Takuya Kamimura

Detecting dynamic signals of ideally ordered nanohole patterned disk media fabricated using nanoimprint lithography

The authors have fabricated ideally ordered alumina nanohole patterned disk media via anodic oxidation and nanoimprint lithography with a thermoplastic resist. The ordered arrays of alumina nanoholes with 100nm pitch, filled with Co by electrodeposition, were created over a macroscopically large area on a hard-disk substrate using these industrially applicable nanofabrication technologies. Stable flight of a perpendicular magnetic head above the media and perpendicular magnetic anisotropy of the Co nanopillars enable high-speed dynamic magnetic recording and playback. Dynamic periodic signals that matched the nanopillar periodicity were clearly observed after writing bit patterns, showing alternate reversal of magnetization of the nanopillars.

Dynamic Write/Read Characteristics of Alumina Nanohole Patterned Media With a Soft Underlayer Measured With a Perpendicular Magnetic Head

We present dynamic write/read characteristics of alumina nanohole patterned media having a soft magnetic underlayer (SUL), which offer good flyability of a perpendicular magnetic head with a flight height of 10 nm. Increase in the head-field gradient in the recording layer owing to the SUL was confirmed by measurements of signal-to-noise ratio and isolated magnetic transition width. The writability of the magnetic nanopillars was clearly demonstrated by visualization of the recorded patterns with a magnetic force microscope

First surface magneto-optical recording of over 36 Gbit/in2 using domain expansion media

First surface magneto-optical (FSMO) recording offers great potential for high-density recording. We have developed a domain expansion media for FSMO recording that uses a finely structured seed layer. Additionally, we clarified the relationship between drop-out and the recording resolution of this type of media. We realized a clear magnetic domain with continuous marks, a low drop-out, and a signal reproduction of 65 nm using domain expansion media. This domain has drastically improved the recording resolution. This was achieved by forming a finely structured seed layer under the memory layer. This technique enables a recording density of over 36 Gbit/in2.