Low-temperature ordering of L10 FePt by PtMn underlayer

The ordering temperature of FePt films grown on PtMn underlayers was reduced due to phase transformation of the PtMn L1(0) phase. The in-plane coercivity of 10 nm FePt on 50 nm PtMn underlayers was 7688 Oe after annealing at 325 degrees C. An exchange field of 554 Oe 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 10500 Oe can be achieved for 35 nm FePt films on PtMn underlayers after 325 degrees C annealing.