JP2550661B2 - Composite magnetic head - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a composite magnetic head, and in particular, a soft magnetic metal magnetic thin film is used as a material of a main core portion, and a single crystal ferrite is used as a material of an auxiliary core portion. The present invention relates to a composite magnetic head suitable for recording and reproduction.

[Conventional technology]

In recent years, in the field of magnetic recording, the density of recording signals has been increasing, and magnetic recording media having high coercive force and residual magnetic flux density have been used. Accordingly, the core material of the magnetic head is required to have high saturation magnetic flux density and magnetic permeability.

As the core material, an oxide magnetic material is generally used, and among them, ferrite is most widely used.
The saturation magnetic flux density is still insufficient to meet the above requirements. Therefore, the magnetic head is composed of two parts, an auxiliary core part and a main core part which is laminated on the auxiliary core part and faces the magnetic gap part. The auxiliary core part is made of an oxide magnetic material such as ferrite. A so-called metal-in-gap type composite magnetic head using a soft magnetic alloy having a high saturation magnetic flux density as a material for the main core has been proposed. Here, the main core part is
It is formed as a metal magnetic thin film made of a soft magnetic alloy. Such a composite magnetic head has already been adopted for some erasing heads.

By the way, in such a metal-in-gap type composite magnetic head, a so-called swell, in which the frequency characteristics of a reproduced signal periodically fluctuates, has been observed. This is a region where the metal magnetic thin film and the oxide magnetic material react at the interface due to high temperature heating during the sputtering or glass fusing step which is indispensable in the manufacturing process of the composite magnetic head, that is, a region where the magnetic permeability is significantly lowered, that is, This is because a reaction layer is formed. In the composite magnetic head in which a portion of the ground surface of the oxide magnetic material facing the magnetic gap is a main surface substantially parallel to the magnetic gap,
A portion of the reaction layer formed along the main surface may act as a pseudo gap. This pseudo gap causes interference with the magnetic flux passing through the original magnetic gap to generate a pseudo signal, which reduces the S / N ratio of the reproduction output.
Such a defect has been a cause of impeding the practical application of the composite magnetic head as a recording / reproducing head.

As one method for avoiding the above-mentioned drawbacks, there has been conventionally proposed a method in which even if a reaction layer is formed, it does not have a surface substantially parallel to the magnetic gap. For example, in Japanese Patent Laid-Open No. 55-58824, the surface of the ferrite used as the auxiliary core portion, which is exposed at the above interface, is roughened by lapping and then the metal magnetic thin film to be the main core portion is sputtered. A technique is disclosed in which the portion formed in parallel with the magnetic gap in the interface between the auxiliary core portion and the main core portion is reduced by forming the film by deposition. Further, in order to solve the problem of a work-affected layer which may occur in this technique, Japanese Unexamined Patent Publication No. 62-102409 discloses a surface of a single crystal ferrite which is exposed at the above interface as a {100} plane. There is disclosed a technique in which a plane having a crystal plane orientation other than the above is used and lapping and etching are performed on this plane.

[Problems to be Solved by the Invention]

According to the above-mentioned conventional technique, the rate of occurrence of a plane parallel to the magnetic gap at the interface between the auxiliary core portion and the main core portion is certainly low, so that the influence of the pseudo gap can be reduced. However, since the formation of the reaction layer itself is not suppressed, it is still difficult to prevent an increase in magnetic resistance and a decrease in magnetic permeability.

Therefore, an object of the present invention is to provide a composite magnetic head capable of reducing the influence of the pseudo gap and preventing an increase in magnetic resistance and a decrease in magnetic permeability.

[Means for solving the problem]

As a result of intensive studies to solve the above problems, the present inventors have found that the rate of formation of the reaction layer at the interface between the auxiliary core portion and the main core portion is a crystal of the surface of the single crystal ferrite that is the material of the auxiliary core portion. The present invention has been completed by finding that it depends on the plane orientation.

That is, in the composite magnetic head according to the present invention, at least one of the magnetic core halves is made up of a pair of magnetic core halves made of a single crystal ferrite and a metal magnetic thin film laminated on the single crystal ferrite. A composite magnetic head having a magnetic gap formed on the abutting surface of a thin film, wherein a portion of the ground surface of the single crystal ferrite facing the magnetic gap is a main surface substantially parallel to the magnetic gap, and the main surface. From the {100} plane to the <110> direction
Either a surface inclined by 10 to 30 degrees, a surface inclined by 10 to 30 degrees from the {110} surface in the <110> direction, or a surface inclined by 10 to 30 degrees from the {100} surface in the <100> direction. It is characterized by that.

[Action]

In the present invention, of the surface of the single crystal ferrite that is the material of the auxiliary core portion, the crystal plane orientation of the main surface that faces the magnetic gap and is substantially parallel to the magnetic gap is from the {100} plane to the <110> direction. -30 degree inclined surface, {110} surface to <110> direction inclined 10 to 30 degree, or {100} surface inclined to <100> direction inclined to 10 to 30 degree. Has been. These planes will be described with reference to the pole figure of the face-centered cubic crystal shown in FIG. These planes roughly exist in the area surrounded by the broken line in the figure, for example, {10
{11} on a surface inclined by 10 to 30 degrees from the 0} surface in the <110> direction
5} plane or {113} plane, etc. from the {110} plane in the <110> direction 10
{133} or {122} planes are inclined by -30 degrees, and {013} or {012} planes are inclined by 10-30 degrees from {100} to <100>. Is included. These surfaces have the property that they do not easily react with the soft magnetic metal laminated as the main core portion even at high temperatures. Therefore, when these planes are used as the main planes of the single crystal ferrite, even if the interface with the soft magnetic metal along the main planes is substantially parallel to the magnetic gap, the reaction that causes the decrease in the magnetic permeability will occur in this portion. The layer is less likely to be formed, and the adverse effect of the pseudo gap can be reduced.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described based on experimental examples.

In this embodiment, Mn-Zn ferrite is used as the oxide magnetic material that is the material of the auxiliary core portion, and Fe-Ga-Si-Ru alloy is the soft magnetic alloy that is used for the metal magnetic thin film that is the main core portion. It is an example of the composite magnetic head used.

Hereinafter, the configuration of the composite magnetic head according to the present embodiment will be first described.
This will be described with reference to the drawings. This figure shows the appearance of a so-called metal-in-gap type composite magnetic head. Such a composite magnetic head is created as separate magnetic core halves (I) and (II) with a magnetic gap (2) located at the center of the recording medium contact surface (1) as a boundary, and finally, a glass core. The magnetic core half body (I) by fusion or the like,
(II) is joined facing each other. A winding groove (11) for winding a coil is formed in at least one of the magnetic core halves (I) and (II). Each of the magnetic core halves (I) and (II) is a metal magnetic thin film that is a main core part composed of auxiliary core parts (3) and (4) composed of Mn-Zn ferrite and Fe-Ga-Si-Ru alloy. It is roughly divided into (5) and (6). A track width Tw is provided at both ends of the magnetic gap (2).
(See FIG. 2) are provided with substantially arcuate cut grooves (7), (8) for restricting the cut grooves (7),
(8) is filled with a non-magnetic material such as glass in order to secure the contact property with the magnetic recording medium and prevent uneven wear due to sliding contact with the magnetic recording medium, and the glass filling layer (9)
Has become. Further, in the composite magnetic head according to the present embodiment, a portion of the metal magnetic thin films (5) and (6) where the magnetic gap (2) is formed, and the metal magnetic thin films (5) and (6). A silicon oxide layer (10) is deposited on a portion which becomes an interface with the glass filling layer (9) and functions as a gap spacer. Here, fused glass may be used as a gap spacer without using the silicon oxide layer (10).

In the structure of the composite magnetic head as described above, the metal magnetic thin films (5) and (6) are the cut grooves (7) and (8).
Is formed so as to surround the magnetic gap (2) and has a shape that converges toward the magnetic gap (2), so that the magnetic flux can be intensively guided to the magnetic gap (2). .

As the metal magnetic thin films (5) and (6), the above-mentioned Fe is used.
In addition to -Ga-Si-Ru alloys, crystalline soft magnetic alloy materials with excellent soft magnetic properties can be used. For example, Fe-Al-Si alloys, Fe-Ga-Si alloys, Fe-Al alloys. -Ge alloys, Fe-Ga-Ge alloys, Fe-Si-Ge alloys, Fe-Co-Si alloys, Fe-Co-Si-Al alloys, etc. are used.

For example, when an Fe-Ga-Si alloy is used, its composition is represented by the following formula Fe _x Ga _y Si _z (where x, y, z represent the composition of each element in atomic%). The composition range is preferably 68 ≦ x ≦ 84 1 ≦ y ≦ 23 6 ≦ z ≦ 31. In order to improve the corrosion resistance and wear resistance of the above alloy, up to 15 atomic% of Fe may be replaced by any of Co, Ni, Ru, or a combination thereof. Ga-Si-Ru alloy is Ru
This is equivalent to replacing with. Fe ₇₄ Ga ₉ Si ₈ Ru _{9 and the} like are typical compositions that have been successfully used in practice.

It is more effective to provide an underlayer between the auxiliary core portions (3) and (4) and the metal magnetic thin films (5) and (6) in order to prevent reaction between the two. The formation of the pseudo gap can be suppressed. As a material for such an underlayer, a magnetic metal or magnetic alloy containing 1 to 30 atomic% of a corrosion-resistant metal, or a nonmagnetic oxide or a nonmagnetic nitride is used.

The metal magnetic thin films (5) and (6) and the underlying layer provided as necessary are formed by a conventionally known method such as various sputtering, ion plating, vacuum vapor deposition method, cluster ion beam vapor deposition method and the like. be able to.

The inventors of the present invention firstly grind the Mn-Zn-based single crystal ferrite to form the composite magnetic head as described above.
An auxiliary core portion (3) as shown in the figure was created. Of the ground surface of the auxiliary core portion (3), the surface facing the magnetic gap and regulating the track width T _w is the main surface (12). The present invention is aimed at setting the crystal plane orientation of this principal plane to be a plane inclined by an angle θ from the {100} plane or {110} plane, which is most commonly used in the past, and is shown in FIG. Is {10
It is illustrated that the 0} plane is tilted in the <110> direction by 15 to 25 degrees to form the {115} plane or the {113} plane. However, in the figure, these planes are explained by the direction vector,
The solid line represents the <100> direction, and the dotted line which is the normal to the principal surface (12) represents the <115> direction or the <113> direction. In the present embodiment, the main surface (12) has a {511} surface and a {311} surface, respectively.
We prepared four types of auxiliary core parts, which are the plane, the {221} plane, and the {331} plane. After mirror-polishing these major surfaces, a Fe-Ga-Si-Ru alloy thin film was deposited by sputtering as a metal magnetic thin film. Next, assuming a glass fusion process, heat treatment was performed at 650 ° C for 1 hour, and depth direction analysis was performed by Auger electron spectroscopy combined with Ar ⁺ ion sputtering. These results are shown in FIGS. 4 (A) to 4 (D), respectively.

For comparison, the main surface is {100} surface, {111} surface,
An auxiliary core portion having {110} planes and {112} planes was also created, and similarly, a metal magnetic thin film was formed by deposition and heat treatment was performed.
Depth profile analysis was performed. In particular, the {112} plane above is {100}
Although it is a surface inclined in the <110> direction from the surface, it is a representative example of the surface whose inclination angle is not included in the range of 10 to 30 degrees. These results are shown in FIGS. 5 (A) to 5 (D), respectively.

In these FIGS. 4 (A) to 4 (D) and FIGS. 5 (A) to 5 (D), the vertical axis represents the Auger peak height in arbitrary units, and the concentration of each element. It provides a measure of. The horizontal axis represents the depth from the surface by the sputtering time (minutes). Therefore, the left end of each figure corresponds to the magnetic gap side, and if you trace from there to the right direction, the metallic magnetic thin film, the interface region, and Mn-Zn
Each phase of the system ferrite will appear in sequence.

First, referring to FIGS. 4 (A) to 4 (D), the value of O sharply increases at the left end of each figure, that is, at the surface of the metal magnetic thin film, because the surface oxidation occurs during the heat treatment. Is. Approximately 70 in terms of sputtering time
About 110 minutes can be regarded as the interface region between the metal magnetic thin film and the Mn-Zn system ferrite, and the Mn-Zn from the metal magnetic thin film side
There is some diffusion of Si and Ga to the ferrite side of the system, and diffusion of oxygen from the Mn-Zn ferrite side to the metallic magnetic thin film side. However, since the Auger peak height corresponding to each element is relatively constant in the region other than the interface region, the composition of the metallic magnetic thin film on the left side of the interface region and the composition of the Mn-Zn-based ferrite on the right side are the boundaries. It can be seen that each is well retained. Therefore, the {115} plane, {113} plane, {122} plane and {133} plane of Mn-Zn ferrite
It can be said that the reaction rate with the metal magnetic thin film on the plane is sufficiently slow.

Although not shown in the drawing, the same effect was confirmed when the {012} plane and the {013} plane were used as the ferrite main surfaces of the Mn-Zn system.

The diffusion of elements in the interface region as described above is
It was more effectively suppressed by providing a conventionally known reaction-preventing layer.

On the other hand, as shown in FIGS. 5 (A) to 5 (D), Fe and O are greatly diffused from the Mn-Zn system ferrite side to the metal magnetic thin film side. The composition of the metal magnetic thin film is also changing. In these cases, the magnetic permeability is remarkably reduced in the interface region, which causes a problem of pseudo gap when the composite magnetic head is formed.

As described above, it has been clarified that the reaction or the diffusion of the constituent element at the interface between the main core portion and the auxiliary core portion can be significantly reduced by appropriately selecting the crystal plane orientation of the main surface facing the magnetic gap.

In this embodiment, the composite magnetic head in which the magnetic metal thin films are formed on both magnetic core halves has been described, but the present invention is not limited to this, and for example, only one magnetic core half is provided. It goes without saying that it can be applied to a composite magnetic head having a metal magnetic thin film formed thereon.

〔The invention's effect〕

As is apparent from the above description, in the composite magnetic head according to the present invention, by appropriately selecting the crystal plane orientation of the portion facing the magnetic gap in the ground surface of the single crystal ferrite that becomes the auxiliary core portion, The reaction at the interface between the main core portion and the auxiliary core portion is effectively suppressed. According to this technique, it is possible to eliminate various influences associated with the formation of the pseudo gap without providing a conventional reaction preventive layer, which is also advantageous from the viewpoint of manufacturing cost and manufacturing time. Therefore, it is possible to economically provide a composite magnetic head having excellent recording / reproducing characteristics.

[Brief description of drawings]

FIG. 1 is an external perspective view showing an embodiment of a composite magnetic head to which the present invention is applied, and FIG. 2 is an enlarged perspective view of an essential part showing its auxiliary core portion. FIG. 3 is a pole figure of a face-centered cubic crystal for explaining a crystal plane of ferrite applied to the present invention. FIGS. 4 (A) to 4 (D) are characteristic diagrams showing depth direction analysis results of Auger electron spectroscopy of the composite magnetic head to which the present invention is applied, and FIG. 4 (A) is Mn-Z.
When the main surface of the n-type ferrite is the {115} plane, Fig. 4 (B) is the {113} plane, and Fig. 4 (C) is the {122} plane.
In the case of the plane, FIG. 4D shows the case of the {133} plane. 5 (A) to 5 (D) are characteristic diagrams showing the results of depth direction analysis by Auger electron spectroscopy of a composite magnetic head as a comparative example. FIG. 5 (A) shows Mn.
-If the main surface of the Zn-based ferrite is the {100} plane, Fig. 5 (B) is the {111} plane, and Fig. 5 (C) is the {110} plane.
In the case of the plane, FIG. 5D shows the case of the {211} plane. I, II …… Magnetic core half 1 …… Recording medium contact surface 2 …… Magnetic gap 3,4 …… Auxiliary core 5,6 …… Metal magnetic thin film 12 …… Main surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mineo Yorisumi 6-5 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Magne Products Co., Ltd. (56) Reference JP-A-62-102409 ( JP, A) JP 61-115204 (JP, A)

Claims (1)

(57) [Claims] 1. A pair of magnetic core halves, at least one magnetic core half of which is composed of a single crystal ferrite and a metal magnetic thin film laminated on the single crystal ferrite, are butted against each other,
A composite magnetic head having a magnetic gap formed on the abutting surface of the metal magnetic thin film, wherein a portion of the ground surface of the single crystal ferrite facing the magnetic gap is a main surface substantially parallel to the magnetic gap, and The above main surface is {10
A surface inclined from the 0} plane to the <110> direction by 10 to 30 degrees, a surface inclined from the {110} plane to the <110> direction by 10 to 30 degrees, or a surface inclined from the {100} plane to the <100> direction by 10 to 30 degrees. A composite magnetic head characterized in that it is one of the surfaces inclined at an angle.