Grain isolated L10 FePt–Ta2O5 nanocomposite films with large coercivity for perpendicular recording applications

L 1 0 FePt–Ta2O5 films with (001) texture were synthesized by cosputtering FePt and Ta2O5 targets and in situ heated at 350 °C. The (001) preferred orientation was preserved even when doped with 20 vol % Ta2O5. The out-of-plane coercivity, Hc, increased from 6.7 kOe (for pure FePt film) to 8.8 kOe when doped with 20 vol % Ta2O5. Further increase in the dopant content to 25 and 30 vol % caused Hc to decrease significantly to below 3 kOe. Well-isolated FePt grains of tall column structures were observed for the 12 nm thick FePt film when doped with 20 vol %. The loop slope parameter, α, of such FePt film approached 1.