JP2510576B2 - Compound magnetic head device - Google Patents

Description

The present invention relates to a magnetic recording device such as a magnetic disc device, a floppy disc device, a magnetic tape device, etc., and is particularly suitable for a device for recording / reproducing with a magnetic head having a narrow track. Magnetic head.

[Prior Art] It has been attempted to use a magnetoresistive head (hereinafter abbreviated as MR head) in combination with the conductive recording head as a magnetic head of a magnetic storage device. Those are the techniques already proposed in, for example, Japanese Patent Laid-Open No. 51449/1976. The MR head is a method of applying a constant external magnetic field (bias magnetic field) to the magnetoresistive effect film (MR film) in order to enhance its sensitivity and linearity, for example, a permanent magnet bias method (Japanese Patent Laid-Open No. 50-17).
12), the shear bias method (Japanese Patent Laid-Open No. 49-74522), the method of tilting the direction of the current flowing through the MR film, the Barber pole method (Japanese Patent Laid-Open No. 50-134624), etc. have already been proposed.
The structure of the MR head equipped with a means for applying a bias magnetic field is as shown in the perspective view of FIG.
Reference numeral 20 is a bias film (for example, a permanent magnet film), and terminals 30 and 31 for adding a current and taking out a resistance change as a voltage change are added to the MR film. The shields 40, 41 sandwiching them are made of soft magnetic material, and have a role of enhancing the spatial resolution as a head by magnetically shielding them. Further, 50 represents a recording medium, and 60 represents the magnetization recorded on the recording medium.

It is natural for the playback head to maximize the resistance change of the MR film and maximize the linearity with respect to the signal magnetic field from the outside, but for that purpose, it is essential to keep the bias magnetic field at a certain value. Becomes However, the bias magnetic field varies greatly depending on the structure of the MR head (such as film thickness) and the magnetic and electrical characteristics of each film, and it is extremely difficult to always apply a constant bias magnetic field to the MR film. Have difficulty. Therefore, it has been proposed to divide the MR head configuration in the track width direction and apply biases in opposite directions to each other so that the output has a differential configuration.
74523). By adopting this method, an output waveform with good linearity can be obtained even if the bias is insufficient for each.

Among the bias methods mentioned above, the method that can take a differential configuration is each of the shunt, current, and barber pole bias methods.
Both are achieved by applying bias currents in opposite directions from the center of the track. In such differentials and configurations, terminals (intermediate terminals) are also required at the center of the tracks. Since the current does not flow in the track width direction at the part (electrode part) where this intermediate terminal is in contact with the MR film (bias film for current bias), an effective bias magnetic field is not generated.
This is the part that does not contribute to the resistance change of the MR film.

For the same reason, the electrode portions of the terminals on both sides also do not contribute to the resistance change of the MR film.

The width of this electrode portion is usually required to be about the MR width (depth from the recording medium facing surface), and therefore the electrode portion of the intermediate terminal is required to be about twice the width of the MR film.

[Problems to be solved by the invention]

In the above-mentioned prior art, especially when a narrow track occurs, the ratio of the electrode portion of the intermediate terminal to the total track width increases, resulting in low output, and when a narrow track occurs, a differential structure is used.
There was a problem that MR head could not be realized.

The object of the present invention is to prevent the output from becoming low by removing the influence of the portion connecting the intermediate terminal to the MR element even if the MR head has a differential structure, and even if a narrow track is used, the differential structure is To provide a possible head.

[Means for solving problems]

The above-mentioned object is achieved by dividing the width of one track into at least two or more sub-tracks and distributing the sub-tracks of adjacent tracks between the sub-tracks as shown in FIG. In the example of FIG. 3, the nth track is divided into two, and the subtrack n ₁
Let n ₂ . The (n-1) th, (n + 1) th, (n + 2) th subtracks are (n-1) ₁ , (n-1) ₂ , (n + 1) ₁ , (n + 1) ₂ , (n + 2) ₁ , (n +
2) ₂ , then in the present invention, the subtraction is (n-1) ₁ ,
They are arranged in the order of n ₁ , (n-1) ₂ , n ₂ , (n + 1) ₁ (n + 2) ₁ (n + 1) ₂ (n + 2) ₂ . The sub-tracks may be arranged not only by separating the original one-track sub-track by 1/2 track but also by 1/2 k times (k is an integer). Even in this case, the track density does not decrease.

After arranging the tracks in this way, play MR head 12
A value of 0 achieves a differential structure by setting the interval at which the sub tracks are arranged to be the electrode width 90 at which the intermediate terminal 80 and the MR element are in contact. When reproducing an adjacent track, the n-1 track is moved to the left by 1/2 in FIG.
1 should move one track to the right.

[Action]

As described above, the electrode part of the intermediate terminal and the electrode parts of the terminals on both sides are dead areas for the MR head, and even if the information of the adjacent track is recorded in this area, it is not possible to reproduce this information. There is no decrease in S / N.

Further, the width of the intermediate terminal can be an integral multiple of the sub-track width, and the differential configuration can be realized even if the track width is narrow.

〔Example〕

An embodiment in which the present invention is applied to a magnetic head of a magnetic disk device will be described. The structure of this head and how to make it
Basically, it is the same as that of JP-A-51-44917. A perspective view of the head is shown in FIG.

Since the magnetic disk device has a track pitch of 25 .mu.m, the width of the gear parts 110, 110 'for recording the recording tracks of the recording head 100 is 11 .mu.m. The width of the effective tracks 130, 130 'of the differential head channel of the reproducing head 120 is 9μ.
It is set to m. Magnetic circuit 140 under the recording head 100
Has a structure that doubles as a shield on the top of the reproduction head 120. A notch 160 is inserted in the upper magnetic circuit 150 between the two gears 110, 110 'of the recording head to separate the gears 110, 110' for recording both tracks. This width is 14 μm. The recording head 100 has a coil 170, which originally forms a spiral as in JP-A-55-84019, but a cut surface is shown in this figure. A magnetic flux is generated in the magnetic circuits 140 and 150 by applying a reversing current to the coil to record the subtraction by the leakage magnetic field from the gear parts 110 and 110 ', but the notch 160 has a large equivalent gear and the leakage is sufficient for recording. No magnetic field is generated,
Data on the disk is not erased or newly recorded at this portion.

The centers of the recording head portions 110 and 110 'and the effective track regions 130 and 130' of the reproducing head one channel are configured such that the centers of the respective track widths coincide with each other.

The reproducing head 120 uses a differential shunt bias type MR head and applies a bias magnetic field to the MR film 190 by a magnetic field generated by a current shunting to a bias width 180. The width of the electrode portion 90 in contact with the MR film of the intermediate terminal 80 is 16 μm, which is sufficiently wider than the width 190 of the MR film, which is 7 μm, and the MR head having the differential structure can be realized. The MR head has an effective sensitivity width (sum of widths of 130 and 130 ') of 18 μm.

When the differential MR head is constructed by using the recording head as a single gear with a track width of 22 μm using the conventional technique, at least the electrode width of 16 μm of the intermediate terminal loses sensitivity.
The effective sensitivity range of the MR head is reduced to 6 μm, and sufficient reproduction is impossible.

In the above-mentioned embodiments, the example applied to the magnetic head of the magnetic disk device has been described, but it is clear that the same effect can be obtained as a head for a floppy device or a magnetic tape device.

Further, although the shunt bias MR head has been described in the present embodiment, it is clear that the MR head having another differential configuration has the same effect regardless of the bias method.

Further, in this embodiment, the magnetic head in which the recording head and the reproducing head are integrated has been described, but it is obvious that the head may be completely independent.

〔The invention's effect〕

By implementing the present invention as described above, a differential MR head can be used as a narrow track magnetic head, particularly as a reproducing head thereof. As a result, a reproduced signal with good linearity can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view for explaining an embodiment of the present invention, FIG. 2 is a perspective view for explaining the structure of the MR head, and FIG.
The figure is a diagram showing the positional relationship of the tracks on the recording medium used in the present invention and the relationship with the planar structure of the reproducing MR head. 10 ... MR film, 20 ... Bias film, 30, 31 ... Lead terminal, 80 ...
Intermediate terminal, 90 ... Electrode part of intermediate terminal, 100 ... Recording head, 110, 110 '... Recording gear, 120 ... MR head, 130, 13
0 '... MR head effective track, 180 ... Shunt film.

Claims (1)

(57) [Claims] 1. A recording in which one track width is divided into two or more sub-tracks, the sub-tracks are separated in the track width direction, and one or more sub-tracks of adjacent tracks are recorded between the sub-tracks. The reproducing head uses a differential type magnetoresistive effect type magnetic head, and the sub-track spacing is set to the width of the intermediate terminal of the differential type magnetoresistive effect type magnetic head.