JPH0448416A - Magnetic head - Google Patents

Abstract

PURPOSE:To suppress the generation of a pseudo gap by forming the ferromagnetic metallic films formed in a track width regulating groove via intermediate films consisting of materials having the coefft. of thermal expansion between the coefft. of thermal expansion of 1st magnetic core half bodies and the coefft. of thermal expansion of the ferromagnetic metallic films and forming the ferromagnetic metallic films formed on gap forming surfaces without via the intermediate films. CONSTITUTION:The value of the coefft. of thermal expansion of the intermediate films 10, 10, 10, 10 is specified to the value between the coefft. of thermal expansion of the ferromagnetic oxide constituting the core half bodies 1,2 and the ferromagnetic metallic films 6,6 in order to prevent the cracking, peeling and deterioration in the the characteristics of the ferromagnetic metallic films 6,6 by the thermal stresses generated from a difference in the coefft. of thermal expansion between the ferromagnetic metallic films 6,6 and the ferromagnetic oxide at the time of welding the films with welding glass 5,5 and forming the ferromagnetic metallic films 6,6. The generation of the pseudo gap is suppressed in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a magnetic head, and in particular to a so-called composite magnetic head in which the vicinity of the magnetic gap is formed of a ferromagnetic metal film. be.

(b) Conventional technology In recent years, the recording signal density has been increased in magnetic recording and reproducing devices such as VTRs, and in order to cope with this high density recording, magnetic recording media are made of strong materials such as Fe, Co, and Ni. Metal tapes made of magnetic metals and having high coercive force are now being used. A magnetic head material for recording and reproducing this type of magnetic recording medium having high coercive force is required to have a high saturation magnetic flux density. For example, in a conventional magnetic head made only of ferrite, the saturation magnetic flux density of the ferrite is about 5000 Gauss, and cannot cope with the above-mentioned increase in coercive force of the magnetic recording medium.

Therefore, a magnetic head compatible with the above-mentioned high coercive force magnetic recording medium is required to increase the saturation magnetic flux density in the vicinity of the gap where the magnetic saturation phenomenon is most likely to occur. In a magnetic head that meets this requirement, the magnetic core half is made of a ferromagnetic oxide such as ferrite, and the area near the magnetic gap has a higher saturation magnetic flux density than the ferromagnetic oxide used as the magnetic core half. A so-called composite magnetic head made of a ferromagnetic metal film such as Sendust has been proposed.

Conventionally, as this type of magnetic head, for example, Japanese Patent Laid-Open No. 6
2-145510 (GIIB 5/127) and the like are known.

FIG. 16 is a perspective view showing the appearance of a conventional magnetic head, and FIG. 17 is a diagram showing a magnetic medium sliding surface of the conventional magnetic head.

In the figure, (1,)(2) are the first ferromagnetic oxides.
, the second magnetic core half. On the gap forming surfaces (9) (9') formed on the gap forming side end faces of the first and second magnetic core halves (1) (2) and on the track width regulating grooves (
3) (3) (3) Inside (3), there are ferromagnetic metal films (6) (6) through interlayer films (10) (10) made of strain-relaxing material.
is formed by adhesion. Said track width regulating groove (3) (
3) (3) (3) is a non-magnetic adhesive (5) (5) made of welded glass (welding conditions: welding temperature 600°C, 10
minute retention) is filled. The pair of first and second magnetic core halves (1) and (2) are S10! They are joined and fixed by the adhesive (5) (5) in a state where they are butted together with a non-magnetic material such as the like interposed therebetween, thereby forming a magnetic gap (4). Incidentally, the second magnetic core half (2) is formed with a winding groove (14) around which a winding is wound.

(c) Problems to be Solved by the Invention However, in the above-mentioned conventional magnetic head, the above-mentioned first,
Ferromagnetic metal film (6) of second magnetic core half (1) (2) (
In order to suppress the distortion of 6), an interlayer film with excellent adhesion (1
0) (10) is the track width regulation groove (3) (3) (3) (
3) It is formed in a substantially --like manner over the entire area from the inside to the top of the gap forming surfaces (9) (9'). Therefore, the intermediate film (10) formed on the gap forming surface of the magnetic head
(10) is parallel to the magnetic gap (4), so the intermediate films (10) and (10) may act as a pseudo gap. Further, the influence of the above-mentioned pseudo gap can be suppressed by reducing the thickness of the intermediate film (10) (10), but in this case, the first and second magnetic core halves (1) (2 ) and the ferromagnetic metal film (6) (6) cannot be sufficiently suppressed.

For example, Cr has particularly excellent adhesion between the ferromagnetic metal films (6) (6) and the first and second magnetic core halves (1) (2).
The film also requires a film thickness of about 400 mm, and in the frequency characteristics of the reproduction output of a head with this Cr film, undulations of 1 to 2 dB due to the pseudo gap occur, and distortion relaxation is not sufficient. There wasn't.

In addition, the adhesive material (5) (5) made of the above-mentioned welded glass
As a method for relaxing the thermal stress of the ferromagnetic metal film (6) (6) during welding, the adhesive material (5) (5) with a low softening point is used.
), but considering the moisture resistance, abrasion resistance, etc. of the adhesive (5) (5), it is difficult to use the adhesive (5) (5) made of fused glass with a low softening point. be.

Therefore, it is an object of the present invention to provide a magnetic head in which the occurrence of pseudo gaps is suppressed and the distortion generated between the magnetic core half and the ferromagnetic metal film is sufficiently suppressed.

(d) Means for Solving the Problems The present invention has been devised in view of the above-mentioned problems, and is made of a ferromagnetic oxide having a gap forming surface whose track width is regulated by a track width regulating groove. A ferromagnetic metal film is formed in the track width regulating groove and on the gap forming surface of the first magnetic core half, and a nonmagnetic metal film is formed in the track width regulating groove. A ferromagnetic metal film filled with an adhesive and formed on the gap forming surface of the first magnetic core half and the second magnetic core half are butted together via a non-magnetic material forming a magnetic gap. In the magnetic head bonded and fixed by the adhesive, the ferromagnetic metal film formed in the track width regulating groove has a coefficient of thermal expansion that is higher than that of the first magnetic core half. A magnetic head characterized in that the ferromagnetic metal film is formed between the magnetic metal film and the intermediate film made of a certain material, and the ferromagnetic metal film formed on the gap forming surface is formed without the intermediary film. It provides:

The invention also includes a first magnetic core half made of a ferromagnetic oxide having a gap forming surface whose track width is regulated by a track width regulating groove; A ferromagnetic metal film is formed on the formation surface, and a non-magnetic adhesive is filled in the track width regulating groove, and a ferromagnetic metal film is formed on the gap formation surface of the first magnetic core half. In a magnetic head in which a metal film and a second magnetic core half are abutted against each other with a non-magnetic material serving as a magnetic gap interposed therebetween and bonded and fixed by the adhesive, the ferromagnetic metal film has a thermal expansion coefficient of the second magnetic core half. 1 is formed between the magnetic core half and the ferromagnetic metal film in the track width regulating groove and on the gap forming surface via an intermediate film made of a certain material, and the intermediate film is formed on the gap forming surface. The present invention provides a magnetic head characterized in that the thickness of the portion formed above is smaller than the thickness of the portion formed within the track width regulating groove.

(e) According to the present invention, the intermediate film occupies most of the end face on the gap forming side of the magnetic core half, and is placed within the track width regulating groove of the magnetic core half, which has a complex shape where stress is concentrated. Because of this, it is possible to sufficiently suppress the strain that occurs between the magnetic core half and the ferromagnetic metal film, and in addition, the gap forming surface of the magnetic core half can be formed without an intermediate film or without an intermediate film. Since the film thickness is small, the occurrence of pseudo gaps can be sufficiently suppressed.

(F) Example Hereinafter, a first example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing the external appearance of the magnetic head of the first embodiment, and FIG. 2 is a diagram showing the medium sliding surface of the magnetic head of the first embodiment.

In the figure, (1) and (2) are first and second magnetic core halves made of ferromagnetic oxide such as Mn-Zn ferrite.

Track width regulating grooves (3) (3) are provided on both sides of the gap forming side end surfaces of the first and second magnetic core halves (1, 2), respectively.
)(3)(3) are formed, and a trunk width T is formed in the portion between the track width regulating grooves (3)(3)(3)(3).
Gap forming surfaces (9) (9) of w are formed. In the track width regulating grooves (3) (3) (3) (3) of the first and second magnetic core halves (1) (2), there are intermediate films (10) (10) made of a strain relaxation material. (10) (10) is 1 μm
It is formed with a thick coating. The intermediate film (10) is disposed within the track width regulating grooves (3) (3) (3) (3) of the end faces on the gap forming side of the first and second magnetic core halves (1) (2). (10) and also through the gap forming surface (9)
(9) l is directly coated with a ferromagnetic metal film (6) (
6) is deposited to a thickness of 3 μm.

Further, on the upper surface of the ferromagnetic metal films (6) (6), S
A non-magnetic material such as in, etc. is deposited to a thickness of 0.1 μm. Said track width regulating groove (3) (3) (3) (
3) includes a non-magnetic adhesive (5) made of fused glass (
5) The first and second magnetic core halves (1) are filled with
The non-magnetic materials (2) are joined in abutted state, and a magnetic gap (4) is formed at the joint. still,
This joining is achieved by melting and assimilating the adhesive (505). A winding groove (14) around which a winding is wound is formed in the second magnetic core half (2). The intermediate film (10) (10) (10) (10) includes the welding of the welded glass (5) (5) and the ferromagnetic metal film (6) (6'
), the difference in thermal expansion coefficient between the ferromagnetic metal film (6) (6) and the ferromagnetic oxide (for example, the thermal expansion coefficient of sendust is 130 x 10-'/''C~1 .60
X 10-'/'C, and ferrite is 90 X I
O-'/"C-110X 10-'/"C. )
The above ferromagnetic metal film (6
) (6) In order to prevent cracking, peeling, deterioration of properties, etc. of the magnetic core half (1), the value of the thermal expansion coefficient is
It may be between the ferromagnetic oxide constituting (2) and the ferromagnetic metal film (6) (6). Specifically, in the case of this example in which the ferromagnetic metal film (6) is Sendust and the ferromagnetic oxide is Mn-Zn ferrite, Fe, MgO, N1, etc. (Thermal expansion coefficients are 135X10-' 130X10-125X1
0/℃. ).

Next, a method of manufacturing the magnetic head of the first embodiment will be described with reference to FIGS. 3 to 11.

First, a first substrate (21) made of a ferromagnetic oxide such as MnZn ferrite with a thickness of 1.3 mm is prepared.
The upper surface of the substrate (21), which will be the end surface on the gap forming side, is mirror-finished. This first substrate (21) is the base material of the first magnetic core half (1). Thereafter, as shown in FIG. 3, a constant pitch P1 is maintained so as to leave a gap forming surface (9) with a track width Tw on the upper surface of the first substrate (21).
Then, a plurality of track width regulating grooves (3) (3) are formed using a dicing saw or the like.

In the next step, as shown in FIG.
) An intermediate film (10) of Fe, MgQ, N+, etc. is formed on the entire upper surface, that is, within the track width regulating grooves (3) (3) and on the gap forming surface (9), to a thickness of 1 μm using a vacuum thin film forming technique such as sputtering. Adhesion is formed.

In the next step, as shown in FIG.
The upper surface of the first substrate (21) is mirror-finished so as to completely remove the intermediate film (10) formed on the gap forming surface (9) of the upper surface of the first substrate (21).

That is, through this step, the track width regulating grooves (3) (3)
) remains only the intermediate film (10) formed within.

The next step is to attach the first substrate (21) as shown in FIG.
A ferromagnetic metal film (6) such as sendust having a higher saturation magnetic flux density than the ferromagnetic oxide constituting the first substrate (21) is deposited to a thickness of 3 μm over the entire upper surface by sputtering or the like. Furthermore, a non-magnetic material (12) such as S]Ol which forms a magnetic gap on the upper surface of the ferromagnetic metal film (6)
The film is deposited to a thickness of 61 μm using an ion blasting method, a sputtering method, or the like.

On the other hand, a second substrate (22) made of a ferromagnetic oxide of Mn-Zn ferrite with a thickness of 1.3 mm is prepared, and the upper surface of the second substrate (22), which will be the end surface on the gap formation side, is mirror-finished. administer. This second substrate (22) is the base material of the second magnetic core half (2). Thereafter, as shown in FIG. 7, the track width Tw is
a constant pitch P so as to leave a gap forming surface (9) of
, a plurality of track width regulating grooves (3) (3) are formed using a dicing saw, etc., and then two track width regulating grooves (3) (3) are formed at a constant pitch P.
A plurality of book bonding grooves (13) (13) and winding grooves (14) are formed using a dicing saw or the like.

The next step is to attach the second substrate (22) as shown in FIG.
An interlayer film (10) of Fe, . It is deposited to a thickness of 1 μm using a vacuum thin film forming technique such as sputtering.

In the next step, as shown in FIG.
) The upper surface of the second substrate (22) is mirror-finished so as to completely remove the intermediate film (1O) formed on the gap forming surface (9).

That is, through this step, the track width regulating grooves (3) (3)
), the winding groove (14), and the adhesive groove (13) (13).

In the next step, as shown in FIG.
2) A ferromagnetic metal film (6) such as Sendust, which has a higher saturation magnetic flux density than the ferromagnetic oxide constituting the second substrate (22), is deposited on the entire upper surface by sputtering or the like to form a film of 3 μm.
Form the film to a thickness of m. Furthermore, the ferromagnetic metal film (6)
A non-magnetic material (2) such as Sin, which will become the magnetic gap (4), is deposited on the upper surface of the substrate to a thickness of 0.1 μm by an ion blasting method or a sputtering method.

Next, as shown in FIG. 11, the first substrate (21) and the second substrate (22) are connected to the first and second substrates (21).
The adhesive grooves (13) (13) and the track width regulating grooves (3) (3) (
3) Adhesive material (5) made of high melting point glass inside (3) (5)
) and held in a vacuum at 600° C. for 10 minutes, and then the adhesives (5) and (5) are solidified and bonded to produce a welded block (23). The thickness of the magnetic gap is approximately determined by the thickness of the non-magnetic material (12) (12), and is 0.2 μm. Thereafter, the welded block (23) is cut along the dotted line AA= and the dotted line B-B-, and then the magnetic medium sliding surface is processed to complete the magnetic head as shown in Fig. 1. do.

In the magnetic head of the first embodiment as described above, the first and second
Track width regulating grooves (3) (303) (3) occupying most of the end face on the gap forming surface side of the magnetic core halves (1) (2)
) (10) (lo) (10) (
10) is formed, the strain occurring between the first and second magnetic core halves (1) (2') and the ferromagnetic metal films (6) (6) can be sufficiently alleviated. Gap forming surface (
9) On (9') there is an interlayer film (10) (10) (10) (
10) is not formed, the intermediate film (10) (10
)(10) A pseudo gap due to (10) does not occur.

A second embodiment of the present invention will be described below.

FIG. 12 is a diagram showing an external view of the magnetic head of the second embodiment, and FIG. 13 is a diagram showing the medium sliding surface of the magnetic head of the second embodiment. In the second embodiment, the same parts as in the first embodiment are denoted by the same reference numerals, and the explanation thereof will be omitted.

In the magnetic head of the second embodiment, the entire area of the end faces on the gap forming side of the first and second magnetic core halves (1) and (2), that is, the track width regulating grooves (3) (3) (3) (3) Intermediate film (10) is applied over the entire area from the inner surface to the gap forming surface (9) (9)
Ferromagnetic metal films (6) (6) are formed via (10). The first and second intermediate films (10) and (10)
Gap forming surfaces (9) of magnetic core halves (1) (2') (
9) The thickness of the first portions (10a) (10a) formed on the track width regulating grooves (3) (3) ( 3) The second portion of the intermediate film (10b) (10b) (10b) (
The film thickness of 10b) is smaller than 1 μm and 100 Å or less. The thickness of the first portions (10a) (10a) of the intermediate film is such that the reproduction output of the pseudo gap caused by the first portions (10a) (10a) is 5% of the reproduction output of the magnetic gap (4). The degree, that is, the waviness of the pseudo gap appearing in the frequency characteristics of the reproduction output is as small as 0.4 dB, and may be set so as to have almost no effect on recording and reproduction.

Next, a method of manufacturing the magnetic head used in the second embodiment will be explained.

First, the first substrate (21) is processed as shown in FIGS. 3 and 4 of the first embodiment described above to prepare the substrate shown in FIG. 4. Further, the second substrate (22) is processed as shown in FIGS. 7 and 8 of the first embodiment described above to prepare the substrate shown in FIG.

After that, in FIGS. 5 and 9 of the first embodiment, the first
An intermediate film (10) formed on the gap forming surface (9) of the "-" surface of the first substrate (21) by ion beam etching or the like instead of the mirror polishing used in the example.
, and only the intermediate film (10) formed on the gap forming surface (9) of the upper surface of the second substrate (22) has a thickness of 10
The first part (10a) (
Form 10a). That is, the inside of the track width regulating groove (3) (3) on the upper surface of the first substrate (21) and the second
Track width regulating grooves (3) (3) on the top surface of the board (22)
), the welding grooves (13), (13), and the winding groove (14) remain without being etched, and the intermediate films (10) (10) formed in the welding grooves (13) (13) and the winding grooves (14) remain without being etched, and the first portions (10a) ( The second portion (10b) (10b) (10b) has a larger film thickness than 10a).
ob) (10b).

Thereafter, the same processing as shown in FIGS. 6, 10, and 11 of the first embodiment described above is performed to complete the magnetic head shown in FIG. 12.

In the magnetic head of the second embodiment as described above, the first and second
Track width regulating grooves (3) (3) (3) (
3) The second part of the intermediate film with a sufficient film thickness within (], 0b) (
10b) (]0b) (10b) is formed,
The strain generated between the first and second magnetic core halves (1) (, 2) and the ferromagnetic metal films (6) (6) can be sufficiently alleviated, and the gap forming surfaces (9) (9) Since the first portions (10a) (10a) of the intermediate film formed above are thin, the influence of the pseudo gap caused by the first portions (10a) (10a) can be sufficiently suppressed.

(G) Effects of the Invention Therefore, according to the present invention, the occurrence of pseudo gaps can be suppressed, and peeling and cracking of the ferromagnetic metal film due to strain occurring between the magnetic core half and the ferromagnetic metal film and the magnetic properties can be prevented. A magnetic head with sufficiently suppressed deterioration can be obtained.

[Brief explanation of the drawing]

1 to 11 relate to the first embodiment of the present invention.
The figure is a perspective view of the magnetic head, Figure 2 is a diagram showing the medium sliding surface of the magnetic head, Figures 3, 4, 5, 6, and 7.
8, 9, 10 and 11 are respectively perspective views showing a method of manufacturing a magnetic head, and FIGS. 12 to 15 relate to a second embodiment of the present invention, and FIG. is a perspective view of the magnetic head, FIG. 13 is a diagram showing the medium sliding surface of the magnetic head,
FIGS. 14 and 15 are perspective views showing a method of manufacturing a magnetic head, respectively. FIG. 16 is a perspective view showing a conventional magnetic head, and FIG. 17 is a diagram showing a medium sliding surface of the conventional magnetic head. (1)...First magnetic core half, (2)...Second magnetic core half, (3)...Trunk width regulating groove, (4)...
・Magnetic gap, (5)...adhesive material, (6)...ferromagnetic metal film, (9)...gap forming surface, (10)...
・Intermediate film, (10a)...first part, (10b)...
-Second portion, (12)...Nonmagnetic material, Tw...Track width.

Claims (2)

[Claims] (1) A first magnetic core half made of a ferromagnetic oxide having a gap forming surface whose track width is regulated by a track width regulating groove; A ferromagnetic metal film is formed on the gap forming surface, and a non-magnetic adhesive is filled in the track width regulating groove. In a magnetic head in which a magnetic metal film and a second magnetic core half are abutted against each other with a non-magnetic material serving as a magnetic gap interposed therebetween and bonded and fixed by the adhesive, the track width of the ferromagnetic metal film is The ferromagnetic metal film formed in the regulating groove is formed via an intermediate film made of a material whose coefficient of thermal expansion is between that of the first magnetic core half and the ferromagnetic metal film, and is formed on the gap forming surface. A magnetic head characterized in that the ferromagnetic metal film formed on the ferromagnetic metal film is formed without interposing the intermediate film. (2) A first magnetic core half made of a ferromagnetic oxide having a gap forming surface whose track width is regulated by a track width regulating groove; A ferromagnetic metal film is formed on the gap forming surface, and a non-magnetic adhesive is filled in the track width regulating groove. In a magnetic head in which a magnetic metal film and a second magnetic core half are abutted against each other with a non-magnetic material serving as a magnetic gap interposed therebetween and bonded and fixed by the adhesive, the ferromagnetic metal film has a thermal expansion coefficient of An intermediate film made of a certain material is formed between the first magnetic core half and the ferromagnetic metal film in the track width regulating groove and on the gap forming surface, and the intermediate film is formed between the first magnetic core half and the ferromagnetic metal film. A magnetic head characterized in that a film thickness of a portion formed on the surface is smaller than a film thickness of a portion formed within the track width regulating groove.