Hitachi, Ltd.

Hitachi Global Storage Technologies Netherlands B.v.

Naoki Kodama

Ryo Suzuki

Masatoshi Takeshita

Teruaki Takeuchi

Yutaka Sugita

Tadashi Ikeda

Takashi Toyooka

Toshihiro Sato

Yasutaro Uesaka

Iwao Matsuyama

Hajime Fukke

Masayuki Katsumoto

Hiroyuki Suzuki

Tsuneo Suganuma

Heigo Ishihara

Katsuo Abe

Hiroshi Umezaki

Katsuyoshi Chiba

Hitoshi Inoue

Yuzuru Hosoe

Yoshihiro Shiroishi

Kiwamu Tanahashi

Kazuetsu Yoshida

Yotsuo Yahisa

Tomoo Yamamoto

Shinji Narishige

Akira Ishikawa

Fumio Kugiya

Kazuo Sakai

Takuji Ogawa

Kazuo Nakagoshi

Futoshi Tomiyama

Masao Iwakura

Tokuho Takagaki

Motoo Akagi

Tomio Suzuki

Nobuyuki Okunaga

Akira Osaki

Naoto Endo

Shinzo Matsumoto

Tatsuya Ishigaki

Ryohheita Hattori

Takao Yonekawa

Emi Mangyo

Toshiaki Kojima

Yoshiharu Terada

Chuma Akira

Embodiments of the present invention pertain to a magnetic head that includes negative expansion material. According to one embodiment, the magnetic head includes a read element, a substrate, and at least a partial layer of negative expansion material to control, at least in part, a fly height between an air bearing surface associated with the magnetic head and a disk surface. The material is manganese nitride based and non-insulating and the layer of negative expansion material is parallel to the substrate, according to one embodiment.

Magnetic head that includes negative expansion material

A magnetic disk drive has a housing for a 3.5 inch form factor and disk media of a diameter for a 2.5 inch form factor. The smaller disk media rotate at a high speed while consuming low electric lower and generating less heat while providing for quick access speeds. Usually, when the magnetic disk media are rotated at a higher speed, the electric power consumption and heat generation are increased because of the load increase. This problem is avoided with the use of cooling fins placed about the periphery of the disk media. Further, the smaller size disk media enable a decrease in torque loss during on-load rotation with the media, and a decrease of electric current to the spindle motor during rotation.

Disc drive having 3.5 inch form factor housing and 2.5 inch form factor disk media

In a magnetic recording system including magnetic recording media, a rotation driving unit for driving these magnetic recording media, read/write magnetic heads, driving apparatus for driving these read/write magnetic heads, and a read/write signal processing apparatus, a reading portion of the respective magnetic heads is arranged by a magnetoresistive head. The magnetic recording media are constructed of multi-layered magnetic media having a plurality of magnetic layers fabricated directly, or via underlayers on a non-magnetic disk substrate, and of non-magnetic intermediate layers arranged among these non-magnetic layers. Furthermore, one coercivity which is measured by applying a magnetic field along a circumferential direction of the magnetic recording media, is selected to be larger than the other coercivity which is measured by applying a magnetic field along a radial direction of the magnetic recording media, so that a higher signal-to-noise ratio is achieved, as compared with that of the conventional magnetic recording system. Since the thickness of the non-magnetic intermediate layers is smaller than or equal to 5 nm, and also the total layer is smaller than or equal to 5 nm, and also the total layer number of the plural magnetic layers is selected to be odd, better characteristics can be achieved. Accordingly, since the MTBF (Mean Time Before Failure) is longer than or equal to 0.15 million hours with high recording density, and the disk substrate and the magnetic head sliders can be mounted at high packaging density, a compact and high-capacity magnetic recording system can be obtained.

Multi-layered magnetic recording medium and magnetic recording system

A magnetic recording medium and magnetic recording apparatus which can provide a high output level and a low noise level are disclosed. A magnetic recording medium includes a multilayer structure of magnetic alloy thin films containing Co, and at least one paramagnetic intermediate region or oxygen-rich region disposed between the magnetic layers. The intermediate region reduces the magnetic interaction between the magnetic layers without the degradation of crystallinity of the magnetic layers. As a result, a magnetic recording medium having such a structure shows low noise performance and a high recording density.

Magnetic recording medium and magnetic recording apparatus

A longitudinal magnetic recording medium with a good overwrite property and a small medium noise is identified by a CRP value, which is defined by

Longitudinal magnetic recording medium exhibiting various coercivitiy

A method for manufacturing a magnetic paint by mixing a resin composition powder as a dispersing binder for a magnetic powder with the magnetic powder, or together with a filler, and grinding the mixture under a high shear stress is disclosed. A magnetic recording medium such as a magnetic disk, etc., prepared by using the magnetic paint, can have a magnetic coating film having a substantially uniform film thickness of not more than 0.9 .mu.m and a surface roughness of not more than 0.05 .mu.m Ra before surface finishing.

Hard disk magnetic recording medium comprising magnetic powder and a

A coating type, magnetic disk is produced by applying a magnetic paint containing magnetic powders in a dispersed state to a non-magnetic substrate, thereby forming a magnetic recording film thereon, and applying surface waves to the magnetic recording film in an undried state. By applying the surface waves to the magnetic recording film, dispersibility and orientation of the magnetic powders are improved and a longitudinally oriented, coating type magnetic disk with distinguished electromagnetic properties, such as a high S/N ratio, etc. can be obtained.

Process for producing a rigid magnetic disk by longitudinally generating

A method for magnetic orientation of a magnetic recording medium using Meissner effect of a superconductor and a system therefor and a magnetic recording medium produced thereby. The magnetic particles of plate hexagonal barium ferrite in the magnetic coating are allowed to orient in the longitudinal direction thereof so that a magnetic recording medium having a magnetic orientation in such direction with the magnetic particles can be obtained.

Method for magnetic orientation of magnetic recording medium using

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.

A hybrid magnetic bubble memory device comprising soft magnetic material propagation tracks and ion-implanted propagation tracks. In the soft magnetic material propagation track region, a layer made of a heat-resistant polymer was provided as an interlaminar insulating layer between a conductor and a pattern of a soft magnetic material. An insulator film made of a heat-resistant polymer was provided on the pattern made of a soft magnetic material. A passivation film made of an inorganic material was provided on the ion-implanted propagation tracks and the insulator film made of a heat-resistant polymer.

A magnetic bubble memory device comprises contiguous-disk ion-implanted magnetic bubble propagation tracks formed by implanting selectively ions in a magnetic layer which can hold magnetic bubbles. At least one of the disks which form the ion-implanted bubble tracks and each of which may have a circular or square shape, is configured to include a combination of arcs of circles having different curvatures or a combination of sides of squares having different sizes.

A hybrid magnetic bubble memory device includes, magnetic bubble propagation tracks formed of partial ion-implantation and bubble propagation tracks formed of a soft magnetic material pattern. At least one of the junctions between the two type tracks is located on a corner soft magnetic material pattern where the bubble propagation direction is changed, and the hairpin conductor is superposed on the part of the corner pattern under which the magnetic material is not ion-implanted to form ion-implanted propagation tracks.

Hybrid magnetic bubble memory device

A highly density magnetic bubble memory device has bubble propagation paths having different pattern periods. The distance between a propagation path having shorter period and a magnetic film for holding magnetic bubbles is made smaller than that between propagation path having longer period and the magnetic film. An insulating layer formed between the propagation path and the magnetic film through another insulating layer has a declining slope having an angle of 60.degree. or less, thereby ensuring steady propagation of the magnetic bubbles along the propagation path.

Disclosed is a magnetic bubble memory device having a first bubble propagation path formed in an ion-implantation pattern and a second bubble propagation path made of permalloy elments in combination. The majority of the area for forming the second propagation path is processed by ion implantation in lower density and to smaller depth than those of ion implantation for forming the first propagation path on the surface of a bubble supporting layer.

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Hachioji, Japan

Naoki Kodama