Hiroki Takao

Highly field sensitive (150 Oe) quadri-valued magnetooptical media for high-speed overwriting

For high-density and high-speed magnetooptical (MO) recording, the use of magnetic multi-valued (MMV) MO media has been proposed. [rf:1] A quadri-valued recording has been achieved using this media and a field modulation recording method. For practical use of this media, it is important to reduce the critical magnetic field to minimize the applied field for realizing the quadri-valued recording. We have achieved reduction of the critical magnetic field down to 150 Oe using a new coupled film, TbFeCo/GdTbFeCo.

Media design of iD PHOTO disk with the CAD structure

We have developed a new MO(Magneto-Optical) disk, which is named iD(image/intelligent disk) PHOTO, as a promising candidate for a digital still camera memory. The iD PHOTO disk achieves 730MB/disk in a 50.8mm diameter by adopting some techniques mainly as follows, CAD (center aperture detection) type Magnetic Super Resolution reading, recording both on land and in groove, magnetic field modulation writing with irradiation of a pulsed laser beam, and PR(1,1) code. The iD PHOTO disk is required high performance in various environments, for it is used in a portable drive. As one of the most important factors, we have previously reported a reduction of electric power consumption by reducing the recording magnetic field. Here, we introduce thermal structure design of iD PHOTO disk to be suit for a drive in a digital still camera.