Kabushiki Kaisha Toshiba

Hiromi Sakata

Hiroaki Yoda

Tadahiko Kobayashi

Kohichi Tateyama

Michiko Hara

Tomohiko Nagata

Akio Hori

Tomomi Funayama

Takashi Koizumi

Naoyuki Inoue

Yoichiro Tanaka

Atsuhito Sawabe

Shigeru Takekado

Takeo Sakakubo

Kazushi Tanimoto

Shigeru Hoshina

Hiroshi Okamura

Seishiro Fujiwara

Takasi Koizumi

Kei Sakoda

A main controller controls the current in an overshoot part included in the write current supplied from a write driver to a head in accordance with write data via an overshoot controller in accordance with the temperature detected by a temperature sensor.

Apparatus and method for controlling write current supplied to head

A magnetoresistive (MR) head device is used as the read head of a disk drive. The magnetoresistive head device is provided with a magnetoresistive layer and conductors. The magnetoresistive layer changes in magnetization direction in response to a recording magnetic field on a disk. The conductors serve as electrodes and used for supplying a sense current to the magnetoresistive layer. The conductors have joint portions that are in contact with the magnetoresistive layer. The joint portions have substantially the same height (thickness) as the magnetoresistive layer, if it is measured from the disk surface. With this structure, a sense current supplied from one of the conductors flows through the magnetoresistive layer in a uniform direction. Hence, the magnetization direction is constant throughout the magnetoresistive layer.

Magnetoresistive head device incorporating joints between magnetoresistive layer and sense current conductors

In a magnetic head, at least its upper insulating layer is formed of a resin having a glass transition temperature of 70&deg; C. to 100&deg; C., a porous material, or polyimide, or the ABS is polished at a high temperature, so when the temperature increases, a deformation, which can reduce a decrease in floating height, an increase in the danger of crash, and an increase TA on the part of a magnetic disk apparatus, does not occur on the ABS side.

Magnetic head and magnetic disk apparatus using the same

There is provided a magnetic recording apparatus capable of carrying out signal reproduction with high accuracy by using a narrow gap head structure corresponding to high recording density. An asymmetric gap structure MR head includes a magnetoresistance element,having a magnetoresistance film,and a pair of electrodes,disposed at the upper side; a reproducing magnetic gap film,disposed only at the lower side of the magnetoresistance element,; a magnetic shielding film,disposed so as to make a laminate with the magnetoresistance element,through the reproducing magnetic gap film,; and an insulating film,disposed at the upper side of the magnetoresistance element,. When a signal is read by use of such a reproducing head, the signal of the present bit is read by subtracting a value obtained by multiplying signals of a plurality of previous bits by predetermined coefficients from the present reproduction signal. As another reproduction signal processing system, a partial response system is adopted.

Magnetic recording apparatus

At least one magnetic pole out of a pair of magnetic poles is provided with a T-shaped magnetic pole having a magnetic pole chip at the position contacting with a magnetic gap and an auxiliary magnetic pole which is wider than thereof. The proximity of an air bearing surface of the T-shaped magnetic pole is composed of a laminated film containing a magnetic material layer with a high saturated magnetic flux density which composes the magnetic pole chip and a portion of the auxiliary magnetic pole and a magnetic material layer with a low saturated magnetic flux density which composes the remaining portion of the auxiliary magnetic pole. When the front portion of the magnetic pole with the track width of 1.8 &mgr;m or less is composed of a laminated film containing a magnetic material layer having a high saturated magnetic flux density and a magnetic material layer having a low saturated magnetic flux density, the thickness of the magnetic material layer having the high saturated magnetic flux density is 0.5 &mgr;m or more. According to the above described magnetic pole, the magnetic saturation near the tip portion of the magnetic pole is controlled, so that preferable magnetic field strength and magnetic field gradient can be attained when the track width is narrowed.

Magnetic head

A thin-film magnetic head comprises a magnetic gap disposed to be positioned on an air bearing surface of the magnetic head, a pair of magnetic poles disposed to hold the magnetic gap therebetween, and a coil positioned between the pair of the magnetic poles to intersect the magnetic poles, wherein at least one of the magnetic poles being composed of a T-shaped magnetic pole, the T-shaped magnetic pole comprising a front part of a magnetic pole contacting with the magnetic gap, an intermediate part of a magnetic pole lying on the front part, and a rear part of a magnetic pole lying on the intermediate part, wherein a width of the front part roughly defines a track width, the rear part has a wider width in a direction of track width than a width of the front part, and the intermediate part contacts with the rear part at an entire width of the rear part at the air bearing surface and has a narrower width at a contacting face with the front part than the width of the rear part.

Thin-film magnetic head having improved magnetic pole structure

At least one magnetic pole out of a pair of magnetic poles is provided with a T-shaped magnetic pole having a magnetic pole chip at the position contacting with a magnetic gap and an auxiliary magnetic pole which is wider than thereof. The proximity of an air bearing surface of the T-shaped magnetic pole is composed of a laminated film containing a magnetic material layer with a high saturated magnetic flux density which composes the magnetic pole chip and a portion of the auxiliary magnetic pole and a magnetic material layer with a low saturated magnetic flux density which composes the remaining portion of the auxiliary magnetic pole. When the front portion of the magnetic pole with the track width of 1.8 .mu.m or less is composed of a laminated film containing a magnetic material layer having a high saturated magnetic flux density and a magnetic material layer having a low saturated magnetic flux density, the thickness of the magnetic material layer having the high saturated magnetic flux density is 0.5 .mu.m or more. According to the above described magnetic pole, the magnetic saturation near the tip portion of the magnetic pole is controlled, so that preferable magnetic field strength and magnetic field gradient can be attained when the track width is narrowed.

A magnetic multi-head unit includes: a specific magnetic head formed so that a pair of magnetic yokes face each other on the same plane via a magnetic gap inclined by a predetermined azimuth angle; and a magnetic head which is adjacent to the specific magnetic head and which is formed so that a pair of magnetic yokes face each other on a plane different from the plane of the specific magnetic head via a magnetic gap inclined by the azimuth angle. The specific magnetic head and the adjacent magnetic head are laminated so as to form a plurality of layers while being shifted from each other in directions in which tracks on a magnetic disk extend. A magnetic disk unit includes: a magnetic disk, on which a plurality of information recording tracks are formed so as to extend in peripheral directions and which is rotated; and a magnetic multi-head including a plurality of transducers as heads for simultaneously writing and/or reading magnetic information on the plurality of information recording tracks of the magnetic disk every predetermined group of the tracks. The plurality of transducers are positioned as one with respect to the predetermined group of the tracks.

Magnetic disk unit having laminated magnetic heads

The magnetic head comprises two magnetoresistance effect elements and a soft magnetic film connecting end portions of the magnetoresistance effect elements with each other. The two magnetoresistance effect elements and the soft magnetic film are arranged in series so as to form a single magnetic circuit, and a magnetic gap is provided in the side of a surface facing a magnetic medium. Magnetic flux from the magnetic medium is introduced into the magnetoresistance effect elements through the magnetic gap. An insulating material may be used to fill the magnetic gap.

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Kawasaki, Japan

Hiromi Sakata