Reduction of grain size and ordering temperature in L1/sub 0/ FePt thin films

Single-layer polycrystalline Fe/sub 52/Pt/sub 48/ alloy thin films were deposited on preheated natural-oxidized (100) silicon wafer b y conventional sputtering method at room temperature. The as-deposited films are soft fcc FePt phase. After suitable temperature annealing and furnace cooling, the as-deposited films are transformed from disordered soft fcc FePt phase into ordered fct L1/sub 0/ FePt phase. The ordering temperature of L1/sub 0/ FePt phase could be reduced to about 350/spl deg/C by preheating substrate to 300/spl deg/C followed by furnace cooling treatment. The grain size of FePt was found to decrease as the ordering temperature of L1/sub 0/ FePt phase was reduced. After annealing at 350/spl deg/C for 1 h, the in-plane coercivity (H/sub c''/) of the 100-nm Fe/sub 52/Pt/sub 48/ alloy thin film is about 6 kOe, and the average grain size is about 6 nm.