Reduction of Grain Size and Ordering Temperature in L10 FePt Thin Films

Abstract

Single-layer polycrystalline Fe52Pt48 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 10 FePt phase. The ordering temperature of 10 FePt phase could be reduced to about 350 C by preheating substrate to 300 C followed by furnace cooling treatment. The grain size of FePt was found to decrease as the ordering temperature of 10 FePt phase was reduced. After annealing at 350 C for 1 h, the in-plane coercivity ( ) of the 100-nm Fe52Pt48 alloy thin film is about 6 kOe, and the average grain size is about 6 nm.