JPH0636221A - Magnetic head and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a magnetic head wherein both recording efficiency and reproduction efficiency are excellent by one magnetic head and manufacturing costs are low and to obtain its manufacturing method. CONSTITUTION:A magnetic thin-film layer 6a whose saturation magnetic flux density Bs is lower than that of magnetic cores 2a, 2b is formed so as to be adjacent to a magnetic gap 3a. Even one magnetic gap 3a cannot generate a magnetic field capable of saturation recording a high-coercive-force medium in a recording operation even when the magnetic thin-film layer 6a provided with the low saturation magnetic flux density Bs is saturated. As a result, an effective magnetic-gap length operates to be wider than the length of the magnetic gap 3a, and it operates at the length of the magnetic gap 3a in a replay operation because a magnetic field from the high-coercive-force medium is weak.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head suitable for a VTR or the like and a manufacturing method thereof.

[0002]

2. Description of the Related Art FIG. 3 is a perspective view showing a conventional magnetic head for a VTR disclosed in Japanese Patent Laid-Open No. 57-55526. In FIG. 3, 1 is a non-magnetic substrate, 2a and 2b are magnetic cores, 3 is a magnetic gap film, 3a is a magnetic gap by the magnetic gap film 3, 4 is a non-magnetic protective plate, and 5 is a winding window W. It is a coil. Magnetic cores 2a and 2b are formed on the left and right sides of the magnetic gap 3a.

FIG. 4 is a front view showing the recording / reproducing surface of the conventional magnetic head. Tw is a track width and corresponds to the film thickness of the magnetic core 2a. The magnetic gap 3 a is inclined at a predetermined azimuth angle θ with respect to the perpendicular of the non-magnetic substrate 1. Normally, the azimuth angle θ is set between 0 and 30 degrees. If tracks are alternately recorded by two magnetic heads having different signs of azimuth angles, crosstalk from adjacent tracks can be reduced, so that it is not necessary to provide a guard band and high-density magnetic recording can be performed.

FIG. 5 is a diagram showing a manufacturing process of the conventional magnetic head shown in FIG. Fig. 5 (a) is a ceramic,
This is a step of forming a magnetic thin film 2A such as permalloy or sendust to be a magnetic core 2a on a non-magnetic substrate 1 such as glass by a method such as sputtering or vapor deposition for a film thickness corresponding to the track width Tw.

FIG. 5B shows a step of forming a magnetic gap forming surface G by removing a part of the magnetic thin film 2A to form a magnetic core 2a. As a method for removing the magnetic thin film 2A, there are methods such as cutting with a diamond bite, ion beam etching, and chemical etching. The magnetic gap forming surface G is set to have an azimuth angle θ.

FIG. 5C shows Al ₂ O ₃ and SiO for forming the magnetic gap 3 a on the magnetic gap forming surface G.
_In this step, the nonmagnetic magnetic gap film 3 such as ₂ is formed by a method such as sputtering or vapor deposition. The length (hereinafter simply referred to as the length) g of the magnetic gap 3a formed by the magnetic gap film 3 in the substrate surface direction is set to a desired magnetic gap length. Although the drawing shows the magnetic gap film 3 formed over the entire surface, a film may be formed on the magnetic gap formation surface G by forming a mask during formation.

FIG. 5D shows a step of forming a magnetic film 2B to be the magnetic core 2b on the entire surface in the same manner as the step of FIG. 5A. It is desirable that the film thickness of the magnetic thin film 2B be slightly thicker than the track width Tw.

FIG. 5E shows a step of removing unnecessary portions of the magnetic thin film 2B and the magnetic gap film 3 to form the magnetic thin film 2B as the magnetic core 2b and flattening the magnetic cores 2a and 2b. As a method of flattening, there are polishing, an etch back method and the like. Finally, the protective plate 4 is joined to complete the magnetic head shown in FIG.

[0009]

In the conventional magnetic head for VTR, one magnetic head is used for both recording and reproduction. From the principle of magnetic recording, it is desirable that the magnetic gap length during recording is wide and the magnetic gap length during reproduction is narrow. Therefore, in the conventional VTR magnetic head, recording,
The magnetic gap length is set in consideration of the balance of reproduction efficiency. Ideally, it is desirable to provide two magnetic heads for recording and for reproducing, each having an optimum magnetic gap length.
However, providing two magnetic heads has a problem that the manufacturing cost is about double.

The present invention has been made in order to solve the above-mentioned problems, and a magnetic head and a method of manufacturing the same which are excellent in both recording and reproducing efficiency even with one magnetic head and whose manufacturing cost is low are obtained. The purpose is to

[0011]

The magnetic head of the present invention is provided with a magnetic thin film layer having a saturation magnetic flux density lower than that of the magnetic core adjacent to the magnetic gap.

A method of manufacturing a magnetic head according to the present invention comprises a step of forming a first magnetic core on a non-magnetic substrate, a step of forming a magnetic gap on the magnetic gap forming surface, and a step of adjoining the magnetic gap. A magnetic thin film layer having a saturation magnetic flux density lower than that of the magnetic core, and a step of forming a second magnetic core.

[0013]

In the magnetic head according to the present invention, one magnetic gap operates so that the effective magnetic gap length is wider than the magnetic gap length during recording, and operates with the magnetic gap length during reproduction.

A method of manufacturing a magnetic head according to the present invention is
By forming a magnetic thin film layer having a saturation magnetic flux density lower than that of the magnetic core adjacent to the magnetic gap, it is not necessary to form two magnetic heads, and a magnetic head that can be efficiently used for both recording and reproduction can be manufactured. .

[0015]

【Example】

Example 1. FIG. 1 is a front view showing a recording / reproducing surface of a magnetic head according to an embodiment of the present invention. In FIG. 1, 1
Is a non-magnetic substrate, and 2a and 2b are a pair of magnetic cores formed on the left and right with a magnetic gap 3a formed non-parallel on the non-magnetic substrate 1 and a magnetic thin film layer 6a adjacent to the magnetic gap 3a. Is a protective plate joined to the side opposite to the non-magnetic substrate 1 when viewed from the pair of magnetic cores 2a and 2b.

The magnetic thin film layer 6a is composed of a magnetic thin film 6 having a saturation magnetic flux density Bs lower than those of the magnetic cores 2a and 2b,
Its length is h. The magnetic gap 3a is made of the magnetic gap film 3, has a length g, and is inclined at a predetermined azimuth angle θ (not shown) with respect to the perpendicular of the nonmagnetic substrate 1. For example, as the magnetic cores 2a and 2b, those having a saturation magnetic flux density Bs of 1 T or more such as Sendust, Co amorphous alloy, iron nitride, etc. can be cited, and as the magnetic thin film 6, permalloy having a saturation magnetic flux density Bs of 0.8 T can be mentioned. Can be mentioned. The magnetic head of this embodiment is different from the conventional one in that a magnetic thin film layer 6a is provided adjacent to the magnetic gap 3a.

In this embodiment, the length of the magnetic gap 3a is g, but at the time of recording, the magnetic cores 2a, 2b and the magnetic thin film layer 6a near the magnetic gap 3a are generated by the magnetic flux generated by the recording current flowing in the coil. Although saturated, the saturation magnetic flux density Bs of the magnetic thin film 6 is lower than that of the magnetic cores 2a and 2b, so that the magnetic thin film layer 6a cannot generate a sufficient recording magnetic field for saturation recording on the high coercive force medium. Therefore, the effective magnetic gap length during recording is the magnetic gap 3
The length is larger than the length g of a, and operates at a value close to the sum g + h of the length of the magnetic gap 3a and the length of the magnetic thin film layer 6a.

On the other hand, since the leakage magnetic field from the high coercive force medium is very small during reproduction, the magnetic thin film layer 6a does not saturate even at a low saturation magnetic flux density Bs, and operates with the length g of the magnetic gap 3a. Therefore, it suffices to select a combination of the length g of the magnetic gap 3a and the length h of the magnetic thin film layer 6a that optimizes the recording and reproducing efficiency.

FIG. 2 is a manufacturing process diagram of the magnetic head showing the first embodiment. The steps up to the formation of the magnetic gap film 3 are the same as the steps of the conventional example shown in FIGS. In the step of removing a part of the magnetic thin film 2A as the first magnetic thin film to be the magnetic core 2a as the first magnetic core in FIG. 5B, the non-magnetic substrate 1 is flattened with the magnetic gap film 3. It is desirable to remove only the film thickness of a part at the same time in order to make the film thicknesses of the magnetic core 2a and the magnetic core 2b as the second magnetic core uniform.
Then, the above steps were performed.

After the steps similar to those shown in FIG.
In (a), a magnetic thin film 6 having a saturation magnetic flux density Bs lower than those of the magnetic cores 2a and 2b is formed on the magnetic gap film 3 and the magnetic thin film layer 6 having a length h adjacent to the magnetic gap 3a is formed.
a is formed. Although the magnetic thin film 6 is shown to be formed on the entire surface in the drawing, it may be formed on at least the magnetic gap forming surface G as in the case of the magnetic gap film 3.

FIG. 2B shows a step of forming a magnetic thin film 2B as a second magnetic thin film to be the magnetic core 2b on the entire surface in the same manner as in the conventional case.

In FIG. 2C, at least unnecessary magnetic thin film 2B, magnetic thin film 6 and magnetic gap film 3 are removed to flatten the magnetic cores 2a and 2b. As a method of this flattening, there are a polishing method, an etchback method, and the like. Note that the upper portion of the magnetic core 2a may be removed during this removal. Finally, join the protective plate 4 to this flattened surface,
The magnetic head shown in FIG. 1 is completed.

Needless to say, the present invention can be applied to a thin film magnetic head in which a coil other than the non-magnetic substrate and the protective plate is thinned.

[0024]

As described above, according to the present invention, the magnetic head is constructed so that the magnetic thin film layer having a saturation magnetic flux density lower than that of the magnetic core is provided adjacent to the magnetic gap.
The effective magnetic gap length of one magnetic gap can be changed to an optimum value during recording and reproduction, and magnetic recording excellent in both recording and reproduction efficiency can be achieved even with one magnetic head.

By manufacturing the magnetic head having the above structure,
A magnetic head with low manufacturing cost can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a front view showing a magnetic head according to a first embodiment of the invention.

FIG. 2 is a diagram showing a manufacturing process according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing a conventional magnetic head.

FIG. 4 is a front view showing a conventional magnetic head.

FIG. 5 is a diagram showing a manufacturing process of a conventional magnetic head.

[Explanation of symbols]

 1 non-magnetic substrate 2A, 2B magnetic thin film 2a, 2b magnetic core 3a magnetic gap 6a magnetic thin film layer G magnetic gap forming surface

Claims (2)

[Claims] 1. A magnetic head having a pair of left and right magnetic cores formed on a non-magnetic substrate with a magnetic gap formed non-parallel to the surface of the non-magnetic substrate interposed therebetween, adjacent to the magnetic gap. A magnetic head comprising a magnetic thin film layer having a saturation magnetic flux density lower than that of the magnetic core. 2. A step of forming a first magnetic thin film which becomes a first magnetic core on a non-magnetic substrate, and a part of the first magnetic thin film is removed so as to be perpendicular to the non-magnetic substrate. A step of forming a magnetic gap forming surface having a desired azimuth angle; a step of forming a magnetic gap on the magnetic gap forming surface; and a magnetic core including the first magnetic core adjacent to the magnetic gap. A step of forming a magnetic thin film layer having a low saturation magnetic flux density, and a second step of forming a second magnetic core
Of the magnetic head, and the step of planarizing the first and second magnetic cores by removing at least an unnecessary portion of the second magnetic thin film are sequentially performed. Production method.