Influence of Intermediate Layer on Magnetic Properties of $L1_{0}$ Ordered FePt Perpendicular Recording Media

The L1 0 ordered FePt thin films have been prepared by magnetron sputtering system on Cr 85 W 15 underlayer at 500°C of substrate temperature. A 3 nm Pt or W thin interlayer was employed to modulate the magnetic properties of FePt films. The crystallographic relationship between the FePt thin film and the CrW underlayer was studied, and the dependence of FePt films structure and magnetic properties on the Pt or W interlayer was investigated. The M-H loop of the FePt films with Pt or W interlayer was analyzed by using a three-dimensional (3-D) micromagnetic model, with careful discussions of the tetragonal symmetry and the magneto-elastic anisotropy due to the stress in the film plane. The stress state in the films and its effect on magnetic properties were discussed.