JPH07201021A - Composite magnetic head - Google Patents

Abstract

PURPOSE:To reduce the recording/reproducing offset by employing a structure near a three-pole structure apparently and to suppress recording fringing. CONSTITUTION:An MR head and an inductive head are stacked on the same substrate. A nonmagnetic thin film layer 9 of <0.1mum is interposed between the upper shield magnetic material 8 of the MR head and the lower layer thin film magnetic core 10 of the inductive head.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite magnetic head suitable for recording / reproducing on / from a hard disk, for example.

[0002]

2. Description of the Related Art For example, a recording / reproducing head of a hard disk drive is a recording head using an inductive thin film magnetic head (hereinafter referred to as an inductive head), and a magnetoresistive effect magnetic head having excellent short wavelength sensitivity (hereinafter referred to as a magnetic head). , MR
It is called a head. ) Is generally a composite type with a reproducing head.

As such a composite magnetic head, for example, as shown in FIG. 10, on a substrate called a slider made of Al ₂ O ₃ --TiC or the like, a contact surface with a hard disk, that is, an ABS (air bearing) is provided.・ Surface)
MR head 1 facing the surface and forming a reproducing magnetic gap
01 and the inductive head 102 forming the recording magnetic gap are laminated.

The MR head 101 is a magnetoresistive effect element 103 (hereinafter referred to as an MR element 103) which is composed of a magnetoresistive effect thin film in which electrodes are laminated at the front end and the rear end.
And a bias conductor that gives the MR element 103 a magnetized state in a desired direction, and the MR element 103 is sandwiched by a pair of shield cores 104 and 105 with a so-called shield structure.

On the other hand, the inductive head 102 includes a pair of recording cores 106 and 107 forming a closed magnetic path and a conductor coil provided between the recording cores 106 and 107, and front end portions of the recording cores 106 and 107 are provided. The structure is such that a recording magnetic gap is formed facing the ABS surface.

This composite magnetic head is an MR head 10
2 layers of shield core 1 and inductive head 102
This is a so-called 4-pole structure having two layers of recording cores. The advantage of the composite magnetic head having a 4-pole structure is that the recording head and the reproducing head can be optimized separately.

However, in the 4-pole structure composite magnetic head, the recording magnetic field generated by the inductive head 102 during recording may leak to the upper shield core 105 of the MR head 101, which may adversely affect the recording characteristics. Therefore, conventionally, the non-magnetic layer 108 is interposed between the upper shield core 105 and the lower recording core 106, and the thickness T thereof is set to about 2 μm to prevent the leakage of the recording magnetic field.

However, if the distance between the MR head 101 and the inductive head 102 is increased, the following inconvenience occurs when recording / reproducing is performed on the hard disk. That is, as shown in FIG. 11, the composite magnetic head 109 is attached to the tip of the suspension 110, and the composite magnetic head 109 is attached to the hard disk 111.
If the MR head 101 and the inductive head 102 are separated from each other as indicated by the arrow in the figure, an offset from the track occurs during reproduction. That is, the track position during reproduction is displaced from the track position during recording.

In this phenomenon, as the diameter of the hard disk 111 becomes smaller, the swing angle of the composite magnetic head 109 becomes larger, and the offset amount increases accordingly.

Therefore, the applicant of the present application has proposed a so-called three-pole structure type composite magnetic head in which the upper shield core and the lower recording core are used in common. As shown in FIG. 12, the composite magnetic head having such a 3-pole structure has an MR
An upper shield core and a lower recording core of the head 101 and the inductive head 102 are constituted by one thin film magnetic core 112. That is, the common thin film magnetic core 11
2 functions as a recording core during recording and functions as a shield core during reproduction.

[0011]

However, in the composite magnetic head having the three-pole structure, as shown in FIG. 13, a thin film magnetic having an intermediate core width of the upper recording core 107 facing the ABS surface of the inductive head 102 is used. Core 112
Since it is narrower than the core width, the recording magnetic flux leaks to the side of the track, so-called recording fringing, which becomes an obstacle to high density recording.

Therefore, the present invention has been proposed in view of the above technical problems, and aims to reduce the recording / reproducing offset and to separate the recording head and the reproducing head by using a structure apparently close to a 3-pole structure. It is an object of the present invention to provide a composite type magnetic head capable of achieving the above optimization.

[0013]

A magnetoresistive element is disposed between a lower shield magnetic body and an upper shield magnetic body, and a reproducing magnetic gap is formed facing a contact surface with a magnetic recording medium. A resistance effect type magnetic head, a lower thin film magnetic core and an upper thin film magnetic core are sequentially laminated on the upper shield magnetic body via a non-magnetic thin film layer, and a magnetic recording medium is formed between the front ends of these thin film magnetic cores. In a composite type magnetic head in which an induction type thin film magnetic head forming a recording magnetic gap facing a contact surface is laminated on the same substrate,
By setting the thickness of the non-magnetic thin film layer to 0.1 μm or less, the above-mentioned problems are solved.

The present invention solves the above-mentioned problems by making the core widths of the upper layer thin film magnetic core and the lower layer thin film magnetic core facing the contact surface of the magnetic recording medium substantially the same.

[0015]

In a 4-pole structure recording / reproducing head in which an MR head forming a reproducing magnetic gap and an inductive head forming a recording magnetic gap are laminated on a substrate so as to face a surface facing a magnetic recording medium, an inductive head is provided. Since the thickness of the non-magnetic thin film layer interposed between the lower thin film magnetic core and the upper magnetic shield of the MR head is very thin, 0.1 μm or less, the inductive head and the M
The R heads are close to each other, and apparently have a three-pole structure, and the recording / reproducing offset is reduced. Further, since the non-magnetic thin film layer is extremely thin, the lower thin film magnetic core and the upper shield magnetic body are magnetically coupled, and the upper shield magnetic body functions as a part of the recording core during recording.

Further, since the core widths of the upper thin film magnetic core and the lower thin film magnetic core of the inductive head facing the contact surface of the magnetic recording medium are substantially the same, the leakage of the recording magnetic flux does not occur on the side of the track. , Recording fringing is suppressed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings. As shown in FIGS. 1 and 2, the composite magnetic head of the present embodiment has an MR head in which a reproducing magnetic gap g ₁ is exposed on an ABS surface 1 which is a contact surface with a hard disk, and an ABS head 1 on the ABS surface 1. It is a so-called 4-pole structure recording / reproducing head in which an inductive head facing the recording magnetic gap g ₂ is laminated on one side surface of the slider 2 made of an Al ₂ O ₃ —TiC substrate or the like.

The MR head has a pair of electrodes 3a and 3b (hereinafter, referred to as an electrode 3a provided on the ABS surface 1 side) for passing a sense current from a constant current source (not shown) to the front end portion and the rear end portion, respectively. , Electrode 3b provided on the rear end side
Is referred to as a rear end electrode 3b. ) Stacked MR element 4
And a bias conductor 5 which gives the MR element 4 a magnetic field in a desired direction.

The MR element 4 has its longitudinal direction in the ABS.
It is provided so as to be perpendicular to the surface 1, and one edge thereof faces the ABS surface 1. Further, the MR element 4 has a structure in which a pair of MR thin films that are magnetostatically coupled via a non-magnetic insulating layer made of, for example, SiO ₂ is laminated to prevent generation of Barkhausen noise. Has become. The MR thin film is made of, for example, a ferromagnetic thin film such as permalloy and has a film thickness of about several hundred angstroms.

One end of the tip electrode 3a has an ABS surface 1
Is laminated on the front end portion of the MR element 4 so as to face the above. The tip electrode 3a has a function as an electrode for supplying a sense current to the MR element 4 by passing a current between the tip electrode 3a and a rear end electrode 3b which will be described later. In addition, the tip electrode 3a functions as a gap film of the reproducing magnetic gap g ₁ .

On the other hand, the rear end electrode 3b is directly laminated on the rear end of the MR element 4 and is electrically connected to the MR element 4.

The bias conductor 5 is formed on the insulating layer 6 provided on the MR element 4 in a direction substantially perpendicular to the MR element 4 (direction perpendicular to the plane of FIG. 1), that is, M.
It is provided so as to cross the R element 4. A bias current from a DC power supply is applied to both ends of the bias conductor 5. Therefore, the direct currents supplied from the both terminal portions flow in the track width direction, and the resulting bias magnetic field is applied in the longitudinal direction of the MR element 4.

In such an MR head, the MR element 4 is provided with the lower shield magnetic body 7 and the upper shield magnetic body 8 made of a magnetic material such as permalloy with the insulating layer 6 interposed therebetween.
It has a so-called shield type configuration sandwiched between and. The shield type configuration is adopted because this type of integrated head is required to reproduce a short wavelength, or the reproduction waveform is required to be the same as the differential output waveform of the inductive head in signal processing.

The lower shield magnetic body 7 provided on the lower side of the MR element 4 is arranged so that one end thereof faces the ABS surface 1 via an insulating layer between the lower shield magnetic body 7 and the slider 2.
It is provided so as to extend perpendicularly to the BS surface 1 to the back side.

On the other hand, the upper shield magnetic body 8 which is provided so as to face the upper shield magnetic body 8 is the same as the lower shield magnetic body 7.
It is provided so that one end thereof faces the BS surface 1 and extends vertically to the ABS surface 1 toward the back side.

On the other hand, the inductive head is laminated on the upper shield magnetic body 8 of the MR head with the non-magnetic thin film layer 9 interposed therebetween. The inductive head has a lower layer thin film magnetic core 10 and an upper layer thin film magnetic core 11, and these thin film magnetic cores 10 and 11 face the ABS 1 and form a recording magnetic gap g ₂ between their front ends. It is supposed to do.

That is, the upper-layer thin-film magnetic core 11 is bent toward the lower-layer thin-film magnetic core 10 at the front end facing the ABS surface 1 and the recording magnetic gap g ₂ is formed in the facing portion where the gap is narrowed. It is like this. The upper thin film magnetic core 11 is adapted to magnetically contact the lower thin film magnetic core 10 at the rear end.

A spiral head winding 13 is provided in the magnetic coupling portion 12 which is a connecting portion between the upper layer thin film magnetic core 11 and the lower layer thin film magnetic core 10 so as to surround the magnetic coupling portion 12. Has been. The head winding 13 includes an upper layer thin film magnetic core 11 and a lower layer thin film magnetic core 10.
An insulating layer 14 is embedded in order to secure insulation between them.

A protective layer 15 for protecting the MR head and the inductive head laminated on the slider 2 is formed on the upper thin film magnetic core 11.

In particular, in this embodiment, the space between the inductive head and the MR head, that is, the upper shield magnetic material 8 is formed.
And a non-magnetic thin film layer 9 provided between the lower thin film magnetic core 10
The film thickness t is 0.1 μm or less. If the film thickness t of the non-magnetic thin film layer 9 is made extremely thin to 0.1 μm or less, a composite magnetic head structure having an apparent 3-pole structure is formed, and the inductive head and the MR head are brought close to each other, and the recording / reproducing offset can be reduced. .

Since the thickness t of the non-magnetic thin film layer 9 is extremely thin, the lower thin film magnetic core 10 and the upper shield magnetic body 8 are magnetically coupled, and the upper shield magnetic body 8 also serves as a recording core. Will work. Therefore, the problem of leakage to the upper shield magnetic body 8 of the recording magnetic field at the time of recording is avoided as in the conventional composite magnetic head having a 4-pole structure in which the inductive head and the MR head are completely separated.

The thickness t of the non-magnetic thin film layer 9 is set to 0.1 μm or less based on the following consideration. First, the thickness t of the non-magnetic thin film layer 9 is set to 0.02 μm, 0.05 μm,
The strength of the magnetic field in the saturation gap when 0.1 μm, 0.3 μm and 0.5 μm was calculated. The structure of the inductive head used for the calculation is shown in FIG. 3 and the calculation result is shown in FIG.

Line A in FIG. 4 shows the case where the thickness t of the non-magnetic thin film layer 9 is 0.5 μm or less, and line B shows the case where the thickness t of the non-magnetic thin film layer 9 is ∞. As can be seen from this result, when the film thickness t of the non-magnetic thin film layer 9 is 0.5 μm or less, the saturation magnetic field is almost the same, and the lower thin film magnetic core 10 is the same.
It can be seen that the upper shield magnetic body 8 functions as a single-layer recording core.

Next, the effect of the pseudo gap was investigated. That is, the thickness t of the non-magnetic thin film layer 9 is 0.5 μm, 0.3 μm.
m, 0.1 μm, 0.05 μm, 0.02 μm, the spacing was 0.2 μm, and the magnetic field distribution near the gap was calculated. The results are shown in FIGS.

FIG. 5 shows the film thickness t = 0.5 μm, FIG. 6 shows the film thickness t = 0.3 μm, and FIG. 7 shows the film thickness t = 0.1 μm.
Is the film thickness t = 0.05 μm, and FIG. 9 is the film thickness t = 0.02 μm
It is the calculation result when. The maximum peak waveform at the zero position on the horizontal axis in these figures is the magnetic field in the recording gap portion, and the small peak waveform at the minus position next to it is due to the non-magnetic thin film layer 9. A pseudo gap is shown. Furthermore, the large and small waveforms in each figure are due to changing the current value.

In FIG. 5 in which the film thickness t of the non-magnetic thin film layer 9 is 0.5 μm, it can be seen that a considerable pseudo gap is generated. The pseudo gap is not a problem when the thickness t of the nonmagnetic thin film layer 9 in FIG. 8 is 0.1 μm. Therefore, in the magnetic field in the saturation gap, it is considered that the film thickness t of the non-magnetic thin film layer 9 can be used even if the film thickness t is 0.5 μm.
μm is the limit.

In the present embodiment, as shown in FIG. 2, the core widths W ₁ and W ₂ of the upper thin film magnetic core 11 and the lower thin film magnetic core 10 of the inductive head facing the ABS surface 7 are shown.
Are almost the same. If the core widths W ₁ and W ₂ of the upper and lower upper thin film magnetic cores 11 and 10 are the same, the recording magnetic flux does not leak from the side of the track, and the problem of recording fringing can be solved.
Therefore, it becomes possible to perform high-density recording on the hard disk.

[0038]

As is clear from the above description, in the four-pole structure composite type magnetic head of the present invention, the non-magnetic layer interposed between the lower layer thin film magnetic core of the inductive head and the upper layer shield magnetic body of the MR head. Since the thickness of the magnetic thin film layer is extremely thin, 0.1 μm or less, the inductive head and the MR head are close to each other and have an apparent three-pole structure, and the recording / reproducing offset can be greatly reduced. Also, since the non-magnetic thin film layer is extremely thin, the lower layer thin film magnetic core and the upper layer shield magnetic body are magnetically coupled, and the upper layer shield magnetic body functions as a part of the recording core during recording, which deteriorates the recording characteristics. There is no fear of doing it.

Further, in the present invention, since the core widths of the upper layer thin film magnetic core and the lower layer thin film magnetic core facing the contact surface of the magnetic recording medium of the inductive head are substantially the same, the recording flux of the recording magnetic flux beside the track. No leakage occurs, recording fringing can be suppressed, and high density recording can be achieved.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a composite magnetic head to which the present invention is applied.

FIG. 2 is a schematic diagram showing a state in which the composite magnetic head of FIG. 1 is viewed from the ABS surface.

FIG. 3 is an enlarged view of a main part showing the structure of a recording head when the strength of a magnetic field in a saturation gap when the film thickness of a nonmagnetic thin film layer is changed is calculated.

FIG. 4 is a characteristic diagram in which the strength of the magnetic field in the saturation gap when the thickness of the non-magnetic thin film layer is changed is calculated and the results are plotted.

FIG. 5 is a characteristic diagram showing generation of a pseudo gap when the thickness of the nonmagnetic thin film layer is 0.5 μm.

FIG. 6 is a characteristic diagram showing generation of a pseudo gap when the thickness of the nonmagnetic thin film layer is 0.3 μm.

FIG. 7 is a characteristic diagram showing generation of a pseudo gap when the thickness of the nonmagnetic thin film layer is 0.1 μm.

FIG. 8 is a characteristic diagram showing generation of a pseudo gap when the thickness of the non-magnetic thin film layer is 0.05 μm.

FIG. 9 is a characteristic diagram showing generation of a pseudo gap when the thickness of the nonmagnetic thin film layer is 0.02 μm.

FIG. 10 shows a conventional composite magnetic head having a 4-pole structure
It is a schematic diagram which shows the state seen from BS surface.

FIG. 11 is a plan view showing a state in which a conventional composite magnetic head having a 4-pole structure is moved between tracks of a hard disk.

FIG. 12 shows a conventional composite magnetic head having a three-pole structure
It is a schematic diagram which shows the state seen from BS surface.

FIG. 13 is a view AB showing how recording fringing occurs.
It is a schematic diagram which shows the state seen from S surface.

[Explanation of symbols]

 1 ... ABS surface 2 ... slider 3a ... front electrode 3b ... rear electrode 4 ... MR element 5 ... bias conductor 7 ... lower shield magnetic body 8 ... upper shield Magnetic substance 9 ... Non-magnetic thin film layer 10 ... Lower layer thin film magnetic core 12 ... Magnetic coupling part 13 ... Head winding 15 ... Protective layer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kosuke Naruzawa 6-735 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation

Claims (2)

[Claims] 1. A magnetoresistive effect type magnetic device comprising a magnetoresistive effect element disposed between a lower shield magnetic body and an upper shield magnetic body, and forming a reproducing magnetic gap facing a contact surface with a magnetic recording medium. A head, a lower-layer thin-film magnetic core and an upper-layer thin-film magnetic core are sequentially laminated on the upper-layer shield magnetic body via a non-magnetic thin-film layer, and a front surface of these thin-film magnetic cores is provided on a surface facing the magnetic recording medium. A composite magnetic head in which an inductive thin film magnetic head facing a recording magnetic gap is laminated on the same substrate, wherein the nonmagnetic thin film layer has a thickness of 0.1 μm or less. Composite magnetic head. 2. The composite magnetic head according to claim 1, wherein the upper layer thin film magnetic core and the lower layer thin film magnetic core have substantially the same core width facing the contact surface with the magnetic recording medium.