JPS6066310A - Magnetic head - Google Patents

Abstract

PURPOSE:To provide one magnetic head with both recording and reproducing characteristics by adding a material with low saturated magnetic flux density to a gap part of the magnetic head consisting of a material with high saturated magnetic flux density. CONSTITUTION:A magnetic layer 2 consisting of garnet or the like and having low magnetic flux density is formed on the gap part of the magnetic head body 1 consisting of ferrite, ''Sendust'' or the like and having high saturated magnetic flux density. The thickness l2 of the magnetic layer is set up to the difference between the gap length l1+l2 at the recording and the gap length l1 at the reproducing to execute optimum recording and reproducing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a V-air head used for magnetic recording and reproduction.

the current. Magnetic recording devices, especially magnetic heads used in floppy disk drives, are advantageous in terms of production costs and device simplification. Recording in which reproduction and recording are performed using a single magnetic head (C) Magnetic heads that do not require raw materials have become mainstream.

Here, when looking at the 1B magnetic head for recording and the 1B magnetic head for reproduction separately, it is better to increase the gap length of the recording magnetic head from the standpoint of recording efficiency.

In the case of a magnetic head for reproduction. On the contrary, it is better to make it smaller in terms of reproduction frequency carrying capacity. Therefore, the gap length of the conventional recording/reproducing magnetic head is set to ycVc, which is about the middle of the can-only magnetic head.

Therefore, the conventional magnetic head for both recording and reproduction.

There was a problem that the characteristics were inferior to those using a recording/reproducing head.

Therefore, the present invention actively utilizes the saturation characteristics of magnetic materials to create a magnetic spatula 1? that has characteristics as if there were two magnetic heads in one magnetic head. This is what we are trying to provide.

Therefore, the gap length of the VC must be greater than the sum of the thickness of the recording layer of the medium and the gap between the magnetic head and the medium, that is, the space sink, so that a large bundle is formed completely on the gap surface.

From the point of view of the head material, it is important that the saturation magnetic flux density of the material is large.

On the other hand, it is necessary to guide the magnetization changes recorded in the Vi medium during reproduction to the coil portion of the magnetic head with high resolution. For this reason, it is important that the gap length be narrow and that the material be custom-made to have a high initial magnetic permeability in order to detect minute magnetic fluxes. For example, if the gap length is larger than the recording wavelength, magnetization changes cannot be generated.

Also, during playback) the magnetic flux density of one material is greater than the other.
Oh υ it's not important.

As described above, all of the characteristics /L54 are required for recording and reproduction, and the present invention aims to provide two magnetic heads having both characteristics.

That is, the present invention can be applied to materials such as Gu-Malloy (Ni-Fe alloy), Sendust (Fe
-8i-A7 alloy), 7 enite, etc. to constitute a recording head, and a small material casing is attached in the gap to form a reproduction gap d7.

At this time, a gap for reproduction is created by 4'
The magnetic material added with VC records i1J by its fusion ratio.
＼＼＾P-bundle apparent reduction 4 and (because of the effect of saturation of recycled materials 1rd,
-'A Magnetic material c /
It is effective to choose a 30% warning rate.

As shown in the following embodiments, by embodying the present invention, a magnetic head for both recording and reproducing purposes can be used, which has characteristics almost the same as those provided with dedicated magnetic heads for recording and reproducing respectively.

This means that the magnetic head can be simplified and the cost can be lowered, and it also greatly contributes to the simplification of the device.

Also, as can be seen by looking at the bundle distribution in the example.

Since the distance of the magnetic flux passing through the low magnetic flux density material is short, the requirements for the initial magnetic permeability of the low magnetic flux density material are moderate.

A few embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 Figure 1 shows the configuration of a magnetic head when the present invention is applied to a perpendicular anisotropy medium 3, and Figure 2 shows a fully enlarged side view of the μ-gap section, and 1 is a conventional one. The main body is made of the same material as ferrite or -db=m, and the low magnetic flux density magnetic material (garnet) layer is provided on one of the magnetic poles of the 2Vi gap part 4, and the shape and characteristics of the magnetic head and medium 3 are as follows. When recording is carried out at 600 mAT with the first-best correction, the above characteristics, the results of simulation analysis of the vertical component of the flux and Shown in Figure m3.

In FIG. 3, the solid line indicates the magnetic head according to the present invention, and the dotted line indicates the magnetic head entirely made of ferrite. Figure) The magnetic spatula r according to the present invention has a distribution center UG (zero Gauss) not at the center of the gap 4, but at the center of the sum of the low saturation-flux density area 2 and the gap length. (The low magnetic flux density layer becomes negligible during recording.) The IJ is operated with a wide gap. In this case, it can be seen from the recording part of the recording characteristic 'ri, -bundle i[j that the distribution is seedling, and the value is large, indicating that the recording performance is good.

Figure 4 shows a quick analysis during playback. In this case, the assumption is that the residual magnetization of the medium is only in the vertical direction, and the boundary of fIa reversal is from the center of the nonmagnetic layer to 0,7
μm l? ffi.

As a result, even in the case of low magnetic flux material, the magnetic flux flowing into the poison head is flowing in the same way as in the case of forming a narrow gap (N (indicated by the dotted line) with ferrite as in the past), and the narrow gap effect during playback is suppressed. It is clear that it has excellent characteristics in both recording and reproduction.

Practical Example 2 This embodiment is based on the above-mentioned implementation according to the present invention! lll's solid head? This was used for conventional horizontal recording, and the medium used was a horizontally anisotropic material as shown in Table 2.

6. Recording using the magnetic head and medium according to the present invention
Figure 5 shows the results of simulation analysis using the equal magnetic flux density water/ton component/N finite element method near the head gap when performed at 00 mAT. In the case of a magnetic head, all dotted lines are for a magnetic head made of ferrite.

As is clear from FIG. 5, in the case of recording by the magnetic head according to the present invention, the low magnetic flux density layer is almost negligible, and the wide gap can be fully confirmed during recording.
Therefore, it can be seen that there is significant saponification in the horizontal direction. In addition, it was packed during playback and analyzed in Figure 6. The assumed conditions are that the residual magnetization of the medium is only the horizontal component, and that the m-inversion boundary surface is 0.7 μm away from the center of the head.

As is clear from FIG. 6, the magnetic flux flowing into the magnetic head according to the present invention is as large as 01ε as in the conventional magnetic head made entirely of ferrite. Therefore, the magnetic head according to the present invention may be suitable for conventional horizontal recording.

It is possible to produce a magnetic recording device with very good characteristics by making full use of the effects of wide-gap recording and narrow-gap reproduction.

Note that the magnetization state VJ recorded on the medium is determined by the magnetic field when the medium 4k leaves the gap of the head, so it is preferable that the magnetic field of the gap changes sharply on the medium advancing side. As shown in FIG. 3, the magnetic flux changes sharply on the side where there is no magnetic layer with low saturation magnetic flux density, so it is preferable to provide the covering layer 2 on the opposite side of the traveling direction of the medium 3, that is, on the opposite side of the recording section.

In addition, ferrite is suitable from the viewpoint of high frequency characteristics of the magnetic head, 1J% corrosion resistance, and 11E property.This 14-coat ferrite has a Curie temperature of 77 (150 It is effective to use garnet having a temperature of ℃ or higher as a low B8 material.

To simplify, the outer gap' can be made of a Bs alloy of 1υ000G or more (amorphous magnetic material is also included), and the low BsJQ·j formed therein can be made of ferrite or garnet.

Embodiment 3 In Embodiments 1 and 2, one low magnetic flux density layer is provided on one side of the gear portion 4, whereas 2' is provided.

The recording/reproducing characteristics of this embodiment are implemented structurally! I
In cases 1 and 2, the low magnetic flux density layer is multilayered, but almost the same result can be obtained.

Therefore, a magnetic head with a low magnetic flux density layer on both sides within the gap can achieve excellent recording and reproducing characteristics in both horizontal and perpendicular recording due to the effects of an extra-large recording gap and a narrow gap during reproduction, similar to those with a single layer on one side. Obtainable.

Note that the film thickness of the low saturation magnetic flux density layer is determined by the external gap length (gap length during recording), which is applied to the M effect during recording, by 2. +t, and if the optimal inner gap (gap length during playback) length for effective VC plowing during playback is tl, then b4.
Most effective.

Here, it means optimal so that the optimum recording wavelength can be observed.

As is clear from the above description, according to the present invention, one magnetic head has the same functions as a recording-only magnetic head and a reproduction-only (I-5) head. It is possible to provide easy-to-use magnetic materials at low prices, and is one of the most popular (lili (t[r).

is extremely large.

[Brief explanation of drawings]

Figure 1 is a side view of an embodiment of the present invention, Figure 2 is an enlarged side view (2) near the gap, Figure 3 is a diagram showing the horizontal component of magnetic flux density within the medium during recording, and Figure 4 is a diagram showing reproduction. Fig. 5 is a diagram showing the horizontal component of the magnetic flux density in the medium at dC0 in different embodiments, ε(r, 6) (Fig. Figure 7 shows an enlarged 4dII plane view of a different embodiment. 1...Main body 2...Low plate (East density magnetic 1* : Jl
-'t3...Media ◆...Gear Tsubu Department Patent Owner Yasukawa 1v Tamaguchi Manufacturing D1 Co., Ltd. YE Data Co., Ltd. Agent Osamu Hattori - Figure 1 Figure 2 Figure 7 PA 6 Figure 4 You-Kitaishi 4 Ton 1 Na) Figure 5

Claims (5)

[Claims] (1) A magnetic head characterized in that a material having a lower saturation magnetic flux density than the main body is added to the gap portion. (2) The magnetic head according to claim 1, wherein the material has a thickness equal to the difference between the gap length during recording and the optimum gap length during reproduction. (3) The magnetic head according to claim 1 or 2, wherein the saturation magnetic flux density of the substance is 30 times lower than the saturation magnetic flux density of the main body. (4) The magnetic head according to any one of claims 1 to 3, wherein the main body is made of an alloy-based magnetic material, and the substance is made of ferrite or garnet. (5) A magnetic head according to any one of claims 1 to 3, wherein the main body is made of ferrite and the material is garnet.