JPS62223807A - Composite magnetic head - Google Patents

Abstract

PURPOSE:To obtain a magnetic head excellent in a recording and producing characteristic and to improve a track width accuracy by distributing the soft magnetic film of a high saturated magnetic flux density only at one side of the magnetic gap. CONSTITUTION:Only at one side carrier of ferrite cores 11 and 11', a magnetic body 12 having a high saturated magnetic flux density is formed and has the structure to bond other ferrite core through nonmagnetic gap materials 13 and 13'. Since a material having the high saturated magnetic flux density is formed at one side to the gap surface, the magnetic field distribution near the gap is more non-symmetrical and broader than the case when the magnetic body is formed at both sides of the gap surface, has the effect in which the gap is probably expanded and facilitates the recording, especially, the occurrence of a large magnetic field. Viewed from the view point of a magnetic field distribution component, the magnetic field component parallel to the media is increased and can play an effective role to the recording in the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic head, and more particularly to a magnetic head intended for use mainly in longitudinal recording in combination with a high coercive force medium.

[Conventional technology]

In recent years, in the field of magnetic recording, high coercive force media and narrow gap magnetic heads have been increasingly used to achieve higher density recording. In this case, in the ferrite-based magnetic head that has been widely used in the past, saturation occurs at the tip of the magnetic head during recording, and the performance of the high coercive force recording medium cannot be fully demonstrated. Therefore, various magnetic heads have been proposed in which a metal-based magnetic material having a high saturation magnetic flux density is formed in the core near the magnetic gap of a ferrite-based magnetic head by a method such as sputtering.

Although FIG. 2 shows the most basic structure, since the magnetic gap and the plane on which the magnetic film is formed are parallel, there is a problem that the output fluctuates irregularly with respect to frequency. Therefore, proposals have been made as shown in Figures 3, 4, and 5 in which the magnetic gap and the surface on which the magnetic film is formed are made non-parallel.

[Problem that the invention seeks to solve]

However, in the structure of the magnetic head shown in Figure 3.4.5, very high precision machining is required for processing the core carrier or magnetic film that defines the track width during recording. , a complicated process must be followed.

Furthermore, in the magnetic heads shown in these known examples, since high saturation magnetic flux density materials are arranged on both sides of a narrow magnetic gap of about 0.3 μm, the magnetic field distribution near the magnetic field gap during writing is too steep. Therefore, it is difficult to generate a sufficient magnetic field to magnetize the medium within the space given by the sum of the spacing between the magnetic head and the medium and the thickness of the recording medium, and the magnetic field has a component perpendicular to the medium. It is thought that this increases the recording efficiency due to the in-plane magnetization process as considered here.

The present invention improves the magnetic field distribution in the magnetic head gap,
The present invention aims to provide a magnetic head that not only improves recording efficiency but also facilitates processing steps.

Means for Solving Problem c] That is, the present invention provides a magnetic material having a high saturation magnetic flux density only on one side of the ferrite core carrier (for example, Ni-Fe alloy, Fe-Al-3i alloy, Co-based alloy). amorphous alloy)
and the other ferrite core is bonded to each other via a non-magnetic gap material.

In the present invention, since the material with high saturation magnetic flux density is formed on one side of the gap surface, the magnetic field distribution near the gap is asymmetric and broader than when the magnetic material is formed on both sides of the gap surface. This has the effect of apparently widening the gap, and facilitates recording, especially the generation of a large magnetic field. Furthermore, from the perspective of magnetic field distribution components, the magnetic field component parallel to the medium increases, making it possible to play an effective role in in-plane recording.

Furthermore, in reproduction, since a magnetic film is formed on the ferrite surface, it is possible that the S/N ratio of the reproduction characteristics is lowered due to a pseudo gap, but in the present invention, since the film is formed only on one side, The effect of the pseudo gap is also reduced. Furthermore, the influence of the pseudo gap can be reduced by making only the film forming surface inclined with respect to the recording medium running direction.

Furthermore, in terms of manufacturing advantages, the head to which the present invention is applied has been proposed as shown in Figures 3 and 4. In Figure 3, the track width is specified. Therefore, it is necessary to draw down the tip of the magnetic film, which poses difficulties such as peeling of the magnetic film during processing.

Furthermore, in FIG. 4, it can be seen that there is a difficulty in processing the ferrite core in precisely grinding it so that only the magnetic film regulating the track width remains. Furthermore, in Figure 5, the tip of the track needs to be mirror-finished with high precision.
Although it depends on the angle of the surface on which the film is formed, processing of about ±1 μm or 1 μm is required.

However, in the present invention, since the track width is defined by a notch provided in the ferrite core, the track width accuracy on the magnetic film forming surface can be achieved by processing that is gentler than on each side described above. It is. That is, it can be seen that the ease of manufacturing the magnetic head is improved.

Note that the state of magnetization recorded on the medium is determined by the magnetic field distribution when the medium leaves the gap of the head and moves to the -1.- row, so it is preferable that the magnetic field from the gap part changes sharply on the medium advancing side. . That is, the effect of the present invention is further improved by arranging the portion where the magnetic film is formed on the outflow side with respect to the recording medium running direction.

〔Example〕

Specific examples of the present invention will be described below.

Example 1 First, grooves as shown in FIG. 6(b) are formed in a single-crystal ferrite core carrier having a mirror finish on one side as shown in FIG. 6(al) using a guising tool.

In this case, the groove shown in FIG. 6(b) can be machined with high accuracy of notch pitch and width of ±1 μm using conventional equipment. Further, the height and pitch of the triangular groove shown in FIG. 6(e) are approximately ±1.5 μm.

Furthermore, a Co-based amorphous alloy is formed on the core in which the triangular grooves are formed. (FIG. 6(')) In this example, the film was formed using a sputtering method.

The properties of the formed film are shown in the table below.

The film thickness is 20 μm, and in forming this magnetic film, an extremely thin insulating layer film of 0.05 μm is formed for the 5 μm magnetic film in order to avoid a decrease in magnetic permeability due to eddy current loss.

Table 1 Next, PBO-based low melting point glass is embedded in the groove of each core carrier, and then the surface of the core carrier is polished by lapping to remove the embedded glass and to determine the track portion of core B. .

Figure 6 ((C1, (A)) The track width determined by this processing is ±1 μm for core A, the same accuracy as the groove processing, but for the core width, the thickness at the lap is Machining accuracy is also included in track width accuracy, so ±3
It has become μm.

Furthermore, grooves for winding are formed in core B.

(Fig. 6 (h)) A gap material of s i C2 is formed on the surfaces of these cores A and B by vacuum evaporation or sputtering, and the cores are brought into contact with each other as shown below.
o While holding at a predetermined temperature so that the amorphous alloy does not crystallize, the glass is fused to join the cores together.

(FIG. 6(1)) When this is cut, the chip shown in FIG. 6U can be completed.

From the examples related to this manufacturing method, it can be seen that the trunk precision can be improved compared to the conventional core with membranes attached on both sides. In fact, a comparison of the obtained trunk accuracies is shown in Table 2.

Table 2 Example 2 Output of the actually produced magnetic hesode core according to the present invention shown in Fig. 1, the core with magnetic films formed on both sides of the gap shown in Fig. 5, and the core made only of ferrite with the characteristics The characteristics are shown in Figure 7.

In the figure, 71 is the characteristic of the magnetic head according to the present invention, 72 is the characteristic of the head shown in FIG. 5, and 73 is the characteristic of the head made only of ferrite. As is clear from the figure, the head using a magnetic film has superior characteristics compared to a head using only ferrite. Furthermore, according to the present invention, a head in which a magnetic film is formed only at one outflow end of the head gap is better.
Output characteristics are improved compared to those formed on both sides. this is,
It is thought that the efficiency at the time of recording was improved only in C゛.

Since these heads have magnetic film formation 11 with non-parallel gaps, no damping of the output voltage due to the influence of the pseudo gap 2 occurs.

〔Effect of the invention〕

According to the present invention, since the recording efficiency is improved compared to conventionally devised heads, it is possible to manufacture a magnetic head with excellent recording and reproducing characteristics. Furthermore, track width accuracy is improved from a manufacturing standpoint. In this way, a head with good characteristics can be provided at a low price, and its industrial value is great.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the magnetic head according to the present invention, FIGS. 2.3.4 and 5 are perspective views showing conventionally devised magnetic heads, and FIG. 6 is a perspective view showing an embodiment of the magnetic head according to the present invention. FIG. 7, which is a schematic diagram of the manufacturing process of the head, shows the electromagnetic conversion characteristics. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 0.1 1 10 Recording frequency (
MHz) Figure 7 Procedural amendment 16□6ko, ii, 1jB Indication of the case 1985 Patent Application No. 66841, Name of the invention Relationship to the Compound Magnetic Head Correction Case Patent Applicant Address Chiyoda, Tokyo 2-1-2 Marunouchi, Ward Name (508) Hitachi Metals Co., Ltd. Amendment 1: The "Detailed Description of the Invention" column of the specification is corrected as follows. (1) "Figure 2" on page 2, line 11 of the specification is corrected to "Figure 2." (2) In line 15 of the same page of the same book, "1 like Figures 3, 4, and 5" is corrected to "Like Figures 3, 4, and 5." (3) "Complicated process J" on page 3, line 2 of the same book is corrected to "complex processing process." (4) In line 11 of the same page of the same book, "recording efficiency due to the in-plane magnetization process as considered here" is corrected to "recording efficiency, especially in recording by the in-plane magnetization process". (5) Change “thickness processing” in page 5, line 12 of the same 17 to “thickness processing”.
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Claims (2)

[Claims] (1) The track width for recording and reproduction is smaller than the thickness of the magnetic head, and is made of ferrite and a soft magnetic film having a high saturation magnetic flux density, and the surface on which the magnetic film is formed is inclined with respect to the magnetic gap forming surface. A recording/reproducing magnetic head characterized in that a soft magnetic film with a high saturation magnetic flux density is disposed only on one side of a magnetic gap. (2) A recording/reproducing magnetic head according to claim 1, characterized in that the track width for recording and reproduction is regulated by a notch in the ferrite core.