Hitachi, Ltd.

Masaaki Sano

Moriaki Fuyama

Katsuya Mitsuoka

Hiroshi Fukui

Shinji Narishige

Takashi Kawabe

Hisashi Takano

Reiko Arai

Kenzo Masuda

Shun-ichi Narumi

Yoshiaki Kita

Hisano Yamamoto

Hiroyuki Hoshiya

Takao Imagawa

Masanobu Hanazono

Susumu Soeya

Kouichi Nishioka

Fumio Sato

Toshihiro Yoshida

Tetsuo Kobayashi

Akira Kumagai

Makoto Saito

Atsushi Nakamura

Yutaka Sugita

Matahiro Komuro

Yohji Maruyama

Masaaki Hayashi

Tomohiro Okada

Noboru Shimizu

Kazuhiro Nakamoto

Katsumi Hoshino

Takashi Onishi

Makoto Morijiri

Yokuo Saitoh

Tadayuki Iwakura

Masanori Tanabe

Makoto Aihara

Shinichi Hara

Yoshikazu Tsuji

Miki Hara

Shuji Sudo

Noboru Yoshida

A magnetic disk apparatus includes a magnetic disk for recording information and a magnetic head which has a reproducing head and a recording head. The reproducing head comprising a lower shield film, a magnetoresistive film, a pair of electrodes and an upper shield, and the recording head comprising an upper magnetic core, a lower magnetic core, and a coil disposed between said upper magnetic core and said lower magnetic core. The upper magnetic core and the lower magnetic core include an electroplated thin film with an average crystal grain size smaller than 500 &angst;, and the electroplated thin film is made of Ni&mdash;Fe alloy of which Ni is 38 to 60 wt % and Fe is 40 to 62 wt %.

Magnetic disk apparatus with magnetic head having upper and lower magnetic cores of an electroplated thin film

A magnetoresistive element includes a first antiferromagnetic film, a first magnetic film having a magnetization direction fixed by magnetic coupling with the first antiferromagnetic film, a second antiferromagnetic film, a second magnetic film having a magnetization direction fixed by magnetic coupling with the second antiferromagnetic film, a third magnetic film having a magnetization direction able to rotate in response to an applied magnetic field, a first nonmagnetic film disposed between the first magnetic film and the third magnetic film, and a second nonmagnetic film disposed between the second magnetic film and the third magnetic film. The third magnetic film is disposed between the first nonmagnetic film and the second nonmagnetic film, the first magnetic film is disposed between the first antiferromagnetic film and the first nonmagnetic film, and the second magnetic film is disposed between the second antiferromagnetic film and the second nonmagnetic film.

Magnetoresistive element

A slider having a thin film magnetic head. The thin film magnetic head has an upper magnetic core, a lower magnetic core and a coil disposed between the upper magnetic core and the lower magnetic core. The upper magnetic core and the lower magnetic core is an electroplated thin film with an average crystal grain size smaller than 500 &angst;, and the electroplated thin film is made of Ni&mdash;Fe alloy of which Ni is 38 to 60 wt % and Fe is 40 to 62 wt %.

Thin film magnetic head with electroplated Ni-Fe alloy thin film having small average crystal grain size range

A thin film magnetic head having a first magnetic core, a second magnetic core formed on the first magnetic core, a coil disposed between the first magnetic core and second magnetic core, and a non-magnetic insulator body for separating the first magnetic core, second magnetic core and coil with respect to each other. At least one of the first magnetic core and the second magnetic core includes an electroplated thin film with an average crystal grain size smaller than 500 &angst; and the electroplated thin film is made of Ni&mdash;Fe alloy of which Ni is 38 to 60 wt % and Fe is 40 to 62 wt %.

Thin film magnetic head and assembled construction thereof

A thin film magnetic head and a disk storage system having a magnetic disk and the thin film magnetic head provided on a floating type slider. The thin film magnetic head has an upper magnetic core and a lower magnetic core, wherein the upper magnetic core and the lower magnetic core are made of an electroplated thin film having sufficient average crystal grain size. The upper magnetic core is made of a Ni&mdash;Fe alloy having Ni of 38 to 60 wt % and Fe of 40 to 62 wt %, and the crystal grain size is smaller than 500 &angst;.

Thin film magnetic head with Ni-Fe alloy thin film

A magnetic storage/read system includes a recording medium having tracks, and a magnetic head, including a magnetoresistive element, which reads a magnetic field from the recording medium. The magnetic storage/read system satisfies a relationship of d&lE;(12.5&times;10,)/Tr where d is a height, expressed in &mgr;m, of the magnetoresistive element in a direction perpendicular to a plane of the recording medium, and Tr is a track density, expressed in tracks per inch, of the tracks of the recording medium. The magnetoresistive element may include a first antiferromagnetic film; a first magnetic film having a magnetization direction which is fixed by magnetic coupling with the first antiferromagnetic film; a second antiferromagnetic film; a second magnetic film having a magnetization direction which is fixed by magnetic coupling with the second antiferromagnetic film; a third magnetic film having a magnetization direction which is able to rotate in response to an applied magnetic field; a first nonmagnetic conductive film disposed between the first magnetic film and the third magnetic film; and a second nonmagnetic conductive film disposed between the second magnetic film and the third magnetic film; wherein the third magnetic film is disposed between the first nonmagnetic conductive film and the second nonmagnetic conductive film, the first magnetic film is disposed between the first antiferromagnetic film and the first nonmagnetic conductive film, and the second magnetic film is disposed between the second antiferromagnetic film and the second nonmagnetic conductive film.

Magnetic head including magnetoresistive element

A magnetic head includes a magnetoresistive element. The magnetoresistive element includes a first magnetic film having a fixed magnetization direction, a second magnetic film having a fixed magnetization direction, a third magnetic film having a rotatable magnetization direction, a first nonmagnetic film, and a second nonmagnetic film. The first magnetic film, the first nonmagnetic film, the third magnetic film, the second nonmagnetic film, and the second magnetic film are stacked in this order.

A magnetic film having a high saturation magnetic flux density larger than 1.5 T and a resistivity larger than 40 .mu..OMEGA..cndot.cm is fabricated through an electroplating method using (40-60)Ni-Fe and by adding Co, Mo, Cr, B, In, Pd or the like to the (40-60)Ni-Fe. Thereby, it is possible to obtain a recording head capable of performing sufficient recording in a high frequency range and to obtain a disk storage system with a high recording density which has a transfer rate higher than 15 MB/s, a recording frequency higher than 45 MHz and a rotating speed of a magnetic disk higher than 4000 rpm.

In order to prevent degradation of the recording performance during radio frequency recording, and to provide a thin film magnetic head and a recording reproducing sectional pattern magnetic head which has a magnetic pole width less than 2 .mu.m and an ultra high density magnetic storage apparatus of 10 Gb/ in.sup.2 grade, a recording head is provided in which a lower part magnetic film serves as a shielding film of a reproducing selection, a non magnetic gap film is formed during formation of the upper part magnetic film and the lower part magnetic film, one part of the lower part magnetic film or the upper part magnetic film has a higher resistivity of more than 80 .mu..OMEGA.cm than other parts, the upper part magnetic film is formed by flame galvanizing, and a gap section of the lower part magnetic film or the upper part magnetic film has a convex shape.

Apparatus and thin film magnetic head with magnetic membrane layers of

A magnetic storage/read system includes a recording medium for magnetically storing a signal and a magnetoresistive element which is driven relative to the recording medium. The magnetoresistive element may include a substrate, a first antiferromagnetic film, a first ferromagnetic film, a first nonmagnetic film, a soft magnetic film, a second nonmagnetic film, a second ferromagnetic film, and a second antiferromagnetic film, wherein the films are sequentially layered directly on the substrate with no intervening layer between any of the films. At least one of the first antiferromagnetic film and the second antiferromagnetic film may be made of nickel oxide. The first ferromagnetic film and the second ferromagnetic film have a first magnetization which is fixed in a predetermined direction, and the soft magnetic film has a second magnetization which is rotatable in response to a magnetic field from the recording medium such that an angle between a direction of the second magnetization and the predetermined direction in which the first magnetization is fixed varies in response to the magnetic field from the recording medium, thereby producing a magnetoresistive effect.

Magnetic storage/read system with read head including magnetoresistive

A magnetic disc unit has a thin film magnetic head in which a lower magnetic core and an upper magnetic core form a magnetic circuit. The upper magnetic core is constructed by magnetic films having at least two layers. A saturation magnetic flux density of the inside magnetic film, of the magnetic films having at least two layers, facing a magnetic gap of the magnetic circuit is larger than that of the outside magnetic films of the upper magnetic core and the lower magnetic core.

Magnetic disc unit having a plurality of magnetic heads which include

A method of fabricating a thin film magnetic head including a bottom magnetic core formed on a substrate, a top magnetic core laminated through an insulation layer, with one end of the top and bottom magnetic cores being joined and another end forming a magnetic gap, and a conductor coil layer which winds around the joined section for a plurality of number of turns. At least one of the top and bottom magnetic cores has its magnetization easy axis oriented substantially orthogonal to the magnetic path direction of the magnetic head by the magnetic annealing process, so that the magnetic head has an increased output and an enhanced write ability.

Thin film magnetic head and the method of fabricating the same

A thin film magnetic head has magnetic films, at least one of which is composed of a material containing major components of nickel and iron and one or more element from nitrogen, oxygen and carbon and has two of face-centered cubic system and body-centered tetragonal system, whereby thin film magnetic heads having a high permeability and low coercive force can be provided.

Thin film magnetic head with mixed crystal structures

A thin film magnetic head provided with a first and a second thin film made of a magnetic material, disposed so as to form a closed magnetic circuit; and an intermediate film made of a non-magnetic material, disposed between the first and the second thin films so as to form a magnetic gap at a part of the magnetic circuit; wherein at least one of the first and the second thin films is made of a quaternary amorphous magnetic alloy, whose principal component is cobalt and which contains hafnium, tantalum and palladium.

Quarternary amorphous magnetic alloy thin film and magnetic head

A thin film magnetic head is disclosed which includes a substrate, a first magnetic core disposed on the substrate, a second magnetic core forming a magnetic path in conjunction with the first magnetic core, a conductor coil wound in the magnetic path and a gap formed between ends of the first magnetic core and the second magnetic core. At least one of the first magnetic core and the second magnetic core includes a thin film of a cobalt alloy. The cobalt alloy includes 20-70 atomic percent of cobalt, 20-60 atomic percent of nickel, 12-30 atomic percent of iron and 5-32 atomic percent of palladium.

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Hitachi, Japan

Masaaki Sano