JPH05266432A - Thin-film magnetic head - Google Patents

Abstract

PURPOSE:To improve the performance of the thin film magnetic head of a composite type integrated with a reproducing head part consisting of a magneto- resistance effect element and a recording head part of, for example, an induction type by suppressing the magnetical interference between the recording part and the reproducing part. CONSTITUTION:This thin-film magnetic head 1 has the reproducing part RH of the magneto-resistance effect element 14 and a pair of magnetic shielding layers 12, 17 holding the element and the recording head part WH having the one magnetic shielding layer 17 as a part of a magnetic core MC. A soft magnetic layer which is deteriorated in the magnetic characteristics of the central part 172 in the thickness direction as compared with the magnetic characteristics of the upper part 173 and the lower part 171 is provided as the magnetic shielding layer 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head in which a reproducing head section composed of a magnetoresistive effect element and an inductive recording head section are integrated.

In a magnetic disk device, the diameter of a magnetic disk, which is a recording medium, is being reduced. Along with this, a thin film magnetic head incorporating a magnetoresistive effect element capable of obtaining a large reproduction output even when the relative movement speed with respect to the magnetic disk is small is drawing attention.

[0003]

2. Description of the Related Art A magnetoresistive effect element can be used only for reading (reproducing) information from a magnetic recording medium. Therefore, it is necessary to use other electromagnetic conversion means for writing (recording) information.

Conventionally, a magnetoresistive effect element and a reproducing head portion composed of a pair of magnetic shield layers (soft magnetic layers) sandwiching the magnetoresistive effect element, a coil and a pair of magnetic poles (soft magnetic layer constituting a magnetic core). A thin film magnetic head in which an inductive recording head section is integrated is known.

Usually, in this type of composite type thin film magnetic head, in order to facilitate head position control relating to recording and reproduction, the above-mentioned head portions are arranged as close to each other as possible.
To have a simple head structure that is advantageous in terms of manufacturing cost,
One of the magnetic shield layers is configured to also serve as a magnetic pole. That is, one magnetic layer is provided as a component common to both the reproducing head section and the recording head section.

FIG. 4 is a sectional view showing the structure of a conventional thin film magnetic head 1j. This figure shows a sectional structure as seen from the recording medium side. The thin film magnetic head 1j has a reproducing head section R.
It is a composite type head having H and a recording head portion WH, and is composed of a support 11 and the following respective parts stacked in order thereon.

First, a lower magnetic shield layer 12 having a predetermined shape is provided on the support 11, and the nonmagnetic layer 1 is formed thereon.
A magnetoresistive effect element layer (hereinafter, referred to as “MR layer”) 14 and an electrode layer 15 are provided via the element 3. MR layer 14
An upper magnetic shield layer and a dual-purpose magnetic layer 17j serving as a lower magnetic pole are provided on the above via a non-magnetic layer 16.
Further, an upper magnetic pole 20 is provided on the upper magnetic pole 20 via a gap layer 19. Then, the protective film 23 is provided as the uppermost layer.

The magnetic shield layer 12 and the combined magnetic layer 17j
Shields the external magnetic field from the MR layer 14. Further, the dual-purpose magnetic layer 17j and the upper magnetic pole 20 are magnetically coupled to each other at a portion (not shown) to form a magnetic core MC for guiding a magnetic flux by a coil (not shown) to the recording medium. The magnetic shield layer 12 and the dual-purpose magnetic layer 17
The j and the magnetic pole 20 are each formed of a soft magnetic layer that is homogeneous in terms of magnetic characteristics.

[0009]

In the conventional thin film magnetic head 1j, the dual-purpose magnetic layer 1 associated with recording in the MR layer 14 is used.
There is a problem that the influence of the magnetization of 7j appears relatively remarkably. That is, due to a Uighur phenomenon in which the magnetic domain wall moves irregularly and discontinuously in the dual-purpose magnetic layer 17j, and a phenomenon in which the magnetic domain wall irregularly moves immediately after recording, the so-called popcorn is added to the reproduction signal of the MR layer 14. There is a problem that noise such as noise is easily superimposed.

In order to solve such a problem, it is conceivable that the reproducing head portion RH and the recording head portion WH are magnetically separated via a non-magnetic layer. In that case, the structure described above is used. You lose the advantages of simplification.

In view of the above problems, it is an object of the present invention to suppress the magnetic interference between the recording section and the reproducing section and improve the head performance.

[0012]

In order to solve the above-mentioned problems, the head according to the invention of claim 1 has a magnetoresistive effect element 14 and a pair of magnetic shield layers 12 sandwiching the magnetoresistive effect element 14, as shown in FIG. A thin film magnetic head 1 having a reproducing head section RH composed of 17 and a recording head section WH having the one magnetic shield layer 17 as a part of a magnetic core MC, wherein the magnetic shield layer 17 has a thickness of Direction central part 17
2 is a soft magnetic layer in which the magnetic characteristics of No. 2 are deteriorated with respect to the magnetic characteristics of the upper portion 173 and the lower portion 171.

A head according to a second aspect of the present invention comprises a magnetoresistive effect element 14 and a pair of magnetic shield layers 1 sandwiching the magnetoresistive effect element 14.
A thin film magnetic head 1B having a reproducing head portion RH composed of 2, 17B and a recording head portion WH having the one magnetic shield layer 17B as a part of the magnetic core MC, wherein the magnetic shield layer 17B is The magnetic characteristic of the central portion 172 in the thickness direction is deteriorated with respect to the magnetic characteristics of the upper portion 173B and the lower portion 171, and the planar shape of the upper portion 173B is made to correspond to the planar shape of the magnetic pole 20 constituting the magnetic core MC. It consists of a magnetic layer.

In the head according to the third aspect of the present invention, the magnetic permeability of the central portion 172 is smaller than that of the upper portions 173, 173B and the lower portion 171.

[0015]

The magnetic shield layers 17 and 17B are soft magnetic layers for both reproduction and recording as a whole, but the magnetic characteristics of the central portion 172 in the thickness direction are higher than those of the upper portions 173, 173B and the lower portion 171. Since the magnetic field is deteriorated (for example, the magnetic permeability is small), the magnetization during recording mainly occurs locally in the upper portion 173. Therefore, in the magnetoresistive effect element 14,
The effect of domain wall movement due to the magnetization of the magnetic shield layers 17 and 17B hardly appears.

The upper portion 173 of the magnetic shield layer 17B
By associating the planar shape of B with the magnetic pole 20 used only for recording, that is, by making the upper 173B and the magnetic pole 20 have substantially the same planar shape at least in the vicinity of the recording medium facing portion, the magnetic flux falls within the recording width range. It is possible to concentrate, and it is possible to suppress recording bleeding due to the spread of magnetic flux.

[0017]

1 and 2 are views showing the structure of a thin film magnetic head 1 according to the present invention. FIG. 1 shows a cross-sectional structure viewed from the recording medium side, and corresponds to a cross section taken along the line II of FIG. FIG. 2A shows a cross-sectional structure viewed from the right side of FIG.
This corresponds to the cross section taken along the line AA of FIG. FIG. 2B shows the planar shape and arrangement relationship of the main constituent elements. In these figures, constituent elements having the same functions as those in FIG. 4 are designated by the same reference numerals, and constituent elements corresponding to FIG. 4 are designated by a reference numeral without the suffix “j”. ..

First, referring to FIG. 2, the thin-film magnetic head 1
Is a composite type head having a reproducing head portion RH due to a magnetoresistive effect and a recording head portion WH due to electromagnetic induction, and is made of a non-magnetic support 11 and a soft magnetic material (high magnetic permeability material) such as permalloy. Lower magnetic shield layer 1
2, an MR layer 14 sandwiched between the non-magnetic layers 13 and 16, an upper magnetic shield layer (hereinafter referred to as “combined magnetic layer”) 17 made of one kind of magnetic material which is also used as a lower magnetic pole, silicon dioxide, etc. The gap layer 19, a spiral coil 22, an interlayer insulator 21 such as a thermosetting resin that covers the coil 22, an upper magnetic pole 20, a protective film 23, and the like.

The dual-purpose magnetic layer 17 and the upper magnetic pole 20 are integrated by a contact portion 30 so as to form a magnetic core MC. The inner end and the outer end of the coil 22 are connected to external connection terminals (not shown). In FIG. 2, the illustration of the electrode layer 15 (see FIG. 1) overlying the MR layer 14 is omitted.

As shown in FIG. 2B, the top pole 20 has a planar shape such that the width of the gap portion (the left end portion in the figure) that defines the track width w is narrower than the others. . On the other hand, in forming the magnetic core MC, the magnetic pole 20
The planar shape of the dual-purpose magnetic layer 17 paired with the track width w is
Since it is necessary to completely cover the MR layer 14 having a longer dimension, the width of the gap portion has the same shape as the others.
That is, the dual-purpose magnetic layer 17 has a region E17b that does not face the magnetic pole 20 as shown by hatching in the figure, and the width of the dual-purpose magnetic layer 17 on the surface facing the recording medium is larger than the width of the magnetic pole 20.

As well shown in FIG. 1, the dual-purpose magnetic layer 17 of the thin-film magnetic head 1 has an upper portion 173 having the magnetic characteristic of the central portion 172 in the thickness direction over the entire area in the plane direction.
And a soft magnetic layer (total film thickness is about 2 to 4 μm) deteriorated with respect to the magnetic properties of the lower portion 171. That is, in the dual-purpose magnetic layer 17, the magnetic permeability of the central portion 172 is higher than that of the upper portion 17.
3 and lower than the lower part 171.

Therefore, in the dual-purpose magnetic layer 17, the whole including the central portion 172 has a function of shielding the external magnetic field from the MR layer 14.
Since 73 and the lower part 171 are magnetically separated (but not completely separated), the role of the magnetic core MC is to serve as the upper part 173 which faces the magnetic pole 20 and is magnetically coupled.
Will be mainly responsible. The lower part 171 and the central part 17
The thicknesses of 2 and the upper portion 173 are substantially the same.

Such a dual-purpose magnetic layer 17 can be easily formed by using a thin film technique. For example, the dual-purpose magnetic layer 17 is made of a nickel-iron (Ni-Fe) magnetic alloy, and a lower portion 171, a central portion 172, and an electrolytic plating method are used.
And the upper portion 173 can be continuously formed. However, at this time, the applied current density of the plating condition is changed between the film formation of the lower part 171 and the upper part 173 and the film formation of the central part 172. This causes a difference in composition relating to magnetic permeability between the central portion 172 and other portions. Therefore, if the set value of the applied current density at each stage is appropriately selected, the permeability of the central portion 172 in the thickness direction is increased. It is possible to obtain the dual-purpose magnetic layer 17 having a magnetic permeability smaller than that of other portions.

When the sputtering method is used as the film forming method, the crystallinity of the film is partially lowered by changing the sputtering conditions such as the degree of vacuum (gas pressure) or the bias voltage during the continuous film formation. As a result, the desired dual-purpose magnetic layer 17
Can be obtained.

The thin film magnetic head 1 constructed as described above.
Then, in the MR layer 14, there is almost no effect of the domain wall movement due to the magnetization of the dual-purpose magnetic layer 17 due to electromagnetic induction, and a good reproduction waveform is obtained.

FIG. 3 is a sectional view showing the structure of a thin film magnetic head 1B according to another embodiment of the present invention. In the figure, components having the same functions as those in FIGS. 1, 2 and 4 are designated by the same reference numerals regardless of the difference in shape, and description thereof will be omitted.

The thin film magnetic head 1B also has a reproducing head portion RH.
And a dual-purpose magnetic layer 17B which is a common constituent element of the recording head portion WH. The dual-purpose magnetic layer 17B is
Similar to the dual-purpose magnetic layer 17 of the thin-film magnetic head 1 described above, it is composed of a soft magnetic layer in which the magnetic characteristics of the central portion 172 in the thickness direction are deteriorated with respect to the magnetic characteristics of the upper portion 173B and the lower portion 171.

In the thin film magnetic head 1B, the dual-purpose magnetic layer 17 is used.
The planar shape of the upper portion 173B of B, that is, the planar shape of the portion that substantially functions as the magnetic core MC is the magnetic pole 2
It is associated with a plane shape of 0. That is, the top 17
The plane shape of 3B is substantially the same as the magnetic pole 20.

As a result, during recording, since the magnetic flux concentrates within the range of the track width w, it is possible to suppress the recording bleeding caused by the spread of the magnetic flux in the area E17b described with reference to FIG. 2B. During reproduction, shielding is performed mainly by the lower portion 171 in the same range as the magnetic shield layer 12, and thus superposition of noise due to the external magnetic field is prevented.

When manufacturing the thin film magnetic head 1B, M
After covering the R layer 14 and the electrode layer 15 with the non-magnetic layer 16, the dual-purpose magnetic layer 17B is formed as follows. First,
By changing the film forming conditions during film formation as described above by using an electrolytic plating method or a sputtering method, a soft magnetic layer having a three-layer structure is formed on the non-magnetic layer 16 in terms of magnetic characteristics. Are patterned into the same shape as the magnetic shield layer 12.

Next, a silicon dioxide film to be the gap layer 19 is provided by the sputtering method so as to cover the entire surface of the patterned soft magnetic layer including the surface of the non-magnetic layer 16, and after the coil 22 and the like are provided. A magnetic layer to be the upper magnetic pole 20 is provided on the silicon dioxide film.

Then, a resist layer having a shape corresponding to the magnetic pole 20 is provided, and the resist layer is used as an etching mask to form a magnetic layer to be the magnetic pole 20, a silicon dioxide film to be the gap layer 19, and a dual-purpose magnetic layer 17B. The resulting soft magnetic layer is collectively etched (patterned) by ion milling.

Then, when the portion of the soft magnetic layer with deteriorated magnetic characteristics (the portion corresponding to the central portion 172) is exposed, the etching is finished. As a result, the dual-purpose magnetic layer 17B having the above structure is obtained. After that, the resist layer is removed to provide the protective layer 23, and the thin film magnetic head 1B
To complete.

According to the above-described embodiment, the central portion 17 of the dual-purpose magnetic layers 17 and 17b is reduced by reducing the magnetic permeability.
Since the magnetic properties of No. 2 are deteriorated, it is possible to provide the dual-purpose magnetic layers 17 and 17b having a three-layer structure by one film forming method and a continuous film forming process only by changing the film forming conditions. The productivity of the thin film magnetic heads 1 and 1B can be improved.

In the above embodiment, the dual-purpose magnetic layer 17,
As a method of deteriorating the magnetic characteristics of the central portion 172 of the 17b, for example, an ion implantation method is used to introduce metal ions such as chromium (Cr), niobium (Nb), and zirconium (Zr) as impurities to locally saturate the saturation magnetic flux. The density may be reduced.

[0036]

According to the present invention, magnetic interference between the recording portion and the reproducing portion can be suppressed and the head performance can be improved.

According to the second aspect of the invention, it is possible to prevent bleeding of recording. According to the invention of claim 3, the formation of the magnetic layer can be facilitated.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of a thin film magnetic head according to the present invention.

FIG. 2 is a diagram showing a structure of a thin film magnetic head according to the present invention.

FIG. 3 is a sectional view showing a structure of a thin film magnetic head according to another embodiment of the present invention.

FIG. 4 is a sectional view showing the structure of a conventional thin film magnetic head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 thin film magnetic head 14 MR layer (magnetoresistive element) 12 magnetic shield layer 17 combined magnetic layer (magnetic shield layer) 173 upper part 172 central part 171 lower RH reproducing head part WH recording head part MC magnetic core 1B thin film magnetic head 17B also combined use Magnetic layer (magnetic shield layer) 173B Upper part 20 Upper magnetic pole (magnetic pole)

Claims (3)

[Claims] 1. A reproducing head portion (RH) comprising a magnetoresistive element (14) and a pair of magnetic shield layers (12) (17) sandwiching the magnetoresistive element, and the one magnetic shield layer (17).
Head part (WH) in which the magnetic head is a part of the magnetic core (MC)
A thin film magnetic head (1) having a magnetic shield layer (17) having a central portion (1) in the thickness direction.
72) the magnetic properties of the upper part (173) and the lower part (171)
A thin-film magnetic head comprising a soft magnetic layer deteriorated with respect to the magnetic characteristics of. 2. A reproducing head portion (RH) comprising a magnetoresistive element (14) and a pair of magnetic shield layers (12) (17B) sandwiching the magnetoresistive element, and the one magnetic shield layer (17).
B) as a part of the magnetic core (MC) recording head section (W
H) and the magnetic shield layer (17B) has magnetic properties of the central portion (172) in the thickness direction of the upper portion (173B) and the lower portion (1B).
71) is deteriorated with respect to the magnetic characteristics and is composed of a soft magnetic layer in which the planar shape of the upper portion (173B) is associated with the planar shape of the magnetic pole (20) constituting the magnetic core (MC). Thin film magnetic head. 3. The thin film magnetic head (1, 1B) according to claim 1, wherein the magnetic permeability of the central portion (172) is the upper portion (173, 1).
73B) and the lower part (171) are smaller than the thin film magnetic head.