JPH0589426A - Magnetic head - Google Patents

Abstract

PURPOSE:To obtain the magnetic head which can maintain and improve recording and reproducing characteristics by forming intermediate magnetic thin films having the coefft. of thermal expansion higher than the coefft. of thermal expansion of nonmagnetic thin films and lower than the coefft. of thermal expansion of high-saturation magnetic flux density magnetic thin films. CONSTITUTION:This annular type magnetic head consists of a ferrite 1-high-saturation magnetic flux density magnetic thin film 3-intermediate magnetic thin film 4-nonmagnetic thin film 5-intermediate magnetic thin film 4'-high-saturation magnetic flux density magnetic thin film 3'-ferrite 1' as the structure near the gap of the magnetic head which executes recording and reproducing of a magnetic recording medium. The coefft. of thermal expansion of the intermediate magnetic thin films 4, 4' is set higher than the coefft. of thermal expansion of the nonmagnetic thin films 5, 5' and lower than the coefft. of thermal expansion of the high-saturation magnetic flux density magnetic thin films 3, 3'. The intermediate magnetic thin films 4, 4' interposed between the thin films 3, 3' and the thin films 5, 5' function as a buffer material. The residual stresses to be generate by a difference in the coefft. of thermal expansion to be maximized between the thin films 3, 3' and the nonmagnetic gap and a change in the crystal structure by heating are thereby decreased and the stable recording and reproducing characteristics are maintained and improved.

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 for a hard disk drive, a VTR, a floppy disk drive, etc. for recording / reproducing information.

[0002]

2. Description of the Related Art In recent magnetic heads, in order to improve the recording density, a high saturation magnetic flux density magnetic thin film such as sendust is formed in the vicinity of the main gap portion of a magnetic head composed of single crystal or polycrystalline ferrite to form a main gap. A structure that makes the leakage magnetic field in the vicinity steep is adopted. A structure in which a high saturation magnetic flux density magnetic thin film is formed on both sides of a main gap showing particularly excellent performance (generally referred to as a double MIG structure) is often used.

The basic idea of the MIG structure of the magnetic head is described in Japanese Utility Model Publication No. 29-11642.

As shown in FIG. 2, the magnetic head having the double MIG structure has a pair of ferrite ring-shaped magnetic heads 101, 101 'having main gap facing surfaces 102,
A high saturation magnetic flux density magnetic thin film 103, 1 such as a metal such as sendust or permalloy, or an amorphous material is provided on the 102 '.
03 'is deposited by sputtering, vapor deposition, ion plating, etc., and further has a high saturation magnetic flux density magnetic thin film 10
3,103 single-layer film of SiO ₂ on at least one or 'high saturation magnetic flux density magnetic thin film 103, 103 as a non-magnetic thin film 106 is interposed between' SiO ₂ - low-melting glass -SiO2 laminated film sputtering It was deposited by vapor deposition or the like. This high saturation magnetic flux density magnetic thin film 103, 10
Ferrite 10 on which 3'and the non-magnetic thin film 106 are formed
1, 101 'were brought into contact with each other and heated to bond them.

As described above, the MIG structure improves the saturation of the magnetic flux in the vicinity of the main gap and makes the generated magnetic field steep during recording,
In addition, recording / reproducing on a recording medium having a high coercive force is possible, and the recording density is increased.

[0006]

However, the stress existing in the vicinity of the gap portion causes damage such as peeling from the vicinity of the non-magnetic thin film 106 during the molding process after the gap bonding, and stable performance cannot be obtained. there were.

This is a structure near the gap of the MIG structure,
That is, ferrite 101-high saturation magnetic flux density magnetic thin film 103
-Nonmagnetic thin film 106-High saturation magnetic flux density magnetic thin film 103 '
- ferrite 101, and the non-magnetic thin film 106 which is a non-magnetic gap is SiO ₂ single layer, or a SiO ₂ - is a laminated film having a low melting point glass -SiO _2, the crystal structure due to the difference and the heating coefficient of thermal expansion different from each member This is because residual stress near the gap is generated due to the change of

In order to improve this phenomenon, a part of the gap junction ferrite surface on the side opposite to the medium facing surface is provided with a notch to reinforce with glass, and the glass and the high saturation magnetic flux density magnetic thin film are wet. Since the property is poor, a Mo film is interposed between the two for strong bonding.
Methods such as 05 have been proposed, but they have not been fully resolved.

The present invention has been devised in view of the above problems, and an object thereof is to reduce the residual stress in the vicinity of the gap due to the difference in coefficient of thermal expansion and the change in crystal structure due to heating. The present invention provides a magnetic head that prevents damage at the gap.

[0010]

The magnetic head of the present invention comprises:
A ring type structure in which the structure near the gap of a magnetic head for recording / reproducing on / from a magnetic recording medium is ferrite-high saturation magnetic flux density magnetic thin film-intermediate magnetic thin film-nonmagnetic thin film-intermediate magnetic thin film-high saturation magnetic flux density magnetic thin film-ferrite In the magnetic head, the coefficient of thermal expansion of the intermediate magnetic thin film is larger than that of the nonmagnetic thin film and smaller than that of the high saturation magnetic flux density magnetic thin film.

[0011]

With the above-described structure, the intermediate magnetic thin film interposed between the high saturation magnetic flux density magnetic thin film and the non-magnetic thin film acts as a buffer material, and particularly the high saturation magnetic flux density magnetic thin film-non-magnetic gap is maximized. The residual stress generated due to the difference in the coefficient of thermal expansion and the change in the crystal structure due to heating can be reduced. Therefore, it is possible to easily manufacture by a simple method, and it is possible to achieve more stable maintenance and improvement of the recording / reproducing characteristics.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a side view showing the structure of the magnetic head of the present invention.

The magnetic head comprises a pair of ferrites 1, 1 '.
And high saturation magnetic flux density magnetic thin films 3, 3 ', intermediate magnetic thin films 4, 4', and non-magnetic thin film 5 formed on the ferrites 1, 1 '.

The pair of ferrites 1 and 1'is composed of two C-shaped bars or one of the C-shaped Mn-Zn ferrites.

A high saturation magnetic flux density magnetic thin film made of a metal such as sendust or permalloy, or an amorphous metal is formed on the facing surfaces 2 and 2'when the pair of ferrites 1 and 1'abut each other to form a ring shape. 3, 3'is formed. Specifically, those materials are formed by a thin film technique such as sputtering, vapor deposition, or ion plating.

On the high saturation magnetic flux density magnetic thin films 3 and 3 ', an intermediate magnetic thin film 4 made of Mn-Zn ferrite, Ni-Zn ferrite, or their alloy ferrite,
4'is formed. Specifically, the ferrite is used as a target and is formed by the above-described thin film technique.

The nonmagnetic thin film 5 is a SiO ₂ film or a SiO ₂ film.
A laminated film of a low melting point glass layer such as ₂ -lead glass and SiO ₂ is formed. Specifically, the intermediate magnetic thin films 4, 4 '
The upper part of the non-magnetic thin film 5 is about half the predetermined thickness of SiO.
₂ film, SiO ₂ - to form a lead glass laminate film. Incidentally, FIG.
Shows a single layer structure of the non-magnetic thin film 5, and FIG. 2 shows a laminated structure.

Thus, the high saturation magnetic flux density magnetic thin film 3,
3 ', the intermediate magnetic thin films 4, 4', and the ferrites 1, 1'on which a part of the non-magnetic thin film 5 is formed are brought into contact with each other and heated at about 540 ° C. to melt-bond the non-magnetic thin film 5 part. To do. Thereby, near the gap, ferrite 1-high saturation magnetic flux density magnetic thin film 3-intermediate magnetic thin film 4-non-magnetic thin film 5
-A magnetic head having a structure of an intermediate magnetic thin film 4'-high saturation magnetic flux density magnetic thin film 3'-ferrite 1 '.

According to the invention, in particular the intermediate magnetic thin film 4,
The coefficient of thermal expansion of 4'is set to be smaller than that of the high saturation magnetic flux density magnetic thin films 3 and 3'and larger than that of the non-magnetic thin film 5. The saturation magnetic flux density of the intermediate magnetic thin films 4 and 4'is set to be lower than that of the high saturation magnetic flux density thin film.

The high saturation magnetic flux density magnetic thin films 3 and 3'have a thickness of 1 to 5 .mu.m, and the intermediate magnetic thin films 4 and 4'have a thickness of about 0.
The thickness of the non-magnetic thin film 5 is selected to be about 1 μm and about 0.1 to 0.3 μm. The coefficient of thermal expansion is 170 × 10 if Sendust is used as the high saturation magnetic flux density magnetic thin films 3 and 3 ′.
^-7 / ° C, and Mn-Zn as the intermediate magnetic thin films 4 and 4 '
When ferrite is used, it becomes 125 × 10 ⁻⁷ / ° C., the nonmagnetic thin film 5 has SiO ₂ of 4 × 10 ⁻⁷ / ° C., and the low melting point lead glass has 100 × 10 ⁻⁷ / ° C. Therefore, the coefficient of thermal expansion of the intermediate magnetic thin films 4, 4'is intermediate between the coefficients of thermal expansion of SiO ₂ of the high saturation magnetic flux density magnetic thin films 3, 3'and the non-magnetic thin film 5, so that the ferrites 1, 1'are joined. Therefore, at the time of heating and joining, the generation of residual stress due to the difference in thermal expansion and the change in crystal structure due to heating can be relaxed.

In the conventional MIG magnetic head, the occurrence rate of gap breakage during heating and joining was 10 to 30%, whereas the occurrence rate of gap breakage in the magnetic head of the present invention was greatly reduced to 5% or less. did it.

Further, during recording on the magnetic recording medium, the above-mentioned intermediate magnetic thin films 4 and 4'are magnetically saturated, and the high saturation magnetic flux density magnetic thin films 3 and 3'act as a magnetic gap, and during reproduction, the intermediate magnetic thin films 4 and 4 '. Since the distance between the two 'acts as a magnetic gap, the recording / reproducing efficiency can be improved.

The MIG type magnetic head having the above-mentioned structure is used alone or in a hard disk drive, a VTR or a floppy disk drive by being joined to a sliding member such as a slider.

[0024]

According to the magnetic head of the present invention, the structure near the gap is ferrite-high saturation magnetic flux density magnetic thin film-intermediate magnetic thin film such as ferrite-nonmagnetic thin film-intermediate magnetic thin film such as ferrite-high saturation magnetic flux density. Since it is a magnetic thin film-ferrite, the difference in the thermal expansion coefficient between the high saturation magnetic flux density magnetic thin film and the non-magnetic thin film is maximum, and the residual stress generated by the change in the crystal structure due to heating is caused by the intermediate thermal expansion coefficient between them. Can be reduced by an intermediate magnetic thin film such as ferrite with
A damage-free magnetic head is achieved in a simple manner. Further, the magnetic head can further maintain and improve the recording / reproducing characteristics.

[Brief description of drawings]

FIG. 1 is a side view showing the structure of a magnetic head of the present invention.

FIG. 2 is an enlarged view of a nonmagnetic thin film in the vicinity of a gap in a laminated structure.

FIG. 3 is a side view showing the structure of a conventional magnetic head.

[Explanation of symbols]

 1, 1 '... Ferrite 2, 2' ... Opposing surface 3, 3 '... High saturation magnetic flux density magnetic thin film 4, 4' ... Intermediate magnetic thin film 5, 5 '... Non-magnetic thin film

Claims (1)

[Claims] 1. A gap of a magnetic head for recording / reproducing on / from a magnetic recording medium comprises ferrite-high saturation magnetic flux density magnetic thin film-intermediate magnetic thin film-nonmagnetic thin film-intermediate magnetic thin film-high saturation magnetic flux density magnetic thin film-ferrite. A magnetic head, wherein the coefficient of thermal expansion of the intermediate magnetic thin film is larger than that of the non-magnetic thin film and smaller than that of the high saturation magnetic flux density magnetic thin film.