JP2836571B2 - Magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used in a magnetic recording apparatus, and more particularly to a composite magnetic head in which a magnetoresistive head and a thin film head are combined.

[0002]

2. Description of the Related Art Conventionally, a thin film head using an inductor has been used as a magnetic head for performing magnetic information processing such as recording and reproduction of information on a magnetic recording medium mounted on a magnetic recording apparatus. However, in recent years, a magnetoresistive head (MR head) characterized by extremely high resolution of information processing and no dependence on the relative speed to a magnetic recording medium has been developed.
A composite magnetic head using a conventional thin film head (inductive head: ID head) on the recording side while using a head has been proposed.

Further, in recent years, in order to reduce the displacement between the recording track and the reproducing track, the upper shield of the MR head and the lower pole of the ID head are formed of a common element in this composite type magnetic head. There has been proposed a magnetic head in which the distance from the recording gap portion of the head to the magnetically sensitive portion of the MR head is reduced. FIGS. 3A and 3B show a magnetic head showing one example thereof, and FIGS. 3A, 3B and 3C. FIG.
FIG. 3 is a front view from a direction parallel to the recording surface of the magnetic recording medium, a cross-sectional view in the same vertical direction, and a plan view of an electrode unit. This composite magnetic head has an ID head on the upper side and an MR head on the lower side. Of the upper pole 12 and the lower pole constituting the upper ID head, the lower pole is connected to the lower M pole.
The upper shield constituting a part of the R head is integrally formed to constitute the lower pole upper shield common element section 2.

In this composite magnetic head, I
The D head is provided with a coil 14 so as to surround a pole joint 13 in which the upper pole 12 and the common lower pole 2 are joined at the end opposite to the magnetic recording medium. The MR head has a soft magnetic film 6, a non-magnetic film 7, and a magnetoresistive film 8 between the lower shield 1 and the upper shield 2 shared as described above via the gap layers 3 and 4, respectively. Are laminated in three layers, a magnetic field application layer 9 is provided on both sides of the three-layer film, and an electrode 10 is formed in contact with the magnetic field application layer 9. The electrodes 10 extend in pairs on both sides of the magnetoresistive film 8, and the other ends extend to the side opposite to the magnetic recording medium, so that a required sense current flows.

[0005]

In such a composite magnetic head, the pole junction 13 of the ID head is arranged at a position facing the sense current path of the electrode 10 of the MR head. Therefore, the magnetic flux leaking from the pole junction 13 of the ID head during the recording operation passes through the sense current path of the electrode 10 of the MR head, and an induced voltage is generated between the electrode pair. Incidentally, the magnetic flux density at the pole junction 13 at a position along the electrode 10 of the MR head is a distribution in which the magnetic flux density at the portion 15 immediately below the pole junction 13 reaches about 2000 G, as shown in FIG. An induced voltage in the electrode 10 is generated by the high magnetic flux density. In particular, as described above, in the composite magnetic head in which the lower pole of the ID head and the upper shield of the MR head are shared, the distance from the pole junction 13 to the electrode 10 becomes shorter, so that this phenomenon becomes remarkable. .

Therefore, in a conventional magnetic head of this type,
In order to prevent an induced voltage from being generated between the electrodes, control is performed to open the sense current path during the recording operation. However, with this measure, it takes about 2 to 4 μS to switch the sense current from off to on,
There is a problem that the format efficiency for the magnetic recording medium is reduced. In addition, there is a problem that the magnetic head cannot be adopted as a magnetic head of a magnetic recording apparatus of a type that performs collation of recording information simultaneously with a recording operation on a magnetic recording medium.

An object of the present invention is to provide a composite magnetic head which suppresses generation of an induced voltage at the electrodes of an MR head and does not require switching of a sense current at the electrodes.

[0008]

According to the present invention, there is provided a magnetic head comprising:
An MR head including a lower shield, a magnetoresistive element, an electrode through which a sense current flows, an upper shield, a lower pole,
In a composite magnetic head in which a coil and an ID head including an upper pole joined to the lower pole are integrally formed, a joint between upper and lower poles of the ID head is provided in a sense current path of an electrode of the MR head. It is configured not to be located. Alternatively, the electrodes of the MR head have a hierarchical structure in which the region portions facing the junctions of the upper and lower poles of the ID head overlap the pole junctions. In particular, the present invention
It is suitable for use in a magnetic head in which the upper shield or lower shield of the MR head is integrated with the lower pole or upper pole of the ID head as a common element.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a magnetic head according to a first embodiment of the present invention. FIGS. 1A, 1B, and 1C are front and sectional views respectively corresponding to the conventional structure of FIG. FIG. The structure of this composite magnetic head will be described in the order of its manufacturing steps. First, a lower shield 1 using NiFe having a thickness of 2 μm is formed on a substrate (not shown). A lower shield soft magnetic film gap layer 3 using Al ₂ O ₃ having a thickness of 0.11 μm is formed thereon by sputtering. A 15 nm-thick C film is formed thereon as a soft magnetic film 6.
oZrMo amorphous film, non-magnetic film 7 having a film thickness of 10
A Ta film having a thickness of 15 nm and a NiFe film having a thickness of 15 nm are formed as a magnetoresistive film 8 by sputtering.

Next, these laminates are formed in a track area,
That is, patterning is performed by ion etching so as to remain only in the magneto-sensitive portion region 5 and formed in a mesa shape. Further, a magnetic field applying layer 9 is provided on both sides of the three-layer film formed in a mesa shape.
A Cr film having a thickness of 10 μm is formed as a base film of, and a film thickness of 25 n is formed thereon as a magnetic field applying layer 9 by sputtering.
A CoCrPt film having a thickness of m is formed. After forming the three-layered films 6, 7, and 8 and the magnetic field applying layer 9, a resist pattern for forming an electrode is formed, and a thickness of 150 nm is formed thereon.
An electrode film made of Au is formed by sputtering. After that, the electrode film is lifted off to form the electrode 10. At this time, a resist pattern is formed such that a region surrounded by a sense current path composed of an electrode pattern formed after lift-off does not include a portion immediately below a pole junction 13 described later.

Next, an Al ₂ layer having a thickness of 0.14 μm is
Upper shield magnetoresistive film gap layer 4 using O ₃
Is formed by sputtering. And on top of that,
After forming an underlayer for the upper shield, a 3 μm thick NiF
The upper shield lower pole common element section 2 made of e is formed by frame plating using a mask. Subsequently, the gap layer 11 between the upper and lower poles is formed by sputtering using Al ₂ O _{3 of} 0.4 μm. A resist process having a thickness of 3 μm is performed on the upper portion of the gap layer, and holes are formed in the gap layer between the upper and lower poles by ion milling to connect the upper and lower poles. Further, a coil base is formed on the resist by sputtering, and after exposing the resist pattern of the coil, the coil 14 is plated with Cu having a thickness of 4.3 μm.

Thereafter, chemical etching is performed to remove the underlayer of the coil, a resist process with a thickness of 2 μm is performed on the coil, and an underlayer film of an upper pole is formed thereon by sputtering. Finally, the upper pole 12 is plated using a 4 μm-thick NeFe. At this time, the hole formed between the upper and lower poles is closed with NeFe for upper pole film formation, and the pole junction 13 is formed.

In the magnetic head thus configured, M
The electrode 10 of the R head does not exist in the portion 15 immediately below the pole joint 13 that joins the upper and lower poles of the ID head. Therefore, as shown in FIG. 4, it is suppressed that a high leakage magnetic flux generated in the pole junction 13 directly affects the electrode 10. Therefore, even when a sense current flows through the electrodes 10, generation of an induced voltage between the paired electrodes 10 is suppressed. Therefore, in this magnetic head, it is not necessary to control the opening of the electrode on the MR head side during the recording operation, so that the decrease in the format efficiency due to the switching of the sense current is improved, and the magnetic disk device that performs the collation of the recorded information is improved. Can be applied.

FIG. 2 shows a second embodiment of the present invention. FIGS. 2 (a), 2 (b) and 2 (c) are a front view, a sectional view and a sectional view, respectively, corresponding to the structure of FIG. It is a top view of an electrode part. In the configuration of the composite magnetic head, the same portions as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted. In this embodiment, the electrode 10 of the MR head is used.
In a portion 15 directly below the pole junction 13 of the ID head, one of the paired electrodes 10 is disposed above the other to form a layered structure of the electrodes, and a vertical line including the pole junction 13 is formed. Are formed so as to overlap in the vertical direction.

In the second embodiment, the pole joint 1
Even if a high leakage flux exists in the portion 15 directly below the electrode 3 and the leakage flux affects the electrode 10, the electrode 10 through which the sense current flows is superposed in the direction of the magnetic flux. Does not penetrate, and generation of an induced voltage between both electrodes is suppressed. Therefore, even with this magnetic head, it is not necessary to control the opening of the electrode on the MR head side during the recording operation, the deterioration of the format efficiency due to the switching of the sense current is improved, and the magnetic disk for collating the recorded information Application to the device becomes possible.

The reproduction output by the voltage induced by the recording magnetic field in the magnetic head of the first embodiment and the magnetic head of the second embodiment is output by the conventional magnetic head shown in FIG. Measurements were made for comparison with the playback output. Recording frequency is 1MHz, recording current is 60mA
When (pp), the read output was 600 μV in the magnetic head having the conventional structure. On the other hand, in the magnetic head of the first embodiment, no reproduction output was observed.
Also, no reproduction output was observed in the magnetic head of the second embodiment. From this measurement result, it is understood that in each of the magnetic heads of the first and second embodiments, no induced voltage is generated due to the magnetic flux leaking from the ID head.

Here, in the above-described embodiment, an example is shown in which the upper shield of the MR head and the lower pole of the ID head are configured as a common element, but the upper and lower arrangement of the MR head and the ID head is reversed. In the head, the present invention can be applied to a magnetic head in which the lower shield of the MR head and the upper pole of the ID head are configured as a common element. Further, the present invention can be similarly applied to a composite magnetic head having a configuration in which the shield of the MR head and the pole of the ID head are not shared. Further, in the above-described embodiment, a magnetoresistive element of a type in which a bias is applied by a soft magnetic film is illustrated. However, a composite magnetic head using a shunt-type bias type magnetoresistive element, or a spin valve film may be used. The same can be applied to the combined magnetic head.

[0018]

As described above, according to the present invention, since the junction of the upper and lower poles of the ID head is not opposed to the sense current path of the electrode of the MR head, the leakage magnetic flux generated by the pole junction is reduced by the MR head. Induced voltage can be prevented from being generated in the sense current by affecting the electrodes. This eliminates the need for control to open the electrode on the MR head side during the recording operation, improves the format efficiency due to the switching of the sense current, and can be applied to a magnetic disk device that performs collation of recorded information. Becomes

[Brief description of the drawings]

FIG. 1 is a front view, a longitudinal sectional view, and a first embodiment of the present invention.
It is a top view of an electrode part.

FIG. 2 is a front view, a longitudinal sectional view, and a second embodiment of the present invention.
It is a top view of an electrode part.

FIG. 3 is a front view, a longitudinal sectional view, and a plan view of an electrode section of a conventional magnetic head.

FIG. 4 is a diagram showing a magnetic flux density distribution in a sense current path of an electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower shield 2 Upper shield lower pole common element part 3 Lower gap layer 4 Upper gap layer 5 Magnetic sensing area 6 Soft magnetic film 7 Nonmagnetic film 8 Magnetoresistance effect film 9 Magnetic field application layer 10 Electrode 11 Gap between poles 12 Upper pole 13 Pole joint 14 Coil 15 Directly below the pole joint

Claims (4)

(57) [Claims] An inductive head including a lower shield, a magnetoresistive element, an electrode through which a sense current flows, an upper shield, a lower pole, a coil, and an upper pole joined to the lower pole. A magnetic head in which the upper and lower poles are not located in the sense current path of the electrode. 2. An inductive head including a lower shield, a magnetoresistive element, an electrode through which a sense current flows, and a magnetoresistive head including an upper shield, a lower pole, a coil, and an upper pole joined to the lower pole. Wherein the electrode has a layered structure such that a region facing the junction between the upper and lower poles overlaps with the pole junction. head. 3. The magnetic head according to claim 1, wherein the magnetoresistive head is arranged below the inductive head, and an upper shield of the magnetoresistive head and a lower pole of the inductive head are integrated as a common element. . 4. The magnetic head according to claim 1, wherein the magnetoresistive head is disposed above the inductive head, and a lower shield of the magnetoresistive head and an upper pole of the inductive head are integrated as a common element.