JP2543689B2 - Composite magnetic head - Google Patents

Description

The present invention relates to a magnetic head used in a magnetic recording / reproducing apparatus.

[Prior Art] A conventional magnetic head, in which a magnetic gap is formed by a magnetic head block having a magnetic thin film formed on a surface facing a gap and is joined using a joining member, is disclosed in FIG. As shown, the magnetic thin film 22 is connected to the magnetic gap.
By forming it so as to be inclined with respect to 23, the magnetically discontinuous surface 12 formed between the magnetic thin film and the magnetic head block 24 reproduces a signal on the medium (parallel to the magnetic gap 23). The structure was such that tilt loss was sometimes caused and the pseudo output reproduced by the discontinuous surface 12 was reduced.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technique, the thickness of the magnetic thin film is related to the recording signal width, so that the film thickness needs to be about 20 μm, and it takes about 20 hours to form the film. There was a problem that it took time. Further, as the film becomes thicker, the internal stress increases and the film is easily peeled off, which causes a problem that the manufacturing yield is low. Further, in forming the gap, it is necessary to strictly control the positional deviation in order to form the two magnetic head blocks by abutting each other after providing a desired recording signal width to the two magnetic head blocks, which increases the number of steps and lowers the yield. He also had points. In addition, since the magnitude of the tilt loss is determined by the angle between the signal and the discontinuous surface, when used in a magnetic disk device, the angle is different between the outer circumference and the inner circumference of the disk, and the magnitude of the pseudo output is different within the disk. However, there is a problem that it is very difficult to make an optimum design. In other words, a major problem is that the structure does not reduce the pseudo output itself.

Therefore, the present invention solves such a problem, and an object thereof is to reduce the pseudo output reproduced from the discontinuity between the magnetic thin film and the magnetic head block to be small or to eliminate the high storage capacity. The magnetic head that can be applied to the magnetic disk drive of the present invention is provided at a low cost.

[Means for Solving the Problems] In the composite magnetic head of the present invention, a U-shaped core 1 formed by crossing deep lateral grooves and a surface formed by crossing shallow lateral grooves and not formed with lateral grooves are provided. The I-shaped cores 2 each having a magnetic thin film formed are aligned with their lateral grooves so that the surface of the U-shaped core on which the deep lateral grooves are formed faces the surface of the I-shaped core on which the magnetic thin film is formed. The magnetic film of the I-shaped core 2 has a length 16 in the gap depth direction of 5 times or more of the length 17 of the U-shaped core 1 in the gap depth direction. It is characterized by having done. Specifically, in the composite magnetic head of the present invention, the magnetic thin film is formed deeper in the back gap direction than the gap depth of the magnetic gap, and the gap depth when the discontinuous surface is considered to be a pseudo gap is formed deep. However, it is characterized by interlinking with the coil so as to close most of the flow of the reproducing magnetic flux at the gap depth portion and reduce the magnetic flux that becomes the reproducing output.

[Embodiment] FIG. 1 (a) is a perspective view of an embodiment according to the present invention, and FIG. 2 is a front view of FIG. 1 seen from the bottom.
This embodiment is a magnetic head core for a general magnetic disk device, and is composed of two magnetic head blocks, a U core 1 and an I core 2. FIG. 1B is an enlarged front view of the magnetic gap portion of this embodiment, in which the magnetic thin film 3 is attached in parallel with the magnetic gap 4.

FIGS. 4A to 4G are perspective views briefly showing the manufacturing process of this embodiment. Two magnetic blocks U core 1 and I
A core 2 is prepared, a lateral groove 5 and a longitudinal groove 6 are formed in the I core 2 as shown in FIG. 4 (b), and a magnetic thin film (3) is formed as shown in FIG. Forming a magnetic head block
11 Next, as shown in (d), the U core 1 and the magnetic head block 11 are glass-bonded, and then a groove 7 for regulating the track width is formed as shown in (e). Then, as shown in (f), glass 25 is used to reinforce the truck 8.
And then sliced along the dotted line 9 shown in (g) to obtain the magnetic head core 10 of FIG.

As shown in FIG. 4 (c), the magnetic thin film is formed on the gap facing surface of the one core 2 so that the film formation is very simple, and as shown in FIG. 4 (e), after the gap is formed, the track processing is performed. Therefore, an accurate butting step is unnecessary.

The reduction of the pseudo output, which is the object of the present invention, will be described below based on the flow of magnetic flux, and the features of this embodiment will be described in detail. FIG. 5 shows the magnetic thin film 3 and the magnetic head block 11.
FIG. 6 is a side view showing the flow of magnetic flux reproduced from the discontinuous surface 12 between and. As shown in FIG. 5, the magnetic flux reproduced from the discontinuity surface 12 is divided into the magnetic flux 14 interlinking the coil 13 and the magnetic flux 15 closing at the discontinuity surface 12, so that the pseudo output is reduced by interlinking with the coil. It is sufficient to reduce the magnetic flux 14 to be generated. And increasing the magnetic flux closing at the discontinuity 12 and the discontinuity 12
It is necessary to reduce the magnetic flux reproduced in. In this embodiment, the film is formed in the back gap direction with a thickness of 100 μm in order to increase the magnetic flux closing at the discontinuous surface. FIG. 6 is a characteristic diagram showing the relationship between the length 16 of the film and the pseudo output. The length 16 of the film is sufficient if it is 30 μm or more, but it is set to 100 μm for easy production. As described above, the length 16 of the film needs to be formed sufficiently larger than the gap depth 17 of the regular gap 4, and it is not appropriate to form it in the U core 1 that regulates the gap depth 17. Therefore, in this embodiment, I
A film is formed on the core 2. Characteristically, it is better to arrange the gap end where the film is formed so as to be on the side where the medium flows out, but the opposite case does not cause a big problem. The above is the feature of the present invention in this embodiment.

Next, in order to reduce the magnetic flux that links the coils,
It suffices to reduce the gap depth 17 of the regular gap shown in the figure. This is effective in increasing the magnetic resistance of the magnetic circuit of the magnetic flux interlinking the coil from the discontinuous surface 12 serving as the pseudo gap. In this embodiment, the gap depth 17 is 2
It is put between ~ 8 μm. The gap depth 17 is also related to the head efficiency of the regular gap 4, and it is desirable that the gap depth 17 is small also from this point.

Now, in order to reduce the magnetic flux reproduced from the discontinuous surface 12, it is necessary to strengthen the adhesion between the film and the I core. In this embodiment, the escape groove is formed so that the film is not attached to the shape of the film-forming surface other than the portion necessary for forming the magnetic core so that the adhesion of the film is improved. This is because when the film area is increased, the film is kept at a high temperature during the gap formation in the subsequent process, and there is a difference in the coefficient of thermal expansion between the magnetic core and the film, so film peeling easily occurs and the gap between discontinuous surfaces is prevented from increasing. Is. As shown in FIG. 7, a magnetic head block
Before forming the magnetic thin film 3 on 11, a horizontal groove 5 and a vertical groove 6 are formed. At this time, the gap between the vertical grooves 6 is 70.
A thickness of less than or equal to μm is desirable from the standpoint of film adhesion, but this distance is related to the head efficiency because it is the width of the back gap 18 shown in FIG. 2 and cannot be extremely reduced. It is set. However, if the back gap depth can be increased, this distance is 20μ.
It can be reduced to about m.

The magnetic thin film in this embodiment is formed of Fe-Al-Si by sputtering. Target composition is about 9.5wt% Si, 5.5
Although it is an alloy of wt% Al and bulk Fe, it has a variation of about 0.5 wt% or more. Sputtering condition is initial pressure 8
Input power at × 10 ^-7 torr, Ar gas pressure 3 mtorr DC300V, 3.2A
1000 Å after pre-sputtering for about 10 minutes under the conditions
Sputter at a rate of / min for 30 minutes to form a magnetic thin film of 3 μm. The substrate bias is Rf100W.

The Fe-Al-Si film is annealed when the U core 1 and the I core 2 are glass-bonded and held when forming a gap. Hold temperature and hold time is 580 ℃ x 6
It takes 0 minutes. In order to prevent the film from being corroded by the glass due to the contact between the glass and the film during the glass bonding and the deterioration of the characteristics, in this embodiment, the film is formed and then 500 is formed.
Å Cr is spattered as a protective layer. However, the Cr film may not be formed in some cases by appropriately determining the holding time and temperature.

FIG. 3 is a perspective view of a magnetic head in which the magnetic head core of this embodiment is combined with a magnetic head slider 19 for a fixed magnetic disk device. The I-core 1 is arranged on the outflow side (→ direction) of the disk, and FIG. 8 is a characteristic diagram of an isolated waveform by this magnetic head, but almost no pseudo output appears. FIG. 9 is a characteristic diagram of an isolated waveform according to the prior art, but a pseudo output 21 is observed.

[Advantages of the Invention] As described above, in the composite magnetic head of the present invention, the U-shaped core 1 formed by crossing the deep lateral grooves and the surface formed by the shallow lateral grooves and not formed with the lateral grooves are magnetic. The I-shaped cores 2 on which thin films are formed have their lateral grooves aligned with each other, and the surface of the U-shaped core on which the deep lateral grooves are formed and the surface of the I-shaped core on which the magnetic thin film is formed face each other. The length 16 in the gap depth direction of the magnetic film of the I-type core 2 is such that the U-type core 1 is bonded so as to have a gap.
The length 16 in the gap depth direction of the magnetic film of the I-type core 2 is 16 times or more than the length 17 in the gap depth direction of
Since the length 17 in the gap depth direction of the U-shaped core 1 is set to 5 times or more, the undesired output generated at the interface between the magnetic thin film and the I-shaped core is reduced to such an extent that it does not pose a practical problem. Since the magnetic thin film of the I-type core is formed after forming the lateral groove, the lateral groove restricts the length 16 in the gap depth direction of the magnetic film, and film peeling of the magnetic thin film due to the difference in thermal expansion coefficient is eliminated. Moreover, since the groove edge portion forms a discontinuity, it is possible to provide a composite magnetic head having a unique effect that even if there is a magnetic thin film in the groove portion, it does not affect the surface forming the magnetic gap. It was Further, since the magnetic thin film is provided in parallel with the magnetic head core, it has a feature that it can be thin as 3 μm, the time required for film formation can be short, and film peeling does not easily occur, and it can be easily manufactured at low cost. .

Moreover, since the pseudo output can be basically eliminated, it can be applied to a magnetic disk device.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment according to the present invention. FIG. 2 is a front view of the bottom surface of FIG. FIG. 3 is a perspective view applied to a head for a fixed magnetic disk device of the magnetic head of this embodiment. FIG. 4 is a perspective view of the manufacturing process of this embodiment. FIG. 5 is a side view showing the flow of reproducing magnetic flux. FIG. 6 is a characteristic diagram showing the relationship between the film length and the pseudo output. FIG. 7 is a perspective view showing the shape of a clearance groove. FIG. 8 is a characteristic diagram of the output waveform in the application example. FIG. 9 is a characteristic diagram of an output waveform according to the prior art. FIG. 10 is a front view of the vicinity of the gap of the composite magnetic head according to the conventional technique. 1 ... U core, 2 ... I core, 3 ... magnetic thin film, 4 ...
Magnetic gap, 5 ... I-core horizontal groove, 6 ... I-core vertical groove, 7 ... Track width limiting groove, 8 ...
… Tracks, 9… Dotted lines showing slice positions, 10…
... magnetic head core of this embodiment, 11 ... magnetic head block (I core), 12 ... discontinuous surface, 13 ... coil, 14 ...
Magnetic flux that links the coils, 15 ... Magnetic flux that closes at discontinuity,
16: length of the film in the back gap direction, 17: gap depth, 18: back gap, 19: slider for magnetic head of fixed magnetic disk device, 20: output waveform from regular gap, 21 ...... Pseudo output waveform from discontinuous surface,
22 …… magnetic thin film, 23 …… magnetic gap, 24 …… magnetic head block, 25 …… glass, 26 …… joining member, 27 …… back gap width,

Claims (1)

(57) [Claims] 1. A U-shaped core 1 having a deep lateral groove formed across it, and an I-shaped core 2 having a magnetic thin film formed on a surface having a shallow lateral groove formed therein and having no lateral groove formed therein. By aligning the lateral grooves with each other, and joining the surface of the U-shaped core on which the deep lateral groove is formed and the surface of the I-shaped core on which the magnetic thin film is formed so as to have a magnetic gap, and The length 16 in the gap depth direction of the magnetic film of the I-shaped core 2 is the length in the gap depth direction of the U-shaped core 1.
Composite magnetic head characterized by being more than 5 times as large as 17.