「Assault on storage density of 1 Terabit / sq-in and beyond」
(IEEE Distinguished lecturer; Dieter Weller (Seagate Research))
The areal density in magnetic recording has surpassed ∼70 Gbit/in2 in products and ∼135 Gbit/in2 in laboratory demonstrations. Respective recording media are Co-alloy nanostructured materials with horizontal orientation of the magnetization (longitudinal recording). Going beyond ∼100 Gbit/in2 requires magnetically harder materials with smaller, thermally stable grains. Enhanced write fields are expected in perpendicular recording owing to a soft magnetic imaging layer, enabling such magnetically harder materials to be recorded on. Basic technology demonstrations of about 170 Gbit/in2 have been reported and modeling suggests that extensions to about 1 Tbit/in2 should be possible. It is envisioned that even higher areal densities are possible by using an assisted assembly process e.g. of chemically synthesized FePt nanoparticles. Writing on such self-organized magnetic array media (SOMA) will require temporal heating and cooling in a magnetic field (HAMR: Heat-Assisted Magnetic Recording). A combination of SOMA and HAMR may once lead to single particle per bit recording, with ultimate density capability of 50 Tbit/in2 (Single particle per bit superparamagnetic limit; 10 yrs storage time, ambient temperature, FePt type anisotropies).
今回の研究会は、IEEE Japan Chapterとの共催によりIEEE Distinguished lecturerに選ばれているD. Weller氏を講師に迎え、磁気記録技術に関する話題を中心に議論を行った。午前に日本語による講演を2件、午後に2時間半の英語による講演と変則的スタイルになったが、約60名の参加者を迎えることが出来、活発な議論を行うことが出来た。