JPH09297918A - Magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the variations in the recording patterns (magnetization transition for recording of information) of a magnetic recording medium and eventually to improve the recording density of the magnetic recording medium by taking the 'structure regulated by a track width and shortest bit length' of the magnetic recording medium into consideration. SOLUTION: A magnetic film 11 is formed on a substrate 10 (flat substrate) and executes the accumulation of information. Plural recording parts 111 which are rectangular regions having the track width and the shortest bit length- regulating lengths as the lengths on the two sides are separated from each other by spacing parts 112 and are arranged at this magnetic film 11. Various kinds of the deformation in consequence of the presence of a ground surface film and the differences, in the structures and shapes of the substrate, the ground surface film and the magnetic film is made possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a magnetic recording medium (magnetic disk or the like) used in a magnetic recording / reproducing apparatus such as a magnetic disk device.

[0002]

2. Description of the Related Art Conventionally, this type of magnetic recording medium has a structure as shown in or below (FIG. 9 (a)).
And (b)).

A magnetic film is formed and formed on a substrate made of aluminum or glass (see FIG. 9A).

A base film for controlling the microscopic structure of the magnetic film is formed on the substrate, and the magnetic film is formed on the base film (see FIG. 9B).

In any case, the magnetic film had a continuous or flat structure over the entire magnetic recording medium.

When information is recorded on such a conventional magnetic recording medium, adjacent magnetization transitions interfere with each other, especially when the recording density becomes high and the shortest bit length becomes short, and this is called partial erasure. A "region in which the magnetization transition partially disappears" occurs, and the possibility of erroneous reading during reproduction increases (see FIG. 10). Further, when the shortest bit length is shortened, a phenomenon in which the magnetization transition varies at the end of the recording track occurs, and the possibility of erroneous reading during reproduction increases.

[0007]

In the above-mentioned conventional magnetic recording medium, the following problems (problems) occur when the recording density becomes high (when the shortest bit length becomes short). It was

The first problem is that the influence of the above-mentioned partial erasure becomes large and the possibility of causing a reproduction error increases.

The second problem is that the variation of the magnetization transition occurs at the end of the recording track as described above, and the possibility of erroneous reading during reproduction increases.

Both of the problems are caused by variations in the recording magnetization state when the recording density becomes high. That is, there is a problem in that the magnetic recording medium has a flat structure as a whole, and the structure defined by the track width and the shortest bit length is not considered at all.

In view of the above points, an object of the present invention is to consider the "structure defined by the track width and the shortest bit length" in the magnetic recording medium, and thereby the recording pattern (for recording information) in the magnetic recording medium. Variation of the magnetization transition) of the magnetic recording medium and the recording density of the magnetic recording medium is improved.

[0012]

A magnetic recording medium of the present invention (a magnetic recording medium used in a magnetic recording / reproducing apparatus) has a flat substrate, a track width and a minimum bit length specified length of two sides. A plurality of recording areas, which are rectangular areas, are arranged separated from each other by a gap and are formed on the substrate, and have a magnetic film for accumulating information. Various modifications can be made to the above magnetic recording medium due to the existence of the underlayer film, the difference in the structure / shape of the substrate, the underlayer film, and the magnetic film. Morphology ").

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to the drawings.

(1) FIG. 1A is a perspective view showing the structure of a first embodiment (an embodiment corresponding to the invention described in claim 1) of the magnetic recording medium of the present invention.

FIG. 1B is a sectional view showing the structure of the magnetic recording medium shown in FIG.

The magnetic recording medium (magnetic disk or the like) of this embodiment comprises a flat substrate 10 (disk substrate or the like) and a substrate 1.
And a magnetic film 11 which is formed on 0 for accumulating information. That is, as shown in FIGS. 1A and 1B, the magnetic film 11 on the substrate 10 is
An area having a minimum recording bit size (a recording area 111 which is a rectangular area having a track width and a minimum bit length specified length as the length of each side) is used as a unit to form a gap (gap portion 11).
It is configured to be lined up with 2).

The magnetic film 11 is formed by arranging a plurality of recording portions 111, which are rectangular areas having a track width and a minimum bit length defined length of two sides, separated from each other by a gap portion 112. Here, "Minimum bit length specified length"
Is the length obtained by subtracting a predetermined “gap length on the shortest bit length side” from the shortest bit length.

As shown in FIG. 1A, the gap 112
Is the "gap length on the shortest bit length side" in the shortest bit length direction.
And has a "gap length on the track width side" in the track width direction.
Having. Due to the presence of the "gap length on the shortest bit length side", variations in magnetization transition due to the influence of partial erasure are reduced. Further, the presence of the “gap length on the track width side” reduces the variation in the magnetization transition at the end of the recording track. As described above, in the present embodiment, and eventually the magnetic recording medium of the present invention, the "structure defined by the track width and the shortest bit length" is considered.

The magnetic film 11 is formed on the recording portion 11 as shown in FIG.
In order to divide into one unit, for example, it is conceivable to add a manufacturing process of etching the region of the gap 112 to a flat magnetic film (a magnetic film in the related art as shown in FIG. 9).

In the magnetic recording medium of this embodiment, the area where information (digital information) is recorded (accumulated) by the magnetic field generated from the recording head is the magnetic film 11 formed on the substrate 10 as described above. The recording unit 111 of FIG.

In digital recording, the recording bit length is an integral multiple of the shortest bit length. Therefore, when the magnetic recording medium has the above-described structure, the magnetization transition portion does not occur in the area (recording section 111) where information is recorded, and the area of the gap between the recording sections 111 (the gap section 112). ) Occurs. Therefore, it is possible to reduce the variation of the magnetization transition due to the partial erasure and the variation of the magnetization transition at the end portion of the recording track, and the conventional problems caused by the variation of the magnetization transition do not occur.

In the structure of the magnetic recording medium of the present embodiment, it is desirable that the area of each recording portion 111 is composed of one crystal grain (see the invention of claim 3).

(2) FIG. 2 shows a second embodiment of the magnetic recording medium of the present invention (an embodiment corresponding to the invention of claim 2).
FIG. 3 is a cross-sectional view showing the structure of FIG.

In the magnetic recording medium of this embodiment, a flat base film 12 is formed on a flat substrate 10, and the base film 1 is formed.
A magnetic film 11 is formed on top of 2. The other points are similar to those of the first embodiment.

Also in the structure of the magnetic recording medium of this embodiment, it is desirable that the area of each recording portion 111 is composed of one crystal grain (see the invention of claim 3).

(3) FIG. 3 shows a third embodiment of the magnetic recording medium of the present invention (an embodiment corresponding to the invention of claim 4).
FIG. 3 is a cross-sectional view showing the structure of FIG.

In the magnetic recording medium of this embodiment, the magnetic film 11
A certain amount of magnetic material remains in the gap 112. Only in this respect is the difference from the first embodiment.

It is effective to perform etching or the like until the gap 112 is free of the magnetic material.
If the magnetic material is formed so as to be thinner (thinner) than the magnetic film of each recording portion 111, the object of the present invention (reduction of variation in magnetization transition) can be achieved by itself. . Therefore, the present invention can be realized only by making the thickness of the magnetic film 11 thinner in the gap portion 112 than in the recording portion 111 as in the present embodiment.

(4) FIG. 4 shows a fourth embodiment of the magnetic recording medium of the present invention (an embodiment corresponding to the invention of claim 5).
FIG. 3 is a cross-sectional view showing the structure of FIG.

In the magnetic recording medium of this embodiment, a flat base film 12 is formed on a flat substrate 10, and the base film 1 is formed.
A magnetic film 11 is formed on top of 2. The other points are similar to those of the third embodiment.

(5) FIG. 5 shows a fifth embodiment of the magnetic recording medium of the present invention (an embodiment corresponding to the invention of claim 6).
FIG. 3 is a cross-sectional view showing the structure of FIG.

The magnetic recording medium of this embodiment has a surface shape in which a plurality of convex portions, which are rectangular areas having a track width and a minimum bit length specified length of two sides, are separated from each other by concave portions. It is configured to include a substrate 10 and a magnetic film 11 formed on the substrate 10 and having an even film thickness to store information.

Substrate 10 having an uneven structure as shown in FIG.
The surface shape of the magnetic film 11 makes the structure of the magnetic film 11 equivalent to the structure of the magnetic film 11 in FIG. Therefore, the magnetic recording medium of the present embodiment (fifth embodiment) can obtain the same characteristics as the magnetic recording medium of the first embodiment having the structure shown in FIG.

(6) FIG. 6 shows a sixth embodiment of the magnetic recording medium of the present invention (an embodiment corresponding to the invention of claim 7).
FIG. 3 is a cross-sectional view showing the structure of FIG.

In the magnetic recording medium of the present embodiment, a base film 12 is formed on a substrate 10 having an uneven structure in the magnetic recording medium of the fifth embodiment shown in FIG. The film 11 is formed. Both the base film 12 and the magnetic film 11 have uniform film thicknesses.

(7) FIG. 7 shows a seventh embodiment of the magnetic recording medium of the present invention (an embodiment corresponding to the invention of claim 8).
FIG. 3 is a cross-sectional view showing the structure of FIG.

The magnetic recording medium of the seventh embodiment has a flat substrate 10, a magnetic film 11 formed on a base film 12 and having a uniform film thickness for accumulating information, and a magnetic recording medium on the substrate 10. The base film 12 to be formed is included.

As shown in FIG. 7, in the base film 12, a plurality of convex portions, which are rectangular regions having a track width and a minimum bit length specified length of two sides, are arranged separated from each other by concave portions. Has a surface shape.

In the manufacture of the magnetic recording medium of this embodiment, after a flat base film (a base film in the prior art as shown in FIG. 9B) is formed on the flat substrate 10, the flat base film is formed. For example, etching treatment is performed so that the surface shape of the underlayer film has an uneven shape as shown in FIG. 7, and then the magnetic film 11 having a uniform film thickness is deposited on the underlayer film 12 having the uneven shape. It

(8) In any of the structures of the above second to seventh embodiments, as in the structure of the first embodiment, the magnetic film 11 for accumulating (holding) information by magnetization is the minimum recording. It is defined by the bit size (a rectangular area having two sides of the track width and the minimum bit length specified length). Therefore, in any structure, the variation of the magnetization transition is reduced, and the reproduced waveform with less variation can be obtained.
Read errors in reproduction can be reduced.
That is, it is possible to achieve the object of the present invention, "to reduce the variation of the recording pattern (magnetization transition for recording information) in the magnetic recording medium, and to improve the recording density of the magnetic recording medium".

(9) By the way, the structure of the magnetic recording medium of the present invention is applicable not only to the longitudinal recording medium (magnetic recording medium adopting the longitudinal recording method) but also to the perpendicular recording medium (magnetic recording medium adopting the perpendicular recording method). Is also effective. That is, even in the perpendicular recording medium, by providing the structure of any one of the above-described embodiments, it is possible to reduce the variation in the magnetization transition and realize a high recording density.

In the case of a perpendicular recording medium, a soft magnetic film may be formed as the underlayer 12 in order to improve the stability of the magnetization of the magnetic film 11 for holding information.
In such a case, the soft magnetic film, which is the underlayer film 12, has irregularities with a period defined by the size of the minimum recording bit (a rectangular area having two sides of the track width and the minimum bit length specified length). The present invention can be appropriately realized by forming the surface shape (this idea corresponds to the invention according to claim 9).

[0043]

【The invention's effect】

(1) The effect of the magnetic recording medium of the present invention will be specifically described with reference to FIG.

Consider a case where recording is performed on the magnetic recording medium of the present invention (referred to as a longitudinal recording medium) with the recording current (recording current corresponding to recording data) shown in FIG. 8A.

In this case, the magnetization of the magnetic recording medium is retained as shown in the magnetization pattern of FIG. 8 (b). In this case, the variation of the recording magnetization state, especially the variation of the magnetization transition region is remarkable in the magnetic film of the magnetic recording medium of the present invention having a shape in which the “structure defined by the track width and the shortest bit length” is taken into consideration. Suppressed.

Next, reproduction of information held on the magnetic recording medium of the present invention will be considered.

The reproduction of the information held on the magnetic recording medium is
This is performed by detecting the magnetic field generated from the magnetic recording medium.

As shown in FIG. 8B, reproduction of recorded data is performed on a magnetic recording medium that does not consider the "structure defined by the track width and the shortest bit length" like the conventional magnetic recording medium. When it is performed, the reproduction waveform becomes as shown in FIG. 8D, and the reproduction waveform varies (for example, the amplitude variation) due to the variation of the magnetization transition.

On the other hand, when the recorded data held in the magnetic recording medium of the present invention as shown in FIG. 8B is reproduced, the reproduced waveform as shown in FIG. 8C is obtained. .
That is, it is possible to obtain a waveform in which the variation of the reproduced waveform due to the variation of the magnetization transition is suppressed.

Further, in the magnetic recording medium having the structure as in the present invention, a small waveform peak appears even in a portion where there is no magnetization transition (see FIG. 8C). By detecting the peak of this small waveform, for example, it is possible to synchronize with the unevenness of the rotation speed of the magnetic disk, and even when the unevenness of rotation is large, the position of the magnetization transition can be accurately measured by performing appropriate signal processing. Can be played. In the conventional magnetic disk, the reproduction waveform itself cannot be synchronized with the rotation of the magnetic disk. Therefore, if the rotation of the magnetic disk is uneven, the peak position variation of the reproduction waveform should be corrected. I couldn't.

(2) As described above, the magnetic recording medium of the present invention has the following effects.

First, by considering the "structure defined by the track width and the shortest bit length" in the magnetic recording medium, variations in the recording pattern (magnetization transition for recording information) in the magnetic recording medium are reduced. It is possible to obtain a reproduced waveform in which variations in amplitude and the like are suppressed (see FIG. 8C), and it is possible to improve the recording density of the magnetic recording medium.

Secondly, as a secondary effect, a small waveform peak appears even in a portion where there is no magnetization transition (see FIG. 8).
By detecting (c), it is possible to synchronize with the unevenness of the rotation speed of the magnetic recording medium (such as a magnetic disk), and it is possible to remarkably reduce the reproduction error in the magnetic recording medium.

[Brief description of drawings]

FIG. 1 is a perspective view and a sectional view showing the structure of a first embodiment of a magnetic recording medium of the present invention.

FIG. 2 is a sectional view showing the structure of a second embodiment of the magnetic recording medium of the present invention.

FIG. 3 is a cross-sectional view showing the structure of a third embodiment of the magnetic recording medium of the present invention.

FIG. 4 is a sectional view showing the structure of a fourth embodiment of the magnetic recording medium of the present invention.

FIG. 5 is a sectional view showing the structure of a fifth embodiment of the magnetic recording medium of the present invention.

FIG. 6 is a sectional view showing the structure of a sixth embodiment of the magnetic recording medium of the present invention.

FIG. 7 is a sectional view showing the structure of a seventh embodiment of the magnetic recording medium of the present invention.

FIG. 8 is a diagram for explaining the effect of the magnetic recording medium of the present invention, (a) is a diagram schematically showing a waveform of a recording current corresponding to recording data, and (b) is a diagram of the present invention. It is a figure which shows typically the magnetization pattern recorded on the magnetic recording medium, (c) is a figure which shows the waveform reproduced from the magnetic recording medium of this invention typically, (d) is conventional magnetic recording. It is a figure which shows the waveform reproduced from a medium typically.

FIG. 9 is a cross-sectional view showing the configurations of two examples of conventional magnetic recording media.

FIG. 10 is a diagram for explaining a problem of a conventional magnetic recording medium, and is a diagram schematically showing a magnetization pattern recorded on the conventional magnetic recording medium.

[Explanation of symbols]

 10 substrate 11 magnetic film 12 base film 111 recording part 112 gap part

Claims (9)

[Claims] 1. A magnetic recording medium used in a magnetic recording / reproducing apparatus, wherein a flat substrate and a plurality of recording portions, which are rectangular areas having a track width and a minimum bit length specified length of two sides, are defined by gaps. A magnetic recording medium, comprising: a magnetic film, which is disposed separately from each other and is formed on the substrate, and stores information. 2. A magnetic recording medium used in a magnetic recording / reproducing apparatus, wherein a flat substrate, a flat base film formed on the substrate, a track width, and a minimum bit length specified length are two sides long. A magnetic recording medium having a plurality of recording portions, which are rectangular areas, which are separated from each other by a gap, are formed on the base film, and have a magnetic film for accumulating information. 3. The magnetic recording medium according to claim 1, wherein each recording portion is composed of one crystal grain. 4. A magnetic recording medium used in a magnetic recording / reproducing apparatus, wherein a flat substrate and a plurality of recording portions which are rectangular areas having a track width and a minimum bit length specified length of two sides are the recording portions. A magnetic recording medium comprising: a magnetic film formed on the substrate and separated from each other by a gap having a thinner film thickness, and storing information. 5. A magnetic recording medium used in a magnetic recording / reproducing apparatus, wherein a flat substrate, a flat base film formed on the substrate, a track width and a minimum bit length specified length are two sides. A plurality of recording portions, which are rectangular areas, are arranged separated from each other by a gap portion having a film thickness smaller than that of the recording portion, and are formed on the base film and have a magnetic film for accumulating information. A magnetic recording medium characterized by the above. 6. A magnetic recording medium used in a magnetic recording / reproducing apparatus, wherein a plurality of convex portions, which are rectangular regions having a track width and a minimum bit length specified length of two sides, are separated from each other by a concave portion. A magnetic recording medium comprising: a substrate having a different surface shape; and a magnetic film formed on the substrate, having a uniform film thickness, and accumulating information. 7. A magnetic recording medium used in a magnetic recording / reproducing apparatus, wherein a plurality of convex portions, which are rectangular areas having a track width and a minimum bit length specified length of two sides, are separated from each other by a concave portion. A substrate having a different surface shape, an underlayer film formed on the substrate and having an even film thickness, and a magnetic film formed on the underlayer film and having an even film thickness for accumulating information. A magnetic recording medium comprising: 8. A magnetic recording medium used in a magnetic recording / reproducing apparatus, wherein a flat substrate and a plurality of convex portions, which are rectangular areas having a track width and a minimum bit length specified length of two sides, are formed by a concave portion. Having a base film formed on the substrate and having a surface shape separated from each other, and a magnetic film formed on the base film, having a uniform film thickness, and accumulating information. A magnetic recording medium characterized by: 9. A magnetic recording medium used in a magnetic recording / reproducing apparatus and adopting a perpendicular recording method, comprising a flat substrate and a rectangular area having a track width and a minimum bit length specified length of two sides. A plurality of convex portions have a surface shape arranged by being separated from each other by concave portions, are formed as a soft magnetic film, and are formed on the substrate, A magnetic recording medium having a film thickness and a magnetic film for storing information.