Hitachi, Ltd.

Yoshihiro Hamakawa

Kazuo Shiiki

Noriyuki Kumasaka

Eijin Moriwaki

Hisashi Takano

Naoki Koyama

Shigekazu Otomo

Isamu Yuito

Hiroyuki Hoshiya

Yoshihiro Shiroishi

Masahiro Kitada

Susumu Soeya

Shigeru Tadokoro

Noritoshi Saito

Isamu Yuitoo

Motoyasu Terao

Toshio Kobayashi

Shigeru Nakamura

Hiroshi Fukui

Seiichi Mita

Hitoshi Nakamura

Masahiro Ojima

Yoshiaki Kawato

Takeshi Nakao

Kenichi Meguro

Kanji Kawakami

Katsumi Hoshino

Yoshinori Miyamura

Takeo Yamashita

Mitsuhiro Kudo

Kiyoshi Matsumoto

Masuo Kasai

Harunobu Saito

Saburo Suzuki

Hiroshi Yasuoka

Kiminari Shinagawa

Eiichi Seya

Shinobu Sasaki

Shiroyasu Odai

Shigeo Aoki

Keiko Shiokawa

Hitoshi Numasaka

There is provided a magnetoresistive head which is capable of suppressing the fluctuation of read output while ensuring a sufficient dielectric breakdown voltage of the shielding portions by constituting the shielding portions with a Co-based material. Namely, the lower shield film is formed of a 2-ply composite film wherein the film ( &prime;) of the lower shield film which is disposed contacting with the lower gap insulation film ( ) is constituted by an amorphous soft magnetic film, while the film ( ) which is disposed away from the lower gap insulation film is constituted by a crystalline soft magnetic film, thereby making it possible to suppress the fluctuation of read output even if the gap is narrowed without deteriorating the yield relative to the dielectric breakdown.

Magnetoresistive head and magnetic storage apparatus

A magnetic head is provided with a magnetoresistive sensor scarcely susceptible to heat and provided with a fixed layer capable of creating a pinned magnetic field of a sufficient intensity. The magnetic head comprises a magnetoresistive effect film having a free layer (,), a fixed layer (,) and an intermediate layer (,), and a pair of electrodes (,) for supplying current to the magnetoresistance effect film. The free layer (,) is formed of a ferromagnetic material and the intermediate layer (,) is formed of a nonmagnetic material. The fixed layer (,) has a first ferromagnetic film (,), a second ferromagnetic film (,) and a nonmagnetic film (,) sandwiched between the first and the second ferromagnetic films (,). The second ferromagnetic film (,) farther from the free layer (,) than the first ferromagnetic layer (,) is formed of a material having the property of permanent magnets. The magnetization of the fist ferromagnetic film (,) and that of the second ferromagnetic film (,) are coupled in an antiferromagnetic coupling fashion.

Magnetic head employing magnetoresistive sensor and magnetic storage and retrieval system

A magnetic head of storage/read separation type in which both a reproducing head of magnetoresistive type and a write head of magnetic induction type are formed through a magnetic shield. The magnetic head includes a ferromagnetic material and an antiferromagnetic material in intimate contact with said ferromagnetic material. At least a part of the antiferromagnetic material acts to bring about unidirectional anisotropy in the ferromagnetic material, and is made of Cr--Mn-based alloy, and at least a part of the ferromagnetic material in intimate contact with the antiferromagnetic material is made of Co or Co-based alloy.

Magnetic layered material, and magnetic sensor and magnetic storage/read

A ferromagnetic and antiferromagnetic material having a high exchange coupling and a high thermal stability, and a magnetic storage system using this material which has excellent reliability and recording density, and a magnetoresistive storage/read separation head having a high sensitivity and a low noise property. The magnetic storage/read system of the invention mounts a magnetoresistive head using a chromium-manganese antiferromagnetic layer/a cobalt alloy layer as a pinning layer or the longitudinal bias layer of the spin-valve type magnetoresistive layered film.

In an inductive-write, magnetoresistive-read type magnetic head having a magnetoresistive read head and an inductive write head superimposed on each other, the magnetic center of the read head is made more coincident with the physical center of the write head by a changing of a magnetization direction of a magnetoresistive element. The recording/reproducing apparatus using this magnetic head can thus have a good S/N ratio even if the track width is narrow.

Magnetic head and recording and reproducing apparatus having an

A magnetoresistive read head includes a magnetoresistive layer having a central active region and end domain control regions, an electrode layer connected to both ends of the magnetoresistive layer, a pattern for providing a transverse bias to the magnetoresistive layer, a soft magnetic film provided on both sides of the magnetoresistive layer for magnetically shielding the magnetoresistive layer, and a substrate for supporting the magnetoresistive layer, pattern and soft magnetic film. A distance between the two end domain control regions of the magnetoresistive layer indicative of a length of the central active region is smaller than a distance between inner end faces of the electrode layer and the distance between the inner end faces of the magnetoresistive substantially corresponds to a read track width. Since both inner end faces of the magnetoresistive layer are set to coincide with the inner end faces of the electrode layer or to be positioned inside thereof, the magnetoresistive read head can prevent generation of Barkhausen noise with a good yield. Further, a track width is determined substantially by the distance between the inner end faces of the hard magnetic layer so that there can be obtained a magnetoresistive read head which is good in its off-track characteristic as well as a magnetic storage system which uses the read head.

Magnetoresistive read head and magnetic storage system using the same

A separation type optical head according to the present invention includes at least a light source portion for emitting collimated beams, a focusing device (a focusing lens) for focusing the collimated beams onto an information recording surface of an optical disc medium, a focal point control mechanism for the position of the spot on the information recording surface, and a photo-detection portion for receiving beams reflected by the information recording surface. The structure is divided into a fixed portion including the light source portion and the photo-detection portion and a movable portion including the focusing device (focusing lens) and the focal point control mechanism. At least the movable portion of the separation type optical head is movably accommodated n a frame (sealing case) for the optical head so as to prevent irregular vibrations of the movable portion due to high speed air flows or turbulence. Furthermore, a focal point control mechanism of an air float type may be employed in the movable portion of the separation type optical head so as to actively utilize the high speed air flow generated due to the rotation of the disc medium to perform a rough adjustment of the focal point of the focusing device.

Stack type optical disc apparatus, sealed and separate type optical head

A thin film magnetic head has a first magnetic core member carried by a substrate, a gap layer formed on the first magnetic core member, and a second magnetic core member formed in a spaced relation with the first magnetic core member. The second magnetic core member is coupled to the first magnetic core member to form a magnetic path and to have an end portion of the gap layer sandwiched by gap defining portions of the first and second magnetic core members. A coil conductor is wound about the magnetic path. In one embodiment, the first magnetic core member includes a first magnetic layer made of a magnetic material having stable magnetic properties during heat treatment and the second magnetic core member includes a second magnetic layer made of a material having a saturation flux density higher than that of the material of the first magnetic core member.

Thin film magnetic head having at least one magnetic core member made at

A thin film magnetic head having a first magnetic layer of a saturation magnetic flux density greater than that of a Ni-Fe alloy and a second magnetic layer of a saturation magnetic flux density grater than that of a Ni-Fe alloy supported by a base layer, the magnetic layers for forming a magnetic core of the head with a non-magnetic material gap layer interposed therebetween, and an electrically insulating layer provided between the magnetic layers so that turns of coil wound about the magnetic core are partly formed in electrically insulated relation within the insulating layer, in which a metal film is provided between the first magnetic layer and the electrically insulating layer so that the electrically insulating layer does not contact with the first magnetic layer and/or another metal film is formed on the second magnetic layer so that the other metal layer is sandwiched between the non-magnetic layer and the second magnetic layer.

Thin film magnetic head including magnetic layers having high saturation

In a thin film magnetic head of the type wherein a lower magnetic pole, a gap layer, a first insulating layer, a coil, a second insulating layer and an upper magnetic pole are formed sequentially on a substrate, the present invention provides a thin film magnetic head characterized in that a surface active layer made of aluminum oxide, for example, is disposed between the first insulating layer and the second insulating layer except where the coil is formed on the first insulating layer so that the surface active layer is disposed between the coil and the second insulating layer. According to the present invention, it is possible to prevent the occurrence of bubbles between coil conductors, and eventually to improve flatness of the surface of the second insulating layer and to prevent degradation of the characteristics of the upper magnetic pole.

Thin film magnetic head

Multilayered magnetic films of the invention comprising at least two unit magnetic films each of which has a thickness of from 0.05 to 0.9 .mu.m and includes a plurality of ferromagnetic layers each having a thickness of from 0.01 to 0.2 .mu.m and a 1 nm to 10 nm thick first intermediate layer consisting of a ferromagnetic, nonmagnetic or antiferromagnetic material and provided between adjacent ferromagnetic layers, and a second intermediate layer having a thickness of from 10 to 40 nm, consisting of a nonmagnetic or antiferromagnetic material and provided between the at least two unit magnetic films. The multilayered magnetic film is suitable as a pole of a thin-film magnetic head. An underlayer may be further provided between the magnetic film and a substrate whereby a multilayered magnetic film having good characteristics can be obtained.

Multilayered magnetic films and thin-film magnetic heads using the same

A magnetic head comprising a magnetic film in at least a part of a magnetic circuit, at least a part of the magnetic film being formed in contact with, or being exposed to, an oxide or oxygen at least in a heating step at 150.degree. C. or higher in a process for preparing the magnetic head is disclosed. An amorphous alloy film for the magnetic film has the following composition formula to give distinguished head characteristics without any oxidation:

Magnetic head made from amorphous magnetic film

A ferromagnetic material is composed of an iron alloy which contains 2 to 12% by weight of silicon and 5 to 25% by weight of at least one element selected from the group consisting of ruthenium, rhodium, palladium, iridium, platinum, gold and silver. This ferromagnetic material exhibits a high saturation flux density and good corrosion resistance. Excellent magnetic characteristics are obtained by a multilayered film which is obtained by alternatingly laminating the above ferromagnetic material and a spacer layer composed of other material. Further, a markedly increased recording density is exhibited by a magnetic head for perpendicular magnetic recording, when the end of the main pole is composed of the ferromagnetic material.

Ferromagnetic material and a magnetic head using the same material

Disclosed is a thin film magnetic head having a structure wherein the main portion of a coil consists of a copper or copper alloy layer and its upper surface is covered with a thin film mask consisting of titanium, titanium oxide, chromium and/or chromium oxide. The magnetic head of the invention can prevent the occurrence of projecting etching residues at the upper edge portion of the coil and can easily increase the cross-sectional area and the winding density of the coil. Furthermore, when the thin film mask consists of titanium and/or titanium oxide, a titanium diffusion prevention film consisting of chromium, for example, is interposed between the thin film mask and the copper or copper alloy, so that the resistance change of the coil scarcely takes place owing to heat treatment in a production process after the formation of the coil and the head reliability can be further improved.

Thin film magnetic head having an improved coil

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Urawa, Japan

Yoshihiro Hamakawa