PtMn L10 phase. The in-plane coercivity of 10nm FePt on 50nm PtMn underlayers was 7688Oe after annealing at 325°C. An exchange field of 554Oe was also observed, which indicates that PtMn may not only induce the ordering of FePt at a reduced temperature, but also may provide extra anisotropy. A large coercivity of 10500Oe can be achieved for 35nm FePt films on PtMn underlayers after 325°C annealing.