JPH0622049B2 - Combined type magnetic head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head for perpendicular magnetic recording, and more particularly to a composite magnetic head having excellent recording and reproducing characteristics at high density.

[Background of the Invention]

Along with the increase in coercive force of the in-plane recording medium, a composite magnetic head formed from a ferrite block coated with a high saturation magnetic flux density magnetic material has been proposed in order to effectively perform recording on the medium. However, in these composite magnetic heads, since the boundary surface of the adhered portion functions as a pseudo gear, a so-called contour effect is likely to occur, and the frequency characteristic of the reproduction output causes a wavy phenomenon. Various ideas were made. For example, JP-A-56
In Japanese Patent Laid-Open No. 129214, it is proposed that the magnetic air gap constituent portion is made of a material having a higher saturation magnetic flux density than the other core portions and is obliquely crossed with the gear portion.

However, in the above-mentioned composite magnetic head, since the high saturation magnetic flux density magnetic materials applied to the first and second magnetic cores are made of the same material and the film thicknesses thereof are almost the same, the recording magnetic field distribution is symmetrical with respect to the gear part. However, a sufficiently steep perpendicular recording magnetic field component cannot be obtained, and even if this head is directly applied to a perpendicular magnetic recording apparatus, there is a drawback that ideal perpendicular magnetic recording cannot be performed especially on a medium with high saturation magnetization. It was

[Object of the Invention]

It is an object of the present invention to provide a composite magnetic head for perpendicular magnetic recording in which the component of the recording magnetic field in the direction perpendicular to the medium is steep and high density recording is possible.

[Outline of Invention]

In order to make the recording magnetic field component in the direction perpendicular to the medium steep, it is considered effective to make the magnetic core structure magnetically asymmetric, and the material of the high saturation magnetic flux density magnetic film to be deposited on the ferrite block is considered. , A composite film head was actually manufactured by changing various characteristics and structures and the characteristics were evaluated. As a result, at least both sides of the projection of the high permeability ferrite block having a projection with a protruding cross-sectional shape on the magnetic recording medium facing surface A first magnetic core having an amorphous magnetic film having a saturation magnetic flux density higher than that of the ferrite coated on its surface, and a polycrystalline magnetic material having a saturation magnetic flux density higher than that of the ferrite at least in the vicinity of the operating gear. The composite magnetic head formed by the second magnetic core deposited on the ferrite block and the second magnetic core, which are relatively opposed to each other at the tip of the protrusion via the operating gear, has a particularly high density. It is found that the alien have excellent recording and reproduction characteristics of. Further, when the second core also has a protrusion having a protruding cross-sectional shape on the surface facing the magnetic recording medium, it is more preferable that the amount of the contour effect is smaller, and the polycrystalline magnetic material is more preferable. Particularly good recording density characteristics were obtained when the saturation magnetic flux density was higher than that of the amorphous magnetic material.

Example of Invention

An embodiment of the present invention will be described below with reference to FIG. Same figure
(a) and (b) show a perspective view and a plan view, respectively, and 11 is M
High permeability blocks such as n-Zn ferrite and Ni-Zn ferrite, and 12 are well-known Co-Zr-Mo and Co-Z.
Amorphous magnetic alloys such as r-Nb, Co-Zr-W, and Co-Ni-Zr, or a laminate of them with an insulating layer such as SiO ₂ or Al ₂ O ₃ , 13 is SiO ₂ , Al ₂ O. An operating gear portion formed of _3, etc., 14 is a non-magnetic filler such as a glass adhesive, and 15 is a well-known Fe-Si-Ru, Fe-Si-A.
l, Fe-Ti, Ni-Fe, so polycrystalline magnetic alloy,
Or laminates of insulating layers such as those with _{SiO 2, Al 2 O 3,} 16 is a high permeability blocks such as Mn-Zn ferrite, Ni-Zn ferrite.

Other embodiments are shown in FIGS. 2, 3, and 4, respectively. Two
1-26, 31-36, 41-46 are 11-1 respectively
6 corresponds to 25, and 25 in FIG. 2 may or may not reach the lower part of 26.

According to the present invention, since the magnetic characteristics of the magnetic core are asymmetric, the recording magnetic field strength in the perpendicular direction is strong and steep. For example, the saturation magnetization is 500 emu / cc, the film thickness is 0.25 μm, and the coercive force is
CoO-Cr thin film of 500 Oe with Co-Zr-of 0.9 μm
When the characteristics are evaluated at a relative speed of 1.25 m / s using a double-layered perpendicular medium lined with a Mo magnetic film, particularly excellent recording characteristics are obtained as shown in FIG. Where 51
Is the characteristic of the head having the structure shown in FIG.
A Mn-Zn ferrite with a saturation magnetic flux density of 0.52T, 1
2 is Co-Zr-having a saturation magnetic flux density of 0.9 T and a film thickness of 5 μm.
An amorphous magnetic layer in which four layers of Nb were laminated with each 0.1 μm SiO ₂ layer, the gap 13 was made of SiO ₂ , the gap length was 0.15 μm, 14 was filled glass, and 15 was a saturated magnetic flux density of 0. Ni-Fe-Mo with 9T and film thickness of 1μm is 0.04μm
Is a polycrystalline magnetic layer in which 15 layers are laminated with each SiO ₂ layer interposed therebetween, θ ₁ is about 60 °, and θ ₂ is about 90 °. Further, 52 is a characteristic of the head having the structure shown in FIG. 2, in which the heads 21 and 26 are replaced with Ni-Zn ferrite.
2 is Co-Zr-having a saturation magnetic flux density of 1.1 T and a film thickness of 6 μm.
An amorphous magnetic layer in which 6 layers of Mo were laminated with Al ₂ O ₃ layers of 0.08 μm each, and the gap 23 was 0.2 μm of SiO ₂ .
Formed by adhering, 24 is filled glass, 25 is saturation magnetic flux density 1.0 T, film thickness 1.5 μm Ni-Fe 0.06 μm
It is a polycrystalline magnetic layer in which eight layers are respectively laminated via m of SiO ₂ and θ ₃ is set to about 50 °. 53 is the characteristic of the head having the structure shown in FIG. 4, and 41 and 46 are Mn-Zn.
A ferrite core, 42 is a Co-Zr-W single layer film having a saturation magnetic flux density of 1.14 T and a film thickness of 20 μm, 43 is a gear cup made of Al ₂ O _{3 and} has a gear length of 0.25 μm, and 44 is filled glass.
45 is Fe- with a saturation magnetic flux density of 1.5 T and a film thickness of 0.2 μm.
Fifty layers of Ti are each formed through 0.05 μm of Al ₂ O ₃ . In the figure, the structure shown in FIG.
The characteristics of both Nos. 2 and 45 formed with Co-Zr-W of 20 μm are shown in 54. It can be seen that the head of the structure according to the present invention is particularly excellent in high density characteristics.

FIG. 6 shows the saturation magnetization of the composite head with the structure shown in FIG.
Coe with 350emu / cc, film thickness 0.2μm and coercive force 700Oe
The characteristics when recording and reproducing were performed on a two-layer film medium in which a Cr thin film was lined with a Co-Zr-W magnetic film of 1.5 μm at a relative speed of 2.5 m / s. 61 is Mn-31 and 36 in FIG.
Zn ferrite, 32, saturation magnetization 13.5 T, film thickness 7 μ
m of Co-Zr-B, each of which was laminated with 5 layers of 0.1 μm of SiO ₂ layer, 33 was 0.2 μm of SiO ₂ , 34.
Is a filled glass, 35 is a saturation magnetization of 1.9 T, and the film thickness is 0.1 μ.
Fe-Si-Ru with a thickness of 0.005 μm Ni-Fe
And 62 are characteristics of the composite head made of a polycrystalline magnetic film laminated by 50 layers respectively, and 62 is a saturation magnetization 1T in 35 parts, Ni-Fe with a film thickness of 0.2 μm, and SiO ₂ with a film thickness of 0.007 μm is 31 layers each. Although excellent characteristics are obtained by the characteristics of the laminated polycrystalline magnetic film and the composite head in which the polycrystalline magnetic film is changed, the saturation magnetic flux density of the polycrystalline magnetic material 35 parts is particularly high. It is understood that the higher the saturation magnetic flux density of the part, the better the characteristics.

Although the embodiments relating to the so-called narrow head type ring head have been described above, this effect can be seen in FIG. 5 even in the structure shown in FIG. Properties similar to those shown were obtained. Here, 71 and 76 are Mn-Zn ferrite, 72 is a Co-Zr-W amorphous magnetic film having a film thickness of 20 μm, 73 and 73 ′ are SiO ₂ gap lengths having a film thickness of ₂ μm, and 7
4 is filled glass, 75 is saturation magnetization 1.8 T, film thickness 0.05 μ
It is a polycrystalline magnetic film in which four layers of Fe-Si-Ru of m and Co of 0.005 μm each are laminated in four layers.

〔The invention's effect〕

As described above, the composite magnetic head according to the present invention not only has excellent recording / reproducing characteristics, but also has a sufficiently small contour effect and is excellent for perpendicular magnetic recording, and particularly has high recording / reproducing characteristics. It is excellent.

[Brief description of drawings]

FIGS. 1 (a), (b), 2 (a), (b), 3 and 4 are perspective views of composite heads in each embodiment of the present invention or actuation of the recording medium facing surface. Plan view of the vicinity of the gear, No. 5
6 and 6 are graphs showing the characteristics of the head, and FIG. 7 is a perspective view of a composite head according to another embodiment. 11,16,21,26,31,36,71,76 ...
Ferrite block, 12, 22, 32, 42, 72 ...
... Thin film made of amorphous magnetic material, 15, 25, 35, 4
5,75 ... Thin film made of polycrystalline magnetic material, 14, 2
4,34,44,74 ... Non-magnetic filler, 13,23,
33, 43, 73, 73 '... Gap portion, 51, 52,
53, 61, 62 ... Characteristics of the composite head according to the present invention, 54 ... Characteristics of conventional head.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Climbing Kumasaka, the inventor 1-280 Higashikoigakubo, Kokubunji, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. (72) Kosei Shinagawa 1-280 Higashikoigakubo, Kokubunji, Tokyo Central Research Laboratory, Hitachi, Ltd. (56) Reference JP-A-56-169214 (JP, A)

Claims (5)

[Claims] 1. A first magnetic core and a second magnetic core, wherein a magnetic material having a saturation magnetic flux density higher than that of the ferrite is coated on a high-permeability ferrite block, with the surfaces of the magnetic material facing each other. In the composite type magnetic head which is relatively opposed via the working gap, the high magnetic permeability ferrite block constituting the first magnetic core has a shape pointed toward the working gap at the surface facing the magnetic recording medium. A composite type having a protrusion and the magnetic body forming the second magnetic core is made of a material having a saturation magnetic flux density higher than that of the magnetic body forming the first magnetic core. Magnetic head. 2. The shape of the high-permeability ferrite block forming the first magnetic core and the shape of the high-permeability ferrite block forming the second magnetic core at the surface facing the magnetic recording medium. The composite magnetic head according to claim 1, wherein the composite magnetic head is asymmetric. 3. A surface facing the magnetic recording medium,
The composite magnetic head according to claim 1 or 2, wherein the high-permeability ferrite block forming the second magnetic core has a smooth concave shape. 4. A surface facing the magnetic recording medium,
The composite magnetic material according to claim 1 or 2, wherein the high-permeability ferrite block forming the second magnetic core has a protrusion having a sharp shape toward the working gap. head. 5. A magnetic material forming the first magnetic core is an amorphous magnetic material, and a magnetic material forming the second magnetic core is a polycrystalline magnetic material. The composite magnetic head according to any one of claims 1 to 4.