Hitachi, Ltd.

Hitachi Maxell, Limited

Teruaki Takeuchi

Ryo Suzuki

Masatoshi Takeshita

Yutaka Sugita

Naoki Kodama

Nobuyuki Inaba

Tadashi Ikeda

Toshihiro Sato

Takashi Toyooka

Fumiyoshi Kirino

Ryo Imura

Kouichirou Wakabayashi

Hiroshi Umezaki

Masaaki Futamoto

Norio Ohta

Yoshiyuki Hirayama

Yukio Honda

Satoshi Matsunuma

Masukazu Igarashi

Yoshio Takahashi

Tomoo Yamamoto

Akira Yano

Keiichi Uehara

Takashi Naito

Hiroki Yamamoto

Katsusuke Shimazaki

Kazumasa Takagi

Tetsuo Nakazawa

Hiroyuki Awano

Atsushi Asano

Mitsutoshi Honda

Nagatugu Koiso

Masaki Sekine

Koichiro Wakabayashi

Youji Maruyama

Shinzo Matsumoto

Tatsumi Hirano

Tsuyoshi Onuma

Tetsunori Koda

Harumi Hieida

Norio Ota

A perpendicular magnetic recording medium has a substrate, a magnetic functional layer provided on the substrate, and a magnetic recording layer stacked in contact with the magnetic functional layer and having perpendicular magnetic anisotropy. &#x2212;4&#xd7;2&#x3c0;Ms&#x2266;Ku&#x2266;6&#xd7;2&#x3c0;Msis satisfied, wherein Ku represents a perpendicular magnetic anisotropy constant of the magnetic functional layer and Ms represents a saturation magnetization. The magnetic moment of the magnetic functional layer is rotated in a direction of an applied magnetic field during the recording, and the magnetic moment acts on the magnetization of the recording layer in such a manner that the applied magnetic field is assisted thereby. Minute magnetic domains can be stably retained and excellent thermal disturbance resistance can be obtained.

Magnetic recording medium having a specific relation of coercive force HC and residual magnetization MR in perpendicular direction to substrate surface

A recording and reproducing apparatus including a recording magnetic head and a reproducing magnetic head with their floating height lowered for high density recordation and reproduction is provided. An information recording medium is provided on which it is possible to densely record information and from which it is possible to densely reproduce information by lowering the floating height of the recording and reproducing heads. The information recording medium includes a flat substrate and a recording layer provided on the substrate. Servo patterns and management information are recorded as magnetic marks on the recording layer in advance by a servo writer or the like. Because the substrate needs no recessed and embossed patterns formed in it, the slider of the recording and reproducing apparatus can be floated at a constant floating height lower than conventionally over the whole area of the medium. During information recordation, the position of the slider is controlled on the basis of the magneto-optical signals from the magnetic marks. During information reproduction, the reproducing magnetic head controls the slider position on the basis of the magnetic leakage fields leaking from the magnetic marks.

Information recording medium with magnetic marks, recording and reproducing apparatus therefor, and head positioning method using detected magnetic leakage fields from the magnetic marks

A magnetic recording medium comprises an information-recording film and a ferromagnetic film on a substrate. The information-recording film is composed of, for example, an amorphous ferrimagnetic material having perpendicular magnetization. Further, the ferromagnetic film is composed of a magnetic material which has saturation magnetization larger than that of the information-recording film. Accordingly, the leak magnetic flux from the ferromagnetic film is larger than that from the information-recording film. The magnetic recording medium and a magnetic recording apparatus are obtained, which are excellent in thermal stability and which are preferred to perform super high density recording.

Magnetic recording medium with high thermal stability, method for producing the same, and magnetic recording apparatus

An information recording medium, an information recording/reproduction head, and an information storage device are provided for performing a track servo operation at a smaller track pitch than that conventionally used without reducing the widths of servo burst patterns. The widths of servo burst patterns () are increased over a track pitch (TP) and the end of the servo burst pattern is disposed so as not to coincide with a center line () of an information track. In addition, a servo magnetic head () and a reproduction magnetic head () are implemented in one magnetoresistance element ().

Information recording medium, information recording/reproducing head, and information storage device

A magnetic recording medium ( ) includes a substrate ( ) and on the substrate ( ) a first underlying layer ( ), a second underlying layer ( ), a magnetic layer ( ), and a protective layer ( ). Because of the existence of the first underlying layer ( ) of Hf, initial growth layer having no specific crystal structure is prevented from growing in the second underlying layer ( ). The second underlying layer ( ) has a structure in which CoO particles having a cross section of a regular hexagon and separated by SiO portion are arranged in honeycomb. Since magnetic particles are epitaxially grown from CoO particles, the size of the magnetic particles and particle size distribution can be controlled, and the magnetic interaction between magnetic particles can be lessened. The underlying layer ( ) and the protective layer ( ) are formed by ECR sputtering. Such a magnetic recording medium is free from noise and thermal fluctuation, and ultrahigh recording density over 40 Gbit/inch is realized.

Magnetic recording medium and its production method, and magnetic recorder

An amorphous magnetic recording medium comprising a substrate and an amorphous magnetic layer, where a magnetic domain formation-controlling layer comprising a main phase and 1 to 3 kinds of discrete spherical isolating phases arranged horizontally in lines in the main phase or 1 to 3 kinds of discrete spherical phases vertically stacked one upon another in the main phase is formed on the top side or the bottom side directly or through at least one of other layers to bring the amorphous magnetic layer into a finer magnetic domain structure, can satisfy high density recording.

Amorphous magnetic recording medium, process for producing the same and magnetic recording and reproduction apparatus

A magnetic recording apparatus includes a laser light source ( ), a recording magnetic head ( ) and a magnetoresistive element. The recording magnetic head includes a pair of magnetic poles ( and ), between which the magnetoresistive element is interposed. A rotary actuator (Sa) positions the recording magnetic head at a desired track of a magnetic recording medium. A laser beam can be radiated onto the magnetic recording medium to raise the temperature of a region ( ) of the medium. This region has a width of the order of the track width. The raised temperature lowers the coercive force of this region, where a recording magnetic field can be applied for high density recording. The rotary actuator may form a yaw angle (&thgr;) with a track of the magnetic recording medium. Even in this case, the recording magnetic head ( ) and the reproducing element have no tracking offset from the code track. In addition, if the size of the magnetic poles ( and ) of the recording magnetic head are set within a predetermined range, the region ( ) heated by the laser beam does not deviate from a recording magnetic field application region ( ).

Read/write head and magnetic recording device

It is an object of the present invention to provide a magnetic recording medium which has a high level of magnetic antisotropy energy, retains stably the state of recording magnetization within the operating temperature range and is suitable for high-density recording with a low noise level, and a magnetic storage device for the magnetic recording medium. For attaining the above object, the magnetic recording film of the magnetic recording medium is characterized in that its magnetic anisotropy energy constant K at an absolute temperature of 300 K is greater than 3.6&times;10 erg/cc and the average particle diameter is larger than 5 nm and smaller than 12 nm.

Method of manufacturing a magnetic recording media

A magnetic recording medium includes a substrate, an underlayer provided on the substrate, a Co alloy magnetic film formed through the underlayer, and a protective film for protecting the magnetic film, wherein the underlayer has a two-layer structure of an lower underlayer contacted with the substrate and an upper underlayer contacted with the Co alloy magnetic film, the upper underlayer is a Co&mdash;Cr &mdash;M alloy film having a hexagonal close-packed structure, where 25 atomic %&lE;x&plus;y&lE;50 atomic %, 0.5 atomic %&lE;y, nonmagnetic element M is one selected from the group of elements B, Si, Ge, C, Al, P, Ti, V, Nb, Zr, Hf, Mn, Rh, Os, Ir, Re, Pd, Pt, Mo, Ta, W, Ag and Au. Thereby the medium can be increased in its coercive force and can be improved in its thermal stability characteristics.

Magnetic recording medium

It is an object of the present invention to provide a magnetic recording medium which has a high level of magnetic anisotropy energy, retains stably the state of recording magnetization within the operating temperature range and is suitable for high-density recording with a low noise level, and a magnetic storage device for the magnetic recording medium. For attaining the above object, the magnetic recording film of the magnetic recording medium is characterized in that its magnetic anisotropy energy constant K at an absolute temperature of 300 K is greater than 3.6&times;10 erg/cc and the average particle diameter is larger than 5 nm and smaller than 12 nm.

Magnetic recording media and magnetic storage device

A ferromagnetic thin film of manganese and aluminum having varied atomic concentrations of manganese and aluminum in the direction perpendicular to the film plane, preferably the Mn atomic concentration being preferably in a range of 45 to 65% by atom, has a spontaneous magnetization equivalent to that of the bulk of manganese-aluminum alloy and also a high magnetic anisotropy. In addition, a magnetic recording medium comprises a substrate and a magnetic film formed on the substrate, the magnetic film being a thin film in a stacked structure of thin layers of manganese and thin layers of aluminum, laid open upon one another alternatingly in the film thickness direction. Finally, a manganese-silicon magnetic multi-layer film comprises thin layers of manganese and thin layers of silicon laid upon one another alternatingly.

Manganese-aluminum and manganese-silicon magnetic films, and magnetic

A Bloch line memory device and a method of erasing information in which, for erasure of a Bloch line pair representative of one bit of information and located in one end portion of one stripe domain, the stripe domain is stretched by decreasing the intensity of a bias magnetic field, an erasure Bloch line pair having a rotation of magnetization opposite to that of the to-be-erased Bloch line pair is injected into the end portion of the stretched stripe domain by supplying a current pulse signal to a conductor arranged substantially perpendicualr to the lengthwise direction of the stripe domain, and the stretched stripe domain is shrinked by restoring the intensity of the bias magnetic field, so that the to-be-erased Bloch line pair is combined with the erasure Bloch line pair to cancel the former.

Bloch line memory device

In a magnetic bubble memory device in which a major line and minor loops are constituted by ion-implanted tracks, a gate is constituted having two functions, i.e., having a replicate function and a pseudo swap function using conductor patterns of two layers that overlap on both the major line and on the minor loops. By controlling the pulsed current supplied to the conductor patterns of the two layers, the replicate function divides the bubble in the minor loop into two bubbles, so that one of the bubbles is taken onto the major line and is propagated to the detector. The pseudo swap function annihilates the bubble in the minor loop, divides the bubble on the major line into two bubbles and introduces one of them into the minor loop, thereby to realize the same function as that of the conventional swap gate.

Magnetic bubble memory device

In a magnetic bubble memory device employing ion-implanted tracks as minor loops for data storage, there is proposed a magnetic bubble memory element employing a minor loop having a folded structure and a turn composed of three tips formed convexly toward an ion-implanted area and two cusps as an inside turn for accomplishing the folding with a center as the ion-implanted area. In this inside turn, the line connecting between the two cusps of the turn includes a gradient in the range of 90 degrees to 120 degrees in relation to the ion-implanted straight line tracks.

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Kokubunji, Japan

Teruaki Takeuchi