JPS6381612A - Magnetic head - Google Patents

Abstract

PURPOSE:To permit easy production by forming a 1st Co-Ta alloy layer having high saturation magnetic flux density and contg. Ta at a low ratio on one of the butt surfaces in a gap part, then forming a 2nd Co-Ta alloy layer having low saturation magnetic flux density and contg. Ta at the ratio higher than in the 1st layer thereon. CONSTITUTION:The magnetic Co-Ta alloy layers 11 contg. Ta at a low ratio are formed on the surface in the gap part of a yoke 10 consisting of Mn-Zn single crystal ferrite and magnetic Co-Ta alloy layers 12 contg layers 12 contg. Ta at the higher ratio are formed thereon. An SiO2 gap material is used for the gap part 13. These magnetic layers are formed by an RF magnetron sputtering method. The magnetic layers 12 of low saturation magnetic flux density to change the effective gap are formed of the Co-Ta alloy contg. Ta at the higher ratio and the magnetic layers 11 of high saturation magnetic flux density are formed of the Co-Ta alloy contg. Ta at the lower ratio, therefore, these layers are easily producible by a sputtering method necessitating mere changing-over of targets. Since the magnetic permeabilities of the two magnetic layer exhibit nearly the same high values, the magnetic head having good characteristics is constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a magnetic head, and more particularly to the structure of a gap portion of a magnetic head.

(Prior art) Currently, in magnetic recording and reproducing devices, from the viewpoint of reducing production costs and simplifying the device, a dual magnetic recording and reproducing device is widely used, which performs recording and reproducing using the same magnetic field. It is being

? When recording, the gap length of the i11 head is better to be larger from the standpoint of recording efficiency, but when reproducing, it is better to have a smaller gap length so that short wavelength signals can be sufficiently reproduced.Therefore, the gap length of the dual-purpose magnetic recording head is Since it is set between each dedicated magnetic head, it has a defect in that its characteristics are inferior to those of dedicated magnetic heads in both recording and reproduction.

To solve this problem, a magnetic head for recording/reproducing with a variable gap has been proposed (Japanese Patent Laid-Open No. 60-66
No. 310, etc.), that is, a magnetic head with a structure in which a magnetic layer with a saturation magnetic flux density lower than that of the head body is inserted in the gap part of the magnetic head, and this magnetic layer is used to withstand the large magnetic flux applied during recording. The magnetic layer is saturated, thereby effectively operating as a magnetic head with a large gap length, and the magnetic flux applied from a recording medium such as a magnetic disk during reproduction does not saturate this magnetic layer, thereby causing a magnetic head with a small gap length. It operates as a head. This variable gap magnetic head is excellent in that it has characteristics equivalent to two magnetic heads dedicated to recording and reproduction.

(Problems with the Prior Art) As shown in FIG. 1, the structure near the gap of the variable gap magnetic head described above includes a main body 1 made of a high permeability magnetic material with a large saturation magnetic flux density, and a main body 1 in the gap. A high permeability magnetic layer 2 with a small saturation magnetic flux density formed on one of the opposing surfaces, or a high permeability magnetic layer 2.2 with a small saturation magnetic flux density formed on both sides as shown in FIG. )
The magnetic layer 2.2 is usually made of Permalloy (Ni-Fe alloy) having a ferrite base, Sendust (Fe-Sl-A1 alloy) having a ferrite base, ferrite, etc. It is composed of garnet, etc.

In this way, since the main body and the magnetic layer in the gap portion are made of different materials, it takes a lot of effort to manufacture the magnetic head. Another problem is that because the materials of the main body and the magnetic layer are different, the wear is uneven and wears unevenly, resulting in changes in characteristics and clogging.

(Objective of the Invention) It is an object of the present invention to economically manufacture a magnetic head for both recording and reproducing with a variable gap length.Another object of the present invention is to economically manufacture a magnetic head of this type that does not wear out on one side. The purpose is to provide.

(Summary of the Invention) The magnetic head of the present invention uses inexpensive ferrite as the main body, and forms a Co-Ta alloy layer with high magnetic permeability and high saturation magnetic flux density on the abutting surfaces of the gap portion, and then on the surface thereof. It is characterized by forming a Co--Ta alloy layer with high magnetic permeability and low saturation magnetic flux density.

(Summary of Effects) According to the above configuration, the magnetic layer with high saturation magnetic flux density and the magnetic layer with low saturation magnetic flux density differ only in the Co and Ta containing layers, so it is possible to easily produce the celadon magnetic layer using the same manufacturing method. The AA4A head can be manufactured more economically and the cost of the AA4A head can be lowered. Furthermore, since the mechanical properties of the celadon magnetic layer are almost the same, uneven wear of the RI1 head is eliminated.

(Detailed Description of the Invention) According to research conducted by the present inventors, it has been found that by changing the composition of the Co--Ta alloy, a magnetic layer having a saturation magnetic flux density of 'Kf1 and a magnetic layer having a low magnetic flux density can be constructed. Such a magnetic layer must have high magnetic permeability during recording and playback, and this magnetic alloy also satisfies this requirement.

Conventional magnetic heads usually use ferrite for the main body and high permeability permalloy or sendust for the gap part, but the present invention also uses inexpensive ferrite for the main body and high permeability material for at least one side of the gap part. A Co--Ta alloy magnetic layer having a high saturation magnetic flux density is formed thereon, and a Co--Ta alloy magnetic layer having an equivalent high magnetic permeability and a low saturation magnetic flux density is formed thereon.

These magnetic layers can be manufactured by any method such as a well-known sputtering film forming technique using the portion of the ferrite yoke that will be the abutting surface of the gap portion as a base. However, in the present invention, since the celadon magnetic layer has a very similar composition,
It is advisable to form the celadon magnetic layer using the same method. In the embodiment of the present invention, an RF magnetron sputtering method was used.

The preferred alloy composition is T for high saturation flux density alloys.
The alloy with a 5.0 to 15.0 at% and low saturation magnetic flux density has a Ta content of 15.1 to 25 at%. Ta content is less than 5at% or 25a
If it exceeds t%, the permeability decreases, which is undesirable, but in general, it is sufficient if there is a sufficient difference in saturation magnetic flux density between the celadon layers.

Embodiment FIG. 3 shows the structure of the magnetic head of the present invention, in which Mn-Zn
Ta is applied to the surface of the gap portion of the n single-crystal two-light yoke 10.
A Go-Ta alloy magnetic layer 11 with a low Ta content is formed, and a Co-Ta alloy magnetic layer 12 with a high Ta content is formed thereon. 5io in the gap part 13
2 Gap material is used. These magnetic layers are formed by RF magnetron sputtering.

C containing Ta in Co in an amount of 0.1 to 25 at%
An o-Ta alloy was manufactured and its magnetic properties were measured.

Figure 4 shows the results.

The saturation magnetic flux density decreases linearly with the Ta content. Therefore, Co with as low a Ta content as possible
-Ta alloy is used as magnetic M11 in Fig. 3, 25%
The magnetic layer 12 is made of a Co-Ta alloy having a Ta content close to
By using the magnetic layer 12 as a variable gap means, the magnetic layer 12 is saturated during recording and has high magnetic permeability during reproduction.

Note that an actual variable gap magnetic hect can be configured as follows, for example.

Gap material Si o 2 0.4
Rugya-7 Depth 10 Pot body M n -Z n single crystal ferrite magnetic layer 11 (high Ms) Co90 atX 28 4Ta
lOatX Magnetic layer 12 (low Ms) Co80 atX 1
hTa 20 at
Since the magnetic layer 11 having a high saturation magnetic flux density is made of a Co--Ta alloy having a low Ta content which is very similar to the magnetic layer 11, it can be easily manufactured by a sputtering method by simply changing the target. Also, is the transparency of both magnetic layers? a
Since * shows almost the same high values, a magnetic head with good characteristics can be constructed. Furthermore, since the mechanical properties of both magnetic layers are extremely similar, no uneven wear occurs.

[Brief explanation of the drawing]

! iS1 and 2 are cross-sectional views of the vicinity of the gap of a conventional variable-gear two-pipe magnetic head, and FIG. 3 is a cross-sectional view of the variable-gap magnetic head of the present invention in the vicinity of the gap.
The figure is a graph showing the relationship between the composition of the magnetic layer and magnetic properties.

Claims (3)

[Claims] (1) Form a Co-Ta alloy first layer with high saturation magnetic flux density and low Ta content on at least one of the abutting surfaces of the gap part, and then form a Co-Ta alloy first layer with low saturation magnetic flux density and higher Ta content than the first layer. A magnetic head characterized in that a Co--Ta alloy second layer is formed. (2) The magnetic head according to item 1 above, wherein the first layer contains 5.0 to 15 at% Ta. (3) The magnetic head according to item 1 or 2 above, wherein the second layer contains 15.1 to 25 at% Ta.