JPH07121804A - Magnetic memory system - Google Patents

Abstract

PURPOSE:To provide the magnetic memory system with lessens fringing in recording and reproducing in spite of eliminating the need for a servo light and with which sufficient reproduced output is obtainable even if the track density of a magnetic recording medium is increased. CONSTITUTION:A thin-film magnetic head 1 is formed with servo mark regions where the surface is previously provided with ruggedness in order to execute tracking control of this head in the diametral direction of the head. The thaw- film magnetic head 1 is formed with coils 15 by using a conductor material in an insulating material between a main magnetic pole 11 and an auxiliary magnetic pole 14. The thin-film magnetic head is arranged with the main magnetic pole 11 as a single magnetic pole head of an electromagnetic induction type and shields 13, 13 facing this main magnetic pole 11. An MR element 12 is disposed between the shields 13 and 13, by which a magnetic disk is subjected to perpendicular magnetic recording.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic storage system in which an information signal is recorded or reproduced by a magnetic head while detecting a servo signal for tracking.

[0002]

2. Description of the Related Art For example, a magnetic disk device using a conventional magnetic storage system records an information signal on a magnetic recording medium via a magnetic head or reproduces an information signal previously recorded on the magnetic recording medium. . Further, in order to store an information signal, a magnetic recording medium is formed by sequentially forming a magnetic recording layer and a protective layer in a plane on a flat disk-shaped substrate. Servo signals for tracking control of the magnetic head are written on the magnetic recording medium one by one using a servo writer.

In a conventional magnetic disk device, for example, recording is performed by a ring type head, and reproduction is performed by a ring type head or a horizontal shield type magnetoresistive effect (hereinafter referred to as MR) head (Shielded Vertical MR Head). Longitudinal magnetic recording is used. The ring head used for the longitudinal magnetic recording has a recording fringing (side writing) and a reproducing fringing (side reading). Even in the MR head, which is a horizontal shield type as shown in FIG. There is reproduction fringing because the MR element also extends outside the defined sense electrode.

Further, research on the perpendicular magnetic recording system has been conducted for many years as a system that can theoretically record at a higher density instead of the longitudinal magnetic recording system to achieve a high recording density.

[0005]

By reducing the recording track pitch, it is necessary to provide a servo signal with higher accuracy in order to achieve a higher recording density of the recording medium. For this reason, high accuracy is required for the servo writer and the hard disk drive mechanism for writing information in the recording medium in advance, and it becomes difficult to increase the throughput of the servo write, so the servo write is a low-priced magnetic recording medium. It will prevent the change.

As described above, the recording / reproducing fringing, which is a combination of the recording fringing and the reproducing fringing of the magnetic head, is about 1 μm, so the guard band width separating the recording tracks of the magnetic recording medium is set to this value. It is difficult to achieve the following, and this is one of the factors that hinder the increase in track pitch.

The perpendicular magnetic recording method using the single magnetic pole head and the double-layered perpendicular medium which are said to be suitable for increasing the linear recording density described above is also advantageous for increasing the track pitch because recording / reproducing fringing hardly occurs. Despite being a scheme
Due to the low reproduction signal level, it has not been put to practical use.

By the way, in the conventional magnetic disk device using the magnetic storage system, by using the magnetic recording medium having the same recording track width and reproducing track width,
In a magnetic head that performs recording / reproduction with a single magnetic pole, an unnecessary signal is generated as an unerased signal during overwriting due to a tracking shift between recording and reproduction. Since this unnecessary signal becomes noise, it must be reduced as much as possible, but it cannot be completely eliminated unless the tracking error is set to zero.

Recently, however, the proportion of this noise cannot be ignored due to the narrower track, and in the case of a head having a reproducing magnetic pole such as an MR element in addition to the recording magnetic pole, the recording head is wider than the reproducing head width. The width is wide, that is, (recording head width> reproducing head width) to absorb the tracking error and not reproduce the unnecessary signal.

However, when the head in which the recording magnetic pole and the reproducing magnetic pole are separated as described above is mounted on the rotary arm, the track center of the recording head and the track center of the reproducing head are caused by the skew angle generated by the rotation. Therefore, it is necessary to make the width of the recording head much larger than the width of the reproducing head. Further, there is a limit on the electrode processing to reduce the reproducing track width, and this factor is one of the factors that hinder the increase in track density.

Therefore, the present invention has been made in view of the above-mentioned circumstances, and it is possible to sufficiently reproduce even if the recording / reproducing fringing is reduced and the track density of the magnetic recording medium is increased without using the servo write. An object is to provide a magnetic storage system capable of obtaining output.

[0012]

In order to solve the above-mentioned problems, the magnetic storage system according to the present invention records an information signal on the recording medium via a thin film magnetic head while rotating the magnetic recording medium. A thin film magnetic head which is a magnetic storage system for reproducing an information signal from the recording medium, and which combines an electromagnetic induction type single magnetic pole head and a magnetoresistive effect element, and tracking control of the thin film magnetic head. In order to achieve this, a servo mark area having an uneven surface is formed in the radial direction in advance, and a magnetic recording medium that divides the data storage area in the servo mark area in the circumferential direction is used, and the magnetic recording medium is at least a substrate. A high magnetic permeability layer and a perpendicular magnetic recording layer are formed, and the perpendicular magnetic recording layer is magnetized in opposite directions at the concave and convex portions of the servo mark portion.

Here, the thin-film magnetic head is provided with a single magnetic pole for recording and reproduction or different magnetic poles for recording and reproduction, and the track portion of the data storage area is previously formed in a convex shape.
While using a board with a concave guard band,
The track width of the thin film magnetic head is formed to be larger than the track width of the magnetic recording medium and smaller than the track pitch.

Further, the step between the track portion and the guard band portion of the servo mark area and the data storage area, which are previously formed on the substrate surface of the magnetic recording medium, is 0.3 μm or less, and the substrate of the magnetic recording medium is formed. The total thickness of the high-permeability layer, the perpendicular magnetic recording layer, and the protective film layer formed on it is set to be the above step amount or less.

The magnetoresistive effect element used for reproducing the thin film magnetic head is arranged at a position where the sense current vector and the direction of the reproducing signal magnetic flux are parallel to each other.

[0016]

In the magnetic storage system according to the present invention, the servo mark region having the uneven surface is formed in the radial direction in advance for tracking control of the thin film magnetic head.
Disable writing servo marks using servo write. Also, a thin-film magnetic head is configured by combining an electromagnetic induction type single magnetic pole head and a magnetoresistive effect element,
By adopting the perpendicular magnetic recording method, recording and reproducing fringing can be almost eliminated, and reproducing output can be secured by using an MR element having high reproducing sensitivity.

[0017]

Embodiments of the magnetic storage system according to the present invention will be described below with reference to the drawings.

A first embodiment of the magnetic storage system of the present invention will be described. The magnetic storage method is a method of recording an information signal on the recording medium or reproducing the information signal from the recording medium via a thin film magnetic head while rotating the magnetic recording medium.

The magnetic storage system according to the present invention is shown in FIG.
Main pole 1 which is an electromagnetic induction type single pole head as shown in
1 and an MR element 12 which is a magnetoresistive effect element, and a surface of the thin film magnetic head 1 in advance for tracking control of the thin film magnetic head 1 as shown in FIG. _A magnetic disk as a magnetic recording medium in which a servo mark portion S _A as an uneven servo mark area is formed in the radial direction, and the data storage portion D _A as the data storage area is circumferentially divided by the servo mark portion S _A 2 and are used.

The thin-film magnetic head 1 has a single-pole type head 11 and shield members 13, 13 as shown in FIG.
Shield type M that shields with MR element 12 sandwiched between
A combination of the R heads 12 can be used, and any magnetic head in which the single magnetic pole head 11 and the MR element 12 are combined can be used. Further, as another portion of the thin film magnetic head 1, an auxiliary magnetic pole 14 is formed on the main magnetic pole 11 by sputtering or the like to form a magnetic path. A coil 15 is formed between the main magnetic pole 11 and the auxiliary magnetic pole 14 by using a conductor material such as Cu having a low electric resistance in an insulating material such as Al ₂ O _{3 and the} like by sputtering, vapor deposition, electroplating or the like. Has been done.

Here, the thin film magnetic head has a single magnetic pole for recording and reproducing or different magnetic poles for recording and reproducing, and the track portion of the data storage area is previously formed in a convex shape.
While using a board with a concave guard band,
The track width of the thin film magnetic head is formed to be larger than the track width of the magnetic recording medium and smaller than the track pitch.

The thin-film magnetic head 1 can efficiently perform perpendicular recording on the magnetic disk 2 by using the single-pole head 11 at the time of recording, so that the recording fringing can be reduced and the MR element is used at the time of reproducing. It is possible to obtain a large reproduction output.

As described above, in the magnetic disk 2,
The servo mark portion S _A extends radially from the center C side of the magnetic disk 1, and the data storage portion D _A is circumferentially divided by the servo mark portion S _A. Therefore,
In the magnetic disk 2, the servo mark portion S _A and the data storage portion D _A appear alternately.

The servo mark portion S _A and the data storage portion D
FIG. 3 shows an enlarged cross-sectional view of a main part of the magnetic disk 2 including both areas _A. This magnetic disk 2 is shown in FIG.
As shown in, the data storage section D _A is formed so as to always have a constant thickness. Further, the surface of the servo mark portion S _A of the magnetic disk 2 has three convex regions S _M1 , S _M2 in the lower region of the gap D, D than the surface D _AS of the data storage unit D _A.
Form S _M3 .

The unevenness formed on the servo mark portion S _A can be stamped by using a dedicated stamping device such as a mastering device for an optical disc by using a synthetic resin material such as polycarbonate or APO for the disc substrate material. It can be molded with extremely high dimensions and positional accuracy. The dimensions and positional accuracy will be described in detail later. On the disk substrate 20 made of stamped synthetic resin, a high magnetic permeability material such as NiFe or Co type amorphous film is formed to form a high magnetic permeability layer 21. On the high magnetic permeability layer 21, CoCr is formed. The perpendicular magnetic recording layer 22 is made of a perpendicular magnetic recording material such as CoPt, CoPtB, CoPtB, or the like and is sequentially and uniformly deposited by a method such as sputtering, vapor deposition, or plating.

In general, a protective film 23 made of C, SiN ₄ , Al ₂ O ₃ or the like is uniformly deposited by sputtering or the like so as to cover the perpendicular magnetic recording layer 22. In this way, each layer is formed to form each layer uniformly, and the magnetic disk is formed by the stamper.

This servo mark portion S_AWithin this area
Of the three convex portions, for example, two convex portions S _M1, S_M2Written in
Signal used for tracking control.
Offsets are applied in the direction orthogonal to the rack.
Checkered pattern S at different positions _M3Place and form the track
Servo signals and address information for controlling
It is possible to play from these areas.

This magnetic disk 2 is shown in FIG. 4, for example.
The servo mark part S on the board _ARecesses formed on
The perpendicular magnetic recording layer 22 is magnetized in the opposite direction between 24 and the convex portion 25.
To be done. FIG. 4 thus shows that a given method can be used.
Servo mark part S_ABy magnetizing the servo
Attached with an arrow that indicates the direction of magnetization between the concave and convex portions of the mark.
The direction of magnetism is reversed. This allows the server
Bomark S_ATo read only the record at the position corresponding to
The servo signal is read out via the thin film magnetic head 1.
Will be done. At this time, as shown in FIG.
Provided on the surface of, for example, the track portion and the guard of the data storage area.
Step T of unevenness of the band portion_GIs 0.3 μm or less and high
Thickness of magnetic permeability layer 21, perpendicular magnetic recording layer 22 and protective layer 23
Total film thickness T_THowever, the step difference should not exceed 0.3 μm.
Film is formed.

By thus limiting the difference between the unevenness, the surface of the magnetic disk accurately transfers the unevenness provided on the surface of the disk substrate, so that a sharp signal waveform can be obtained.

In this embodiment, as shown in FIGS. 3 to 5, the data storage portion D _A is shown as a convex portion, but conversely, the data storage portion D _A is formed as a concave portion. The substrate may be stamped on.

Therefore, if the magnetic disk 2 thus formed is used, a highly accurate servo signal can be obtained from the thin-film magnetic head 1 at regular time intervals, and the servo write becomes unnecessary.

Further, as shown in FIG. 7, a vertical shield type MR head (S
Unlike the horizontal shield type MR head shown in FIG. 6, since there is no MR material outside the reproduction track width P _tw , there is almost no reproduction fringing and a higher track density in the magnetic recording medium. Suitable for

Next, another embodiment of the magnetic storage system of the present invention will be briefly described. Here, the same reference numerals are given to the portions common to the above-described embodiments. In this embodiment, a part of the magnetic path of the single pole type head is cut as shown in FIG.
The MR layer 1 is formed in the gap portion 16 formed by this cutting.
2a, M formed by stacking a bias layer 12b on this
The thin film magnetic head 1 having a so-called yoke type MR element in which the R element 12 is arranged is used. In addition, the magnetic disk 2 is a modification of the above-described embodiment, for example, as shown in FIG.
As shown in FIG. 3, not only the servo mark portion S _A but also the data storage portion D _A are provided with irregularities when molding the disk substrate. In the data storage area D _A, the recording track portion _RT is a convex portion and the guard band portion R _G is a concave portion.

By forming in this way, the magnetic spacing in the guard band portion R _G becomes larger than that in the recording track portion R _T during recording and reproduction, so that a signal is not reproduced from this portion due to spacing loss. .
The thin film magnetic head 1 used in this embodiment has a recording track width T _wh wider than the data track width T _wm . By combining the magnetic disk 2 and the thin-film magnetic head 1 in this way, the tracking position difference between recording and reproduction, that is, by making the difference between the recording track width and the data track width larger than the tracking error, Even if there is an error, the unnecessary signal can be prevented from being reproduced. Therefore, in this embodiment, even if a magnetic head using a single magnetic pole having the same recording track width and reproducing track width as shown in FIG. In a head that uses different magnetic poles for reading and reproducing, it is not necessary to make the recording track width larger than the reproducing track width.

Therefore, this magnetic storage system enables a higher track density of the magnetic recording medium as compared with the conventional magnetic recording medium such as a magnetic disk having no guard band groove. In fact, the magnetic disk is 200TPMM (Tracks Per
mm) or higher track density and high precision tracking with a track pitch of 5 μm or less can be realized.

With the above-mentioned structure, since the servo write is unnecessary in this magnetic storage system,
A magnetic recording medium having excellent productivity can be provided because the cost can be kept low and the stamper can easily produce the magnetic recording medium.

Further, in this magnetic storage system, since the position information is accurately obtained from the servo mark portion, the recording / reproducing fringing is small, and the unnecessary signal caused by the tracking deviation between the recording and the reproducing is not reproduced, the guard band groove is formed. The track density of the magnetic recording medium can be made higher than that of the conventional magnetic recording medium such as a magnetic disk.

[0038]

According to the magnetic storage system of the present invention, servo marks are formed in advance in the radial direction in order to control the tracking of the thin film magnetic head, and the servo marks are formed by using servo write. It is possible to provide a magnetic recording medium having excellent productivity by making it unnecessary to write the data, suppressing the cost to be low, and being easily produced by the stamper.

Further, in this magnetic storage system, a thin film magnetic head is combined with an electromagnetic induction type single magnetic pole head and a magnetoresistive effect element, and a perpendicular magnetic recording system is adopted, whereby recording and reproducing fringing is performed. It is possible to almost eliminate the problem, and since an unnecessary signal generated due to a tracking deviation between recording and reproduction is not reproduced, the magnetic recording medium is higher than a magnetic recording medium without a guard band groove such as a conventional magnetic recording medium. Track density can be increased, and reproduction output can be secured by using an MR element having high reproduction sensitivity.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a thin film magnetic head used in an embodiment of a magnetic storage system according to the present invention.

FIG. 2 is an external perspective view of a magnetic disk used in the magnetic storage system.

FIG. 3 is an enlarged cross-sectional view of a part of the magnetic disk.

FIG. 4 is a sectional view for explaining a magnetization direction in a servo mark portion of the magnetic disk.

FIG. 5 is a cross-sectional view for explaining the relationship between the discrepancy amount and the total film thickness of the magnetic disk.

FIG. 6 is a schematic diagram illustrating a current flow in a conventional horizontal shield type MR head.

FIG. 7 is a schematic diagram illustrating the flow of current in a vertical shield type MR head.

FIG. 8 is a cross-sectional view showing the structure of a thin film magnetic head used in another embodiment of the magnetic memory system according to the present invention.

FIG. 9 is an enlarged external perspective view of a main part of a magnetic disk used in the magnetic storage system, in which a partial surface is enlarged.

[Explanation of symbols]

1 ---. Thin-film magnetic head 2 .--- Magnetic disk 11 --- Main magnetic pole 12 --- MR element 13 ---・ ・ ・ Shield 14 ・ ・ ・ ・ ・ ・ Auxiliary magnetic pole 15 ・ ・ ・ ・ ・ ・ Coil 16 ・ ・ ・ ・ ・ ・ Gap part 20 ・ ・ ・ ・ ・ ・ Disc substrate 21: High magnetic permeability layer 22: Perpendicular magnetic recording layer 23: Protective film S _A: Servo mark part D _A・ ・ ・ ・ ・ ・ Data storage part R _T・ ・ ・ ・ ・ ・ Recording track part R _G・ ・ ・ ・ ・ ・ Guard band part

Claims (4)

[Claims] 1. A magnetic storage system for recording an information signal on the recording medium or reproducing the information signal from the recording medium via a thin-film magnetic head while rotating the magnetic recording medium. Thin-film magnetic head in which a single-pole magnetic head of a magnetic field type and a magnetoresistive effect element are combined, and a servo mark region having an uneven surface in advance is formed in the radial direction for tracking control of the thin film magnetic head. And a magnetic recording medium that divides the data storage area in the circumferential direction into a region, in which at least a high magnetic permeability layer and a perpendicular magnetic recording layer are formed on a substrate, and a concave portion of a servo mark portion is formed. A magnetic storage system characterized in that the perpendicular magnetic recording layer is magnetized in the opposite direction to the convex portion. 2. The thin-film magnetic head is provided with a single magnetic pole for recording and reproduction or different magnetic poles for recording and reproduction, and the track portion of the data storage area has a convex shape and the guard band portion has a concave shape in advance. 2. The magnetic storage system according to claim 1, wherein the substrate having the above-mentioned structure is used, and the track width of the thin film magnetic head is formed larger than the track width of the magnetic recording medium and smaller than the track pitch. 3. The level difference between the track portion and the guard band portion of the servo mark area and the data storage area which are previously formed on the substrate surface of the magnetic recording medium is 0.3 μm or less, and the substrate of the magnetic recording medium is formed. 3. The magnetic storage system according to claim 1, wherein the total thickness of the high-permeability layer, the perpendicular magnetic recording layer, and the protective film layer formed thereon is set to be equal to or less than the step amount. 4. The magnetic memory according to claim 1, wherein the magnetoresistive effect element used at the time of reproducing the thin film magnetic head is arranged at a position where the sense current vector and the direction of the reproducing signal magnetic flux are parallel to each other. method.