Sharp Kabushiki Kaisha Corporation

Kosuke Watanabe

Hiroyuki Katayama

Kunio Kojima

Junichi Sato

Kenji Ohta

Hiroshi Fuji

Masaki Hamamoto

Kazuhisa Takayama

A magnetic signal recording method of the present invention superimposes a recording edge of a recordable region on a region where there is substantial equality between (a) a coercive force in a region on a magnetic recording medium in which the coercive force has been varied, and (b) magnetic field intensity, which is generated by a magnetic recording head. The magnetic field intensity has a magnetic field distribution whose lowering rate in an in-track position is maximum in the region. The magnetic recording head, whose recording magnetic field is distributed in a rectangular shape, is used in this way so as to form a magnetic bit having a rectangular shape that is suitable for reproduction performed by a common reproduction head having a rectangular reproduction region, thereby improving an S/N of a reproduction signal dramatically.

Magnetic signal recording method and magnetic recording-reproduction apparatus

An information recording and reproducing device includes a magnetic information detecting section for magnetically detecting magnetic information recorded at a given position on a recording medium, an optical information detecting section for optically detecting optical information recorded at a given position on each track of the recording medium, and a positional control section for controlling a position on the track using the detected magnetic information and optical information.

Information recording and reproducing device and tracking servo system therefor

A magnetic recording medium, which includes a substrate and an amorphous magnetic layer, made of an amorphous magnetic material, for magnetic recording of data, is provided with an underlayer between the substrate and the amorphous magnetic layer, the underlayer being made of amorphous metal element, and having a mean thickness of 10 nm or less. In this manner, movement of magnetic domain walls of the amorphous magnetic layer is effectively limited by minute irregularities on a surface of the underlayer. This realizes a stable formation of a minute recording mark. This realizes recording having a sufficient signal quality, even when the high-density recording is performed by forming such a minute recording mark that a shortest length of the recording mark is less than 100 nm. Moreover, this allows the magnetic recording medium to have a simplified layer structure. Further, a magnetic recording apparatus magnetically records data onto a magnetic recording medium having the above arrangement, by heating a portion of the magnetic layer by radiating a light beam locally, and by applying a magnetic field on at least part of the portion of the magnetic layer on which the light beam is radiated. This provides a magnetic recording apparatus for high-density recording.

Magnetic recording medium and magnetic recording apparatus using same

Growing community of inventors

Yao, Japan

Kosuke Watanabe