JP2000331309A - Compound type magnetic head and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of cracks on an oxide magnetic member and to improve recording capability by providing first metallic magnetic films on the opposing surfaces of the operating magnetic gap of the oxide magnetic member and second metallic magnetic films on the side surfaces that are not parallel with respect to the opposing surfaces of the gap. SOLUTION: First metallic magnetic films 14 are formed by sputtering on the surfaces of core member blocks made of single crystal ferrite that form core basic bodies 12A and 12B of C and I core half bodies 10 and 11. Then, heat treatment is executed for the blocks in a constant directional magnetic field so as to reduce the compressive stress accumulated in the films 14. Then, track width control grooves are formed using a high precision dicer or the like. Then, second metallic magnetic films 15 and nonmagnetic magnetic gap control films 16a and 16b are formed with a fixed thickness. Note that the total thickness of the films 16a and 16b becomes the operating magnetic gap of a completed magnetic 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 use in a magnetic recording / reproducing apparatus such as an analog VTR, a digital VTR, and a data streamer, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In the field of magnetic recording such as digital VTRs, HDDs (hard disk drives), and data streamers, higher recording densities have progressed, and conventional magnetic heads using ferrite cores have been moved closer to the working magnetic gap. A composite magnetic head provided with a metal magnetic film having a high saturation magnetic flux density (a so-called metal-in-gap magnetic head) has been put to practical use.

Here, an outline of a manufacturing process of a composite magnetic head mounted on a magnetic recording / reproducing apparatus such as a digital VTR and a data streamer will be described.

In manufacturing a composite magnetic head, first,
A pair of mirror-finished oxide magnetic material substrates (mainly ferrite substrates) are prepared. Then, one ferrite substrate is subjected to groove processing such as a track width regulating groove, a fused glass groove, and a winding groove using a dicer or the like, thereby obtaining a base material block that becomes a C core half body. The other ferrite substrate is subjected to groove processing other than the winding groove processing in the same manner to obtain a base material block that becomes an I-core half body. Then, a metal magnetic film is formed on the mirror-finished surface by using a thin film forming technique such as sputtering, and a gap regulating film is further formed.

[0005] Next, the I-core half and the C-core half on which the gap regulating film has been formed are accurately positioned and abutted on the abutting surfaces, and a fused glass rod is set in the winding groove and the fused glass groove. Thereafter, the two base material blocks are heated and joined in a state where they are pressed together to obtain a joined block. After forming the sliding width regulating groove using a high-precision dicer or the like, the joining block is cut into a head chip. After that, mirror surface processing and curved surface processing of the sliding surface are performed, whereby
The magnetic head 90 shown in FIG.

In FIG. 16, reference numerals 80 and 81 denote core halves, and core bases 82A and 82B made of a ferrite material.
Metal magnetic film 8 having a higher saturation magnetic flux density than ferrite material
4 and a non-magnetic film 83 disposed at the interface between the core bases 82A and 82B and the metal magnetic film 84. Core half 8
Reference numerals 0 and 81 abut on the front and rear sides, and form an operating magnetic gap having a predetermined track width by interposing an operating magnetic gap regulating film 86 on the front side, and are integrally joined by a fusion glass 87. Reference numeral 88 denotes a winding window used for winding a coil (not shown). 8
Reference numeral 9 denotes a step formed to regulate the sliding width.

The magnetic head 90 having the structure shown in FIG.
Compared with a ferrite head which does not use the metal magnetic film 84, the magnetic field intensity generated from the operating magnetic gap (86) can be made large and steep. Are better.

A composite magnetic head used for an HDD or the like employs a configuration in which a metal magnetic film is formed only on a surface facing a gap.

Such a composite magnetic head is disclosed in
No. 9-305913.

[0010]

The digital V
In the field of magnetic recording such as TRs and data streamers, track widths are becoming narrower in order to achieve higher recording densities. On the other hand, magnetic recording media such as magnetic tapes and magnetic disks have been designed to have a high coercive force.

As the track width becomes smaller, the volume of the ferrite portion near the operating magnetic gap of the magnetic head becomes smaller. When a composite magnetic head having a small track width is to be manufactured, a large force is applied to the ferrite portion due to stress from a metal magnetic film or the like in the composite magnetic head manufactured by the conventional manufacturing method. Cracks occur in the part. As a method of reducing the stress applied to the ferrite portion, it is conceivable to reduce the thickness of the metal magnetic film, but the recording characteristics are reduced.

In the composite magnetic head mounted on the HDD, a metal magnetic film is not formed on a slope portion (side surface) that is not parallel to the surface facing the operating magnetic gap.
No magnetic flux is transmitted from the slope portion, and the recording capability is lower than that of the composite magnetic head in which the metal magnetic film is formed on the slope portion. A compound magnetic head for an HDD normally has a gap depth of several μm (1 to 2 μm), so there is no problem. However, a digital VTR and a data streamer usually have a gap depth of about 10 μm or more. This is not practical for a system that requires a large gap depth in terms of recording characteristics.

In the composite magnetic head, in order to generate a sufficiently strong magnetic field from the working magnetic gap by utilizing the high saturation magnetic flux density of the metal magnetic film, it is necessary to make the working magnetic gap surface high in magnetic flux density. is there. For this purpose, a sufficient magnetic flux must be efficiently guided to the working magnetic gap. At present, the saturation magnetic flux density of the oxide magnetic material (mainly ferrite) used as the core substrate is about 0.5 to 0.6T. On the other hand, the saturation magnetic flux density of the currently developed metal magnetic film is 1.0 to 1.6T.
It is.

FIGS. 17A and 17B show the magnetic flux flowing through the C core half during recording. Here, reference numeral 91 denotes a core substrate of an oxide magnetic material (mainly ferrite), 92 denotes a metal magnetic film, 93 denotes an operating magnetic gap regulating film (operating magnetic gap portion), and 94 denotes a winding window. In the metal magnetic film 92, the density of the maximum magnetic flux Φf that can be transmitted directly from the core substrate 91 of the oxide magnetic material to the back surface of the operating magnetic gap portion metal magnetic film 92a, which is a part involved in recording, The saturation magnetic flux density of the ferrite serving as the base 91 is 0.5 to 0.6T. Therefore, the metal magnetic film 92
In order to obtain a strong magnetic field with a larger magnetic flux density at the working magnetic gap surface, the working magnetic gap portion metal magnetic film portion 92a needs to have a side metal magnetic film portion 92 on the side of the metal magnetic film 92.
It is necessary to transmit magnetic flux from b. Since the magnetic flux Φm that can be transmitted from the side metal magnetic film portion 92b is proportional to the film thickness of the metal magnetic film, it is necessary to increase the film thickness of the metal magnetic film 92 in order to generate a stronger magnetic field. . However, when trying to increase the thickness of the metal magnetic film 92, as described above, the oxide magnetic material (ferrite) is used.
The problem arises that cracks occur in the core base 91 constituted by the above.

One object of the present invention is to suppress the occurrence of cracks in an oxide magnetic member that is affected by a metal magnetic film formed on the surface of an oxide magnetic member that forms the core of a composite magnetic head. While generating a strong magnetic field in the operating magnetic gap.

Another object of the present invention is to propose a method of manufacturing a composite magnetic head capable of producing a composite magnetic head capable of obtaining high recording characteristics by generating a strong magnetic field in the operating magnetic gap with a high yield. Is to do.

[0017]

SUMMARY OF THE INVENTION The present invention relates to a composite magnetic head having a core in which an operating magnetic gap is formed at the junction of two core halves each having a metal magnetic film provided on the surface of an oxide magnetic member. A first metal magnetic film formed on the working magnetic gap facing surface of the oxide magnetic member and having a width substantially equal to the track width direction on the working magnetic gap facing surface, and a side surface not parallel to the working magnetic gap facing surface; Is provided with a second metal magnetic film bonded to the first metal magnetic film.

Specifically, the track width is set to 2 μm to 18 μm.
m.

Further, the second metal magnetic film is provided so as to cover the first metal magnetic film on the surface facing the working magnetic gap, or the second metal magnetic film is provided on the surface facing the working magnetic gap. Is provided so as to be joined to the side end face of the first metal magnetic film.

The first metal magnetic film and the second metal magnetic film are metal magnetic films having substantially the same composition or metal magnetic films having different compositions.

When the first and second metal magnetic films have different compositions, it is desirable that the saturation magnetic flux density of the second metal magnetic film be higher than the saturation magnetic flux density of the first metal magnetic film. The first metal magnetic film is made of a Fe—C microcrystalline material, and the second metal magnetic film is made of a highly corrosion-resistant Fe—C
N-based microcrystalline materials are preferred.

Further, the present invention provides a method of forming a track width regulating groove after forming a first metal magnetic film on a core base material of an oxide magnetic material, and thereafter forming a second metal magnetic film. The composite magnetic head is manufactured.

Further, according to the present invention, a track width regulating groove is formed after forming a first metal magnetic film on a core base material of an oxide magnetic material, and then a plurality of layers of a second metal magnetic film are formed thereon. The composite magnetic head is manufactured by forming a film and then polishing the second metal magnetic film of the working magnetic gap forming junction until the first metal magnetic film is exposed to form a core half. .

After the first metal magnetic film is formed, a heat treatment is performed, a track width regulating groove is formed thereafter, a second metal magnetic film is formed, and the heat treatment is further performed to reduce the film stress. ease.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is desirably implemented in consideration of the following technical studies.

The inventors of the present invention have studied the relationship between the thickness of the metal magnetic film and the occurrence of cracks (ferrite cracks) in the oxide magnetic member and the relationship between the thickness of the metal magnetic film and the recording characteristics for the composite magnetic head having a narrow track width. As a result of an experimental study of the above, it was found that the cause of the cracks mainly occurred immediately after forming the metal magnetic film on the grooved ferrite core base material. Further, as described above, it has been found that sufficient recording characteristics cannot be obtained with a composite magnetic head mounted on an HDD or the like, particularly when the gap depth is large. In the composite magnetic head, in order to sufficiently bring out the recording characteristics, it is necessary to determine how the metal magnetic film formed inside the track width regulating groove processing surface and the winding window processing surface which is not parallel to the operation magnetic gap surface is used. It is important that the magnetic flux can be transmitted to the surface.

In a conventional method of manufacturing a composite magnetic head mounted on a digital VTR, a data streamer, or the like, a track width regulating groove, a winding window groove, and the like are formed on an oxide magnetic member, and then the processed surface is formed. A metal magnetic film is formed on the entire surface by using a thin film forming technique such as sputtering. In such a manufacturing method, the metal magnetic film is formed on the entire surface of the grooved surface, and stress is applied to the convex portion of the ferrite core base material from the entire surface, which may be a major cause of ferrite cracking. In other words, in order to suppress the occurrence of ferrite cracks and to obtain a composite magnetic head having excellent recording performance, a metal magnetic film is formed so that film stress is not concentrated on the projections of the base material of the ferrite core, and the operation is performed. It is necessary to increase the thickness of the metal magnetic film near the magnetic gap.

Specifically, a step of forming a track width regulating groove after forming a first metal magnetic film on a core base material of an oxide magnetic material which has been subjected to a winding window groove processing, and then forming a second metal magnetic film. And a composite magnetic head obtained by a manufacturing method employing the step of forming the metal magnetic film. In the composite magnetic head manufactured by such a method, the force applied to the core base material can be changed by selecting the film thickness of the first metal magnetic film and the film thickness of the second metal magnetic film. Therefore, it is possible to manufacture a composite magnetic head in which the occurrence of ferrite cracks is suppressed, and at the same time, to regulate the track width in the vicinity of the first and second metal magnetic films formed inside the winding window groove and the working magnetic gap. Since the second metal magnetic film formed in the groove can transmit magnetic flux to the working magnetic gap surface, high recording performance can be obtained.

Further, a step of forming a track width regulating groove, a winding window groove and the like after forming a first metal magnetic film on a core base material made of an oxide magnetic material, and thereafter, a step of forming a second metal magnetic film The present invention is also effective in a composite magnetic head manufactured by a manufacturing method employing the step of forming a magnetic head. The processing of the track width regulating groove uses a cutting device such as a high-precision dicer. A metal magnetic film (for example, Co) applied to a composite magnetic head capable of preventing peeling
(Amorphous amorphous alloy films, Fe-based microcrystalline films, etc.) have compressive stress stored in the film immediately after film formation. However, since this film stress can be reduced by a heat treatment process, ferrite cracks due to film stress can be reduced. As a means for reducing the problem, “(first) metal magnetic film formation” → “relaxation of film stress by heat treatment” → “(second) metal magnetic film formation” → “relaxation of film stress by heat treatment” Is also effective.

More specifically, after a metal magnetic film is formed on the core material of the oxide magnetic material on which the winding window groove has been processed, a heat treatment is performed to reduce the film stress, and thereafter, a track width regulating groove or the like is formed. Perform groove processing, then form a metal magnetic film again,
By performing the heat treatment, the generation of ferrite cracks can be suppressed. Further, a composite magnetic head having a sufficient thickness required for recording can be obtained.

In the composite magnetic head manufactured as described above, the thickness of the metal magnetic film in the vicinity of the working magnetic gap can be increased, and the rounding of the end of the working magnetic gap can be reduced. Because it is possible, it is also effective against the problem of side erase.

Here, the first metal magnetic film and the second metal magnetic film may have substantially the same constituent elements and film compositions. When the constituent elements and compositions of the first metal magnetic film and the second metal magnetic film are different, the saturation magnetic flux density of the second metal magnetic film is made larger than the saturation magnetic flux density of the first metal magnetic film. It is effective. When the first metal magnetic film has low corrosion resistance, the reliability of the head can be improved by using a highly corrosion-resistant metal magnetic film as the second metal magnetic film.

Further, a step of forming a track width regulating groove after forming a first metal magnetic film on a core base material made of an oxide magnetic material having a winding window groove processed therein, The same effect can be obtained in a composite magnetic head manufactured by a manufacturing method employing a step of forming two or more layers via a magnetic layer, and thereafter, a step of polishing the operating magnetic gap surface until the first metal magnetic film is exposed. Is obtained. Further, in the composite magnetic head manufactured in this manner, the film thickness in the vicinity of the working magnetic gap can be increased, so that the recording performance is high. Further, the metal magnetic film formed on the side surface portion that is not parallel to the working magnetic gap portion Can be formed into a multi-layer structure with a non-magnetic layer interposed therebetween, so that it is effective as a high-frequency compatible composite magnetic head.

When the track width is less than 2 μm, it is difficult to completely suppress the occurrence of ferrite cracks. On the other hand, when the track width is more than 18 μm, the problem of ferrite cracks occurs even if a film thickness sufficient for practical use is formed. The present invention is particularly effective for a composite magnetic head having a track width of 2 μm to 18 μm, since no occurrence occurs.

Hereinafter, embodiments of the present invention will be described in detail.

First Embodiment FIG. 1 is a perspective view showing an appearance of a composite magnetic head 1 according to a first embodiment of the present invention, in which coils are not shown. This embodiment is an example of application to a VTR head having a ferrite-metal composite structure. Ferrite single crystal, which is an oxide magnetic material constituting the core substrate,
Mn-Zn single crystal ferrite is used, and the first metal magnetic film and the second metal magnetic film are made of Co having substantially the same composition.
A system amorphous material (saturation magnetic flux density: 1.2T) was used.

In FIG. 1, reference numerals 10 and 11 denote a C core half and an I core half, respectively, core bases 12A and 12B made of a Mn-Zn single crystal ferrite material and a first metal made of a Co-based amorphous material. Magnetic film 14 and second metal magnetic film 15
And the core bases 12A and 12B and the first metal magnetic film 1
It comprises a nonmagnetic film 13 disposed at the interface between the fourth and second metal magnetic films 15 and an operating magnetic gap regulating film 16.

The core halves 10 and 11 abut against each other on the front and rear sides, and form an operating magnetic gap having a predetermined track width by interposing the operating magnetic gap regulating film 16 on the front side.

The fusion glass 17 is heated and welded while the core halves 10 and 11 are pressed against each other.
The core halves 10, 11 are integrally connected. Winding window 1
A coil (not shown) is wound around 8. Reference numeral 19 denotes a step formed by a sliding width regulating groove for regulating the sliding width.

FIG. 2 is an enlarged view of a sliding surface of the magnetic head 1. Here, the operating magnetic gap regulating film 16
Is a polymerized film of the operating magnetic gap regulating films 16a and 16b formed on the C-core half 10 and the I-core half 11, respectively. The operating magnetic gap regulating film 16 is formed by the C core half 1
A predetermined working magnetic gap may be formed by a working magnetic gap regulating film formed on either side of the 0 or I core half 11.

Next, a method of manufacturing the composite magnetic head shown in FIGS. 1 and 2 will be described with reference to FIGS.

First, a pair of base material blocks of Mn—Zn single crystal ferrite was prepared.
As shown in (1), a winding window groove 21 is formed to form a C core base material block 20. Next, as shown in FIGS. 4 and 5,
The surface on which the winding window groove 21 of the C-core base material block 20 is formed and the other base material block (I-core base material block) 22
The first metal magnetic film 14 is formed to a predetermined thickness on the surface of the substrate by using a thin film forming technique such as sputtering, whereby the first metal magnetic film 14 is formed.
Then, a C-core base material block 23 with a metal magnetic film and an I-core base material block 24 with a metal magnetic film are formed. At this time, if necessary, a nonmagnetic film having a thickness of about 20 to 200 ° is formed on the interface between them (the interface between the ferrite and the metal magnetic film). Since this non-magnetic film is mainly formed as a base film for the purpose of preventing diffusion and peeling of the ferrite and the metal magnetic film, it is unnecessary depending on the combination of the core base material block and the metal magnetic film. is there.

Next, the base material blocks 23, 2 with metal magnetic films
4 by heat treatment in a magnetic field in a predetermined direction.
Then, the compressive stress stored in the metal magnetic film 14 is relaxed. Then, the base material blocks 23 and 24 with the metal magnetic film are processed by using a high-precision dicer or the like, as shown in FIGS. Then, a track width regulating groove 25 for regulating the track width and a fused glass groove 26 are formed to obtain a grooved C core preform block 27 and a grooved I core preform block 28.
This processing is performed by a combination of etching techniques such as photo-etching as necessary so that the first metal magnetic film 14 does not peel off.

Thereafter, the grooved C core base material block 27
And thoroughly wash the grooved I-core base material block 28,
As shown in FIGS. 8 and 9, by forming the second metal magnetic film 15 and the gap regulating films 16a and 16b to a predetermined thickness, the C core half base material block 29 and the I core half base material are formed. Block 30 is obtained. At this time, if necessary, a nonmagnetic film is formed at the interface between the ferrite and the metal magnetic film for the purpose of preventing diffusion and peeling. This non-magnetic film
Since the portion substantially parallel to the working magnetic gap acts as a pseudo magnetic gap and may adversely affect the recording performance, it is desirable that the film thickness be about 20 to 200 °. In addition, before forming the nonmagnetic film, the surface of the first metal magnetic film 14 is removed from the surface by using an etching method such as ion beam etching.
This is effective in suppressing generation of pseudo signal output. In addition, the second magnetic film is directly formed on the first metal magnetic film 14 without forming the non-magnetic film.
It is effective to perform ion beam etching even when the metal magnetic film 15 is formed.

Subsequently, after both base material blocks 29 and 30 are subjected to a heat treatment in a magnetic field in a predetermined direction to relieve the film stress, as shown in FIG. The glass window rod 31 is accurately positioned and butted, and the fused glass rod 31 is inserted into the winding window groove 21 and the fused glass groove 26.
a and 31b are set. Then, both base material blocks 2
9 and 30 are pressed against each other and heated to form a fused glass rod 31.
By melting both a and 31b and joining the two base material blocks 29 and 30, a core base material joining block 32 as shown in FIG. 11 is obtained.

Then, a sliding width regulating groove (19) is formed in the core base material joining block 32 by using a high-precision dicer or the like, and then cut along an imaginary line 33 to divide the head chip. obtain. After that, the mirror surface processing and the curved surface processing of the sliding surface are performed to obtain the composite magnetic head 1 as shown in FIG.

In the first embodiment, the track (Tw) width is about 2 μm, 9 μm, 18 μm, and 25 μm, and the thickness of the metal magnetic film (the metal magnetic film formed in a portion substantially parallel to the operating magnetic gap) About 2μm, 5μ
A plurality of types of composite magnetic heads having m, 8 μm, and 13 μm were manufactured, and the occurrence of cracks in the core substrates (ferrites) 12A and 12B was examined. Table 1 shows the results of the composite magnetic head manufactured by the conventional manufacturing method. In the table, ○ indicates that cracks were not found, and x indicates that cracks were found.

In the composite head manufactured by the conventional manufacturing method, cracks were not observed in the composite magnetic head having a track width of 18 to 25 μm, but cracks were generated when the track width was reduced to 2 to 9 μm. You can see.

On the other hand, as shown in Table 2, the composite magnetic head according to the first embodiment of the present invention (the first metal magnetic film thickness is the thickness of the metal magnetic film in a portion substantially parallel to the operating magnetic gap) (About 70% of the total thickness), it can be seen that the proof strength against crack generation is large. In a composite magnetic head having a track width of 9 μm, the limit of the conventional composite magnetic head was to limit the thickness of the metal magnetic film to about 2 μm. However, in the composite magnetic head according to the first embodiment of the present invention, According to the magnetic head, the thickness of the metal magnetic film (the total thickness of the first metal magnetic film and the second metal magnetic film) is 8 μm.
It can be seen that the thickness can be increased to the extent.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

[Table 3]

Table 3 shows the recording characteristics of the conventional composite magnetic head and the composite magnetic head obtained in the first embodiment of the present invention. As a recording medium, the coercive force is 15
A 00 Oe magnetic tape was used. A comparison was made between composite magnetic heads having a track width of 9 μm and a gap depth of 15 μm. In the conventional composite magnetic head, the thickness of the metal magnetic film is 2 μm in consideration of the occurrence of cracks.
Although the extent is limited, the composite magnetic head according to the first embodiment of the present invention has a large resistance to crack generation, and therefore the thickness of the metal magnetic film (the first metal magnetic film). (The total thickness of the second metal magnetic film) and the thickness of the second metal magnetic film can be increased to about 8 μm. Therefore,
It can be seen that the recording characteristics, especially in the low frequency range, can be significantly improved (about 1 to 2 dB) as compared with the conventional composite magnetic head.

This effect can be obtained even when the composition of the first metal magnetic film is different from the composition of the second metal magnetic film.
Can be obtained as well. However, in this case, from the viewpoint of improving the recording characteristics, it is desirable that the saturation magnetic flux density of the second metal magnetic film be higher than the saturation magnetic flux density of the first metal magnetic film.

Also, a composite magnetic head manufactured using an Fe—C microcrystalline material as the first metal magnetic film and an Fe—N microcrystalline film having high corrosion resistance as the second metal magnetic film. Can achieve higher reliability than a composite magnetic head made of a single Fe—C-based microcrystalline film.

Second Embodiment FIG. 12 is a perspective view schematically showing a composite magnetic head 2 according to a second embodiment of the present invention, in which coils are not shown. In FIG. 12, the same or equivalent parts as those in the first embodiment described above are denoted by the same reference numerals, and the description of the overlapping part will be omitted. FIG. 13 is an enlarged view of an operating magnetic gap portion.

In the composite magnetic head 2 according to this embodiment, the metal magnetic film on the opposing surface of the operating magnetic gap is formed by the thickness of the first metal magnetic film and the second metal magnetic film in the first embodiment. By forming the first metal magnetic film 14 to have a thickness equal to the total thickness of the composite magnetic head, the core bases 12A and 12B made of an oxide magnetic material (Mn—Zn single crystal ferrite) that forms the main body of the core of the composite magnetic head are formed. A strong magnetic field can be generated in the operating magnetic gap while suppressing generation of cracks.

Next, a method of manufacturing the composite magnetic head 2 will be described with reference to FIGS.

First, a pair of base material blocks of Mn-Zn single crystal ferrite is prepared, and one base material block is subjected to a winding groove processing to form a C core base material block. The other base material block is an I-core base material block. Subsequently, a first metal magnetic film is formed to a predetermined thickness on the surface of the C-core base material block on which the winding groove is processed and the surface of the I-core base material block by using a thin film forming technique such as sputtering.
A C core base material block with a metal magnetic film and an I core base material block with a metal magnetic film are obtained. At this time, if necessary, a nonmagnetic film having a thickness of about 20 to 200 ° is formed at the interface between them.

Next, the base material block with the metal magnetic film is subjected to a heat treatment in a magnetic field in a predetermined direction to reduce the stress generated by the thin film forming. By forming a track width regulating groove and a fused glass groove using a precision dicer or the like, a grooved C-core preform block and a grooved I-core preform block are obtained.

Then, after the grooved C-core base material block and the grooved I-core base material block are sufficiently washed, a second metal magnetic film is laminated with a non-magnetic film interposed therebetween. In the second embodiment, the first and second metal magnetic films are:
Co-based amorphous material of the same composition (saturation magnetic flux density: 1.2
T), the second metal magnetic film had a two-layer structure.

FIG. 14 is an enlarged view of a part of the grooved C-core base material block in which the metal magnetic films are laminated, 12A is a core base, and 13a and 13b are non-magnetic films (lower portions). Ground film and interlayer film), 14 is a first metal magnetic film, 15
Reference numerals a and 15b denote second metal magnetic films. The same applies to the grooved I-core base material block.

Then, after a heat treatment is performed in a magnetic field in a predetermined direction to relax the stress of the metal magnetic film, the mating surface is polished until the first metal magnetic film 14 is exposed, as shown in FIG. . Thereafter, an operating magnetic gap regulating film is formed on the butted surface of the grooved C-core base material block and the grooved I-core base material block.

Thereafter, by performing the same processing as the steps after the step shown in FIG. 10 in the first embodiment described above, the composite magnetic head 2 as shown in FIG. 12 is completed.

In the second embodiment, the track (Tw) width is set to about 9 μm, 18 μm, 25 μm,
The thickness of the metal magnetic film 14 after polishing (the thickness of the metal magnetic film formed in a portion substantially parallel to the operating magnetic gap) is about 2 μm.
m, 5 μm, 8 μm, and 13 μm, and the film thickness of the side surface (slope) of the second metal magnetic film (the film thickness of the metal magnetic film formed on the side surface non-parallel to the operating magnetic gap) and film structure Was fabricated in a two-layer structure having a thickness of 0.7 μm, and the occurrence of cracks in the core substrates (ferrites) 12A and 12B was examined. Table 4 shows the occurrence of cracks in the composite magnetic head manufactured by the manufacturing method according to the second embodiment. It can be seen that the composite magnetic head according to the second embodiment also has a high resistance to crack generation, similarly to the composite magnetic head according to the first embodiment.

[0066]

[Table 4]

[0067]

[Table 5]

Table 5 shows the recording characteristics of the conventional composite magnetic head and the composite magnetic head obtained in the second embodiment. As a recording medium, the coercive force is 1500
Oe magnetic tape was used. And the track width is 9μ
m and a composite magnetic head having a gap depth of 15 μm were compared. In the conventional composite magnetic head, the thickness of the metal magnetic film is limited to about 2 μm in consideration of the occurrence of cracks. However, the composite magnetic head of the present invention has a large resistance to crack generation. Thus, the thickness of the metal magnetic film (the thickness of the metal magnetic film in a portion substantially parallel to the operating magnetic gap) can be increased to about 8 μm. Therefore, it can be seen that the recording characteristics, especially in the low frequency range, are significantly improved (about 1.5 dB) as compared with the conventional composite magnetic head.

Such characteristics can be obtained even when the composition of the first metal magnetic film is different from the composition of the second metal magnetic film.
Obtained similarly.

[0070]

According to the present invention, the first magnetic metal formed on the opposing magnetic gap facing surface of the oxide magnetic member, which is the main body of the core half, is formed to have a width substantially equal to the track width direction. By providing the second metal magnetic film bonded to the first metal magnetic film on a side surface that is not parallel to the magnetic film and the opposing surface of the operating magnetic gap, cracks occur in the oxide magnetic member even in a configuration with a narrow track width. It is possible to obtain a composite magnetic head which can suppress occurrence of the magnetic field and has a high recording capability.

As a manufacturing method, a track width regulating groove is formed after forming a first metal magnetic film on a core base material of an oxide magnetic material, and then a second metal magnetic film is formed. It is effective to adopt a process.

Further, by adding a step of relaxing the film stress by performing a heat treatment after the formation of the metal magnetic film, the production can be performed with a high yield.

Such a composite magnetic head is particularly effective when the track width is 2 μm to 18 μm.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of a composite magnetic head according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a sliding surface of the composite magnetic head according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating a manufacturing process of the composite magnetic head according to the first embodiment of the present invention, and is a perspective view of a C-core base material block.

FIG. 4 is an explanatory diagram showing a manufacturing process of the composite magnetic head according to the first embodiment of the present invention.
It is a perspective view of a core base material block.

FIG. 5 is an explanatory view showing a manufacturing process of the composite magnetic head according to the first embodiment of the present invention.
It is a perspective view of a core base material block.

FIG. 6 is an explanatory view showing a manufacturing process of the composite magnetic head according to the first embodiment of the present invention, and is a perspective view of a grooved C-core base material block.

FIG. 7 is an explanatory diagram showing a manufacturing process of the composite magnetic head according to the first embodiment of the present invention, and is a perspective view of a grooved I-core base material block.

FIG. 8 is an explanatory diagram illustrating a manufacturing process of the composite magnetic head according to the first embodiment of the present invention, and is a perspective view of a C-core half base material block.

FIG. 9 is an explanatory view illustrating a manufacturing process of the composite magnetic head according to the first embodiment of the present invention, and is a perspective view of an I-core half base material block;

FIG. 10 is an explanatory view showing a manufacturing process of the composite magnetic head according to the first embodiment of the present invention, and is a perspective view in a step of joining the core half base material blocks.

FIG. 11 is an explanatory diagram illustrating a manufacturing process of the composite magnetic head according to the first embodiment of the present invention, and is a perspective view of a core base material joining block.

FIG. 12 is a perspective view showing an appearance of a composite magnetic head according to a second embodiment of the present invention.

FIG. 13 is an enlarged view of a sliding surface of the composite magnetic head according to the second embodiment of the present invention.

FIG. 14 is an explanatory diagram showing a manufacturing process of the composite magnetic head according to the second embodiment of the present invention, and is an enlarged plan view showing a part of a grooved C-core base material block.

FIG. 15 is an explanatory view showing a manufacturing process of the composite magnetic head according to the second embodiment of the present invention, and is an enlarged plan view showing a part of a polished grooved C core base material block.

FIG. 16 is a perspective view showing an appearance of a composite magnetic head manufactured by a conventional manufacturing method.

FIG. 17 is an explanatory diagram showing transmission of magnetic flux during recording of the composite magnetic head.

[Explanation of symbols]

1, 2 ... composite magnetic head, 10 ... C core half, 11 ...
I core half, 12A, 12B: core substrate, 13: non-magnetic film (base film), 14: first metal magnetic film, 15: second metal magnetic film, 16: working magnetic gap film.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Kenkichi Inada 1410 Inada, Hitachinaka-shi, Ibaraki Pref., Ltd. Within AV Division, Hitachi, Ltd. F-term in business division (reference) 5D093 AA01 AB03 AD05 BB04 CA07 DA02 JA06 5D111 AA23 BB12 CC26 FF08 GG03 JJ05 KK01 KK11

Claims (11)

[Claims] 1. A composite magnetic head comprising a core having a magnetic gap formed at a junction of two core halves each having a metal magnetic film provided on a surface of an oxide magnetic member, wherein the operation of the oxide magnetic member is performed. The magnetic gap forming junction is
A first metal magnetic film formed on the opposing surface of the working magnetic gap so as to have a width substantially equal to the track width direction; A composite magnetic head comprising a metal magnetic film. 2. The method according to claim 1, wherein the track width is 2 μm or less.
A composite magnetic head having a thickness of 18 μm. 3. The composite magnetic head according to claim 1, wherein the second metal magnetic film is provided so as to cover the first metal magnetic film on a surface facing the operating magnetic gap. . 4. The method according to claim 1, wherein the second metal magnetic film is provided so as to be joined to a side end surface of the first metal magnetic film on a surface facing the operating magnetic gap. Composite magnetic head. 5. A composite magnetic head according to claim 1, wherein said first metal magnetic film and said second metal magnetic film are metal magnetic films having substantially the same composition. . 6. The composite magnetic head according to claim 1, wherein said first metal magnetic film and said second metal magnetic film are metal magnetic films having different compositions. 7. The composite magnetic head according to claim 6, wherein a saturation magnetic flux density of said second metal magnetic film is higher than a saturation magnetic flux density of said first metal magnetic film. 8. The Fe--N microcrystalline material according to claim 6, wherein said first metal magnetic film is made of a Fe--C microcrystalline material, and said second metal magnetic film is made of a highly corrosion-resistant Fe--N microcrystalline material. A composite magnetic head characterized by being formed by using. 9. A track width regulating groove is formed after forming a first metal magnetic film on a core base material of an oxide magnetic material, and thereafter, a second metal magnetic film is formed. Item 1. The method for manufacturing a composite magnetic head according to item 1. 10. A track width regulating groove is formed after forming a first metal magnetic film on a core base material of an oxide magnetic material, and then a plurality of second metal magnetic films are formed thereon. 5. The method according to claim 1, further comprising polishing the second metal magnetic film of the operating magnetic gap forming junction until the first metal magnetic film is exposed to form a core half. Of manufacturing a combined magnetic head. 11. The method according to claim 9, wherein a heat treatment is performed after forming the first metal magnetic film, a track width regulating groove is formed thereafter, and then a second metal magnetic film is formed. A method of manufacturing a composite magnetic head.