Low-temperature in-situ growth of high-coercivity Fe-Pt films

FePt films with high coercivity, large energy product and corrosion resistance, have high potential in applications such as MEMs and ultra-high density magnetic recording. Much attention has been paid to the preparation of high quality films at substrate/annealing temperatures as low as possible to accommodate processing adopted in the manufacture of MEMs or sensors. In this study Fe/sub x/Pt/sub 1-x/ thin films were deposited by DC magnetron sputtering onto Si[100] and CrMo-seeded glass substrates at a substrate temperature (Ts) 30 to 600/spl deg/C with or without further post-annealing. Optimum magnetic properties of our studied films were obtained at the Fe/sub 53/Pt/sub 47/ composition as-deposited at Ts 300/spl deg/C. The in-plane coercivity (Hc) is 8 kOe for as-deposited films on both Si[100] and glass substrates. The films on Si[100] showed a maximum magnetization (M2T) and a maximum energy product of 950 emu/cm/sup 3/ and 15.8 MGOe, respectively. The squareness ratio (M/sub r//M/sub s/) of the as-deposited FePt films on glass substrate increases with increasing Ts. Minor hysteresis loops reveal that domain-wall-pinning dominates the magnetic hardening of the FePt films. Post annealing at 400/spl deg/C substantially enhances coercivity and energy product for the Fe/sub 53/Pt/sub 47/ films on glass substrate. Ordering parameters were studied by XRD and quantitatively correlated to magnetic properties.