L1_0-CoPt Bit Patterned Media with Tilted Easy Axis for Ultrahigh Areal Density over 2.5 Tb/in~2

摘要

Ultrahigh areal density is the key target of hard disk drive technology. Hence, writing field strength from head and switching field, H_(sw), of media should be improved. In this work, we propose the one of alternative method to increase data density and reduce H_(sw) of the media by using tilted easy axis technology for bit patterned media (BPM) at areal density beyond 2.5 Tb/in~2. Moreover, transition noise and superparamagnetic limit have been eliminated owing to characteristics of BPM. The effect of exchange coupled between adjacent bits, A_(dot), of tilted easy axis of BPM is analyzed by micromagnetic simulation software - the object oriented micromagnetic framework based on Landau-Lifshitz-Gilbert equation. The BPM with tilted easy axis perform clearly the reduction of Hsw below perpendicular media and available writing head field. The A_(dot) of BPM has no effect on decreasing H_(sw). Anisotropy and Zeeman energy density of BPM with tilted easy axis are higher and lower than perpendicular BPM, respectively. Thereby, BPM with tilted easy axis have high potentiality to improve H_(sw) of media at ultrahigh data density.