We investigated the optimized condition of the high remanent magnetization for L10-ordered FePt on MgO/(001) i-GaAs substrate. Perpendicularly magnetized FePt films with different thicknesses of 5 and 10 nm were prepared at a substrate temperature Ts = 300°C by magnetron sputtering. The ratio of remanent magnetization to saturation magnetization for the 5-nm-thick FePt layer was increased to 0.93 by post-annealing at Ta = 350°C for 60 min, whereas that of the 10-nm-thick FePt layer was increased only to 0.3. The uniaxial magnetic anisotropy constant and the degree of long-range order for the 5-nm-thick FePt were Ku = 1.0 ± 0.1 × 107 erg/cm3 and S = 0.75 ± 0.15. respectively, which are almost comparable to those of FePt on a (001) MgO substrate.
- L1-ordered FePt
- Perpendicular magnetic anisotropy