JP3343339B2 - Method for manufacturing in-plane magnetic recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording method in which a master information carrier having specific information according to a shape pattern is used, and its information signal is statically and collectively recorded on a magnetic recording medium.

[0002]

2. Description of the Related Art At present, magnetic recording / reproducing apparatuses tend to have a high recording density in order to realize a small size and a large capacity.
In the field of hard disk drives, which are typical magnetic storage devices, devices with surface recording densities exceeding 10 Gbit / in2 have already been commercialized, and furthermore, rapid technological advancements have been made to discuss the practical use of 20 Gbit / in2 Is recognized.

[0003] As a technical background enabling such a high recording density, the improvement of the medium performance, the head-disk interface performance, and the improvement of the linear recording density due to the emergence of a new signal processing system such as a partial response are also significant. Is a factor.

Here, the partial response is a method of intentionally giving known inter-symbol interference at the time of waveform equalization performed to avoid inter-symbol interference when the linear recording density is increased. In addition, it is characterized in that the deterioration of S / N can be prevented as compared with the conventional peak detection and integral detection.

However, in addition to the emergence of such a signal processing method, in recent years, the trend of increasing the track density has greatly exceeded the trend of increasing the linear recording density, which is a main factor for improving the areal recording density. This is due to the practical use of a magnetoresistive element type head which is much more excellent in reproduction output performance than a conventional inductive type magnetic head. At present, the practical use of the magnetoresistive element type head makes it possible to reproduce a track width signal of only a few μm or less with good S / N. On the other hand, with further improvement of head performance in the future,
It is expected that the track pitch will reach the submicron range in the near future.

For the head to accurately scan such a narrow track and reproduce a signal with good S / N, the tracking servo technique of the head plays an important role. With regard to such tracking servo technology, in a current hard disk drive, a tracking servo signal, an address information signal, a reproduction clock signal, and the like are recorded at a constant angular interval in one round of the disk, that is, within 360 degrees in angle. (Hereinafter, referred to as a preformat). By reproducing these signals at regular intervals, the magnetic head can accurately scan the track while confirming and correcting the position of the head.

The above-described tracking servo signal, address information signal, reproduction clock signal, and the like serve as reference signals for the head to accurately scan the track. Required. In a current hard disk drive, after a disk is incorporated in the drive, preformat recording is performed by a magnetic head whose position is strictly controlled using a dedicated servo recording device.

In preformat recording of a servo signal, an address information signal, a reproduction clock signal, and the like by a magnetic head using a dedicated servo recording device as described above,
There were the following issues.

First, recording by a magnetic head is basically line recording based on a relative movement between a head and a medium. Therefore, in the above-described method of performing recording while strictly controlling the position of the magnetic head using a dedicated servo recording device, preformat recording requires a lot of time, and the dedicated servo recording device is considerably expensive. This results in a very high cost.

Second, because of the spread of the recording magnetic field due to the spacing between the head and the medium and the pole shape of the recording head,
There is a point that the magnetization transition at the end of the track on which the preformat recording is performed lacks sharpness. The current tracking servo technology detects the position of the head based on the amount of change in the reproduction output when the head scans off the track. Therefore, the signal track recorded in the preformat is not only excellent in S / N when the head accurately scans the track as in reproducing the data information signal recorded between the servo areas, but also in the head. Is required to have a steep reproduction output change amount when scanning off the track, that is, off-track characteristics. The above-mentioned problem is contrary to this requirement, and makes it difficult to realize an accurate tracking servo technique in future submicron track recording.

As a means for solving the problem of preformat recording by a magnetic head as described above, the present inventors disclosed in Japanese Patent Application Laid-Open No. 10-45544 a ferromagnetic thin film pattern corresponding to an information signal on the surface of a substrate. The main purpose is to transfer the magnetization reversal pattern corresponding to the ferromagnetic thin film pattern on the surface of the master information carrier onto the magnetic recording medium by surface transfer recording by bringing the surface of the master information carrier with the surface formed thereon into contact with the surface of the magnetic recording medium. Proposing preformat technology.

In the structure disclosed in the publication, the recording magnetic field generated from the ferromagnetic thin film on the surface of the master information carrier magnetized in one direction causes the magnetic recording medium to correspond to the ferromagnetic thin film pattern of the master information carrier. The magnetization reversal pattern is transferred and recorded. That is, by forming a ferromagnetic thin film pattern corresponding to a tracking servo signal, an address information signal, a reproduction clock signal, and the like on the master information carrier surface by photolithography technology or the like,
Information signals corresponding to these can be preformat-recorded on the magnetic recording medium.

The recording by the conventional magnetic head is basically a dynamic linear recording based on the relative movement between the head and the medium. On the other hand, the feature of the above configuration is that the recording is accompanied by the relative movement between the master information carrier and the medium. There is no static surface record. Due to such features, the technology disclosed in the publication can exert the following extremely effective effects on the problems related to the preformat recording described above.

First, because of surface recording, the time required for preformat recording is very short as compared with the conventional recording method using a magnetic head. Further, an expensive servo recording device for performing recording while strictly controlling the position of the magnetic head is not required. Therefore, productivity related to preformat recording can be significantly improved, and production cost can be reduced.

Secondly, since static recording does not involve relative movement between the master information carrier and the medium, the surface between the master information carrier and the magnetic recording medium is brought into close contact with each other to reduce the spacing between them during recording. Can be minimized. Furthermore, unlike the recording by the magnetic head, the recording magnetic field does not spread due to the pole shape of the recording head. For this reason, the transition of the magnetization at the end of the track on which the preformat recording is performed has an excellent steepness as compared with the recording by the conventional magnetic head, and more accurate tracking is possible.

FIG. 5 shows an example of the configuration of the surface of the master information carrier disclosed in the publication. FIG. 5 shows, for example, a master information pattern recorded in a preformat area provided at a constant angle in the circumferential direction of the magnetic disk medium for only 10 tracks in the radial direction of the disk medium (that is, the recording track width direction). It is. For reference, a track portion that becomes a data area on the disk medium after the master information pattern is recorded on the disk medium is indicated by a broken line. The actual master information carrier surface corresponds to the recording area of the magnetic disk medium on which the master information is recorded, at a constant angle in the circumferential direction of the disk, and for all recording tracks in the radial direction of the disk medium,
A master information pattern as shown in FIG. 5 is formed.

As shown in FIG. 5, for example, the master information pattern is formed by sequentially arranging respective areas of a clock signal, a tracking servo signal, an address information signal and the like in the track length direction. This master information pattern is formed by an array of ferromagnetic thin films 3 corresponding to information signals. For example, in FIG. 5, a hatched portion is a portion configured by the ferromagnetic thin film 3.
Although the planar shape of the ferromagnetic thin film 3 is all rectangular in FIG. 5, it is not actually limited to this, and can take various shapes depending on the application.

FIGS. 6 and 7 show a dashed line L shown in FIG.
Shows a configuration example of a cross-section of the master information carrier in L _1.
Incidentally, one-dot chain line LL ₁ corresponds to the circumferential direction of the magnetic disk medium, the paper laterally, also matches the signal recorded on the magnetic disk medium in the time axis direction of the signal obtained by reproducing by the magnetic head. As shown in FIG. 6, the master information carrier may have a configuration in which a pattern shape made of the ferromagnetic thin film 3 is embedded and arranged in a surface layer portion of the non-magnetic substrate 8.
Alternatively, as shown in FIG. 7, a configuration in which the pattern of the ferromagnetic thin film 3 is arranged in a convex shape on the surface of the nonmagnetic substrate 8 may be used. 6 is more excellent.

[0019]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the preformat technology disclosed in Japanese Patent No. 544,
The ferromagnetic thin film pattern on the surface of the master information carrier corresponds to the magnetization pattern recorded on the magnetic disk medium. Therefore, for example, the length A of each ferromagnetic thin film pattern or the distance B between each ferromagnetic thin film pattern is set on the surface of the master information carrier illustrated in FIGS. The ferromagnetic thin film patterns may be arranged in accordance with a desired signal length in the pattern, that is, a length between a pair of adjacent magnetization transition regions in the magnetization pattern.

However, according to the study by the present inventors, the length between the magnetization transition regions in the magnetization pattern recorded on the magnetic disk medium is actually the length A of each ferromagnetic thin film pattern and the length of each individual ferromagnetic thin film pattern. Distance B between ferromagnetic thin film patterns
Does not match exactly. Therefore, the length A of the ferromagnetic thin film pattern or the distance B between the ferromagnetic thin film patterns
Is exactly equal to the desired length between the magnetic transition regions on the magnetic recording medium, the actual length between the magnetic transition regions on the magnetic disk medium differs from the desired length. Would. As a result, in the reproduced waveform when the recorded magnetization pattern is reproduced by the magnetic head, the reproduced pulse position is shifted from the desired pulse position by a predetermined time.

In this case, the reproduction pulse shift amount is
If the width is sufficiently smaller than the detection window width of the reproduction signal processing circuit, no problem occurs. However, when the detection window width exceeds the allowable limit, the reproduction signal processing circuit cannot detect the reproduction pulse, and a reproduction signal error occurs.

[0022]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a more desirable magnetic pattern recorded on a magnetic recording medium by using the preformat technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 10-45544. This realizes a configuration that realizes a length between the magnetization transition regions close to the design value of the above, thereby preventing a reproduction signal error from occurring. In order to realize the above means, the present invention has two structural features as described below.

First, in a first configuration of the present invention, a magnetic field is applied by bringing the surface of a master information carrier having information signals into close contact with the surface of an in-plane magnetic recording medium by a shape pattern formed by the arrangement of ferromagnetic thin films deposited on the surface of a substrate. A method for manufacturing an in- plane magnetic recording medium in which an information signal corresponding to an arrangement of ferromagnetic thin films is recorded as magnetization information on the in- plane magnetic recording medium, the method comprising: Corresponds to the length between a pair of adjacent magnetic transition regions
The length of the ferromagnetic thin film on the master information carrier is set to be longer than the length between magnetization transition regions desired as a recording signal on the longitudinal magnetic recording medium.

According to a second configuration of the present invention, the surface of a master information carrier having an information signal is brought into close contact with the surface of an in-plane magnetic recording medium by a shape pattern formed by an array of ferromagnetic thin films deposited on the surface of a substrate to generate a magnetic field. A method for manufacturing an in- plane magnetic recording medium, wherein an information signal corresponding to a ferromagnetic thin film array is recorded as magnetization information on the in-plane magnetic recording medium by applying the magnetization signal, the magnetization information being recorded on the in- plane magnetic recording medium. The length between the pair of ferromagnetic thin films on the master information carrier corresponding to the length between the pair of magnetic transition regions adjacent to each other is set between the magnetic transition regions desired as a recording signal to the longitudinal magnetic recording medium. It is characterized by being smaller than the length.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail.

First, the outline of the magnetic recording method of the present invention is as follows.
This will be described with reference to FIG. FIG. 8 is a cross-sectional view in the circumferential direction of the in-plane magnetic disk medium 2, in which the lateral direction of the drawing shows the magnetization pattern recorded on the in-plane magnetic disk medium 2 when reproduced using a magnetic head. It also matches in the time axis direction. First, as shown in FIG. 8A, an in-plane magnetic disk medium 2 on which an information signal is recorded is prepared. next,
As shown in FIG. 8 (b), the surface of the in-plane magnetic disk medium 2 on which the ferromagnetic thin film of the master information carrier as shown in FIGS. Apply.

FIG. 8 shows an example of the configuration when the master information carrier having the configuration shown in FIG. 6 is used.
May be used.

By applying the magnetic field 9, a leakage magnetic flux 10 corresponding to the shape pattern of the ferromagnetic thin film 3 is generated on the surface of the master information carrier.
In FIG. 8, a magnetization pattern corresponding to the shape pattern of the ferromagnetic thin film 3 is recorded as shown in FIG.

In FIG. 8C, an unrecorded area corresponding to the surface portion of the ferromagnetic thin film 3 and an area where the magnetization 4 is recorded by the leakage magnetic flux 4 are arranged alternately via the magnetization transition area 6. It has a magnetization pattern. Prior to recording using the master information carrier, if the in-plane magnetic disk medium 2 has been erased to a neutral point in advance by AC erasing or thermomagnetic erasing, as shown in FIG. The magnetization pattern will be recorded.

On the other hand, as shown in FIG. 9A, prior to bringing the in-plane magnetic disk medium 2 into close contact with the master information carrier surface, the in-plane magnetic disk medium is uniformly DC-erased. By providing the initial magnetization 11 in FIG.
As shown in (c), the magnetization due to the residual initial magnetization 11 and the magnetization recorded by the leakage magnetic flux 4 are in the magnetization transition region 6.
It is possible to record the magnetization patterns alternately arranged via. At this time, the polarity of the initial magnetization 11 is opposite to the polarity of the applied magnetic field 9. When reproducing a magnetization pattern recorded on an in-plane magnetic disk medium using a magnetic head,
In the configuration shown in FIG. 9, it is possible to obtain about twice the amplitude of the reproduced signal as compared with the configuration shown in FIG.

FIG. 1 is a diagram showing the magnetic recording method of the present invention in more detail, showing a ferromagnetic thin film pattern when performing preformat recording on a longitudinal magnetic disk medium 2 using a master information carrier 1. FIG. 2 is a schematic cross-sectional view showing a relationship between a recorded magnetization pattern and a waveform reproduced by the magnetic head of the magnetization pattern. Fig. 1
Is a cross-sectional view of the in-plane magnetic disk medium 2 in the circumferential direction. The lateral direction of the paper coincides with the time axis direction when the magnetization pattern recorded on the in-plane magnetic disk medium 2 is reproduced using a magnetic head. I do.

As a comparative example, an example of a configuration in a conventional magnetic recording method using a preformat technique is shown in FIG. 4 corresponding to FIG. 1 and 4 show FIG.
1 shows a configuration in which an initial magnetization 11 is given to the in-plane magnetic disk medium 2 in advance.

In the conventional example of FIG. 4, the length A of the ferromagnetic thin film pattern and the distance B between the ferromagnetic thin film patterns are set to the desired lengths a and b between the magnetization transition regions on the in-plane magnetic disk medium 2. It is configured to match exactly.

According to the study by the present inventors, when preformat recording is performed on the in-plane magnetic disk medium 2 in the configuration of FIG. 4, the magnetization transition region 6 in the actually recorded magnetization pattern is a ferromagnetic thin film. It was found that the ferromagnetic thin film 3 was not located at both ends but shifted slightly inward from the end of the ferromagnetic thin film 3. Therefore, the actual length a ₁ between the magnetization transition regions in the portion corresponding to the ferromagnetic thin film pattern length A is shorter than the desired value a on the in-plane magnetic disk medium 2, and conversely, The actual length b ₁ between the magnetization transition regions in the portion corresponding to the distance B between the thin film patterns is longer than the desired value b on the in-plane magnetic disk medium 2.

Accordingly, when the recorded magnetization pattern is reproduced by the magnetic head, the difference between a and a ₁ between the actual reproduced waveform 5 and the desired reproduced waveform 7 is shown in FIG.
Alternatively, a pulse shift corresponding to the difference between b and b ₁ occurs. If the amount of the pulse shift exceeds the allowable limit of the detection window width of the reproduction signal processing circuit, the reproduction signal processing circuit cannot detect the reproduction pulse, and a reproduction signal error occurs.

On the other hand, in the configuration of the present invention shown in FIG. 1, the magnetizations are changed so that the desired lengths a and b between the magnetization transition regions in the magnetization pattern recorded on the in-plane magnetic disk medium 2 are obtained. The length A of the ferromagnetic thin film pattern on the master information carrier 1 and the distance B between the ferromagnetic thin film patterns are corrected in advance in consideration of the shift amount of the transition region 6 from the end of the ferromagnetic thin film 3.

That is, the length A of the ferromagnetic thin film pattern is
The inter-ferromagnetic thin film pattern distance B is larger than the desired inter-magnetization transition region length a on the in-plane magnetic disk medium 2 by an appropriate correction amount α.
By making the correction amount α smaller than the desired inter-magnetization transition region length b above, the desired inter-magnetization transition region lengths a and b in the magnetization reversal pattern recorded on the in-plane magnetic disk medium 2 are obtained. And a desired reproduction waveform 7 can be obtained.

In the configuration of FIG. 1, the appropriate correction amount α is
For example, by observing the reproduced waveform in the conventional example shown in FIG. 4, the difference between the desired inter-magnetization transition region length a and the actual inter-magnetization transition region length a ₁ or the desired inter-magnetization transition region length between actual magnetization transition region and b from the difference between the length b ₁ can be estimated as a known value. Appropriate correction amount α
Are the magnetic characteristics and film thickness of the ferromagnetic thin film 3, the desired length a and b between the magnetization transition regions, and the in-plane magnetic disk medium 2
It is necessary to estimate experimentally and empirically as described above according to each embodiment, since it differs depending on the magnetic characteristics and the like.

In this embodiment, a Co film having a saturation magnetic flux density of 1.6 T is used as the ferromagnetic thin film 3 on the master information carrier 1.
The thickness of the ferromagnetic thin film is 0.2 μm to 1.0 μm, the desired length a and b between the magnetization transition regions is 0.5 μm to 5.0 μm, and the coercive force of the in-plane magnetic disk medium 2 is 150 kA / m to 300 kA / m. According to the results of the examination in the above, the correction amount α is appropriately in the range of 0.05 μm to 1.0 μm according to the values of the lengths a and b between the magnetization transition regions, and the correction amount α / a and α / b 0.01 ~
A value of 0.8 is appropriate.

With this correction amount α, the amount of pulse shift in the reproduced waveform by the magnetic head could be kept below the allowable limit of the detection window width of the reproduced signal processing circuit.

The ferromagnetic thin film pattern on the master information carrier surface can be manufactured using various known lithography techniques. By the way, in the configuration of FIG. 1, an example of the configuration in which the cross-sectional shape of the ferromagnetic thin film 3 is substantially rectangular has been described. However, depending on such features of the lithography technique,
It is not always necessary to realize a rectangular cross-sectional shape as shown in FIG.

FIGS. 2 and 3 show another configuration example of the present invention, in which the cross-sectional shape of the ferromagnetic thin film 3 is substantially trapezoidal. In such a master information carrier,
The length A of the ferromagnetic thin film pattern and the length B between the ferromagnetic thin film patterns may be controlled at the outermost surface portion of the master information carrier that faces the in-plane magnetic disk medium 2.

In other words, in FIGS. 2 and 3, in the lower bottom portion of the cross section of the ferromagnetic thin film on the trapezoid, the length A of the ferromagnetic thin film pattern is adjusted by an appropriate correction amount α from the desired inter-magnetization transition region length a. On the contrary, the effect of the present invention can be obtained by making the distance B between the ferromagnetic thin film patterns smaller than the desired length b between the magnetization transition regions by the correction amount α.

In the configuration shown in FIG. 1, there is shown a configuration example in which there is no step between the surface of the ferromagnetic thin film 3 and the surface of the nonmagnetic substrate 8 and the surface is almost flat. However, the configuration of the present invention is not limited to this. The configuration may be such that the surface of the ferromagnetic thin film is depressed by a certain amount with respect to the surface of the nonmagnetic substrate as shown in FIG. As described above, a configuration in which the surface of the ferromagnetic thin film protrudes by a predetermined amount from the surface of the nonmagnetic substrate may be employed.

However, in the configuration shown in FIG. 2, when the amount of depression of the surface of the ferromagnetic thin film with respect to the non-magnetic substrate is larger than a certain amount, a spacing loss occurs during signal recording.
The spacing loss varies depending on the recording density of the signal. In general, when recording a signal whose magnetization transition region length a or b is several μm or less, the above-mentioned dent amount is set to 100%.
It is desirable to set it to nm or less.

In the configuration shown in FIG. 3, when the amount of protrusion of the surface of the ferromagnetic thin film with respect to the surface of the non-magnetic substrate is larger than a predetermined amount, sufficient durability may not be obtained in the master information carrier. From such a viewpoint, in the configuration of FIG. 3, it is desirable that the protrusion amount be 100 nm or less.

In the structure of the present invention shown in FIGS. 1 to 3, the correction amount α is set so that the desired lengths a and b between the magnetization transition regions on the in-plane magnetic disk medium 2 are accurately realized. Strict control is not necessary. That is, it is only necessary that the amount of pulse shift in the reproduced waveform by the magnetic head can be controlled to be equal to or less than the allowable limit of the detection window width of the reproduced signal processing circuit by the correction amount α. From this viewpoint, it is sufficient that the correction amount α can be controlled to a range in which a certain allowable amount is added to an optimum value that can accurately realize the desired lengths a and b between the magnetization transition regions.

Now, comparing the configurations of FIGS. 1 to 3,
In order to accurately realize the desired lengths a and b between the magnetization transition regions, strictly speaking, in the configuration of FIG.
Is larger than the configuration of FIG. 1, and in the configuration of FIG. 3, the correction amount α needs to be smaller than that of the configuration of FIG.
However, in many cases, the difference in the correction amount between the configurations shown in FIGS. 1 to 3 is as small as the allowable limit of the detection window width of the reproduction signal processing circuit and can be ignored.

Although the embodiments of the present invention have been described above, the configuration of the present invention can be applied to various embodiments. For example, in the specification of the present application, the description has been made with a primary focus on application to a magnetic disk medium mounted on a hard disk drive or the like, but the present invention is not limited to this, and a flexible magnetic disk, a magnetic card Also, the present invention can be applied to a magnetic recording medium such as a magnetic tape, and the effects of the invention can be obtained in the same manner as described above.

The information signals recorded on the magnetic recording medium have been described with a focus on preformat signals such as a tracking servo signal, an address information signal, and a reproduction clock signal. The applicable information signal is not limited to the above.

For example, it is possible in principle to record various data signals, audio and video signals using the configuration of the present invention. In this case, the method of magnetic recording on the magnetic recording medium using the master information carrier of the present invention enables mass production of soft disk media to be produced and can be provided at low cost.

[0052]

According to the present invention, there is provided a magnetic recording method for statically collectively recording preformat signals such as a servo signal for tracking, an address information signal, and a reproduction clock signal on a magnetic recording medium using a master information carrier. By modifying the arrangement of the ferromagnetic thin film patterns on the master information carrier, it is possible to record a desired magnetization pattern closer to the design value on the magnetic recording medium, thereby achieving a magnetic recording medium that does not cause a reproduction signal error. Can be provided.

As a result, in the pre-format technology based on the static batch recording, it is possible to further promote the improvement of the performance related to the quality of the signal recorded on the magnetic recording medium.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a relationship between a configuration example of a magnetic recording method of the present invention and a waveform reproduced by a magnetic head.

FIG. 2 is a schematic cross-sectional view showing the relationship between a configuration example of the magnetic recording method of the present invention and a waveform reproduced by a magnetic head.

FIG. 3 is a schematic cross-sectional view showing the relationship between a configuration example of the magnetic recording method of the present invention and a waveform reproduced by a magnetic head.

FIG. 4 is a schematic cross-sectional view showing the relationship between a configuration example of a conventional magnetic recording method and a waveform reproduced by a magnetic head.

FIG. 5 is a plan view showing one configuration example of a master information carrier surface used in the magnetic recording method of the present invention.

FIG. 6 is a cross-sectional view showing one configuration example of a cross section of a master information carrier used in the magnetic recording method of the present invention.

FIG. 7 is a sectional view showing one configuration example of a section of a master information carrier used in the magnetic recording method of the present invention.

FIG. 8 is a schematic sectional view showing one configuration example of the magnetic recording method of the present invention.

FIG. 9 is a schematic cross-sectional view showing one configuration example of the magnetic recording method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Master information carrier 2 In-plane magnetic disk medium 3 Ferromagnetic thin film 4 Magnetization 5 Reproduction waveform 6 Magnetization transition region 7 Desired reproduction waveform 8 Nonmagnetic substrate 9 Applied magnetic field 10 Leakage magnetic flux 11 Initial magnetization

──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Yasuaki Ban 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Hideyuki Hashi 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-11-273069 (JP, A) JP-A 10-320768 (JP, A) JP-A-10-40544 (JP, A) JP-A-10-275435 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 5/62-5/86

Claims (3)

(57) [Claims] 1. A ferromagnetic thin-film array by applying a magnetic field to a surface of a master information carrier having information signals in close contact with a surface of an in-plane magnetic recording medium by a shape pattern based on an array of ferromagnetic thin films deposited on a substrate surface. A method of manufacturing an in-plane magnetic recording medium for recording an information signal corresponding to the above as magnetization information on the in-plane magnetic recording medium, comprising a pair of adjacent magnetic information in the in-plane magnetic recording medium. The length of the ferromagnetic thin film on the master information carrier corresponding to the length between the magnetization transition regions is larger than the length between the magnetization transition regions desired as a recording signal to the in-plane magnetic recording medium. Of manufacturing a longitudinal magnetic recording medium. 2. A ferromagnetic thin-film array by applying a magnetic field to a surface of a master information carrier having information signals in close contact with a surface of an in-plane magnetic recording medium by a shape pattern based on an array of ferromagnetic thin films deposited on a substrate surface. A method of manufacturing an in-plane magnetic recording medium for recording an information signal corresponding to the above as magnetization information on the in-plane magnetic recording medium, comprising a pair of adjacent magnetic information in the in-plane magnetic recording medium. The length between the pair of ferromagnetic thin films on the master information carrier corresponding to the length between the magnetization transition regions is made smaller than the length between the magnetization transition regions desired as a recording signal on the in-plane magnetic recording medium. A method for manufacturing a longitudinal magnetic recording medium. 3. Prior to applying a magnetic field while bringing the surface of the master information carrier into close contact with the surface of the longitudinal magnetic recording medium, direct current erasing of the longitudinal magnetic recording medium is performed uniformly and with a polarity opposite to the magnetic field. The method for manufacturing a longitudinal magnetic recording medium according to claim 1, wherein: