Abstract
This work has been focused on the study of patterning L10 FePt and its magnetic properties by using anodic aluminum oxide (AAO) as template. Ordered L10 FePt thin films with perpendicular anisotropy were prepared by sequential planetary sputtering on SiO2 substrate and annealed at 450oC by rapid thermal annealing (RTA) process. Aluminum was then deposited on L10 FePt, and FePt film was used as electrode to anodize aluminum. The hysteresis loops of FePt thin film were nearly unchanged after the anodization process. Ta layer was sputtered on top of the AAO, we then removed the alumina, leaving part of Ta that went into the bottom of the pores and was used as the hard mask for subsequent etching process. After etching process by inductive coupled plasma etcher using CO/NH3 gas mixture, FePt dot array was clearly observed by SEM with dot size similar to the pore size of AAO. Meanwhile, the coercivity was significantly increased compared to FePt thin film and the magnetic reversal behavior shifted from domain wall motion to Stoner-Wohlfarth rotation model. Furthermore, we also create Fe/FePt composite nanostructure by similar fabrication process, the nanostructure was like exchange-coupled patterned media with a fair coercivity, which is suitable for real magnetic recording application.