JPH10283610A - Magnetic head and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of an MIG type magnetic head for imparting tensile stress to the vicinity of a gap of magnetic ferrite material, sufficiently drawing the characteristic of the original ferrite material out and attaining high reproducing efficiency and its manufacture. SOLUTION: A glass film 2 with the coefficient of thermal expansion lower than the magnetic ferrite material 1 is formed on the magnetic ferrite material 1 to be baked, and the tensile stress is applied to the vicinity of the gap 5 of the magnetic ferrite material 1 by the stress of the glass, and the reproducing efficiency of the magnetic head is improved. Further, when a ferromagnetic metallic film 2 is formed on the glass film 2 by a method of sputtering, etc., the metallic film sticking strength is improved, and film exfoliation hardly occurs, and further, since the glass film 2 is relatively thick, and since the ferromagnetic metallic film 3 is separated perfectly from the magnetic ferrite material 1 not to be reacted to each other, the magnetic head with high reliability, high yield and an excellent characteristic is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used in a magnetic recording / reproducing apparatus and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, in the field of magnetic recording, the density of signal recording has been increased, and recording media having high coercive force and high residual magnetic flux density have been used. To cope with this, a magnetic core having a high saturation magnetic flux density and a high magnetic permeability is also required for a magnetic head. From such a demand, conventionally, a ferromagnetic metal film having a higher saturation magnetic flux density than ferrite is formed near the gap on the surface of an oxide magnetic material such as ferrite, which is widely used as a magnetic head material. An in-gap (MIG) type magnetic head has been proposed.

[0003] As is well known, the configuration of a MIG type magnetic head is such that a track width regulating groove is formed on the opposing surfaces of a pair of magnetic ferrite materials, and on the opposing surfaces, a reaction preventing film is interposed.
A ferromagnetic metal film is formed. In order to prevent the reaction between the ferromagnetic metal film and the magnetic ferrite material, the reaction prevention film is often formed of a thin film such as SiO ₂ or Al ₂ O ₃ . next,
In order to prevent the reaction between the bonding glass and the ferromagnetic metal film and secure the gap length, a glass or oxide is formed on the ferromagnetic metal film and the surfaces are butted together to join the track width regulating groove. The glass is melt-filled and the pair of magnetic core halves are joined and integrated.

[0004]

However, it is generally known that in the case of a magnetic head having such a configuration, the reproduction efficiency is lower than that of a so-called conventional ferrite magnetic head made of only a magnetic ferrite material. Have been.
It is believed that this is due to the difference in thermal expansion coefficient between the magnetic ferrite material and the ferromagnetic metal film formed thereon. In general, among oxides and metal materials having sufficient magnetic properties, the metal material has a larger coefficient of thermal expansion,
At the time of heat treatment at the time of gap joining, a compressive stress is applied to the magnetic ferrite material due to a difference in thermal expansion coefficient. In the case of a ferrite magnetic head, the gap abutting surface is set to (111)
When the main magnetic path plane is set to the (110) plane, and the crystal axes <110> are set to draw arrows that approach each other in the direction toward the sliding surface in the (110) plane, the reproduction is performed. The highest efficiency is known from JP-B-62-18968 and JP-B-63-3365. A magnetic head made in such a setting should be made of a glass material that gives tensile stress near the side of the gap to the magnetic ferrite material near the gap, which greatly affects the reproduction efficiency, to improve the reproduction efficiency But, Tokiko Sho 62-1
No. 8968. The above publication also discloses that a composition having a crystal magnetic anisotropy constant K ₁ of around 1 × 10 ⁴ erg / cc is excellent in magnetic properties.

[0005] From these facts, it is unavoidable that a magnetic head having a structure in which a ferromagnetic metal film is formed on a magnetic ferrite material has lower reproduction efficiency than a magnetic head using only ferrite. The present invention proposes a structure and a manufacturing method of a MIG type magnetic head for applying a tensile stress in the vicinity of a gap of a magnetic ferrite material, sufficiently extracting characteristics of the original ferrite material, and achieving high reproduction efficiency. .

[0006]

In order to achieve this object, a magnetic head and a method of manufacturing the same according to the present invention provide a magnetic head comprising a magnetic ferrite material having a track width regulating groove formed therein and a ferromagnetic metal film. It has a lower thermal expansion coefficient than ferrite material, and is also characterized by forming a glass having a higher melting point than the bonding glass filling the groove portion of the track width regulating groove. The tensile stress is applied to the vicinity of the gap, which improves the reproduction efficiency of the magnetic head. In addition, since the ferromagnetic metal film is formed on the glass film by sputtering, the adhesion strength of the metal film is improved, and film peeling occurs. And the ferromagnetic metal film and the magnetic ferrite material are completely isolated by the glass film because the glass film is relatively thick, so that they react as before. Not at all a. Thereby, the reproducing efficiency is improved, and a magnetic head having good characteristics that can sufficiently cope with a high coercive force tape can be obtained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, a track width regulating groove is formed on a facing surface of a pair of magnetic ferrite materials, and a ferromagnetic metal film is formed on the facing surface. To form first and second magnetic core halves, and the first and second magnetic core halves are formed.
A gap material is formed on the ferromagnetic metal film of the half of the magnetic core, and the gap materials are joined together while pressing the gap materials to form a magnetic gap. In a method of manufacturing a magnetic head in which a joining glass is melt-filled in a groove portion and a first and a second magnetic core halves are joined and integrated, a magnetic ferrite material having the track width regulating groove formed therein, A magnetic head having a smaller thermal expansion coefficient than the magnetic ferrite material between the metal films, and a glass having a higher melting point than the bonding glass filling the groove portion of the track width regulating groove. In the manufacturing method of (1), a tensile stress is applied to the vicinity of the gap of the magnetic ferrite material, whereby the original characteristics of the ferrite material can be sufficiently obtained, and high reproduction efficiency can be obtained.

According to a second aspect of the present invention, a pair of magnetic core halves each having a side surface near a gap formed of a magnetic ferrite material, a high melting point glass film, a reaction prevention film, and a ferromagnetic metal film in this order, A magnetic head having a structure in which ferromagnetic metal films abut each other via a gap material. With such a structure, the magnetic metal film and the magnetic ferrite material are
Since it is completely isolated by the glass film, it does not react at all as in the past, and gives a tensile stress to the magnetic ferrite material near the gap by making the thermal expansion coefficient of the high melting point glass film smaller than that of the magnetic ferrite material Therefore, the reproduction efficiency can be improved.

According to a third aspect of the present invention, the difference between the thermal expansion coefficient of the magnetic ferrite material and the thermal expansion coefficient of the high melting point glass formed between the magnetic ferrite material and the ferromagnetic metal film is 10 ×. in the magnetic head according to claim 2, wherein a is 10 ^-7 / deg or more, the stress in the glass, the gap near the magnetic ferrite material is subjected to tensile stress, the magnetic ferrite material draw sufficient characteristics.

According to a fourth aspect of the present invention, there is provided a high melting point glass formed between a magnetic ferrite material and a ferromagnetic metal film, and a track width regulating groove formed on a pair of magnetic ferrite materials opposed to each other. 3. The magnetic head according to claim 2, wherein a difference in glass transition temperature (Tg) of the bonding glass to be filled is 20 deg or more, wherein the difference in glass transition temperature (Tg) is 20 deg or more. ,
At the time of heating at the time of melting and filling the bonded glass, no change occurs in the glass film formed on the magnetic ferrite material.

An embodiment of the present invention will be described below with reference to the drawings. (Embodiment 1) An example of the structure of a magnetic head according to an embodiment of the present invention is shown in a front view of a tape sliding surface in FIGS. 1 and 2, and a manufacturing process is shown in a process diagram of FIG. As shown in FIG. 3, a track width regulating groove is formed in a magnetic ferrite material 1, and a glass film 2 is formed thereon by sputtering or CV.
D and the like. Thereafter, the glass is melted and baked on the magnetic ferrite material 1. As this glass material, one having a value sufficiently lower than the thermal expansion coefficient of the magnetic ferrite material 1 is used. Due to the stress of the glass, the vicinity of the gap of the magnetic ferrite material 1 receives a tensile stress, and the magnetic ferrite material 1 can bring out sufficient characteristics.

Next, the gap surface is polished to remove the glass film at the portion where the magnetic ferrite material 1 and the ferromagnetic metal film 3 are joined. After chemical etching is performed to remove the work-affected layer of the magnetic ferrite material 1 by polishing, after forming a reaction prevention film (not shown) for preventing a reaction between the ferromagnetic metal film 3 and the magnetic ferrite material 1 The ferromagnetic metal film 3 is formed by means such as sputtering.

Next, after a gap material is formed on the ferromagnetic metal film 3, the surfaces thereof are butted against each other, the track width regulating groove portion is melt-filled with a joining glass 4, and a pair of magnetic cores are joined together. Become Since the glass film 2 formed on the magnetic ferrite material 1 does not change due to the heating during the melting and filling of the bonding glass 4, the magnetic ferrite material 1
It is desirable that the glass transition temperature (Tg) between the glass film 2 and the bonding glass 4 formed thereon has a difference of 20 deg or more.

By adopting such a structure, a tensile stress is applied near the gap of the magnetic ferrite material 1, and
In addition to improving the reproduction efficiency of the magnetic head, the ferromagnetic metal film 3 is formed on the glass film 2 by a sputtering method, so that the adhesion strength of the metal film is improved, and the film is hardly peeled off. Since the film 2 is relatively thick, the ferromagnetic metal film 3 and the magnetic ferrite material 1 are completely separated by the glass film 2 and do not react at all as in the conventional case.

Hereinafter, the steps of the embodiment of the present invention will be described with reference to FIG. The present invention will be described with reference to a specific embodiment with reference to FIG. 3, but it is needless to say that the present invention is not limited to this embodiment. First, a track width regulating groove is formed in a pair of magnetic ferrite materials 1 (FIG. 3A). Next, a glass having a thermal expansion coefficient (α) of 95 × 10 ⁻⁷ / deg and a glass transition point (Tg) of 420 ° C. is formed on the track width regulating groove forming surface to a film thickness of 2,000, 5,000, and 10,000 ° by sputtering. (FIG. 3B). The magnetic ferrite material 1 used had a coefficient of thermal expansion (α) of 115 × 10 ⁻⁷ / deg. When the magnetic head is completed, the magnetic ferrite material 1
The sliding surface is the (211) surface, and the gap butting surface is the (11) surface.
The (1) plane, the adjacent plane of the sliding surface and the gap abutting surface are (110) planes, the (110) plane, and the crystal axis is <11.
0> The axes were set so as to draw a pattern of arrows approaching each other in the direction toward the sliding surface. The crystal magnetic anisotropy constant K
₁ was 1 × 10 ⁴ erg / CC.

Next, in order to apply a tensile stress to the vicinity of the gap side of the magnetic ferrite material 1, the sputtered glass material is heated to 650 ° C. and fused, as shown in FIG. Baking (Fig. 3
(C)). In order to join the ferromagnetic metal film 3 and the magnetic ferrite material 1, the glass surface is removed by polishing the gap surface of which the track width is regulated, and the surface is mirror-finished (FIG. 3D).

Further, in order to remove the affected layer on the gap forming surface, chemical etching was performed with phosphoric acid (FIG. 3E). Thereafter, in order to prevent the reaction between the ferromagnetic metal film 3 and the magnetic ferrite material 1,
iO ₂ was formed to a thickness of 100 ° by a sputtering technique (FIG. 3F).

Next, on the surface, a Fe, Ta, N film was formed by sputtering with a thickness of 5 μm in an atmosphere of Ar and N ₂ using a target of Fe, Ta (FIG. 3).
(G)). After that, SiO ₂ is formed as a gap material on the ferromagnetic metal film as a gap material at a thickness of 1000 ° by a sputtering method, and the surfaces thereof are abutted to each other, and the track width regulating groove is melt-filled with a joining glass to join a pair of magnetic cores. Integrated.

A winding window is formed on one of the pair of magnetic cores. (Not shown)
A glass transition point (Tg) of 400 ° C. and a coefficient of thermal expansion (α) of 90 × 10 ⁻⁷ / deg was used. The heating temperature during joining and integration was 500 ° C. The magnetic head produced by the above process has no looseness of the glass film between the magnetic ferrite material 1 and the ferromagnetic metal film 3, and does not peel off the ferromagnetic metal film or react with the ferromagnetic metal film and the magnetic ferrite material. There was none. The reproduction output compared with the conventional method is shown below.

[0020]

[Table 1]

As can be seen from the above data, it has been demonstrated that it is possible to increase the reproduction efficiency by applying a tensile stress to the vicinity of the gap side surface of the magnetic ferrite material, which is the object of the present invention. Incidentally, such a method is not limited to the MIG type magnetic head, and also in a ferrite magnetic head, a glass for applying a tensile stress to a ferrite material in the vicinity of the gap is molded with a pair of magnetic cores for joining and integrating a pair of magnetic cores. Use the bonding glass separately,
It indicates that the optimal glass can be set,
It is also applicable to such uses.

[0022]

As described above, the present invention is to form a glass having a smaller thermal expansion coefficient than a magnetic ferrite material and a higher melting point than a bonding glass between a magnetic ferrite material and a ferromagnetic metal film. A tensile stress is applied in the vicinity of the gap between the magnetic ferrite material and the properties of the magnetic ferrite material are sufficiently brought out, and the magnetic ferrite material and the ferromagnetic metal film are completely separated by the glass film. And there is no peeling of the ferromagnetic metal film. Therefore, a magnetic head having improved characteristics and excellent characteristics capable of sufficiently coping with a high coercive force tape can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view of a tape sliding surface for explaining a configuration of the present invention.

FIG. 2 is a front view of a tape sliding surface side for explaining another configuration of the present invention.

FIG. 3 is a process chart for explaining a manufacturing process of the magnetic head of the present invention.

[Explanation of symbols]

 Reference Signs List 1 magnetic ferrite material 2 glass film 3 ferromagnetic metal film 4 bonding glass 5 gap

Claims (4)

[Claims] 1. A track width regulating groove is formed on a facing surface of a pair of magnetic ferrite materials, and a ferromagnetic metal film is formed on the facing surface to form first and second magnetic core halves. A gap material is formed on the ferromagnetic metal films of the first and second magnetic core halves, and the gap materials are joined while pressing the gap materials in a state where the gap materials abut each other. And forming the first and second magnetic core halves by melting and filling a joining glass into the groove portions of the track width regulating grooves simultaneously with forming the track width regulating grooves. Between the magnetic ferrite material in which the groove is formed and the ferromagnetic metal film, the coefficient of thermal expansion is smaller than the magnetic ferrite material, and more than the bonding glass filling the groove portion of the track width regulating groove,
A method for manufacturing a magnetic head, comprising forming a glass having a high melting point. 2. A pair of magnetic core halves each having a side surface near a gap formed of a magnetic ferrite material, a high-melting glass film, a reaction prevention film, and a ferromagnetic metal film in this order. A magnetic head with a structure where butts are abutted. 3. The method according to claim 1, wherein the difference between the coefficient of thermal expansion of the magnetic ferrite material and the coefficient of thermal expansion of the high melting point glass formed between the magnetic ferrite material and the ferromagnetic metal film is 10 × 10 ⁻⁷ / deg or more. The magnetic head according to claim 2, wherein: 4. A glass transition temperature between a high melting point glass formed between a magnetic ferrite material and a ferromagnetic metal film and a bonding glass filling a track width regulating groove formed on a pair of magnetic ferrite materials facing each other. 3. The magnetic head according to claim 2, wherein the difference is 20 deg or more.