JPH08147621A - Magnetic head - Google Patents

Abstract

(57) [Abstract] [Purpose] In a MIG type magnetic head in which a magnetic alloy thin film is formed on an oxide magnetic material, a magnetic head having a structure capable of preventing generation of a pseudo gap and accurately obtaining a track width. I will provide a. A MIG type magnetic head having a structure in which a type of magnetic alloy thin film formed on an oxide magnetic material is changed for each layer, and a magnetic alloy thin film having a higher magnetic permeability is disposed closer to a magnetic gap formation surface. Alternatively, a MIG type magnetic head having a structure in which the thickness of each magnetic alloy thin film is changed for each layer, and a magnetic alloy thin film having a smaller thickness is arranged closer to a magnetic gap forming surface.

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 as a video head for a VTR, and more particularly to a magnetic head whose yield and productivity are improved.

[0002]

2. Description of the Related Art In a conventional magnetic head using two kinds of magnetic materials such as an oxide magnetic material and an alloy magnetic thin film, there is one in which a joint surface of the two kinds of magnetic materials is parallel to a magnetic gap. According to this method, the productivity is good, but the two kinds of magnetic material joint surfaces act as a pseudo gap, and the magnetic characteristics are greatly deteriorated.

Therefore, as shown in FIG. 3, a high permeability magnetic material, usually an oxide magnetic material 1, such as a single crystal ferrite, is V-shaped so that the two magnetic material bonding surfaces and the magnetic gap are not parallel to each other. A method has been proposed in which a groove is provided and another magnetic material, usually an alloy magnetic thin film 2, is formed on the groove by sputtering or the like to prevent the occurrence of a pseudo gap. Note that FIG. 4 shows a magnetic core constructed by this method.

However, in this method, the track width portion 6 is formed by polishing the V-shaped tip portion with a lap master or the like, so the track width is determined by the polishing amount.
It is difficult to ensure its accuracy. On the other hand, the track width accuracy required for recent VTR video heads is ± 1 μm or less. Therefore, the rate of occurrence of track width defects is high, and the production yield is reduced.

Therefore, Cr is formed on the magnetic gap forming surface so that the two kinds of magnetic material joint surfaces do not act as pseudo gaps even if the two kinds of magnetic material joint surfaces are parallel to each other.
A method of forming a non-magnetic metal thin film such as the above has been proposed.
However, even this method cannot completely prevent the action of the pseudo gap, and it is difficult to obtain good electromagnetic conversion characteristics.

[0006]

In the above-mentioned prior art, it is difficult to completely prevent the generation of the pseudo gap that causes the deterioration of the electromagnetic conversion characteristics and the reduction of the production yield due to the poor track width accuracy, as described above. is there. SUMMARY OF THE INVENTION It is an object of the present invention to provide a MIG type magnetic head which eliminates these drawbacks and prevents the generation of pseudo gaps, and has a high production yield and good productivity.

[0007]

In order to achieve the above-mentioned object, the present invention changes the type of a multilayer film of a magnetic alloy formed on an oxide magnetic material by sputtering or the like, and the arrangement is magnetic. The closer to the gap forming surface, the higher the magnetic permeability. For the same purpose, the thickness of the magnetic alloy thin film is changed so that the magnetic alloy thin films are arranged in order such that the closer to the magnetic gap forming surface, the thinner.

It is easy to change the type of magnetic alloy thin film by using a multi-source sputtering apparatus, and the sputtering time may be adjusted to change the film thickness. Targets for forming various kinds of magnetic alloy thin films include, for example, Co—Zr.
An amorphous material made of —Nb can be obtained by gradually changing the composition ratio.

[0009]

As a result, the generation of the pseudo gap can be prevented by the interaction caused by the contact between the magnetic alloy thin films having different magnetic permeability, and the magnetic gap forming surface is made non-parallel to the bonding surface between the oxide magnetic material and the magnetic alloy thin film. You do not have to take the method of doing. Therefore, it is not necessary to provide a V-shaped groove on the oxide magnetic material, and a MIG type head with a good yield can be obtained with good productivity.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows an I core or C of the magnetic head of the present invention.
FIG. 3 is a sectional view of the core, and FIG. 2 is a perspective view of the magnetic head according to the present invention. 1 is an oxide magnetic material, usually single crystal ferrite is used, and 2 is an alloy magnetic thin film, usually amorphous. Reference numeral 3 is a magnetic gap made of high melting point glass or the like, 4 is a track width control groove normally filled with low melting point glass, and 5 is a winding groove.

To obtain the magnetic head of the present invention, first, a magnetic alloy thin film is formed on an oxide magnetic material. The magnetic alloy thin film formed at this time is sputtered with several types of targets in the order of low magnetic permeability using a multi-source sputtering apparatus. Alternatively, when a kind of magnetic alloy is used as the target, the sputtering time is adjusted so that the magnetic alloy thin films are arranged in the order of increasing thickness. Next, a track width control groove is formed by using a dicer or a wire saw by a known method as in a normal magnetic head. After this, a winding groove is provided in the magnetic core which will be the C core, a high melting point glass thin film is formed on the magnetic gap forming surface by sputtering, etc., and the magnetic gap is produced by an electric furnace or the like. Of course, the magnetic gap length is regulated by the high melting point glass thin film. Further, the track width control groove is filled with a low melting point glass and is also melted and fixed in an electric furnace or the like. Next, a pair of magnetic blocks having a desired size is cut to obtain a magnetic head chip. The magnetic head chip manufactured by the above method is bonded to a predetermined base with an adhesive at a desired position, and then winding is performed to obtain the magnetic head of the present invention.

[0012]

In the magnetic head according to the present invention, even if the magnetic gap, the oxide magnetic material and the alloy magnetic thin film bonding surface are parallel to each other, the magnetic alloy thin films having different magnetic permeability are multilayered. The generation of the pseudo gap can be prevented by the interaction of the magnetic flux of the thin film. Further, when the thicknesses of the magnetic alloy thin films are sequentially changed, the same result is obtained when the magnetic alloy thin films having different magnetic permeability are arranged side by side.
Therefore, it is not necessary to form the V-shaped groove in the oxide magnetic material and polish the tip of the groove to determine the track width, so that there is no precision defect in the track width determining and polishing step, and the processing man-hour can be shortened. Therefore, it is possible to obtain the MIG type magnetic head having excellent electromagnetic conversion characteristics while preventing the occurrence of the pseudo gap, and to improve the productivity.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an I core or a C core of a magnetic head according to the present invention.

FIG. 2 is a perspective view of a magnetic head according to the present invention.

FIG. 3 is a sectional view of an I core or a C core of a conventional magnetic head.

FIG. 4 is a perspective view of a conventional magnetic head.

[Explanation of symbols]

1 oxide magnetic material 2 alloy magnetic thin film 3 magnetic gap 4 track width control groove 5 winding groove 6 magnetic gap formation surface or track width control groove formation surface

Claims (2)

[Claims] 1. In a MIG type magnetic head in which a magnetic alloy thin film on a magnetic gap forming surface is composed of multiple layers, the magnetic alloy thin film is made different in type for each layer, and the magnetic permeability becomes higher as the magnetic alloy thin film becomes closer to the magnetic gap forming surface. A magnetic head characterized in that it is arranged in this manner. 2. The magnetic head according to claim 1, wherein the thickness of the magnetic alloy thin film is changed for each layer, and the magnetic alloy thin film is arranged to be thinner toward a magnetic gap forming surface. Magnetic head.