Fujitsu Corporation

Masayoshi Shinohara

Iwao Okamoto

Kenji Sato

Hiroaki Wakamatsu

Minoru Takahashi

Kenichi Aoshima

Isatake Kaitsu

Noboru Takada

Chie Takeda

Takayuki Yamamoto

Yuki Yoshida

Yoshiharu Kasamatsu

Kiyoshi Yamaguchi

Yasuji Ikeda

Chiaki Okuyama

Masao Hiyane

Hideyuki Akimoto

Seizi Hattori

Koichi Makino

Takehiko Nakagawa

Yukio Nakamura

The present invention relates to a magnetic recording medium for use in an external memory device of an information processing apparatus etc., and an object thereof is to reduce noise, achieve high coercive force, and use the substance as a magnetic recording medium for detecting signals in a magnetoresistance head. In the magnetic recording medium comprising the magnetic recording layer including ferromagnetic grains and a nonmagnetic substance , the improvement in structure comprises that the ferromagnetic grains are formed to have respectively an average grain diameter of 50 nm or less and not to be overlapped in the film thickness direction and to be isolated in the direction along a layer surface, and that a product of residual magnetization and a film thickness of the magnetic recording layer is less than or equal to 150 Gauss&bull;&mgr;m.

Magnetic recording medium

A magnetic recording medium and a magnetic disk device using the same. The magnetic recording medium comprising a nonmagnetic substrate having applied thereon, through two or more chromium-based underlayers, a magnetic recording layer having a circumferential direction of easy magnetization and containing cobalt as a principal component thereof, and also containing chromium and platinum in combination with tantalum or tantalum and niobium. Using the magnetic recording medium, a reproducing output and S/N ratio can be increased without causing an increase in noise.

Magnetic recording medium possessing a ratio of Hc(perpendicular) to Hc(horizontal) that is not more than 0.22 and magnetic recording disk device

A magnetic disk drive has a magnetic disk and a magnetic head assembly mounted on an arm. The assembly is utilized in the recording and reproducing of data on and from a recording/reproducing surface of a magnetic disk. The magnetic head assembly includes a support body for connecting the magnetic head assembly to the arm and a head chip attached to the support body. The head chip is configured and arranged for making substantially continuous sliding contact with the recording/reproducing surface of the magnetic disk during recording/reproducing. The head chip includes a wafer base, a read/write element for recording/reproducing data from the recording/reproducing surface of the magnetic disk. The read/write element is formed from a plurality of thin film layers superposed upon the wafer base and the head is elongated in a direction generally perpendicular to a plane generally defined by the recording/reproducing surface.

Magnetic head assembly with contact-type head chip mounting and electrically connecting arrangements

A magnetic recording medium comprising a nonmagnetic substrate and a magnetic recording film of a magnetic metal material deposited through a primer layer of a nonmagnetic metal material on the substrate, wherein the primer layer is formed of a metallic material composed mainly of chromium or chromium and molybdenum and the magnetic recording film is formed of a metallic material composed mainly of at least one member selected from the group consisting of cobalt, chromium, tantalum, and platinum. The magnetic recording medium enables high-density recording by taking advantage of high coercive force and, at the same time, can reduce the noise level and improve the S/N ratio.

Magnetic recording medium and magnetic disk device

There is provided a magnetic recording/reproducing apparatus which has an improved reliability for a reproduced signal by eliminating a deformation in a reproduced signal waveform due to a residual magnetization generated in a magnetic head. The magnetic recording/reproducing apparatus has a magnetic recording medium including a magnetic film to which information is magnetically recorded and a thin-film magnetic head including a magnetic pole and a coil provided around the magnetic pole. A current supplying circuit supplies a current to the coil so that a magnetic state of the magnetic pole is stabilized. The current is supplied to the coil after a recording operation has been completed by the thin-film magnetic head. The current may demagnetize the magnetic pole of the magnetic head, or stabilize the magnetic state of the magnetic pole.

Magnetic recording/reproducing apparatus with a current supplying

Magnetic recording/reproducing apparatus and method for supplying a

A non-magnetic substrate, a Cu layer having a film thickness ranging from 0.5 to 10 nm, a Cr layer having a film thickness of 100 nm or less, a magnetic layer made of CoCrPt alloy in which a percentage content of Cr ranges from 12 atoms % to 20 atoms % and a percentage content of Pt ranges from 4 atoms % to 18 atoms %, a protective layer and a lubricating layer are arranged in that order to form a magnetic recording medium. Because the Cu layer is sufficiently thinned, a medium noise is sufficiently reduced, and a medium S/N ratio is sufficiently heightened. Because the film thickness of the Cr layer is 100 nm or less, the medium noise is reduced. Because the composition of CoCrPt alloy is limited in the magnetic layer, the medium S/N ratio is heightened. In addition, it is preferred that another Cu layer having a film thickness ranging from 0.5 to 10 nm be inserted into the magnetic layer to divide the magnetic layer into two layers. In this case, the medium noise is reduced by 20%, and the medium S/N ratio is heightened. Therefore, even though a magnetoresistive effect type magnetic head is used to record or reproduce information in/from the magnetic recording medium, the medium noise is sufficiently reduced, and the medium R/N ratio is sufficiently heightened.

Magnetic recording medium and magnetic recording drive

The present invention relates to a magnetic recording medium for use in an external memory device of an information processing apparatus etc., and an object thereof is to reduce noise, achieve high coercive force, and use the substance as a magnetic recording medium for detecting signals in a magnetoresistance head. In the magnetic recording medium comprising the magnetic recording layer 25 including ferromagnetic grains 22 and a nonmagnetic substance 23, the improvement in structure comprises that the ferromagnetic grains 22 are formed to have respectively an average grain diameter of 50 nm or less and not to be overlapped in the film thickness direction and to be isolated in the direction along a layer surface, and that a product of residual magnetization and a film thickness of the magnetic recording layer 25 is less than or equal to 150 Gauss.cndot..mu.m.

A magnetic head for vertical magnetic recording includes a return portion having a sufficiently large area confronting a magnetic recording medium, a main pole having its front end portion confronting the magnetic recording medium, a magneto-resistive film provided in the middle of a magnetic circuit, including the return portion, the main pole, and the magnetic recording medium. The magnetic head has its initial magnetization set in the direction virtually orthogonal to the direction of flux in the magnetic circuit. A first and a second terminal are connected to both ends of the magneto-resistive film. The magnetic circuit also includes a bypass magnetic path magnetically connecting the main pole with the return portion.

Magnetic head having bypass magnetic path and set magnetic reluctance

A thin film of ferrite for use as a magnetic recording medium includes (a) Cu and Ti or (b) Cu, Ti and Co. The inclusion of Ti extends upwards the upper limit of the range of temperature for reducing .alpha.-Fe.sub.2 O.sub.3 to Fe.sub.3 O.sub.4, whereas the inclusion of Cu extends downwards the lower limit of this range. Further, the inclusion of both Ti and Cu enables the stable production of .gamma.-Fe.sub.2 O.sub.3 over a wide range of temperature for oxidizing Fe.sub.3 O.sub.4 to said .gamma.-Fe.sub.2 O.sub.3. The inclusion of Co improves the magnetic properties of the ferrite.

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Kawasaki, Japan

Masayoshi Shinohara