JP5001768B2 - Method for manufacturing perpendicular magnetic recording disk - Google Patents

Description

  The present invention relates to a method of manufacturing a perpendicular magnetic recording disk mounted on a perpendicular magnetic recording type HDD (hard disk drive) or the like.

  Various information recording techniques have been developed with the recent increase in information processing capacity. In particular, the surface recording density of HDDs using magnetic recording technology continues to increase at an annual rate of about 100%. Recently, an information recording capacity exceeding 160 GB has been required for a 2.5-inch diameter perpendicular magnetic recording disk used for HDDs and the like, and in order to meet such a demand, one square is required. It is required to realize an information recording density exceeding 250 Gbits per inch.

  In order to achieve a high recording density in a magnetic recording disk used for an HDD or the like, a perpendicular magnetic recording disk of a perpendicular magnetic recording system has recently been proposed. The perpendicular magnetic recording system is adjusted so that the easy axis of magnetization of the magnetic recording layer is oriented in the direction perpendicular to the substrate surface. The perpendicular magnetic recording method can suppress the thermal fluctuation phenomenon as compared with the conventional in-plane recording method, and is suitable for increasing the recording density.

  In the perpendicular magnetic recording system, a single pole type perpendicular head is used to generate a magnetic field perpendicular to the magnetic recording layer. However, simply using a single magnetic pole type vertical head makes it impossible to apply a sufficiently strong magnetic field to the magnetic recording layer because the magnetic flux exiting the single magnetic pole end immediately returns to the return magnetic pole on the opposite side. Therefore, a strong magnetic field in the perpendicular direction is applied to the magnetic recording layer by providing a soft magnetic layer under the magnetic recording layer of the perpendicular magnetic recording disk and forming a magnetic path in the soft magnetic layer. That is, the soft magnetic layer is a layer in which the magnetization direction is aligned by a magnetic field when writing and dynamically forms a magnetic path.

  The soft magnetic layer is a layer used at the time of writing, and the magnetization direction is aligned along the magnetic field at the time of writing. However, since a magnetic field that aligns the magnetization direction is not applied to the soft magnetic layer when reading, the magnetization direction is scattered in an irregular direction in principle. This irregular direction is a three-dimensional direction, and if a perpendicular component is included in the magnetization direction of the soft magnetic layer, it may be picked up as noise together with the signal of the magnetic recording layer when reading by the magnetic head.

  Therefore, an AFC (Antiferro-magnetic exchange coupling) structure in which the soft magnetic layer is divided into two layers and a nonmagnetic spacer layer is interposed between the two layers has been proposed and implemented. In the AFC structure, the magnetization direction is reversed between the lower layer and the upper layer, and they are coupled and fixed by attracting each other (exchange coupling). Therefore, the magnetization directions of the soft magnetic layers when no magnetic field is applied are antiparallel to each other (parallel and opposite to each other), that is, parallel to the main surface of the substrate. As a result, the noise generated from the soft magnetic layer can be reduced because the perpendicular component of magnetization is extremely reduced.

  The strength of exchange coupling in the AFC structure is represented by an exchange coupling magnetic field Hex. As the Hex is stronger, the magnetization direction of the soft magnetic layer is less affected by the external magnetic field, and the magnetic path formation due to the leakage magnetic field can be prevented, so that the SNR (Signal-Noise Ratio) can be improved.

  Further, since the soft magnetic layer originally has a weak coercive force (Hc) and is amorphous, it has not been discussed that a magnetic domain is formed. However, subsequent research has revealed that magnetic domains are formed in the single soft magnetic layer before the AFC medium, and no magnetic domains are formed in the AFC medium.

  A magnetic domain is a region in which the magnetization direction is the same direction. When a magnetic domain (domain) is formed, a domain wall (domain wall) is formed at the boundary of the magnetic domain. Since the magnetization direction of the domain wall is reversed, when the magnetic head passes through the domain wall, the signal level is suddenly increased and detected as spike noise.

However, since the two soft magnetic layers are each made into a single magnetic domain by forming the AFC structure and it is possible to prevent the occurrence of domain walls, spike noise can be reduced. That is, it was found that the AFC medium not only eliminated the perpendicular component of the magnetization direction but also contributed to the prevention of spike noise.
JP200345015

  As described above, in the AFC medium, as the exchange coupling magnetic field (Hex) increases, the magnetization stability of the soft magnetic layer increases, and noise caused by the soft magnetic layer can be suppressed. Therefore, in order to improve the reproduction signal quality, it is indispensable to increase the Hex of the soft magnetic layer, but the size of Hex is not necessarily sufficient in the AFC structure of the soft magnetic layer which is currently mainstream.

  Accordingly, an object of the present invention is to provide a method of manufacturing a perpendicular magnetic recording disk capable of increasing the SNR by increasing the Hex of the soft magnetic layer and improving the reproduction signal quality.

  As a cause of hindering the increase in Hex, the inventors have intensively studied. When a soft magnetic layer is formed by DC magnetron sputtering (hereinafter abbreviated as sputtering), it is used to apply a magnetic field to plasma. It was conceived that the leakage magnetic field of the rotating magnet affected the vicinity of the substrate surface. That is, the layer formed by sputtering is formed in the leakage magnetic field of the rotating magnet, so that the easy axis of magnetization is oriented in the direction of the magnetic field while migration occurs, and is fixed in that state. As a result, the magnetization direction has anisotropy in one direction (radial direction).

  Here, since the two soft magnetic layers formed above and below the spacer layer are formed by the same apparatus and procedure, the magnetization direction has anisotropy in the same direction. After that, it is considered that the easy magnetization axis of one soft magnetic layer of the two soft magnetic layers is reversed in the antiparallel direction and exchange-coupled with the easy magnetization axis of the other soft magnetic layer. Further, the inventors require a large amount of energy to perform exchange coupling by reversing the magnetization easy axis of one soft magnetic layer with respect to the original magnetization direction (during film formation), and the coupling is weak. Or found that it is unstable. As a result, Hex is reduced, and it is conceived that the improvement of the reproduction signal quality, particularly the signal-to-noise ratio (SNR) is hindered, and the present invention has been completed.

  That is, according to the typical configuration of the present invention, at least the first soft magnetic layer, the nonmagnetic spacer layer, the second soft magnetic layer, and the magnetic recording layer are provided on the substrate in this order. In the method of manufacturing a perpendicular magnetic recording disk in which the magnetic layer and the second soft magnetic layer have an antiferromagnetic exchange coupling (AFC) structure, the first soft magnetic layer is formed while applying a magnetic field inward or outward in the radial direction. The second soft magnetic layer is formed while applying a magnetic field in a direction opposite to that when forming the first soft magnetic layer.

  According to the above method, by changing the magnetic field when forming the two soft magnetic layers, the first soft magnetic layer and the second soft magnetic layer have respective opposite magnetization directions at the stage of film formation. Become. As a result, since the easy magnetization axis of any soft magnetic layer is not reversed, the energy required for exchange coupling is reduced, and stable coupling can be achieved. Therefore, Hex can be increased.

  When forming the first soft magnetic layer or the second soft magnetic layer, the main surface of the substrate may be formed by applying a magnetic field in the same direction, either inward or outward in the radial direction. .

  Originally, the purpose of applying a magnetic field at the time of film formation by sputtering is to attract the plasma-targeted particles to the substrate. However, as a result of the leakage magnetic field passing through the substrate, the soft magnetic layer was magnetized due to the influence of the leakage magnetic field. Then, as described above, rotating magnets are installed on both sides of the main surface of the substrate, and by applying a magnetic field in the same direction, either inward or outward in the radial direction, the magnetic flux passing between the rotating magnets increases, and positively In particular, the magnetic field applied to the substrate increases. From this, the magnetization direction of the soft magnetic layer can be more reliably oriented.

  Further, when forming the first soft magnetic layer or the second soft magnetic layer, it is preferable to deposit only a single substrate in the same chamber.

  By depositing only a single substrate in the same chamber and forming a film, a circular and radial magnetic field can be formed on the main surface of the substrate without being affected by other magnetic fields, and the magnetization of the soft magnetic layer It becomes possible to make the direction constant in all directions.

  As described above, according to the method for manufacturing a perpendicular magnetic recording disk according to the present invention, the perpendicular magnetic recording disk capable of increasing the SNR and increasing the reproduction signal quality by increasing the Hex of the soft magnetic layer. Can be manufactured.

[Example]
An embodiment of a method for manufacturing a perpendicular magnetic recording disk according to the present invention will be described. FIG. 1 is a diagram for explaining the configuration of a perpendicular magnetic recording disk according to this embodiment. Note that dimensions, materials, and other specific numerical values shown in the following embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified.

  FIG. 1 is a diagram for explaining the configuration of a perpendicular magnetic recording disk 100 according to the present embodiment. A perpendicular magnetic recording disk 100 shown in FIG. 1 includes a substrate 10, an adhesion layer 12, a first soft magnetic layer 14a, a spacer layer 14b, a second soft magnetic layer 14c, an orientation control layer 16, a first underlayer 18a, and a second lower layer. The base layer 18b, the miniaturization promoting layer 20, the first magnetic recording layer 22a, the second magnetic recording layer 22b, the auxiliary recording layer 24, the medium protective layer 26, and the lubricating layer 28 are formed. The first soft magnetic layer 14a, the spacer layer 14b, and the second soft magnetic layer 14c together constitute the soft magnetic layer 14. The first base layer 18a and the second base layer 18b together constitute the base layer 18. The first magnetic recording layer 22a and the second magnetic recording layer 22b constitute the magnetic recording layer 22 together.

  First, an amorphous aluminosilicate glass was formed into a disk shape by direct pressing to produce a glass disk. This glass disk was subjected to grinding, polishing, and chemical strengthening in order to obtain a smooth nonmagnetic substrate 10 made of a chemically strengthened glass disk.

  The substrate 10 is preferably nonmagnetic glass. Specific examples include aluminosilicate glass, aluminoborosilicate glass, soda lime glass, and aluminosilicate glass is particularly preferable. Since the aluminosilicate glass is smooth and has high rigidity, the magnetic spacing, particularly the flying height of the magnetic head, can be more stably reduced. Aluminosilicate glass can obtain high rigidity and strength by chemical strengthening. When the soft magnetic layer is amorphous, the substrate is preferably made of amorphous glass.

  On the obtained substrate 10, a film forming apparatus that performs evacuation is used to sequentially form a film from the adhesion layer 12 to the auxiliary recording layer 24 by sputtering in an Ar atmosphere, and the medium protective layer 26 is formed by a CVD method. Was formed. Thereafter, the lubricating layer 28 was formed by dip coating. Note that it is also preferable to use an in-line film forming method in terms of high mass productivity. Hereinafter, the configuration and manufacturing method of each layer will be described in detail.

  The adhesion layer 12 was formed using a Ti alloy target so as to be a 10 nm Ti alloy layer. By forming the adhesion layer 12, the adhesion between the base 10 and the soft magnetic layer 14 can be improved, so that the soft magnetic layer 14 can be prevented from peeling off. As a material of the adhesion layer 12, for example, a CrTi alloy can be used. From the practical viewpoint, the thickness of the adhesion layer is preferably 1 nm to 50 nm.

  The soft magnetic layer 14 has an AFC (Antiferro-magnetic exchange coupling) structure by interposing a nonmagnetic spacer layer 14b between the first soft magnetic layer 14a and the second soft magnetic layer 14c. It was configured to provide. Thereby, the magnetization direction of the soft magnetic layer 14 can be aligned along the magnetic path (magnetic circuit), and the noise generated from the soft magnetic layer 14 can be reduced by reducing the perpendicular component of the magnetization.

  FIG. 2 is an explanatory diagram for explaining the magnetization characteristics of the AFC structure. Referring to such magnetization characteristics, a soft magnetic layer having no AFC structure maintains a positive or negative magnetization state when an external magnetic field H is not applied, whereas a soft magnetic layer having an AFC structure has a magnetic field H Is not applied, a magnetic flux is formed between the first soft magnetic layer 14a and the second soft magnetic layer 14c as shown in (b), and the magnetization M becomes zero. When a magnetic field H is applied in either direction, the magnetic fluxes of both soft magnetic layers 14a and 14c are oriented in the same direction as indicated by arrows (a) and (c).

  The coupling strength of the AFC structure is determined based on the exchange coupling magnetic field (Hex) shown in FIG. 2, and the larger the Hex, the stronger the coupling (exchange coupling) of AFC. The Hex is set so as to be magnetized with respect to the magnetic field for writing of the corresponding magnetic recording layer 22 and not to react with the magnetic field for writing of the adjacent magnetic recording layer 22.

  The composition of the soft magnetic layer 14 is CoCrFeB, but is not particularly limited, and a known soft magnetic material can be used. For example, FeCo alloys (FeCoB, FeCoSiB, FeCoZr, FeCoTaZr, FeCoZrB, etc.), Fe alloys (FeTaN, FeTaC, etc.), Co alloys (CoTaZr, CoZrNb, CoB, etc.) and the like can be mentioned. The composition of the spacer layer 14b is preferably Ru (ruthenium).

  The total thickness of the soft magnetic layer 14 is 20 nm to 120 nm, preferably 30 nm to 100 nm. If the total thickness of the soft magnetic layer 14 is less than 20 nm, the overwrite (OW) characteristics may be affected.

  The soft magnetic layer 14 is formed by sputtering. FIG. 3 is an explanatory diagram for explaining an image of DC magnetron sputtering. When performing sputtering, a high voltage is applied between the target 30 and the shield 32 to turn Ar into plasma and ionize the target 30 particles. In order to attract the ionized vapor deposition particles to the substrate 10, a magnetic field 38 is applied by the rotating magnet 36. As shown in FIG. 3, a rotating magnet is installed behind the target so as to face the main surface of the substrate 10 installed on the holder 34.

  When forming the first soft magnetic layer 14 a, as shown in FIG. 3A, a rotating magnet 36 that generates a radially outward magnetic field 38 is used, and the first soft magnetic layer 14 a is formed while applying the magnetic field 38. When the second soft magnetic layer 14c is formed, as shown in FIG. 3B, a magnetic field 38 is generated in a direction opposite to that at the time of forming the first soft magnetic layer 14a, that is, inward in the radial direction. Using a rotating magnet, the film is formed while applying a magnetic field.

  By making the magnetic field 38 applied at the time of forming each soft magnetic layer in the reverse direction as in the above process, the magnetization direction of the soft magnetic layer 14 is reversed between the first soft magnetic layer 14a and the second soft magnetic layer 14c. become. As a result, when the first soft magnetic layer 14a and the second soft magnetic layer 14c form an AFC structure, the magnetization axis of one soft magnetic layer does not need to be reversed in the reverse direction, the coupling is stabilized, and Hex is reduced. It can be increased. In the above process, the same effect can be obtained even if the direction of the magnetic field of the rotating magnet is reversed when the first soft magnetic layer 14a is formed and when the second soft magnetic layer 14c is formed.

  Further, when the soft magnetic layer 14 is formed in the above process, the rotating magnet 36 is installed on both sides of the main surface of the substrate 10 and the magnetic field 38 is applied to form the soft magnetic layer 14 so that the soft magnetic layer 14 can be removed from one rotating magnet 36. Thus, a magnetic field 38 reaching the other rotating magnet 36 is generated. As a result, a magnetic field in the same direction, either inward or outward in the radial direction, is applied to both main surfaces of the substrate. Since the magnetic field 38 passes through the substrate 10, the magnetic field 38 can be positively applied to the substrate 10, and the magnetization direction of the soft magnetic layer can be more reliably oriented.

  Furthermore, if two substrates 10 are put into one chamber, the same number of rotating magnets 36 as the substrates 10 need to be arranged. However, if a plurality of rotating magnets 36 are arranged (arranged), the magnetic fields influence each other, and the magnetic field applied to the substrate 10 is not necessarily circular. Therefore, when the soft magnetic layer 14 is formed, only the single substrate 10 is placed in one chamber and formed, so that the main surface of the substrate 10 is circular and radial without being affected by other magnetic fields. Thus, the magnetization direction of the soft magnetic layer 14 can be made constant in all directions.

  The orientation control layer 16 has an action of protecting the soft magnetic layer 14 and an action of promoting alignment of crystal grains of the underlayer 18. The orientation control layer 16 preferably has an fcc structure or an hcp structure. The material of the orientation control layer 16 can be selected from Ni, Cu, Pt, Pd, Zr, Hf, and Nb. Furthermore, it is good also as an alloy which contains these metals as a main component and contains any one or more additional elements of Ti, V, Ta, Cr, Mo, and W. For example, NiW, CuW, or CuCr can be suitably selected. The film thickness is preferably 50 nm or less. If it exceeds 50 nm, the overwrite (OW) characteristics may be affected.

  The underlayer 18 has an hcp structure, and the crystal of the hcp structure of the magnetic recording layer 22 can be grown as a granular structure. Therefore, the higher the crystal orientation of the underlayer 18 is, the more the orientation of the magnetic recording layer 22 can be improved. The material of the underlayer 18 can be selected from RuCr and RuCo in addition to Ru. Ru has an hcp structure and can satisfactorily orient the magnetic recording layer containing Co as a main component.

  In this embodiment, the underlayer 18 has a two-layer structure made of Ru. When forming the second base layer 18b on the upper layer side, the Ar gas pressure is set higher than when forming the first base layer 18a on the lower layer side. When the gas pressure is increased, the free movement distance of the plasma ions to be sputtered is shortened, so that the film formation rate is reduced and the crystal orientation can be improved. Moreover, the size of the crystal lattice is reduced by increasing the pressure. Since the size of the Ru crystal lattice is larger than that of the Co crystal lattice, if the Ru crystal lattice is made smaller, it approaches that of Co, and the crystal orientation of the Co granular layer can be further improved.

The miniaturization promoting layer 20 is a nonmagnetic granular layer. A nonmagnetic granular layer is formed on the hcp crystal structure of the underlayer 18, and the granular layer of the first magnetic recording layer 22 a is grown thereon, whereby the magnetic granular layer is grown from the initial growth stage (rise). Has the effect of separating. The composition of the miniaturization promoting layer 20 was nonmagnetic CoCr—SiO ₂ .

  The magnetic recording layer 22 includes a thin first magnetic recording layer 22a and a thick second magnetic recording layer 22b.

The first magnetic recording layer 22a is a 2 nm CoCrPt—Cr ₂ O ₃ hcp crystal structure using a hard magnetic target made of CoCrPt containing chromium oxide (Cr ₂ O ₃ ) as an example of a nonmagnetic substance. Formed. The nonmagnetic material segregated around the magnetic material to form grain boundaries, and the magnetic particles (magnetic grains) formed a columnar granular structure. The magnetic grains were epitaxially grown continuously from the granular structure of the miniaturization promoting layer.

The second magnetic recording layer 22b was formed using a CoCrPt—TiO ₂ hcp crystal structure of 10 nm using a hard magnetic target made of CoCrPt containing titanium oxide (TiO ₂ ) as an example of a nonmagnetic substance. Also in the second magnetic recording layer 22b, the magnetic grains formed a granular structure.

The magnetic recording layer 22 may be made of a known hard magnetic material other than those described above. Specifically, a CoCrPt-based material, a CoCrPt-O-based material, a CoCrPt-oxide (SiO ₂ , Ta ₂ O _5, etc.)-Based material, or the like can be given. Also, rare earth metals can be added for the purpose of improving SNR characteristics.

  The film thickness of the magnetic recording layer 22 is preferably in the range of 10 nm to 30 nm, for example. In this embodiment, the magnetic recording layer 22 has a two-layer structure, but it may have a single-layer structure or a structure of two or more layers made of materials having different compositions.

  The auxiliary recording layer 24 forms a CGC structure (Coupled Granular Continuous) by forming a thin film (continuous layer) showing high perpendicular magnetic anisotropy on the granular magnetic layer. Thereby, in addition to the high density recording property and low noise property of the granular layer, the high thermal fluctuation resistance of the continuous film can be added. The composition of the auxiliary recording layer 24 was CoCrPtB.

The medium protective layer 26 was formed by depositing carbon by a CVD method while maintaining a vacuum. The medium protective layer 26 is a protective layer for protecting the magnetic recording layer 22 from the impact of the magnetic head. In general, carbon deposited by the CVD method has improved film hardness as compared with that deposited by sputtering, so that the magnetic recording layer 22 can be more effectively protected against the impact from the magnetic head. A conventionally known material can be used for the medium protective layer 26. For example, C, SiO ₂ , ZrO ₂ or the like. From the viewpoint of increasing the recording density, the thickness of the medium protective layer is preferably 1 nm or more and 5 nm or less.

  The lubricating layer 28 was formed by dip coating using PFPE (perfluoropolyether). Other known materials can also be used. Specific examples include fluorinated alcohols and fluorinated carboxylic acids. The film thickness of the lubricating layer 28 is about 1 nm.

  Through the above manufacturing process, the perpendicular magnetic recording disk 100 was obtained. The effectiveness of the present invention will be described below using examples and comparative examples.

[Evaluation]
FIG. 4 is a graph showing the relationship between the thickness of the spacer layer and the strength of the exchange coupling magnetic field (Hex) in Examples and Comparative Examples. The embodiment is a perpendicular magnetic recording disk in which a first soft magnetic layer and a second soft magnetic layer are formed while applying a magnetic field in the opposite direction as described above, and the comparative example is in a state where a leakage magnetic field in the same direction is applied. A perpendicular magnetic recording disk having first and second soft magnetic layers formed thereon.

  As shown in FIG. 4, in both the example and the comparative example, when the spacer layer is gradually thickened, Hex increases once and reaches a peak, and when the thickness is further increased, Hex tends to decrease. . Here, when the peak is reached, since the value of Hex is larger in the example than in the comparative example, it is understood that the exchange bond is stronger and the bond is more stable in the example.

  FIG. 5 is a graph showing the relationship between the signal noise ratio (SNR) (dB) and the track width (nm) in the example and the comparative example.

  As shown in FIG. 5, the SNR tends to decrease as the track width becomes narrower. Here, it can be seen that the example shows a higher SNR than the comparative example at any track width. Therefore, according to the present invention, it is possible to provide a perpendicular magnetic recording disk in which the SNR is increased and the reproduction signal quality is improved as long as the track width is the same as the conventional one. In addition, if the reproduction signal quality is the same as that of the prior art, a perpendicular magnetic recording disk with a narrower track width and an improved recording density can be provided.

  Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  The present invention can be used as a method of manufacturing a perpendicular magnetic recording disk mounted on a perpendicular magnetic recording type HDD or the like.

It is a figure explaining the structure of the perpendicular magnetic recording disk concerning this embodiment. It is explanatory drawing for demonstrating the magnetization characteristic by an AFC structure. It is explanatory drawing for demonstrating the image of DC magnetron sputtering. It is a graph which shows the relationship between the film thickness of a spacer layer and the intensity | strength of an exchange coupling magnetic field (Hex) in an Example and a comparative example. It is a graph which shows the relationship between a signal noise ratio (SNR) and a track width (MWW) in an Example and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Base | substrate 12 ... Adhesion layer 14 ... Soft magnetic layer 14a ... First soft magnetic layer 14b ... Spacer layer 14c ... Second soft magnetic layer 16 ... Orientation control layer 18 ... Underlayer 18a ... First underlayer 18b ... Second lower Base layer 20 ... miniaturization promoting layer 22 ... magnetic recording layer 22a ... first magnetic recording layer 22b ... second magnetic recording layer 24 ... auxiliary recording layer 26 ... medium protective layer 28 ... lubricating layer 30 ... target 32 ... shield 34 ... holder 36 ... Rotating magnet 38 ... magnetic field 100 ... perpendicular magnetic recording disk

Claims (3)

On the substrate, at least a first soft magnetic layer, a nonmagnetic spacer layer, a second soft magnetic layer, and a magnetic recording layer are provided in this order, and the first soft magnetic layer and the second soft magnetic layer are antiferromagnetic. In a method of manufacturing a perpendicular magnetic recording disk having an exchange coupling (AFC) structure,
The first soft magnetic layer is formed while applying a magnetic field inward or outward in the radial direction, and the second soft magnetic layer is applied with a magnetic field in a direction opposite to that when forming the first soft magnetic layer. A method of manufacturing a perpendicular magnetic recording disk, wherein film formation is performed while the film is formed.   When forming the first soft magnetic layer or the second soft magnetic layer, a film is formed by applying a magnetic field in the same direction, either radially inward or outward, to both main surfaces of the substrate. The method of manufacturing a magnetic recording disk according to claim 1.   2. The magnetic recording disk according to claim 1, wherein when forming the first soft magnetic layer or the second soft magnetic layer, the film is formed by introducing only a single substrate into the same chamber. Manufacturing method.

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