JP3960163B2 - Magnetic transfer method to a magnetic recording medium having two recording layers - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data writing / reading head written on the surface of a magnetic recording medium in a hard disk drive (hereinafter abbreviated as HDD) or the like using a magnetic film as a recording material which is currently used as an external storage device of a computer. The present invention relates to a technique for writing positioning servo information using a magnetic transfer technique, and more particularly to a magnetic transfer method and a magnetic recording medium to a magnetic recording medium having two recording layers.
[0002]
[Prior art]
By applying a magnetic field from the outside in a state in which a magnetic transfer master disk in which a linear or island-shaped soft magnetic pattern is embedded in a surface portion is in close contact with or close to a magnetic recording medium (HDD magnetic recording disk), A new servo write technique that magnetically transfers servo information for positioning of a data write / read head written in a soft magnetic pattern to a magnetic recording layer on the surface of a magnetic recording medium has recently attracted attention. This transfer technology can efficiently write the position information (servo pattern) necessary for controlling the head of the HDD to the hard disk in a very short time, so it is highly likely that the manufacturing cost of the HDD will be greatly reduced. It is also expected to lead to higher density HDDs and the creation of new added value.
[0003]
FIG. 7 shows a conventional process of such a transfer technique. As shown in FIG. 7 (a), the magnetic recording medium (magnetic recording disk) 1 is first moved on its surface by moving a permanent magnet 4 in the circumferential direction while maintaining a constant interval. An external magnetic field Hex sufficiently larger than the coercive force Hc is applied (initial magnetization step), and is magnetized uniformly in the right direction (circumferential direction) 6 in FIG. Reference numeral 5 denotes a yoke made of a soft magnetic material that forms a ring type head together with the permanent magnet 4.
[0004]
Next, as shown in FIG. 7B, a magnetic transfer master disk 3 is arranged and aligned on the medium 1 that has undergone the initial magnetization process. An embedded magnetic film 3a (Co-based soft magnetic film) is surrounded by a substrate surface portion 3b and embedded in a discrete manner on the surface of the master disk 3. In this way, with the master disk 3 superimposed on the surface of the medium 1, the permanent magnet 4 for magnetic transfer is moved on the master disk 3, and the direction opposite to the external magnetic field applied in the initial magnetization process 7 The magnetic transfer is completed by applying the external magnetic field Hex.
[0005]
More specifically, when the permanent magnet 4 is moved in the transfer step, the leakage magnetic field from the permanent magnet 4 (the direction of the magnetic transfer writing magnetic field, the direction opposite to the initialization magnetic field) is a portion of the substrate surface portion 3b. Then, the light passes through and reaches the magnetic layer on the surface of the medium 1 and reverses the initial magnetization to obtain a high coercive recording magnetization. However, the embedded magnetic film 3a passes through in a creeping direction so as to form a magnetic path with a small magnetic resistance. As a result, it is difficult to reach the magnetic layer of the medium 1, so that the initial magnetization remains as it is, and the negative pattern of the pattern of the embedded magnetic film 3a is magnetically transferred to the medium 1. This magnetic transfer technique does not magnetize the medium 1 by the leakage magnetic field of the embedded magnetic film 3a itself of the master disk 3, but the embedded magnetic film 3a functions as a magnetic transfer mask for blocking the leakage magnetic field from the permanent magnet 4. Thus, the leakage magnetic field from the permanent magnet 4 is selectively magnetized with respect to the medium 1 via the substrate surface portion 3b (see JP 2001-34939 A).
[0006]
Hereinafter, the relationship between the magnitude of the external magnetic field Hex that performs magnetic transfer in the transfer process and the coercive force Hc of the medium 1 will be described.
As described above, a fine soft magnetic pattern is embedded in the surface of the master disk 3. FIG. 8A is a cross-sectional view showing an enlarged magnetic field distribution around the soft magnetic pattern 3a. The graph of FIG. 8B represents the distribution of the horizontal component of the magnetic flux on the medium 1.
[0007]
As shown in FIG. 8A, the magnetic flux is collected in the soft magnetic pattern 3a having a high magnetic permeability at the place where the soft magnetic pattern 3a exists, and once in the portion 3b where the soft magnetic pattern does not exist, the soft magnetic pattern 3a. The magnetic flux converged on the magnetic field spreads from the soft magnetic pattern 3a to the space. Therefore, the magnetic field Ha immediately below the central portion of the soft magnetic pattern 3a is small because the magnetic flux is collected in the pattern, and the magnetic field Hb at both ends of the soft magnetic pattern is maximum because the converged magnetic flux is applied to the medium 1. Further, the magnetic field Hg at the center of a certain soft magnetic pattern 3a and the adjacent soft magnetic pattern 3a is smaller than the magnetic field Hb at both ends because the magnetic flux once collected is sufficiently spread.
[0008]
The graph of FIG. 8B is a plot of the magnetic fields Ha, Hb, and Hg against the external magnetic field Hex. When the external magnetic field Hex is increased because of the soft magnetic pattern 3a, the magnetic fields Hb and Hg always increase while maintaining a larger value than the external magnetic field Hex. Therefore, the lines of the magnetic fields Hb and Hg are always located above the broken line having a slope of 1 on the graph. On the other hand, the magnetic field Ha is always smaller than the external magnetic field Hex because of the soft magnetic pattern 3a, and is always located below the broken line having a slope of 1 on the graph. Here, the magnetic field Ht in the figure indicates the magnetic field intensity that magnetically saturates the soft magnetic pattern 3a. Therefore, the magnetic field Ha applied to the medium 1 immediately below the soft magnetic pattern 3a rapidly increases with an increase in the external magnetic field Hex above the magnetic field Ht.
[0009]
Therefore, when transferring to the magnetic medium 1 having the coercive force Hc, an external magnetic field Hex that satisfies the conditions of Hb >> Hc, Hg >> Hc, and Ha << Hc is applied to the master disk 3 and the medium 1. By doing so, magnetic transfer is performed.
[0010]
[Problems to be solved by the invention]
The conventional transfer technique described above describes a magnetic transfer method to a magnetic recording medium having only one recording layer.
However, if the above-described method described in the prior art is used, the soft magnetic pattern of the master disk cannot be independently transferred to each layer of the magnetic recording medium having two recording layers.
[0011]
The present invention has been made in view of the above points, and an object of the present invention is to realize a magnetic field in which different magnetic signals are independently transferred to each recording layer of a magnetic recording medium having two recording layers. It is an object to provide a transfer method and a magnetic recording medium.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a magnetic transfer master disk comprising a non-magnetic substrate with a soft magnetic layer processed into a linear or island-shaped pattern embedded in a surface portion, in close contact with the surface of a magnetic recording medium. Or a magnetic transfer method for magnetically transferring information written in the soft magnetic pattern to the magnetic recording layer of the magnetic recording medium by applying a magnetic field from the outside in the proximity of the magnetic recording medium. An initialization process for initializing the magnetic recording medium by applying a horizontal magnetic field to a magnetic recording medium having two recording layers, and after executing the initialization process, the magnetic transfer master disk is A first transfer step of applying a horizontal magnetic field in a direction opposite to the applied magnetic field of the initialization step to both the magnetic transfer master disk and the magnetic recording medium in a state of being superimposed on the recording medium. It is characterized in.
[0013]
Here, after executing the first transfer step, the magnetic transfer master disk is overlapped with the magnetic recording medium, and the same magnetic field as that applied in the initialization step is applied to both the magnetic transfer master disk and the magnetic recording medium. And a second transfer step of applying a horizontal magnetic field in the direction.
Further, as the magnetic transfer master disk, a first magnetic transfer master disk is used in the first transfer process, and a second magnetic transfer master disk is used as the first magnetic transfer master disk in the second transfer process. It is preferable to use it after replacement.
[0014]
The applied magnetic field of the first transfer step and the applied magnetic field of the second transfer step are preferably different from each other, and the coercivity of the two recording layers of the magnetic recording medium is preferably different from each other. .
Further, the coercive force of the recording layer on the magnetic recording medium is Hc1, the coercive force of the lower recording layer is Hc2, the applied magnetic field in the first transfer step is Hex2, and the applied magnetic field in the second transfer step. It is preferable that Hc1 << Hc2, Hex1 << Hex2, Hc1 << Hex2, and Hex1 << Hc2.
[0015]
Further, by making the patterns of the first magnetic transfer master disk and the second magnetic transfer master disk different, the upper recording layer is a data layer and the lower recording layer is a data to the upper recording layer. Servo signal layer that does not disappear even when writing.
Therefore, in the magnetic recording medium on which information is magnetically transferred by the magnetic transfer method, it is preferable that a separation layer composed of at least one non-magnetic material exists between the two recording layers. .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, referring to the graph of FIG. 1, what kind of transfer is performed when external magnetic fields Hex1 and Hex2 having different magnitudes are applied to magnetic recording media having different coercive forces Hc1 and Hc2. Will be explained.
[0017]
Here, it is assumed that Hc1 << Hc2, Hex1 << Hex2, Hc1 << Hex2, and Hex1 << Hc2 hold, and the positions of Hc1, Hc2, Hex1, and Hex2 on the transfer map are as shown in FIG. To do.
(1) When transferring to Hc1 medium with Hex1:
Prior to the transfer, the medium is magnetized by an initialization process until it is magnetically saturated in one direction. As shown in FIG. 1A, the recording magnetic fields Ha and Hb generated when Hex1 is applied to the master disk and the medium, and the relationship between Hg and Hc1 are Hb >> Hc1, Hg >> Hc1, and Ha. Since << Hc1 is established, good transfer is possible.
[0018]
As described with reference to FIG. 8, Ha is a recording magnetic field immediately below the central portion of the soft magnetic pattern 3a, Hb is a recording magnetic field at both ends of the soft magnetic pattern 3a, and Hg is a recording magnetic field between the soft magnetic patterns 3a. .
(2) When transferring to Hc2 medium with Hex2:
Also in this case, as shown in FIG. 1B, the recording magnetic fields Ha and Hb generated when Hex2 is applied to the master disk and the medium, and the relationship between Hg and Hc2 are Hb >> Hc2, Hg >>. Since Hc2 and Ha << Hc2 are satisfied, good transfer is possible.
[0019]
(3) When transferring to Hc1 medium with Hex2:
In this case, as shown in FIG. 1H, the recording magnetic fields Ha and Hb generated when Hex2 is applied to the master disk and the medium, and the relationship between Hg and Hc1 are Hb >> Hc1, Hg >>. Hc1 and Ha >> Hc1. Therefore, the magnetization of the medium under the soft magnetic pattern 3a magnetized in the initialization process is also reversed by the transfer. In this way, when an external magnetic field Hex sufficiently larger than the coercive force Hc is applied to the master disk 3, even if the master disk 3 is superposed on the surface of the medium 1, the external magnetic field causes the magnetic disk to be in a direction opposite to the initial magnetization direction. Thus, the transfer signal cannot be written.
[0020]
(4) When transferring to Hc2 medium with Hex1:
In this case, as shown in FIG. 1G, the recording magnetic fields Ha and Hb generated when Hex1 is applied to the master disk and the medium, and the relationship between Hg and Hc2 are Hb << Hc2, Hg <<. Hc2 and Ha << Hc2. Accordingly, the magnetization of the medium magnetized in the initialization process is not reversed by transfer under a portion of the pattern 3a or under a portion where the pattern does not exist, and the remaining transfer signal remains in a state in which the initial magnetization is uniformly maintained. Can not write.
[0021]
On the other hand, if the above four combinations of the coercive forces Hc1 and Hc2 and the external magnetic fields Hex1 and Hex2 are successfully used as described later, the soft magnetic pattern of the master disk is independently applied to each layer of the recording medium having two recording layers. Can be transferred. Hereinafter, the principle will be described with reference to FIG. Note that the magnitude relationship among the coercive forces Hc1 and Hc2 and the external magnetic fields Hex1 and Hex2 of the magnetic recording medium 1 used in the following is the same as that described above.
[0022]
FIG. 2A shows an initial magnetization process. Although a simplified medium structure is shown, the coercivity of the upper recording layer 1a constituting the magnetic recording medium 1 is Hc1, and the coercivity of the lower recording layer 1b is Hc2. In this initialization step, the recording layers 1a and 1b are initially magnetized by applying an external magnetic field Hex2 sufficiently larger than the coercive forces Hc1 and Hc2 of the medium 1.
[0023]
Next, in the first transfer step shown in FIG. 2B, the master disk 3 is superimposed on the magnetic recording medium 1, and an external magnetic field Hex2 (a magnetic field in the direction opposite to the initial magnetization) is applied. At this time, the recording layer 1a having the coercive force Hc1 is uniformly magnetized in the direction opposite to the initial magnetization by the external magnetic field Hex2, as described in "(3) When transferring to Hec2 medium with Hex2". On the other hand, the recording layer 1b having the coercive force Hc2 is satisfactorily transferred by the external magnetic field Hex2, as described in "(2) When transferring to Hec2 medium with Hex2."
[0024]
Thereafter, in the second transfer step shown in FIG. 2C, another master disk 2 is preferably superimposed on the magnetic recording medium 1, and an external magnetic field Hex1 (magnetic field in the same direction as the initial magnetization) is applied. . At this time, the recording layer 1a having the coercive force Hc1 is satisfactorily transferred by the external magnetic field Hex1, as described in "(1) When transferring to Hec1 medium with Hex1". On the other hand, the recording layer 1b having the coercive force Hc2 is not written by the external magnetic field Hex1 as described in "(4) When transferring to the medium of Hc2 with Hex1," and the magnetization before the second transfer process is not performed. Retained.
[0025]
The above transfer method is summarized as follows.
(1) In a magnetic recording medium having two recording layers, the upper recording layer has a coercive force Hc1 and the lower recording layer has a coercive force Hc2.
(2) It is assumed that there is a relationship of Hc1 << Hc2 between the coercive forces of each other.
(3) An external magnetic field Hex2 is applied in the first transfer process. At this time, between the recording magnetic fields Ha, Hb, Hg and the coercive forces Hc1, Hc2, Hb >> Hc2, Hg >> Hc2, and Ha << Hc2, and Hb >> Hc1, Hg >> Hc1, and Ha>. > Hc1 holds. Therefore, good transfer is performed only on the lower recording layer 1b, and no transfer is performed on the upper recording layer 1a. Instead, the upper recording layer 1a is uniformly magnetized in the opposite direction to the initial magnetization.
(4) An external magnetic field Hex1 is applied in the second transfer step. At this time, between the recording magnetic fields Ha, Hb, Hg and the coercive forces Hc1, Hc2, Hb << Hc2, Hg << Hc2, and Ha << Hc2, and Hb >> Hc1, Hg >> Hc1, and Ha <. <Hc1 holds. Therefore, this time, good transfer is performed only on the upper recording layer 1a, and the lower recording layer 1b is not affected and the magnetization pattern is maintained.
[0026]
In this manner, it is possible to independently transfer the soft magnetic pattern of the master disk to each layer of the recording medium having two recording layers.
[0027]
【Example】
Furthermore, specific examples of implementation of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 3 shows the steps of the first embodiment of the present invention. In this embodiment, the coercive force Hc1 of the upper recording layer 1a of the magnetic recording medium 1 having two recording layers is 3000 (Oe), and the coercive force Hc2 of the lower recording layer 1b is 6000 (Oe). This embodiment is intended to perform magnetic transfer only on the recording layer 1b by a transfer process. In the initialization step of FIG. 3A, the magnetic recording medium 1 is initially magnetized together with an external transfer magnetic field of about 7000 (Oe).
[0028]
Thereafter, in the transfer step of FIG. 3B, transfer is performed with an external magnetic field Hex6000 (Oe) in the direction opposite to the initial magnetization. By this transfer, the recording layer 1a is uniformly magnetized and the soft magnetic pattern 3a of the master disk 3 is transferred only to the recording layer 1b. The line width of the soft magnetic pattern 3a on the used master disk 3 is 0.5 μm to 3 μm, and the thickness of the soft magnetic layer is 500 nm. The master disk substrate is a single crystal silicon substrate, and the material of the soft magnetic pattern is pure cobalt.
[0029]
(Second embodiment)
FIG. 4 shows the steps of the second embodiment of the present invention. Also in the second embodiment, the coercive force Hc1 of the recording layer 1a of the magnetic medium having two recording layers is 3000 (Oe), and the coercive force Hc2 of the recording layer 1b is 6000 (Oe). In this embodiment, magnetic transfer is independently performed on the recording layer 1b by the first transfer step and on the recording layer 1a by the second transfer step.
[0030]
4A, the magnetic recording medium 1 is initially magnetized in the recording layers 1a and 1b by an external transfer magnetic field of about 7000 (Oe).
Thereafter, in the first transfer process of FIG. 4B, transfer is performed with an external magnetic field 6000 (Oe) in the direction opposite to the initial magnetization. By this transfer, the recording layer 1a is uniformly magnetized and the soft magnetic pattern 3a of the master disk 3 is transferred only to the recording layer 1b.
[0031]
Next, in the second transfer step of FIG. 4C, transfer is performed with an external magnetic field 3000 (Oe) in the same direction as the initial magnetization. By this transfer, the recording layer 1b is not affected by the change in magnetization, and the soft magnetic pattern 3a of the master disk 3 is transferred only to the recording layer 1a. The second embodiment corresponds to the case where the master disks used in the first and second transfer processes are the same.
[0032]
(Third embodiment)
FIG. 5 shows the steps of a third embodiment of the present invention. The third embodiment corresponds to the case where the master disk patterns used in the first transfer process and the second transfer process are different.
Also in the third embodiment, the coercive force Hc1 of the recording layer 1a of the magnetic medium having two recording layers is 3000 (Oe), and the coercive force Hc2 of the recording layer 1b is 6000 (Oe).
[0033]
In the initialization step of FIG. 5A, the magnetic recording medium 1 is initially magnetized together with the quantity recording layers 1a and 1b by an external transfer magnetic field of about 7000 (Oe).
Thereafter, in the first transfer process of FIG. 5B, transfer is performed with an external magnetic field 6000 (Oe) in the direction opposite to the initial magnetization. By this transfer, the recording layer 1a is uniformly magnetized and the soft magnetic pattern 2a of the master disk 2 is transferred only to the recording layer 1b.
[0034]
Next, in the second transfer process of FIG. 5C, the master disk 3 is used in place of the master disk 2 in the first transfer process, and is transferred with an external magnetic field 3000 (Oe) in the same direction as the initial magnetization. I do. By this transfer, the recording layer 1b is not affected by the change in magnetization, and the soft magnetic pattern 3a of the master disk 3 is transferred only to the recording layer 1a.
[0035]
In this way, by changing the pattern of the master disk used in the first transfer step and the second transfer step, for example, the upper layer 1a of the magnetic recording medium 1 is used as the data layer, and the lower layer 1b is used when writing data to the upper layer. Servo signal layer that does not disappear.
(Fourth embodiment)
FIG. 6 shows an embodiment of a cross-sectional structure of a magnetic recording medium having two recording layers corresponding to the second invention of the present invention. As shown in FIG. 6, first, a nonmagnetic first underlayer 10 is formed on a medium substrate 9 made of aluminum or glass by sputtering for the purpose of controlling the easy magnetic axis direction of the recording layer. An alloy such as CoCr, CoW, or CoTi is used as the material for the underlayer 10.
[0036]
A metal magnetic film (for example, a magnetic film made of an alloy material such as CoCrPtTa or CoCrPtB) is formed on the underlayer 10 with, for example, metal Co as a main component and Pt, Cr, Ta, B, or the like added to it by several to dozens. The lower recording layer 11 (corresponding to the lower recording layer 1b in FIGS. 2 to 5) is formed.
Next, a nonmagnetic separation layer 12 mainly composed of Co such as CoCr, CoW, and CoTi, and a nonmagnetic second underlayer 13 mainly composed of Co such as CoCr, CoW, and CoTi are formed. . Here, the underlayer 13 and the separation layer 12 are alloy materials mainly composed of Co, but are different in composition and combination of materials.
[0037]
On the underlayer 13, an upper recording layer 14 (corresponding to the upper recording layer 1a in FIGS. 2 to 5) is formed. The recording layer 14 is an alloy composed mainly of the same metal Co as that of the recording layer 11 and added with Pt, Cr, Ta, B, etc., but for the purpose of lowering the coercive force than the recording layer 11, the composition of the added metal is used. Is different.
Finally, a carbon film (carbon protective layer) 15 is formed on the recording layer 14 for the purpose of protecting the magnetic film from corrosion or deterioration due to friction with the recording write / read head.
[0038]
【The invention's effect】
As described above, according to the present invention, different magnetic signals can be independently transferred to each recording layer of a magnetic recording medium having two recording layers. And the lower layer can be a servo signal layer that does not disappear even when data is written to the upper layer.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an embodiment of the present invention, and how an external magnetic field Hex1 and Hex2 having different magnitudes are applied to magnetic recording media having different coercive forces Hc1 and Hc2. It is a graph explaining whether a simple transfer is performed.
FIG. 2 is a diagram for explaining an embodiment of the present invention. When four combinations of coercive forces Hc1 and Hc2 and external magnetic fields Hex1 and Hex2 are used, each layer of a recording medium having two recording layers is used. It is process drawing explaining the principle which becomes possible to transfer the soft magnetic pattern of a master disk independently.
FIG. 3 is a process diagram of the first embodiment of the present invention.
FIG. 4 is a process diagram of a second embodiment of the present invention.
FIG. 5 is a process diagram of a third embodiment of the present invention.
FIG. 6 is a sectional view showing an example of a sectional structure of a magnetic recording medium having two recording layers as a fourth embodiment of the present invention.
FIG. 7 is a process diagram for explaining the prior art.
FIGS. 8A and 8B are diagrams for explaining the prior art, in which FIG. 8A is a cross-sectional view showing an enlarged magnetic field distribution around a soft magnetic pattern, and FIG. 8B is a horizontal view of magnetic flux on a magnetic recording medium; It is a graph showing distribution of a component.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Recording layer 1b on the magnetic recording medium 1a Recording layer 2 under the master 2 Master disk 3 Master disk 4 Permanent magnet which comprises a ring type head 5 Yoke which consists of a soft magnetic material which comprises a ring type head 6 External magnetic field of initialization process Direction 7 Direction of external magnetic field in transfer process 8 Direction of external magnetic field in second transfer process 9 Media substrate 10 First underlayer 11 Recording layer 12 below Separation layer 13 Recording layer 15 on second underlayer 14 Carbon Protective layer

Claims (4)

A magnetic transfer master disk consisting of a non-magnetic substrate with a soft magnetic layer processed into a linear or island-shaped pattern embedded in the surface portion is in close contact with or close to the surface of the magnetic recording medium, and a magnetic field is applied from the outside. By applying the magnetic information, the information written in the soft magnetic pattern is magnetically transferred to the magnetic recording layer composed of the recording layer on the magnetic recording medium and the lower recording layer having a larger coercive force. A magnetic transfer method,
An initialization step of initializing the magnetic recording medium by applying a horizontal magnetic field to the magnetic recording medium;
After executing the initialization step, a horizontal magnetic field in a direction opposite to the applied magnetic field of the initialization step is applied to both the magnetic transfer master disk and the magnetic recording medium with the magnetic transfer master disk overlaid on the magnetic recording medium. Applying a first transfer step;
After executing the first transfer step, the magnetic transfer master disk is overlapped with the magnetic recording medium, and both the magnetic transfer master disk and the magnetic recording medium are horizontal in the same direction as the applied magnetic field of the initialization step. A second transfer step of applying a magnetic field,
In the first transfer step, an applied magnetic field larger than the coercive force of the lower recording layer and the coercive force of the upper recording layer is applied, and information is transferred only to the lower recording layer,
In the second transfer step, an applied magnetic field smaller than the coercive force of the lower recording layer and larger than the coercive force of the upper recording layer is applied, and information is transferred only to the upper recording layer. Magnetic transfer method to a magnetic recording medium provided with two recording layers. As the magnetic transfer master disk, the first magnetic transfer master disk is used in the first transfer process, and the second magnetic transfer master disk is replaced with the first magnetic transfer master disk in the second transfer process. A method of magnetic transfer to a magnetic recording medium comprising two recording layers according to claim 1 . The coercive force of the recording layer on the magnetic recording medium is Hc1, the coercive force of the lower recording layer is Hc2, the applied magnetic field in the first transfer step is Hex2, and the applied magnetic field in the second transfer step is Hex1. And Hc1 << Hc2, Hex1 << Hex2, Hc1 << Hex2, and Hex1 << Hc2, respectively. Magnetic properties on a magnetic recording medium having two recording layers according to claim 1 or 2 , Transcription method. By making the patterns of the first magnetic transfer master disk and the second magnetic transfer master disk different, the upper recording layer is a data layer and the lower recording layer is a data write to the upper recording layer. magnetic transfer method of the recording layer to the magnetic recording medium having two layers according to any one of claims 1 to 3, also characterized by a servo signal layer indelible when.

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