Magnetic Properties of L1₀ Ordered FePt Films Prepared on a Fe–Si–B–Nb–Cu Soft Magnetic Underlayer

Abstract

(001)-oriented FePt films with large perpendicular magnetic anisotropy have been obtained on a soft magnetic underlayer (SUL). A nanocrystalline Fe–Si–B–Nb–Cu alloy film has been chosen as SUL, showing the coercivity H_c of less than 80 A/m after annealing at 400°C. It has been found that the crystal orientation and magnetic properties of FePt films are improved by the introduction of a MgO interlayer between FePt and Fe–Si–B–Nb–Cu. The strong (001) texture and the large coercivity of 565 kA/m have been obtained in the tri-layer structure of Fe–Si–B–Nb–Cu (200 nm)/MgO (5 nm)/FePt (10 nm).