JPH08124122A - Magnetoresistive reproducing head and magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE: To increase the reproducing output of a magnetoresistive reproducing head. CONSTITUTION: A lower shielding film (NiFe film) 10 of 2μm thickness, a magnetic gap forming insulating film (Al2 O3 film) 20 of 0.2μm thickness, a soft magnetic film (NiFeNb film) 30 of 20nm thickness a nonmagnetic electrically conductive film (Ta film) 40 of 15nm thickness and a magnetoresistive film (NiFe film) 50 of 20nm thickness are successively laminated on a substrate 5 and patterning is carried out so as to decide the height of the magneto- resistive film 50. An org. resist film is then laminated and patterning is carried out in the desired shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing head for reading an information signal from a magnetic recording medium, and more particularly to an improved magnetoresistive effect reproducing head and a magnetic recording / reproducing apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, a magnetic reading converter called a magnetoresistive effect (MR) sensor or head is known. MR sensors utilize the resistance change of a read element made of a magnetoresistive material to detect a magnetic signal as a function of the amount and direction of magnetic flux sensed by the element,
Compared with the case of using the conventional inductive head,
A larger reproduction output can be obtained.

However, as the recording density increases,
The magnetic field generated from the recording medium becomes small, and it becomes difficult to secure an appropriate reproduction output even if an MR head is used.

Incidentally, it has been conventionally shown that it is necessary to apply two bias magnetic fields in order for the MR element to operate optimally. A lateral bias field is generally used to bias the MR element so that its response to the magnetic flux is linear. This bias field is perpendicular to the plane of the magnetic medium and parallel to the flat MR element surface. Current bias, shunt bias,
Soft Bias, Soft Aji Centrair (hereinafter SA
L) There are various methods such as bias. These lateral biases are generated at a level sufficient to bias the head into the most linear range of the RH characteristic curve. Of these, the present invention uses the SAL bias method, but is also applicable to other bias methods.

Another bias field used in MR elements is what is referred to in the art as the longitudinal bias field,
It is parallel to the surface of the magnetic medium and parallel to the longitudinal direction of the MR element. The function of the longitudinal bias magnetic field is to suppress Barkhausen noise caused by multi-domain effect in the MR element. The longitudinal bias magnetic field is disclosed in Japanese Patent Laid-Open Nos. 62-40610 and 63.
There is a method of using an antiferromagnetic film as shown in Japanese Unexamined Patent Publication No. 117309, and a method of using a permanent magnet film as shown in Japanese Unexamined Patent Publication Nos. 2-220213 and 3-29105.
Of these, the present invention uses the permanent magnet film bias method or the antiferromagnetic film bias method, but other bias methods are also applicable. The antiferromagnetic film bias method is used, the antiferromagnetic film or the magnetoresistive film is provided directly under the electrode, or the soft magnetic film is provided directly under the electrode. It is applicable to either method.

[0006]

By the way, the magnetic field entering the magnetoresistive film of the magnetic head from the recording medium is maximum at the medium facing surface, and sharply decreases as the distance from the medium facing surface increases. Therefore, when the magnetic field from the medium is applied, the magnetization in the magnetoresistive effect film largely rotates in the vicinity of the medium facing surface, and the magnetization hardly changes on the side opposite to the medium facing surface. The portion where the magnetization hardly changes has only an effect of increasing noise and has almost no effect on the output. However, if this part is simply deleted, due to the demagnetizing field,
The area in which the magnetization rotates when the magnetic field from the medium enters is further reduced.

An object of the present invention is to solve the above-mentioned drawbacks and to provide an MR head capable of obtaining a high reproduction output at a high recording density.

[0008]

As shown in FIG. 1 or FIG. 2, the distance a between the surfaces of the magnetoresistive film on the side opposite to the medium facing surface is defined as the distance between the surfaces of the electrodes on the side opposite to the medium facing surface. By making the length longer than b, the region in which the magnetization rotates when a magnetic field from the medium is applied is enlarged, and thus a magnetoresistive head having a large reproduction output is produced.

The magnetoresistive head of the present invention is preferably combined with an inductive thin film head for magnetic recording to form a recording / reproducing separated type magnetic head. The recording / reproducing head of the present invention is particularly effective in reproducing a signal from a recording medium having a high coercive force of 2000 Oe or more.

[0010]

In the present invention, a large amount of current flows through the portion 1 of the magnetoresistive film of FIG. 1 or 2 which faces the separated electrode 80, but the portion of the magnetoresistive film which does not face the separated electrode. 2 does not have much current. However, the presence of this portion increases the region where the magnetization of the magnetoresistive film rotates when a magnetic field is applied from the medium, as described above, so that the reproduction output can be increased.

The present invention relates to a soft magnetic film for applying a lateral bias,
The present invention relates to a magnetoresistive head having a nonmagnetic conductive film and a magnetoresistive film, but a nonmagnetic insulating film is used instead of another magnetoresistive head, for example, a nonmagnetic conductive film. For a head, a dual type MR head using a magnetoresistive film instead of a soft magnetic film for applying a lateral bias, or for applying a lateral bias magnetic field,
It is also effective for a head using a permanent magnet film.

[0012]

【Example】

(Embodiment 1) FIG. 3 shows a cross-sectional view in the easy axis direction of a magnetic sensing portion of a magnetoresistive head according to an embodiment of the present invention.

A lower shield film having a thickness of 2 μm is formed on the substrate 5.
(NiFe film) 10, 0.2 μm thick insulating film (Al ₂ O ₃ film) 20 for forming a magnetic gap, 20 nm thick soft magnetic film (NiFeNb film) 30, 15 nm long non-magnetic conductive film (Ta) 40), 20 nm thick magnetoresistive film (Ni
After stacking the Fe film) 50, patterning is performed to determine the height of the magnetoresistive effect film. Next, after stacking the organic resist film, patterning is performed into a desired shape.

Further, a base film (Cr film) 60 for a permanent magnet film having a thickness of 30 nm and a permanent magnet film (CoCrPt film) 70 having a thickness of 30 nm are laminated and processed into a desired shape, and then Nb / Au / Nb. Are laminated and processed to form an electrode 80.
Further, an insulating film (Al ₂ O ₃ film) 90 having a thickness of 0.155 μm and an upper shield film (NiFe film) 100 having a thickness of 2 μm were laminated and processed into a desired shape to form a magnetic head.

The magnetoresistive head manufactured through the above process has a length a of 3.5 μm and a b of 2.5 in FIG.
and the distance between the electrodes was 3.5 μm. The reproduction output at 100 kFCI obtained using this head is 0.19 mV, and the conventional a and b lengths are both 2.
The characteristics were improved by about 60% as compared with the head reproduction output of 0.12 mV which is equal to 5 μm.

(Embodiment 2) FIG. 4 shows a cross-sectional view in the easy axis direction of a magnetic sensing part of a magnetoresistive head according to another embodiment of the present invention. On the substrate 5, a 2 μm thick lower shield film (N
iFe film) 10, 0.2 μm thick insulating film (Al ₂ O ₃ film) 20 for magnetic gap formation, 20 nm thick NiO film 110 for controlling magnetic domains, 20 nm thick insulating Al ₂ O ₃ film 12
After stacking 0, the uppermost Al ₂ O ₃ film is processed into a desired shape. Next, a magnetoresistive film (NiF) having a thickness of 20 nm is formed.
e film) 50, non-magnetic conductive film (Ta film) 4 having a thickness of 15 nm 4
After stacking a soft magnetic film (NiFeNb film) 30 having a thickness of 0 and a thickness of 20 nm, it is processed into a desired shape. Next, Nb / for electrode
After stacking Au / Nb80 and processing it into a desired shape, a magnetic gap forming film (Al ₂ O ₃ film) 9 having a thickness of 0.155 μm 9
0, magnetic shield film (NiFe film) 100 with a thickness of 2 μm
Was laminated and processed into a desired shape to obtain a magnetic head.

The magnetoresistive head manufactured through the above process has a length a of 3.5 μm and a b of 2.5 in FIG.
and the distance between the electrodes was 3.5 μm. The reproduction output at 100 kFCI obtained using this head is 0.
19 mV, both conventional a and b have a length of 2.5μ
Compared to the playback output of the head equal to m of 0.12 mV,
The characteristics were improved by about 60%.

(Embodiment 3) The magnetoresistive effect element of the present invention was used as a reproducing head, and a recording / reproducing separated type magnetic head using a conventionally known inductive type thin film head as a recording head was manufactured. FIG. 5 shows a perspective view in which a part of the recording / reproducing separated type head according to the present embodiment is cut.

A sintered body containing Al ₂ O ₃ .TiC as a main component was used as the substrate 5 for the slider. After the lower shield film 10 is formed by the method shown in Embodiment 2, an insulating film (Al ₂ O ₃ film) for forming a magnetic gap, a NiO film for controlling a magnetic domain, and an Al ₂ O ₃ film for insulating are laminated thereon, The upper Al ₂ O ₃ film was processed into a desired shape. Next, a magnetoresistive film (NiFe film),
Non-magnetic conductive film (Ta film), soft magnetic film (N film) with a thickness of 20 nm
After the iFeNb film) 30 is laminated, it is processed into a desired shape. Next, Nb / Au / Nb80 for electrodes is laminated and processed into a desired shape, and then a magnetic gap forming film (Al ₂ O
₃ films) and a magnetic shield film (NiFe film) 100 were formed. The above part functions as a reproducing head.

Next, as a magnetic recording head, the thickness is 3 μm.
After forming an insulating film of Al ₂ O _{3 of} m, the lower magnetic pole 1
An inductive thin film head composed of 30, the upper magnetic pole 140 and the coil 150 was formed. Lower magnetic pole 130, upper magnetic pole 1
40 has a film thickness of 3.0 μm formed by the sputtering method.
Ni-20 at% Fe alloy was used. For the gap layer between the lower magnetic pole 130 and the upper magnetic pole 140, Al ₂ O ₃ having a film thickness of 0.2 μm formed by the sputtering method was used.
Cu having a film thickness of 3.0 μm was used for the coil 150.
The lower magnetic pole 130 and the upper magnetic pole 140 are magnetically coupled to form a magnetic circuit, and the coil 150 is linked to the magnetic circuit.

When a recording / reproducing experiment was conducted using the magnetic head having the above-mentioned structure and the sense current flowing through the magnetoresistive effect element at 1 × 10 ⁷ A / cm ² , the distance between the MR film and the surface opposite to the medium-opposing surface was measured. A 60% larger output value was obtained as compared with the case of using a conventional magnetic head in which is equal to the distance on the side opposite to the medium facing surface of the electrode.

(Embodiment 4) Using the magnetic head according to the present invention described in Embodiment 3, a magnetic disk device was manufactured. FIG. 6 schematically shows the structure of the magnetic disk device.

For the magnetic recording medium 160, a material made of a Co-Ni-Pt-Ta alloy having a residual magnetic flux density of 0.75T was used. The magnetic recording medium 160 is rotationally driven by the driving unit 170. The track width of the recording head of the magnetic head 180 is 2 μm, and the track width of the reproducing head is 1.5 μm.
m. The magnetic head 180 is rotationally driven by the driving unit 190 and can select a track on the magnetic recording medium 160. The recording / reproducing signal from the magnetic head 180 is processed by the recording / reproducing signal processing system 200.

The magnetoresistive effect element used in the magnetic head 180 produces 1.6 times the output of the magnetoresistive effect element of the conventional structure, so that a magnetic disk device having a narrower track width and a higher recording density is manufactured. You can also

[0025]

According to the present invention, it is possible to increase the reproduction output of the magnetoresistive reproducing head.

[Brief description of drawings]

FIG. 1 is a sectional view of a magnetoresistive film and an electrode according to the present invention when a permanent magnet film is used as a longitudinal bias.

FIG. 2 is a sectional view of a magnetoresistive film and an electrode according to the present invention when an antiferromagnetic film is used as a longitudinal bias.

FIG. 3 is a sectional view of a magnetoresistive element according to the present invention when a permanent magnet film is used as a longitudinal bias.

FIG. 4 is a sectional view of a magnetoresistive element according to the present invention when an antiferromagnetic film is used as a longitudinal bias.

FIG. 5 is a perspective view showing the structure of a recording / reproducing separated type magnetic head using the magnetoresistive effect element of the present invention.

FIG. 6 is an explanatory diagram of a recording / reproducing device.

[Explanation of symbols]

5 ... Substrate, 10 ... Lower shield film, 20 ... Insulating film for forming lower magnetic gap, 30 ... Soft magnetic film, 40 ... Nonmagnetic conductive film, 50 ... Magnetoresistive film, 60 ... Underlayer film for permanent magnet,
70 ... Permanent magnet film, 80 ... Electrode, 90 ... Insulating film for forming upper magnetic gap, 100 ... Upper shield film.

Front page continuation (72) Inventor Makoto Aihara 1-280 Higashi Koikekubo, Kokubunji, Tokyo Inside Hitachi Central Research Laboratory (72) Inventor Kaetsu Yoshida 1-280 Higashi Koikeku, Tokyo Kokubunji City Inside Central Research Laboratory, Hitachi Ltd. (72) Inventor Hiroshi Fukui 2880 Kokuzu, Odawara City, Kanagawa Stock Company Hitachi Storage Systems Division

Claims (6)

[Claims] 1. A soft magnetic film for applying a lateral bias, a non-magnetic conductive film, a magnetoresistive effect film, and a pair for longitudinal bias application provided on both ends of the magnetoresistive effect film, which are laminated on a substrate. In the magnetoresistive head including the permanent magnet film and the pair of electrodes provided on the permanent magnet film, the distance between the surface of the magnetoresistive film opposite to the medium facing surface is the magnetoresistive effect. A magnetoresistive effect reproducing head characterized in that it is longer than the distance between the surface of the electrode in contact with the film and the surface opposite to the medium. 2. A soft magnetic film for applying a lateral bias, a non-magnetic conductive film, a magnetoresistive film, and a pair of anti-strength films provided separately on the magnetoresistive film, which are laminated on the substrate. A magnetoresistive effect reproducing head comprising: a multilayer film including a magnetic film; and a pair of electrodes provided on the multilayer film, wherein the pair of antiferromagnetic films are provided in a region below the electrodes. Magnetoresistance, characterized in that the distance between the surface of the magnetization rotating portion of the effect film opposite to the medium facing surface is longer than the distance between the surface of the electrode contacting the antiferromagnetic film and the surface opposite to the medium. Effect playhead. 3. A multi-layered film including a pair of antiferromagnetic films laminated on a substrate, a magnetoresistive film laminated thereon, a non-magnetic conductive film, and a soft magnetic film for applying a bias magnetic field. A pair of electrodes provided on the multilayer film, wherein the soft magnetic film is provided below the pair of electrodes. The distance between the medium facing surface and the surface on the opposite side in
A magnetoresistive effect reproducing head characterized in that it is longer than a distance between a surface of the electrode in contact with the soft magnetic film and a surface opposite to the medium. 4. The pair of magnetic shield films according to claim 1, 2 or 3, further comprising a pair of magnetic shield films provided in the stacking direction so as to be separated from each other, wherein the multilayer film and the pair of electrodes are provided between the pair of magnetic shield films. A magnetoresistive head provided. 5. The induction type for magnetic recording according to claim 1, 2, 3 or 4, comprising a pair of magnetic poles, magnetic circuit means for magnetically sintering the pair of magnetic poles, and a coil interlinking with the magnetic circuit. A recording / reproducing separated type magnetic head comprising a thin film head and a magnetoresistive effect reproducing head. 6. The method according to claim 1, 2, 3, 4 or 5.
A magnetic recording / reproducing apparatus including the magnetic recording medium, a head, a driving unit that relatively drives the magnetic recording medium, and the head, and a recording / reproducing signal processor connected to the head.