FePt Patterned Media Fabricated by Deep UV Lithography Followed by Sputtering or PLD

Continuous and patterned FePt films (40 nm) were fabricated on silicon (100) substrates using deep ultraviolet lithography with the wavelength of 248 nm followed by sputter deposition or pulsed laser deposition at room temperature, liftoff, and postannealing in vacuum. The structures and magnetic properties of the films were characterized by X-ray diffractometry, X-ray photoelectron spectroscopy, scanning electron microscopy, and alternating gradient force magnetometry. A buffer layer of Ag or MgO was inserted between the Si substrate and FePt to prevent a chemical reaction between Si and FePt. The phase transformation from face-centered cubic to face-centered tetragonal started after annealing at 400 degC for continuous films, while for the patterned FePt films, phase formation was retarded. High coercivities of 10-15 kOe have shown potential in hard magnetic applications. The effects of Ag and MgO top layers on the coercivities were also investigated