JPH07129920A - Magnetic head, its production and magnetic recording and reproducing device formed by using the same - Google Patents

Abstract

PURPOSE:To provide a excellent magnetic head by increasing the film thickness of the winding groove slope of an apex part without increasing the film thick ness of a gap surface and further, improving the characteristics of the soft magnetic metallic film on the winding groove slope. CONSTITUTION:The substrate consisting of an oxide magnetic material is set by inclining the substrate in such a manner that the angle T4 (theta1) formed by the winding groove slope and a target surface is made small in the case of formation of the magnetic metallic film on the oxide magnetic substrate. The angle formed by the groove slope and the target on one side is made small and the magnetic thin film having the good film thickness and excellent characteristics is formed on the groove slope if the substrate is so set that the tape-sliding surface of the oxide magnetic material substrate parallels approximately with the target surface by using a counter target type sputtering method. at the time of forming the soft magnetic metallic film. The relation between numerical values T1, T2, theta1 is selected at Cos((3/4)Xtheta1)/Cos((1/4)Xtheta1)XT2<=T 1<=XCos(theta1)XT2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head suitable for recording and reproducing information at a high density on a magnetic recording medium having a high coercive force used in a system such as a VTR, a method for manufacturing the same, and a magnetic head using the same. The present invention relates to a recording / reproducing device.

[0002]

2. Description of the Related Art It is generally known that, for high density magnetic recording and reproduction, it is only necessary to increase the coercive force of a recording medium and the saturation magnetic flux density (hereinafter, Bs) of a magnetic head. ing. Conventionally, a ferrite material that has been mainly used as a magnetic head material has a Bs of about 0.5 T, and when used in a metal tape having a high coercive force of 1000 Oe or more, magnetic saturation occurs and recording is not sufficiently performed. Therefore, at present, a material having a larger Bs than the ferrite material, a sendust alloy film (Bs: about 1.0 T), a Co-based amorphous film (Bs: about 0.8 to 1.1 T), and further a Bs of 1.3 T or more. Magnetic heads using new materials such as Co-based superstructure nitride films, Fe-based superstructure nitride films, and Fe-based nitride films, and in particular, MIG heads are being actively researched.

As shown in FIG. 3, the structure of the magnetic head is such that the main core is made of ferrite 1, and the vicinity of the gap and the side surface of the track are made of a metal soft magnetic material (hereinafter, soft magnetic film) 2.
There is an MIG head (hereinafter referred to as a parallel type MIG head) in which the boundary surface between the soft magnetic film formed on the ferrite gap surface and the ferrite is parallel to the gap surface. These heads
Consumer analog VTRs such as VHS, S-VH
It is applied to products such as S and 8 mVTR.

[0004]

In the current consumer analog VTR, the frequency of the signal recorded and reproduced on the magnetic tape is at most 10 MHz. In this case, the relative magnetic permeability of ferrite is about 400. Considering digital VTRs in the future, the frequency of the recording / reproducing signal is about 20 MHz,
The frequency used is about twice the frequency used in the current analog VTR. In this case, the relative magnetic permeability of ferrite is considerably low, and may be 300 or less. Further, as the frequency becomes higher, the magnetic permeability of ferrite further decreases. In this case, in particular, in the ferrite portion near the gap, the magnetic resistance increases because the cross-sectional area of the core is small, which causes a reduction in head efficiency.

In the case of the parallel type MIG head, a metal soft magnetic film is also formed on the slope of the winding groove forming the apex portion. When observing the vicinity of the apex in a cross section parallel to the side surface of the head (FIG. 4), compared with the film thickness T2 on the gap surface of the soft magnetic film, the film thickness in the direction perpendicular to the slope of the film formed on the slope of the winding groove. It can be seen that T1 (hereinafter, the film thickness on the slope of the winding groove) is small. The film thickness T1 is approximately represented by the following equation, where θ1 is the angle formed by the slope of the winding groove and the gap surface (hereinafter, apex angle).

T2 × COS (θ1) At high frequency, the permeability of ferrite decreases as described above, so that the soft magnetic film having high permeability greatly contributes to the reproduction sensitivity, and especially the winding near the apex. The influence of the soft magnetic film on the groove slope is large. Therefore, the reproducing sensitivity of the head can be increased by thickening the magnetic film on the slope of the winding groove. However, even in this case, if the film thickness at the hypotenuse portion is simply increased, the film thickness at the gap surface is also increased, which causes various adverse effects such as an increase in stress exerted on ferrite and film peeling.

When a metal soft magnetic film is formed on the gap surface of the oxide magnetic material by a method such as sputtering as a method of forming the metal soft magnetic material, the gap surface of the oxide magnetic material substrate is substantially parallel to the target surface. In this case, the film quality of the soft magnetic film formed on the slope of the winding groove deteriorates due to the effect of oblique incidence, and the soft magnetic film is softer than the metal soft magnetic film formed on the gap face. The characteristics are degraded.

As a result, the head efficiency at high frequencies is lowered and the recording / reproducing characteristics are deteriorated.

[0009]

Means for Solving the Problems A magnetic resistance in the vicinity of the gap is reduced by increasing the film thickness T1 of the winding groove slope forming the apex portion. In this case, T1 is increased without increasing the thickness T2 of the gap surface. At this time, the soft magnetic characteristics of the metal soft magnetic film on the slope of the winding groove are also improved, and the high relative permeability of this portion is utilized to increase the head efficiency.

As a method of increasing the film thickness T1 on the slope of the winding groove or improving the soft magnetic characteristics of the soft magnetic film, a conventional method is used when a metal soft magnetic film is formed on an oxide magnetic substrate. Is approximately 0 degree (angle (T3) formed by the target surface and the gap surface (at this time, the angle (T
4) was set to be equal to the apex angle and θ1), but this can be achieved by inclining this so that T4 becomes small and installing the substrate of the oxide magnetic material.

When the metal soft magnetic thin film is formed, the opposed taper type sputtering method is used so that the magnetic tape sliding surface of the oxide magnetic material substrate is substantially parallel to the target surface. By installing the substrate on the substrate, the angle formed by the slope of the winding groove and the target on one side is reduced, and a metal magnetic thin film with excellent film quality and soft magnetic characteristics is formed on the oblique side of the winding groove. It becomes possible.

[0012]

The operation of this technical means is as follows.

With respect to the metal soft magnetic film formed on the slope of the winding groove, the angle T4 formed by the slope of the winding groove and the target surface is smaller than in the prior art, so that a film having excellent soft magnetic characteristics can be formed. Further, since T4 is smaller than the conventional one, the ratio between the film thickness T1 of the winding groove slope and the film thickness T2 of the gap surface is small, and T1 is larger depending on the angle, and the same film thickness is formed on the gap surface. Even if the soft magnetic film is formed, the film thickness on the slope of the winding groove can be made larger than in the conventional case.

FIG. 5 shows the theoretical calculation of how much the head efficiency is improved by increasing T1. FIG. 5 is a diagram showing how the head efficiency increases when T1 increases by the magnetoresistive method. Apex angle θ
1 to 60 degrees, gap depth 15 μm, frequency used is 2
Since 0 MHz is assumed, the relative permeability of ferrite is 3
00, the relative magnetic permeability of the soft magnetic film was set to 1000. From this result, by increasing T1, it becomes possible to realize a magnetic head with high head efficiency by utilizing the high relative magnetic permeability of the soft magnetic film. Further, since the film thickness of this portion is large at the time of recording, a large amount of magnetic flux can be made to flow, and a magnetic head having excellent recording characteristics can be obtained.

Further, by utilizing the effect of oblique incidence, the direction of the gap depth and the inclined surface of the winding groove, that is, the magnetic path direction can be made the direction of the hard axis of magnetization.
It is possible to form a metal soft magnetic film having a high magnetic permeability in the magnetic path direction even in a high frequency region exceeding Hz.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic head according to an embodiment of the present invention will be described below with reference to the drawings.

First, an example of the structure of the magnetic head will be described. 1 and 2 show an embodiment of the magnetic head of the present invention. 1 and 2 are a cross-sectional view and an enlarged view near the gap when the magnetic head shown in FIG. 3 is cut along a line AB. The main core is composed of ferrite 1, and the soft magnetic film 2 is formed on the gap surface of the ferrite. FIG. 1 shows that the winding groove is formed only on one side, and FIG. 2 shows that the winding groove is formed on both sides. Regarding the soft magnetic film 2, the film thickness T2 on the gap surface is substantially equal to the film thickness T1 on the slope of the winding groove. Although T1 and T2 will be described in detail in FIG. 8, they are substantially determined by the angles formed by the gap surface and the winding groove slope with the target surface.

FIG. 3 shows an external view of this head. The boundary surface between the soft magnetic film 2 and the ferrite 1 is parallel to the gap surface. Both sides of the truck are reinforced with glass 3.

FIG. 6 shows an embodiment of the magnetic head manufacturing method of the present invention. This figure is a schematic diagram when a soft magnetic film is deposited on a substrate of an oxide magnetic material having a winding groove. A winding groove is formed in at least one of the cores of a set of two oxide magnetic material cores, and the cores are processed to obtain a desired track width. At this time, the apex angle is θ1. When depositing a soft magnetic film on this core, with respect to the core having winding grooves, the gap surface 4 and the target surface 1
The core is installed so that (1/4) × θ1 ≦ T3 ≦ θ1 where T3 is the angle formed by 1 and T4 is the angle formed by the hypotenuse of the winding groove and the target surface.

FIG. 7 shows the relationship between the angle T3 formed by the gap surface and the target surface and the film thickness of the soft magnetic film on the slope of the winding groove.
Here, the film thickness at the gap surface is 3 μm.
(A) has an apex angle of 60 degrees, and (b) has an angle of 45 degrees. These are the results of observing the film thickness of the gap surface and the winding groove slant surface in the state shown in FIGS. 1 and 2 after polishing the head side surface after manufacturing the head chip.

Regarding the film thickness of the film on the slope,
Assuming that the direction 20 of particles coming from the get is almost perpendicular to the target plane, it can be calculated by the simple model shown in FIG. The angle formed with the target surface 23 is θA,
The film thickness on the slopes 21 and 22 of θB (TH21, TH
The relationship of 22) is roughly as follows.

TH22 = (TH21) X (COSθB / COSθA) As for FIG. 7, it is almost on this curve. The factors that deviate from the curve are that, in the case of soft magnetic film sputtering, if the installation position of the substrate deviates from the center, the film thickness may change slightly due to the effect of oblique incidence, etc., or the direction in which particles fly from the target is not always vertical. There is no such thing.

FIG. 9 shows an example of an embodiment of the magnetic head manufacturing method of the present invention. This is a method of depositing a soft magnetic film on a core in which a winding groove has been processed, and uses a facing target type sputtering method. In this case, in order to improve the film quality of the slope of the winding groove, the oxide magnetic material substrate is installed so that the sliding surface 32 of this substrate is substantially parallel to the surface of the target 33. At this time, in the core 35 installed on the right side of the center between the two targets, the winding groove slope 34 is on the right target surface, and the core 36 installed on the left side of the center is on the left target. Turn to face. By this manufacturing method, it is possible to form a thick soft magnetic film having excellent film quality on the winding groove slope 34.

The film thickness of the winding groove slope of the magnetic head on which the soft magnetic film is formed by using the facing target sputtering method is
Compared with a conventional method (a method of forming a soft magnetic film by making the gap surface of an oxide magnetic material substrate substantially parallel to the target surface), in the case of a core with an apex angle of 60 degrees, The thickness is 1.5 μm in the method, and 2.3 μm in the case of using the facing target type sputtering method, and the film thickness of the winding groove slope can be increased by using the method of the present invention. It has become possible.

(Table 1), (Table 2), (Table 3), the film thickness (T of the winding groove slope) when the film thickness of the gap surface is 3 μm
1) and the angle between the target surface and the gap surface (T
3) and the head characteristics are shown.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3]

Here, as a manufacturing method, the soft magnetic film was formed by a method of tilting the substrate as shown in FIG. Here, the soft magnetic film is a nitride film containing Fe as a main component and Ta added thereto.

A list of heads used for measurement is shown in (Table 4).

[0031]

[Table 4]

Head shapes A and B are cores with winding grooves on one side,
C is provided on the cores on both sides. A has an apex angle (θ1) of 60 degrees, B has 45 degrees, and C has 45 degrees on each side. As a manufacturing method, when the gap surface is substantially parallel to the target surface (T3 = 0), that is, when the film thickness is 1.5 μm for A, 2.1 μm for B and C, the recording / reproducing characteristic of the head is 0 dB. . The measurement conditions of the head are
The relative speed was 10 m / s, the recording / reproducing frequency was 20 MHz, and a commercially available ME tape was used, and the head characteristic was an average value of 10 pieces each.

Table 1 shows the results of the head shape A. A
Then, when the film thickness (T1) of the winding groove slope is 2.2 μm (at this time T3 = 15 degrees (θ1 / 4)), it becomes +0.7 dB,
When the film thickness is larger than this, the head characteristics are further improved. A characteristic was obtained in which T1 exceeds 3 dB to 4.1 μm (T3 is 30 degrees to 45 degrees) and exceeds +1 dB. T1 is 6
Even in μm (T3 = 60 degrees: the winding groove slope and the target surface are parallel at this time), a slightly higher characteristic than T3 = 0 degrees (+
0.5 dB) is obtained. When T3 is set to 45 degrees or more, the head characteristics start to deteriorate even though the film thickness on the slope of the winding groove increases. It may be worse. From this result, T1 is 2.2
μm to 6 μm (T3 is 15 degrees (θ1 / 4) to 60 at this time)
(Θ1)), it is possible to obtain a head having excellent characteristics as compared with the conventional one, and T1 is 3 μm to 4.1 μm.
(At this time, T3 is 30 degrees (θ1 / 2) to 45 degrees (θ1 ×
By setting in the range of (3/4))), +1 compared to the conventional
A head having characteristics exceeding dB can be obtained.

Table 2 shows the results of the head shape B. B
Then, T1 is 2.5 μm (at this time, T3 = 11 degrees (approximately θ1
/ 4)) is +0.7 dB, and the head characteristics are improved as T1 increases. T1 is 3.5 μm (T3 = 3
(4 degrees) shows a tendency to show almost the maximum value, and T1
Is 4.2 μm (T3 = θ1: 45 °: winding groove slope and
+0.7 dB when the get surfaces are parallel, but T
+1 dB when 1 is 4.6 μm (T3 = 50 degrees)
Thus, the characteristics were almost the same as T3 = 0 degree. From this result, T1 is 2.5 μm to 4.2 μm (at this time, T3 is 1 μm).
When the angle is 1.3 degrees (θ1 / 4) to 45 degrees (θ1), a head having excellent characteristics can be obtained as compared with the conventional one, and 3 μm to 3.5 μm.
(T3: 22.5 degrees (θ1 / 2) to 33.8 degrees (θ1 ×
In the case of (3/4))), a head having a characteristic exceeding +1 dB as compared with the conventional case can be obtained.

Table 3 shows the results of the head shape C. C
However, the same tendency as B was obtained, and when T1 was 2.5 μm, +0.8 dB, and when T1 was increased, the head characteristics were further improved, and when T1 was 4.6 μm (T3 = 50 degrees), T3 =
It was almost the same as when it was zero.

(Table 5) and (Table 6) show the results of measuring the head characteristics when the head shape A and the thickness of the gap surface were 4 μm and 2 μm, respectively.

[0037]

[Table 5]

[0038]

[Table 6]

The tendency shown at this time was almost the same as the result of (Table 1). When the film thickness is 2 μm, the output increase is large compared to 3 μm and 4 μm. When the film thickness is 2 μm, recording is insufficient due to the thin film thickness of the soft magnetic film on the gap surface in the conventional method. Since the recording characteristics are improved due to the increase in the film thickness, the output increase is increased.

The above results are summarized in (Table 7).

[0041]

[Table 7]

When the apex angle is θ1 and the film thickness on the gap surface is T2, the film thickness T1 on the slope of the winding groove is COS (3/4 × θ1) / COS (1/4 × θ1) × T2 ≦ T1 ≦ T2 / COS (θ1) (1) A magnetic head with better characteristics than the conventional one can be obtained when (1) is satisfied, and T2 ≦ T1 ≦ COS (1/4 × θ1) / COS (3/4 × θ1) It can be seen from Table 7 that when xT2 (2) is satisfied, a head having a characteristic exceeding +1.0 dB is obtained as compared with the magnetic head manufactured by the conventional method (Table 7). T1 is (1) in the right-hand column of (Table 1), (Table 2), (Table 3), (Table 5) and (Table 6),
When the formula (2) was satisfied, an O mark was put.

As a method of manufacturing the magnetic head at this time,
In forming the soft magnetic film, in order for the angle T3 formed by the gap surface of the oxide magnetic material substrate and the target surface to satisfy Expression (1), 1/4 × θ1 ≦ T3 ≦ θ1 (3) Expression (3) In order to satisfy 2), the substrate may be installed so that 1/2 × θ1 ≦ T3 ≦ 3/4 × θ1 (4).

The characteristics of the magnetic head manufactured by the facing target type sputtering method shown in FIG. 9 were also measured under the same conditions. The results are shown in (Table 8). Compared with magnetic heads made by conventional manufacturing methods, A, B, C
A head having a characteristic of +0.9 to 1.5 dB in both the shapes was obtained.

[0045]

[Table 8]

In this embodiment, the soft magnetic film is made of Fe as an example.
Although an example of a nitride film containing Ta as a main component has been shown,
It goes without saying that the material is not limited to this material, and it goes without saying that a metal soft magnetic film having a high magnetic permeability and a low coercive force, which is used for the core material of the head, exhibits the same effect. For example, a nitride film containing Fe as a main component, a soft magnetic film containing Fe as a main component, a superstructure nitride film having a structure in which the nitrogen composition is modulated in the thickness direction, and a Co-based amorphous film are given as examples. A film, a sendust film, a permalloy film, etc. can be used.

FIG. 10 shows an example of a magnetic recording / reproducing apparatus equipped with the magnetic head of the present invention. This is a view showing a cylinder on which the magnetic head of the present invention is mounted and a tape running portion. Also in this apparatus, the excellent recording / reproducing characteristics of the magnetic head of the present invention were exhibited, higher head characteristics were obtained as compared with the case of using the conventional head, and the system performance could be improved.

[0048]

As shown in the present invention, it is possible to improve the head efficiency at high frequencies by increasing the film thickness of the slope of the winding groove. Further, by the manufacturing method as shown here, a soft magnetic film having an excellent film quality can be provided on the slope of the winding groove, and the MIG type magnetic head having excellent head efficiency and recording / reproducing characteristics, its manufacturing method, and the same. It is possible to realize a magnetic recording / reproducing apparatus using the.

[Brief description of drawings]

1A is a cross-sectional view of an embodiment of a magnetic head of the present invention in which a winding groove is formed only on one side, and FIG. 1B is an enlarged view near a magnetic gap of FIG.

2A is a cross-sectional view of an embodiment of a magnetic head of the present invention in which winding grooves are formed on both sides, and FIG. 2B is an enlarged view near the magnetic gap of FIG.

[Fig. 3] External view of a magnetic head

FIG. 4 is a sectional view of an example of a conventional magnetic head.

FIG. 5 is a diagram showing a calculation result of a film thickness on a winding groove slope and a head efficiency.

FIG. 6 is a diagram showing an embodiment of a magnetic head manufacturing method of the invention.

FIG. 7 shows the relationship between the angle formed by the gap surface and the target surface and the film thickness. (A) is a diagram when the apex angle is 60 degrees, and (b) is a diagram when the apex angle is 45 degrees.

FIG. 8 is a diagram of the concept of the film thickness of the film formed on the slope.

FIG. 9 is a diagram showing an embodiment of a magnetic head manufacturing method of the invention.

FIG. 10 is a diagram showing an embodiment of a magnetic recording / reproducing apparatus of the present invention.

[Explanation of symbols]

 1 Ferrite 2 Soft Magnetic Film 3 Glass 4 Ferrite Gap Surface 5 Winding Groove Slope 11 Target Surface 12 Target 13 Core with Winding Groove 20 Particle Flying Direction 21 Slope with Angle θA Formed with Target Surface 22 Slope with an angle of θB to the target surface 23 Target surface 32 Sliding surface 33 Target 34 Winding groove slope 35 Core 36 Core 41 Magnetic head 43 Rotating cylinder 44 Magnetic tape 45 Inclined post 46 Fixed cylinder

Claims (6)

[Claims] 1. A core at least on one side is composed of an oxide magnetic material and a metal soft magnetic thin film, and a boundary surface between the metal soft magnetic thin film and the ferrite formed on the gap facing surface is substantially parallel to the gap surface. In the magnetic head, regarding the metal soft magnetic thin film, the film thickness in the direction perpendicular to the slope of the winding groove slope forming the apex portion of the core in which the winding groove is formed is T1, and the film thickness on the gap surface is T.
2. T1 is COS ((3/4) × θ1) / COS ((1/4) × θ1) × T2 ≦ T1 where θ1 is the angle between the winding groove slope and the gap surface.
A magnetic head characterized in that ≦ COS (θ1) × T2. 2. A winding groove slant surface having a film thickness in the direction perpendicular to the slant surface of the winding groove constituting the apex portion of the core in which the winding groove is formed, in the direction perpendicular to the slant surface, T2, and the winding surface slant surface. When the angle between the gap surface and the gap surface is θ1, T
1 is T2 ≦ T1 ≦ COS ((1/4) × θ1) / COS ((3/4) × θ1)
The magnetic head according to claim 1, wherein the magnetic recording head has a size of × T2. 3. A core on at least one side is composed of an oxide magnetic material and a metal soft magnetic thin film, and the boundary surface between the metal soft magnetic thin film and the ferrite formed on the gap facing surface is substantially parallel to the gap surface. In the method of manufacturing the magnetic head, when forming the metal soft magnetic thin film, the angle formed by the gap surface of the oxide magnetic material and the target surface is T3, and the angle formed by the winding groove slant surface and the gap surface is θ1. Sometimes T
3. A method of manufacturing a magnetic head, characterized in that the substrate of the oxide magnetic material having the winding groove is installed so that 3 is (1/4) × θ1 ≦ T3 ≦ θ1. 4. When the angle formed by the gap surface and the target surface of the oxide magnetic material is T3 and the angle formed by the winding groove slant surface and the gap surface is θ1, T3 is (1/2) × θ1 ≦ 4. The method of manufacturing a magnetic head according to claim 3, wherein T3 ≦ (3/4) × θ1. 5. A core on at least one side is composed of an oxide magnetic material and a metal soft magnetic thin film, and the boundary surface between the metal soft magnetic thin film and the ferrite formed on the gap facing surface is substantially parallel to the gap surface. In the method of manufacturing a magnetic head, a facing target sputtering method is used when the metal soft magnetic thin film is formed, and a target in which a winding groove of a substrate of an oxide magnetic material is formed is a target. A method of manufacturing a magnetic head, characterized in that the oxide magnetic material substrate is installed such that the surface and the magnetic tape sliding surface of the core are substantially parallel to each other. 6. A magnetic recording / reproducing apparatus having the magnetic head according to claim 1 mounted therein.