Potential of Metallic Glass Thin Films as a Soft Magnetic Underlayer for ${\rm L}1_{0}$ FePt-Based Recording Media

We report on the use of metallic glass (FeHfNbYB) thin film as a soft magnetic underlayer for the fabrication of L1
₀
FePt-based bit patterned recording media (BPM). Preferred oriented phase of L1
₀
(111) FePt is obtained either by depositing it in situ on a heated soft magnetic metallic glass/SiO
₂
/Si or at room temperature (FePt/metallic glass/SiO
₂
/Si) followed by annealing at 400 °C-450 °C for 20 min. Fabrication of recoding bits of size ~2 μm to 20 nm is demonstrated using electron beam lithography. Magnetic measurements on ~500 nm bit patterns show a narrow switching field (SF) distribution with SF of ~3 kOe. The ability to read/write this BPM is demonstrated with a commercial head in perpendicular geometry in a static tester. Results strongly suggest that the soft magnetic metallic glass thin films can solve the problem of writability in high anisotropy L1
₀
FePt-based recording media.