JP2013175254A - Manufacturing method of magnetic recording medium, and magnetic recording replay device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method that can manufacture a magnetic recording medium permitting to prevent distortion of a soft magnetic lining layer accompanied by thermal imprinting, and prevent diffusion of an element at an interface part between a soft magnetic alloy film and a non-magnetic coupling film, and having excellent magnetic characteristics.SOLUTION: The manufacturing method of the magnetic recording medium is configured to include: a lining layer formation step of forming a soft magnetic lining layer 11 having a plurality of antiferromagnetically coupled soft magnetic alloy films 3 and 5 laminated by interposing a non-magnetic coupling film 4 on a non-magnetic substrate 1; and a patterning step of forming a vertical magnetic recording layer 8 having a magnetically separated magnetic recording pattern 8a using a thermal imprinting scheme on the soft magnetic lining layer 11. In the lining layer formation step, distortion relaxation films A and B are provided between the soft magnetic alloy films 3 and 5 and the non-magnetic coupling film 4.

Description

  The present invention relates to a method for manufacturing a magnetic recording medium used in a hard disk drive (HDD), which is a kind of magnetic recording / reproducing apparatus, and a magnetic recording / reproducing apparatus including a magnetic recording medium manufactured using the same.

  The perpendicular magnetic recording system is a system in which the easy axis of magnetization of the magnetic recording layer provided in the magnetic recording medium is directed from the in-plane direction of the medium in the direction perpendicular to the surface of the medium. In the perpendicular magnetic recording method, the demagnetizing field in the vicinity of the magnetization transition region, which is the boundary between the recording bits, is small, and the higher the recording density, the more stable the magnetic field and the better the thermal fluctuation resistance. It is known that this method is suitable for the above.

  In a perpendicular magnetic recording type magnetic recording medium, when a soft magnetic backing layer made of a soft magnetic alloy is provided between the nonmagnetic substrate and the perpendicular magnetic recording layer, the magnetic recording medium is a so-called perpendicular double-layer medium. Therefore, high recording ability can be obtained. In such a magnetic recording medium, the soft magnetic underlayer plays a role of refluxing the recording magnetic field from the magnetic head. By using a soft magnetic alloy film having a high saturation magnetic flux density, a low coercive force, and a high magnetic permeability as the soft magnetic backing layer, the effect of improving the recording / reproducing efficiency of the magnetic recording medium can be obtained.

  Further, for magnetic recording media, it is required to achieve higher recording density in the future. For this reason, it is required to further increase the coercive force, the high signal-to-noise ratio (SNR), and the high resolution of the perpendicular magnetic recording layer. In recent years, efforts have been made to increase the surface recording density by increasing the track density as well as improving the linear recording density.

  In the latest magnetic recording apparatus, the track density reaches 400 kTPI. As the track density is increased, magnetic recording information between adjacent tracks interferes with each other, and a problem occurs that the magnetization transition region in the boundary region between tracks becomes a noise source and impairs the SNR. This directly leads to a deterioration of the bit error rate (BER), which is an obstacle to an improvement in recording density.

  In order to increase the surface recording density, it is necessary to make the size of each recording bit on the magnetic recording medium finer and ensure as much saturation magnetization and magnetic film thickness as possible for each recording bit. On the other hand, when the recording bit is miniaturized, the minimum magnetization volume per bit is reduced, and there arises a problem that the recording data is lost due to magnetization reversal due to thermal fluctuation.

  For example, when the recording density is 2 Tbpsi, the area occupied by one bit is 322 square nm at the maximum (equivalent diameter of circle is about 18 nm), and the effective area when considering the interaction between adjacent bits is about 193 parallel. It is narrowed to nm (equivalent circle diameter of about 14 nm). If an attempt is made to secure a particle size that can keep the data thermally stable with this area, the number of magnetic particles for maintaining the SNR required in the magnetic recording device cannot be secured. On the other hand, if the number of magnetic particles is ensured by miniaturizing the magnetic particles in order to maintain the SNR, the recorded magnetic data cannot be maintained due to thermal instability resulting from the decrease in volume per magnetic particle.

  Further, as the track density of the magnetic recording medium is increased, the distance between the tracks becomes closer. Therefore, an extremely accurate track servo technique is required in the magnetic recording / reproducing apparatus. For this reason, in a magnetic recording / reproducing apparatus, a method is generally used in which data is written wider during recording, while data is read narrower than during recording during reproduction to eliminate as much influence from adjacent tracks as possible. . However, this method can minimize the influence between tracks, but it is difficult to obtain a sufficient reproduction output, and it is difficult to ensure a sufficient SNR.

In addition, as one of the methods for solving the thermal fluctuation problem in the magnetic recording medium and ensuring sufficient SNR and output, irregularities along the track are formed on the surface of the recording medium, and the tracks are physically separated. Attempts have been made to increase the track density.
For example, Patent Document 1 discloses a magnetic recording medium having a ferromagnetic layer having a convex and concave portion reflecting a convex portion and a concave portion of a soft magnetic layer, and having a recording region magnetically separated from the periphery in the convex portion region. Proposed.
A magnetic recording medium having such a magnetically separated track pattern is generally called a discrete track medium.

  In order to further increase the recording density, irregularities are formed for each bit in the longitudinal direction (circumferential direction) of the track to physically separate magnetic particles from each other, and both between the track and between the bits. A magnetic recording medium in which one magnetic particle is recorded as one bit by using a magnetic recording pattern in which is magnetically separated has been proposed. Such a magnetic recording medium is called a bit patterned medium.

  In the bit patterned medium, both the tracks and the bits are magnetically separated in the magnetic recording pattern, so that the magnetic interaction between them is suppressed. As a result, the stability of the recorded data can be improved. Further, in a bit patterned medium, since one bit is composed of a single magnetic particle, transition noise due to boundary disturbance is suppressed and SNR is improved, so that finer magnetic recording becomes possible. .

  In general, when manufacturing a so-called patterned medium such as a discrete track medium or a bit patterned medium, a mask layer having a shape corresponding to the magnetic recording pattern is formed on the magnetic layer, and etching is performed using this mask layer. The magnetic layer is patterned into a shape corresponding to the magnetic recording pattern by processing.

  In Patent Document 2, as a technique capable of realizing a discrete track medium or a patterned medium, a concavo-convex pattern is formed by thermal imprinting on the surface of the first layer of soft magnetic metal glass, and the concavo-convex pattern of the first layer is formed. A method for manufacturing a perpendicular magnetic recording medium is described in which a nonmagnetic second layer is formed in a state in which the concave portion is filled, and a recording layer is provided above the first layer and the second layer.

  In Patent Document 3, in a perpendicular magnetic recording medium in which a perpendicular magnetic film is provided on a nonmagnetic substrate via a backing magnetic layer, the backing magnetic layer is composed of three layers of ferromagnetic layer / nonmagnetic layer / ferromagnetic layer. By adopting a structure and antiferromagnetic coupling between the ferromagnetic layers, leakage magnetic flux generated from the magnetic wall of the backing magnetic layer is prevented from flowing into the reproducing head, and the domain wall existing in the backing magnetic layer does not move easily. A technique for realizing a perpendicular magnetic recording medium fixed in such a manner and having low noise characteristics is described.

JP 2004-164692 A JP 2010-165392 A JP 2001-331920 A

  In a conventional method for producing a patterned medium, a magnetic recording layer having a magnetically separated magnetic recording pattern is generally formed by performing physical unevenness on the magnetic layer using a mask layer. . After the magnetic recording pattern is formed, the mask layer that is no longer needed is removed from the magnetic recording layer using dry etching or wet etching. For this reason, in the conventional method for manufacturing a patterned medium, when the mask layer is removed from the magnetic recording layer, the magnetic recording layer is contaminated or dissolved, and the magnetic characteristics are impaired. there were.

  In order to solve this problem, for example, as in the technique described in Patent Document 2, a concavo-convex pattern is formed on a soft magnetic metallic glass by thermal imprinting, and magnetically separated using the concavo-convex pattern. It is conceivable to form a magnetic recording layer having a recording pattern. In this case, a magnetic recording layer having a magnetic recording pattern can be formed without forming a mask layer, and a magnetic recording layer having a magnetic recording pattern can be simplified without causing a decrease in magnetic characteristics due to removal of the mask layer. And it can be formed at low cost.

  However, in the technique described in Patent Document 2, a concavo-convex pattern is formed on a soft magnetic metal glass by thermal imprinting. Therefore, by performing thermal imprinting, the thermal imprinting is performed on the nonmagnetic substrate before performing thermal imprinting. In some cases, the laminated film has an adverse effect that contributes to the deterioration of the magnetic characteristics of the magnetic recording medium. Specifically, due to heating associated with thermal imprinting or pressurization by a stamper, strain is introduced into the film laminated on the nonmagnetic substrate before thermal imprinting, or at the interface of the laminated film. There is a risk that the magnetic properties of the manufactured magnetic recording medium may deteriorate due to element diffusion.

  In the magnetic recording medium, when a soft magnetic backing layer is disposed between the nonmagnetic substrate and the perpendicular magnetic recording layer, a plurality of soft magnetic alloy films are sandwiched as a soft magnetic backing layer with a nonmagnetic coupling film interposed therebetween. It is preferable to provide a structure in which a plurality of soft magnetic alloy films are antiferromagnetically bonded by laminating. However, when such a soft magnetic underlayer is formed on a non-magnetic substrate before performing thermal imprinting, the characteristics are likely to deteriorate, particularly due to heating or stamping with thermal imprinting. Therefore, it was a problem.

The present invention has been proposed in view of the above circumstances. A magnetic recording pattern can be formed by using thermal imprinting without forming a mask layer, and softness associated with thermal imprinting can be achieved. Manufacture of a magnetic recording medium that can prevent distortion of the magnetic backing layer and prevent diffusion of elements at the interface between the soft magnetic alloy film and the nonmagnetic coupling film, and can manufacture a magnetic recording medium having high electromagnetic conversion characteristics It aims to provide a method.
It is another object of the present invention to provide a magnetic recording / reproducing apparatus including a magnetic recording medium having high electromagnetic conversion characteristics manufactured using the manufacturing method of the present invention.

  In order to solve the above problem, the present inventor has laminated a plurality of soft magnetic alloy films on a nonmagnetic substrate with a nonmagnetic coupling film interposed therebetween, so that the plurality of soft magnetic alloy films are antiferromagnetically coupled. When a soft magnetic backing layer is formed before thermal imprinting, a soft magnetic backing layer having a strain relaxation film between the soft magnetic alloy film and the nonmagnetic coupling film is formed. Thus, the inventors have found that a magnetic recording medium having excellent magnetic properties can be produced by preventing adverse effects on the soft magnetic backing layer associated with thermal imprinting, and the present invention has been completed.

The present invention provides the following means.
(1) A backing layer forming step of forming a soft magnetic backing layer having a plurality of antiferromagnetically coupled soft magnetic alloy films laminated on a nonmagnetic substrate with a nonmagnetic coupling film interposed therebetween; A patterning step of forming a perpendicular magnetic recording layer having a magnetic recording pattern magnetically separated using a thermal imprint method on a soft magnetic backing layer, the method for producing a magnetic recording medium, A method of manufacturing a magnetic recording medium, comprising: providing a strain relaxation film between the soft magnetic alloy film and the nonmagnetic coupling film in a backing layer forming step.

  (2) In the patterning step, a metal glass film is provided on the soft magnetic backing layer, and an unevenness corresponding to the magnetic recording pattern is formed on the surface of the metal glass film using a thermal imprint method. Forming a film to be a perpendicular magnetic recording layer on the metallic glass film, and planarizing a surface of the film to be the perpendicular magnetic recording layer to magnetically form the film to be the perpendicular magnetic recording layer; The method for manufacturing a magnetic recording medium according to (1), further comprising a flattening step of forming the magnetic recording pattern separately.

(3) The metal glass film is made of PdCuNiP, PdCuPtP, ZrAlNiCu, ZrAlAgCu, TiCuNiSi, ZrCuNiSi, HfCuNiSi, CuZrTi, NiNbTiZr, or an alloy thereof (2) A method for producing the magnetic recording medium according to claim.
(4) The method for manufacturing a magnetic recording medium according to any one of (1) to (3), wherein the nonmagnetic coupling film is made of Ru or a Ru alloy.
(5) The average interatomic distance of the strain relaxation film is between the average interatomic distance of the soft magnetic alloy film and the average interatomic distance of the nonmagnetic coupling film, or the soft magnetic alloy film and (5) The method for producing a magnetic recording medium according to any one of (1) to (4), wherein the average interatomic distance of the nonmagnetic coupling film is the same.

(6) The magnetic recording medium according to any one of (1) to (5), wherein a saturation magnetization (Ms) of the strain relaxation film is equal to or greater than a saturation magnetization of the soft magnetic alloy film. Production method.
(7) The soft magnetic alloy film contains Co, Fe, B, and Nb, and the contents of these elements are Co a atom%, Fe b atom%, B x atom%, and Nb y atom. % ≦ y + b ≦ 84, 14 ≦ a / b ≦ 17, 14 ≦ x ≦ 17, and 0.5 ≦ y ≦ 3 are satisfied (1) to (6) The method for manufacturing a magnetic recording medium according to any one of (6).
(8) The magnetism according to any one of (1) to (7), wherein the strain relaxation film is made of any one selected from the group consisting of Co, Ni, and Fe or an alloy thereof. A method for manufacturing a recording medium.

  (9) A magnetic recording medium manufactured using the method for manufacturing a magnetic recording medium according to any one of (1) to (8), and a magnetic head for recording and reproducing information on the magnetic recording medium. A magnetic recording / reproducing apparatus comprising:

  In the method of manufacturing a magnetic recording medium of the present invention, a soft magnetic backing layer having a plurality of antiferromagnetically coupled soft magnetic alloy films laminated on a nonmagnetic substrate with a nonmagnetic coupling film interposed therebetween is formed. A backing layer forming step, and a patterning step of forming a perpendicular magnetic recording layer having a magnetic recording pattern magnetically separated using a thermal imprint method on the soft magnetic backing layer, In the layer forming step, since a strain relaxation film is provided between the soft magnetic alloy film and the nonmagnetic coupling film, the strain relaxation film prevents distortion of the soft magnetic underlayer accompanying thermal imprinting. The diffusion of elements at the interface between the soft magnetic alloy film and the nonmagnetic coupling film is prevented.

As a result, according to the method for manufacturing a magnetic recording medium of the present invention, it is possible to obtain a magnetic recording medium that has high electromagnetic conversion characteristics and can cope with higher recording density while improving the recording and reproducing characteristics.
Further, in the method for manufacturing a magnetic recording medium according to the present invention, a magnetic recording pattern is formed by using a thermal imprint method, and therefore, compared with a case where physical unevenness processing is performed on a magnetic layer using a mask layer. Thus, the productivity of the magnetic recording medium can be significantly increased.
Moreover, according to the present invention, a magnetic recording / reproducing apparatus including a magnetic recording medium having high electromagnetic conversion characteristics manufactured using the manufacturing method of the present invention can be provided.

FIG. 1 is a cross-sectional view showing an example of a magnetic recording medium manufactured using the method of manufacturing a magnetic recording medium of the present invention. FIG. 2 is a schematic process diagram for explaining the method of manufacturing the magnetic recording medium shown in FIG. 1, and is a schematic cross-sectional view showing the magnetic recording medium in the process of manufacturing. FIG. 3 is a graph showing a DSC curve (Differential scanning calorimetry curve) of the 42.5Pd-30Cu-7.5Ni-20P film. FIG. 4 is a perspective view showing an example of the magnetic recording / reproducing apparatus of the present invention. FIG. 5 is a graph showing the relationship between the annealing temperature of the evaluation samples manufactured in Example 1 and Comparative Examples 1 to 3, and the bias magnetic field (Hbias) acting between the two soft magnetic alloy films.

  Hereinafter, a method for manufacturing a magnetic recording medium and a magnetic recording / reproducing apparatus according to the present invention will be described in detail with reference to the drawings. In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent. In addition, the materials, dimensions, and the like exemplified in the following description are merely examples, and the present invention is not necessarily limited thereto, and can be appropriately modified and implemented without departing from the scope of the invention. .

  Hereinafter, as an example of the method for manufacturing the magnetic recording medium of the present invention, the method for manufacturing the magnetic recording medium shown in FIG. 1 will be described as an example. FIG. 1 is a cross-sectional view showing an example of a magnetic recording medium manufactured using the method of manufacturing a magnetic recording medium of the present invention. A magnetic recording medium 10 shown in FIG. 1 includes a barrier layer 2, a soft magnetic backing layer 11, a metallic glass film 6, an intermediate layer 7, a perpendicular magnetic recording layer 8, a protective layer 9, and a lubricating film (on a nonmagnetic substrate 1. (Not shown) are stacked in this order.

"Non-magnetic substrate"
As the nonmagnetic substrate 1, a metal substrate made of a metal material such as aluminum or aluminum alloy may be used, or a nonmetal substrate made of a nonmetal material such as glass, ceramic, silicon, silicon carbide, or carbon may be used. Good.
Examples of the glass material used for the nonmagnetic substrate 1 include amorphous glass and crystallized glass. As the amorphous glass, for example, general-purpose soda lime glass or aluminosilicate glass can be used. Moreover, as crystallized glass, for example, lithium-based crystallized glass can be used.

"Barrier layer"
The barrier layer 2 has an effect of suppressing corrosion caused by components of the nonmagnetic substrate 1 and adsorbed moisture, and is formed as necessary.
As the barrier layer 2, for example, Cr, Cr alloy, Ti, Ti alloy or the like can be appropriately selected. The thickness of the barrier layer 2 is preferably 2 nm (20 mm) or more.

"Soft magnetic backing layer"
1 includes a first soft magnetic alloy film 3, a nonmagnetic coupling film 4, a second soft magnetic alloy film 5, a nonmagnetic coupling film 4, and a first soft magnetic alloy film. 3 and a second strain relaxation film B disposed between the nonmagnetic coupling film 4 and the second soft magnetic alloy film 5. A soft magnetic backing layer 11 shown in FIG. 1 includes a plurality of soft magnetic alloy films (a first soft magnetic alloy film 3 and a second soft magnetic alloy film 5 in FIG. 1) stacked with a nonmagnetic coupling film 4 interposed therebetween. The first soft magnetic alloy film 3 and the second soft magnetic alloy film 5 are antiferromagnetically coupled by the nonmagnetic coupling film 4.

  The soft magnetic backing layer 11 has a function of increasing the perpendicular component of the magnetic flux generated from the magnetic head provided in the magnetic recording / reproducing apparatus with respect to the substrate surface and the magnetization direction in which information of the perpendicular magnetic recording layer 8 is recorded. And has a function of fixing in a direction perpendicular to the nonmagnetic substrate 1. These functions are particularly remarkable when a magnetic head based on a single magnetic pole structure is used as a recording / reproducing magnetic head.

  The soft magnetic backing layer 11 is desirably amorphous in order to eliminate the domain wall, to make the magnetostriction zero, and to improve the surface flatness. For this reason, when the soft magnetic backing layer 11 is formed on the nonmagnetic substrate 1 before thermal imprinting, it is preferable to avoid crystallization of the soft magnetic backing layer 11 due to thermal imprinting.

  Further, in the magnetic recording medium 10 of the present embodiment, the soft magnetic backing layer 11 has a plurality of antiferromagnetically coupled soft magnetic alloy films 3 and 5 laminated with the nonmagnetic coupling film 4 interposed therebetween. Therefore, it is possible to increase resistance to an external magnetic field and resistance to a WAIT (Wide Area Track Erasure) phenomenon that is a problem peculiar to a perpendicular magnetic recording medium.

  In the present embodiment, the soft magnetic underlayer 11 has a plurality of antiferromagnetically coupled soft magnetic alloy films 3 and 5 stacked with the nonmagnetic coupling film 4 interposed therebetween. The bias magnetic field Hbias acting between the two layers of the soft magnetic alloy film 3.5 can be 50 Oe or more. On the other hand, when the two soft magnetic alloy films arranged with the nonmagnetic coupling film interposed therebetween are not antiferromagnetically coupled, it is difficult to set the bias magnetic field Hbias to 50 Oe or more.

(Soft magnetic alloy film)
In this embodiment, the material of the soft magnetic alloy film used for the first soft magnetic alloy film 3 and the second soft magnetic alloy film 5 may be the same or different. As a material used for the soft magnetic alloy film, it is preferable to use a material that is difficult to be crystallized by heating accompanying a thermal imprint method described later.

Examples of the material that is difficult to be crystallized by heating accompanying the thermal imprint method include an amorphous or microcrystalline structure material including at least one selected from Fe, Ni, and Co.
Specific examples of the material for such a soft magnetic alloy film include CoFe alloys (CoFeTaZr, CoFeZrNb, etc.), FeCo alloys (FeCo, FeCoB, FeCoV, etc.), FeNi alloys (FeNi, FeNiMo, FeNiCr, FeNiSi, etc.). FeAl alloys (FeAl, FeAlSi, FeAlSiCr, FeAlO, etc.), FeTa alloys (FeTa, FeTaC, FeTaN, etc.), FeMg alloys (FeMgO, etc.), FeZr alloys (FeZrNb, FeZrN, etc.), FeC alloys, FeN Alloy, FeSi alloy, FeP alloy, FeNb alloy, FeHf alloy, FeB alloy and the like.

In addition, as a material for a soft magnetic alloy film that is difficult to crystallize, a Co alloy containing Co as a main component and containing at least one of Zr, Nb, Ta, Cr, Mo, etc., and having an amorphous or microcrystalline structure can be given. It is done.
Specific examples of such a soft magnetic alloy film include CoZr, CoZrNb, CoZrTa, CoZrCr, and CoZrMo.

In particular, in the present invention, the soft magnetic alloy film is preferably made of a soft magnetic alloy having an amorphous structure that does not contain nanocrystalline particles (hereinafter, sometimes referred to as “soft magnetic alloy A”).
Such a soft magnetic alloy A contains, for example, Co, Fe, B, Nb, and the content of these elements is Co: a atomic%, Fe: b atomic%, B: x atomic%, Nb And y satisfying the relationship of 80 ≦ a + b ≦ 84, 14 ≦ a / b ≦ 17, 14 ≦ x ≦ 17, and 0.5 ≦ y ≦ 3.

The soft magnetic alloy A contains Co, Fe, B, Nb in the above content, further contains Si, and the relationship of 0.5 ≦ z ≦ 6 when the Si content is z atomic%. May be satisfied.
B (or B and Si) which is a metalloid element has a negative heat of mixing with respect to Fe and Co which are main constituent elements, and forms a eutectic to lower the melting point of the soft magnetic alloy A. It is. When the soft magnetic alloy A forming such a eutectic alloy is thinned, the soft magnetic alloy A is solidified in an amorphous state without a crystal structure, and becomes a soft magnetic alloy film that exhibits good soft magnetic properties.

  In addition, since the soft magnetic alloy film made of the soft magnetic alloy A does not contain nanocrystalline particles, the progress of crystallization based on the nanocrystalline particles generated by performing thermal imprinting is promoted. The soft magnetic alloy film is suppressed and has low magnetostriction and coercive force. As a result, the magnetic permeability characteristics of the soft magnetic backing layer 11 provided with this soft magnetic alloy film can be enhanced, and the electromagnetic conversion characteristics of the magnetic recording medium 10 can be improved. In addition, the soft magnetic alloy film made of the soft magnetic alloy A does not contain nanocrystal particles, and therefore has a smooth surface and excellent corrosion resistance.

(Non-magnetic coupling film)
The material of the nonmagnetic coupling film 4 is not particularly limited, but it is preferable to use a nonmagnetic material containing at least one or two or more selected from Ru, Ir, and Rh, and particularly Ru or Ru alloy. It is preferable to use it.
The film thickness of the nonmagnetic coupling film 4 is preferably selected so that the antiferromagnetic coupling between the first soft magnetic alloy film 3 and the second soft magnetic alloy film 5 is maximized, and is usually 0.2 nm. It is set within a range of ˜4 nm.

(Strain relaxation film)
The first strain relaxation film A and the second strain relaxation film B (strain relaxation films A and B) prevent distortion of the soft magnetic backing layer 11 due to thermal imprinting, and the first soft magnetic alloy film 3 and the second strain relaxation film B. The diffusion of elements at the interface between the two soft magnetic alloy films 5 and the nonmagnetic coupling film 4 is prevented.
In the present embodiment, the materials used for the first strain relaxation film A and the second strain relaxation film B may be the same or different.

  In the present embodiment, the average interatomic distance between the strain relaxation films A and B is between the average interatomic distance of the soft magnetic alloy films 3 and 5 and the average interatomic distance of the nonmagnetic coupling film 4, or The average interatomic distance of the soft magnetic alloy films 3 and 5 and / or the nonmagnetic coupling film 4 is preferably the same. Such strain relaxation films A and B are used for the strain between the soft magnetic alloy films 3 and 5 and the nonmagnetic coupling film 4 due to the thermal imprint method, and for the soft magnetic alloy films 3 and 5 and the nonmagnetic cup. It becomes possible to more effectively prevent the constituent elements from diffusing with the ring film 4.

  As a method for measuring the average interatomic distance of the strain relaxation films A and B, the soft magnetic alloy films 3 and 5 and the nonmagnetic coupling film 4 in the present invention, a known method can be used. For example, E.I. A. Brandes, G .; B. Brook, Smiths Metals Reference Book, seventh Ed. , Butterworth Heinemann, (1998), the average interatomic distance calculated from the X-ray diffraction results can be used.

  Specifically, the average interatomic distance measured using this measurement method is as follows: CoFe-based amorphous thin film: about 0.20 nm, Ru: about 0.27 nm, Si: about 0.24 nm, Cr: about 0.25 nm Fe: about 0.25 nm, Co: about 0.25 nm, Ni: about 0.25 nm, Cu: about 0.25 nm.

  Further, the saturation magnetization (Ms) of the strain relaxation films A and B is preferably equal to or higher than the saturation magnetization of the soft magnetic alloy films 3 and 5. Such strain relaxation films A and B reduce the magnetic properties of the soft magnetic underlayer 11 even if diffusion of constituent elements slightly occurs between the soft magnetic alloy films 3 and 5 and the nonmagnetic coupling film 4. This is preferable because it can prevent the electromagnetic conversion characteristics of the magnetic recording medium 10.

As a material having a high saturation magnetization (Ms) and capable of easily obtaining the strain relaxation films A and B equal to or higher than the saturation magnetization of the soft magnetic alloy films 3 and 5, any one selected from the group consisting of Co, Ni and Fe Alternatively, it is preferable to use an alloy thereof.
Further, as a material of the strain relaxation films A and B, in order to adjust the average interatomic distance and Ms of the strain relaxation films A and B, any one selected from the group consisting of Co, Ni, and Fe or an alloy thereof is used. , Si, Cr, Cu, Ru, Ta, Mo, B, Zr, Nb, and Nd may be used.

  The film thicknesses of the strain relaxation films A and B are preferably in the range of 1 nm to 4 nm. By setting the film thicknesses of the strain relaxation films A and B to 1 nm or more, the strain between the soft magnetic alloy films 3 and 5 and the nonmagnetic coupling film 4 due to the thermal imprint method, the soft magnetic alloy film 3 5 and the nonmagnetic coupling film 4 can be more effectively prevented from diffusing. Further, if the thickness of the strain relaxation films A and B is greater than 4 nm, the influence of the magnetic characteristics of the strain relaxation films A and B increases, noise from the soft magnetic backing layer 11 increases, and the SNR characteristics are insufficient. It is not preferable because there is a risk of becoming.

"Metal glass film"
As shown in FIG. 1, the metallic glass film 6 has a surface on which irregularities 6 a corresponding to the magnetic recording pattern 8 a of the perpendicular magnetic recording layer 8 are formed.
Examples of the material of the metallic glass film 6 include metallic glass materials based on Zr, Cu, Ni, Pd, and Pt. Specifically, for example, PdCuNiP, PdCuPtP, ZrAlNiCu, ZrAlAgCu, TiCuNiSi, ZrCuNiSi, HfCuNiSi, CuZrTi, NiNbTiZr, etc. can be used as the material of the metallic glass film 6. The metallic glass film 6 made of these materials does not crystallize even if it is slowly cooled (for example, cooled at 1 ° C. for 1 second or 0.02 ° C. for 1 second) after heating for thermal imprinting. This is preferable because the same structure as that of amorphous can be maintained.

  Among the materials of the metallic glass film 6 described above, PdCuNiP, PdCuPtP, and ZrAlNiCu have a feature that the glass forming ability is large, and ZrAlNiCu has a feature that a wide supercooled liquid region (127K) is provided. , Zr, Hf) CuNiSi is characterized by high strength (2000 MPa). Further, CuZrTi is characterized by high strength (2000 MPa) and high toughness (elongation of 40% or more). Furthermore, NiNbTiZr has high strength (2700 MPa), and has the characteristics of having high corrosion resistance and high wear resistance.

  For example, when PdCuNiP is used as the metallic glass film 6, 42.5Pd-30Cu-7.5Ni-20P (the number is atomic%) can be used as the composition ratio. In the present composition, a large amount of P vitrifies the Pd alloy.

"Middle class"
The intermediate layer 7 is for controlling the orientation and crystal size of the perpendicular magnetic recording layer 8 provided on the intermediate layer 7. As shown in FIG. 1, the intermediate layer 7 is formed along the inner wall surface of the recess corresponding to the magnetic recording pattern 8 a formed on the metal glass film 6.

The intermediate layer 7 may be composed of one layer, but may have a two-layer structure including a first intermediate layer and a second intermediate layer.
For example, when the intermediate layer 7 has a two-layer structure of a first intermediate layer and a second intermediate layer, the first intermediate layer is any one of Ni, Ni alloy, Pt, Pt alloy, Ta, Ta alloy, Cr, and Cr alloy. It is preferable to make it from any of these materials.

Ni, Ni alloy, Pt, Pt alloy, Ta, Ta alloy, Cr, Cr alloy used for the first intermediate layer should be reduced in crystal size and crystal lattice size consistency with the second intermediate layer described later. For the purpose, a predetermined element can be added.
Specifically, examples of the element added for the purpose of reducing the crystal size include B and Mn. The addition amount is preferably 6 atomic% or less. Examples of the element added for the purpose of enhancing the consistency of the crystal lattice size with the second intermediate layer include Ru, Pt, W, Mo, Ta, Nb, and Ti.

  The thickness of the first intermediate layer is preferably in the range of 1 nm to 10 nm. If the thickness of the first intermediate layer is less than 1 nm, the effect of forming the first intermediate layer becomes insufficient, the effect of reducing the particle size cannot be obtained, and the orientation deteriorates, which is not preferable. . On the other hand, if the thickness of the first intermediate layer exceeds 10 nm, the crystal size increases, which is not preferable.

Further, as the material of the second intermediate layer, it is preferable to use Ru or a Ru alloy.
The layer thickness of the second intermediate layer is preferably 16 nm or less, and more preferably 12 nm or less. By reducing the thickness of the second intermediate layer, the distance between the magnetic head and the soft magnetic underlayer 11 can be reduced, and the magnetic flux from the magnetic head can be made steep. Therefore, even if the thickness of the soft magnetic backing layer 11 is reduced, the function of the soft magnetic backing layer 11 can be sufficiently obtained, and it is possible to improve the productivity by reducing the thickness of the soft magnetic backing layer 11. Become.

"Perpendicular magnetic recording layer"
The perpendicular magnetic recording layer 8 has an axis of easy magnetization perpendicular to the surface of the medium, and has a magnetically separated magnetic recording pattern 8a formed using a thermal imprint method. It is. As shown in FIG. 1, the magnetic recording pattern 8 a of the perpendicular magnetic recording layer 8 is formed in the recess corresponding to the magnetic recording pattern 8 a of the metallic glass film 6 via the intermediate layer 7.
The planar shape of the magnetic recording pattern 8a is not particularly limited. For example, the magnetic recording pattern 8a has a pattern shape suitable for the perpendicular magnetic recording layer 8 of a discrete track medium or a bit patterned medium.

As the perpendicular magnetic recording layer 8, a material containing at least Co and Pt and further added with an oxide, Cr, B, Cu, Ru, Ta, Zr or the like can be used for the purpose of improving SNR characteristics. .
Examples of the oxide contained in the perpendicular magnetic recording layer 8 include SiO ₂ , SiO, Cr ₂ O ₃ , CoO, Ta ₂ O ₃ , and TiO ₂ . The volume ratio of such an oxide in the perpendicular magnetic recording layer 8 is preferably in the range of 15 to 40% by volume. If the volume ratio of the oxide in the perpendicular magnetic recording layer 8 is less than 15% by volume, the SNR characteristic may be insufficient, which is not preferable. On the other hand, if the volume ratio of the oxide in the perpendicular magnetic recording layer 8 exceeds 40% by volume, it is difficult to obtain a coercive force sufficient for high recording density, which is not preferable.

  The perpendicular magnetic recording layer 8 can have a single layer structure or a structure of two or more layers made of materials having different compositions. In particular, a structure in which a magnetic layer not including an oxide is sequentially stacked on a magnetic layer having a granular structure including an oxide is preferable. With such a configuration, it becomes possible to more easily control and adjust the characteristics of the magnetic recording medium 10.

  The layer thickness of the perpendicular magnetic recording layer 8 is preferably in the range of 6 to 20 nm. When the perpendicular magnetic recording layer 8 has a granular magnetic layer containing an oxide and the thickness of the perpendicular magnetic recording layer 8 is within the above range, a sufficient output can be secured, The recording characteristics (OW characteristics) are not deteriorated, which is preferable.

  Further, as the perpendicular magnetic recording layer 8, a Co / Pt or Co / Pd artificial lattice may be used. In this case, when the intermediate layer 7 is made of Pt or Pd, the orientation control of the perpendicular magnetic recording layer 8 can be more preferably performed. Further, when a Co / Pd artificial lattice is used as the perpendicular magnetic recording layer 8 and a metal glass film 6 containing Pd as a main component is used, the metal glass film 6 also functions as the intermediate layer 7. Therefore, the intermediate layer 7 may not be provided.

"Protective layer"
The protective layer 28 is for preventing corrosion of the perpendicular magnetic recording layer 8 and preventing damage to the medium surface when the magnetic head comes into contact with the magnetic recording medium 10.
As the protective layer 28, a conventionally known material can be used, for example, a material containing C, SiO ₂ , ZrO ₂ or the like. When the thickness of the protective layer 28 is in the range of 1 nm to 5 nm, the effect of providing the protective layer 28 can be sufficiently obtained, and the distance between the magnetic head and the magnetic recording medium 10 can be reduced. From the point of view is desirable.

"Lubricating film"
For the lubricating film, conventionally known materials such as perfluoropolyether, fluorinated alcohol, fluorinated carboxylic acid and the like can be used.

<Manufacturing method>
Next, a method for manufacturing the magnetic recording medium 10 shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a schematic process diagram for explaining a method of manufacturing the magnetic recording medium shown in FIG. 1, and is a schematic cross-sectional view showing the magnetic recording medium in the process of manufacturing.
To manufacture the magnetic recording medium 10 shown in FIG. 1, first, a barrier layer 2 (not shown in FIG. 2) is formed on the nonmagnetic substrate 1 by a conventionally known method.

  Next, as shown in FIG. 2A, the first soft magnetic alloy film 3, the first strain relaxation film A, the nonmagnetic coupling film 4, and the second strain relaxation film B are formed on the barrier layer 2. The soft magnetic backing layer 11 having a plurality of antiferromagnetically coupled soft magnetic alloy films 3 and 5 formed in sequence with the second soft magnetic alloy film 5 and laminated with the nonmagnetic coupling film 4 interposed therebetween. 1 for each layer of the soft magnetic backing layer 11) (backing layer forming step).

Next, a perpendicular magnetic recording layer 8 having a magnetic recording pattern 8a magnetically separated using a thermal imprint method is formed on the soft magnetic backing layer 11 (patterning step).
In the patterning step, first, as shown in FIG. 2B, a metallic glass film 6 is provided on the soft magnetic backing layer 11.

Next, the nonmagnetic substrate 1 on which the layers up to the metallic glass film 6 are laminated is mounted on a heating stage (not shown) and heated.
FIG. 3 is a graph showing the results of measuring the relationship between the temperature and the amount of heat when a 42.5Pd-30Cu-7.5Ni-20P film was heated at a rate of temperature increase of 0.67 K / s (DSC curve ( Differential scanning calorimetry curve)). In the present embodiment, the nonmagnetic substrate 1 is heated so that the metal glass film 6 has a temperature higher than the glass transition temperature (Tg) and lower than the crystallization start temperature (Tx) in the DSC curve. .

Subsequently, with the nonmagnetic substrate 1 heated to a temperature higher than the glass transition temperature of the metallic glass film 6 and lower than the crystallization start temperature, as shown in FIG. The metallic glass film 6 is subjected to thermal imprinting, and the unevenness 6a corresponding to the magnetic recording pattern 8a is transferred to the surface of the metallic glass film 6 (imprinting process).
When the magnetic recording medium 10 is a discrete track medium (DTM), unevenness along the circumference is formed as unevenness 6a on the surface of the metal glass film 6. Further, when the magnetic recording medium 10 is a bit patterned medium (BPM), the bit pattern-shaped irregularities 6 a are formed on the surface of the metallic glass film 6.

  In the present embodiment, since the strain relaxation films A and B are provided between the soft magnetic alloy films 3 and 5 and the nonmagnetic coupling film 4 in the backing layer forming process, the metal glass film 6 is formed in the patterning process. Even when thermal imprint processing is performed, the strain relaxation films A and B prevent distortion of the soft magnetic backing layer 11 due to thermal imprinting, and the soft magnetic alloy films 3 and 5 and the nonmagnetic coupling film 4 Diffusion of elements at the interface is prevented.

  In addition, the metallic glass film 6 does not crystallize even if it is gradually cooled (for example, cooled at 1 ° C. for 1 second or 0.02 ° C. for 1 second) after heating for thermal imprinting, and is similar to amorphous When the metal glass film 6 is made of a material capable of maintaining the structure, it is preferable that the metal glass film 6 is not adversely affected by the thermal imprint process.

  Thereafter, the intermediate layer 7 is formed on the metallic glass film 6 on which the irregularities 6a are formed by a conventionally known method. The thickness of the intermediate layer 7 is preferably smaller than the depth of the recess formed on the surface of the metal glass 6 by the stamper 24 in consideration of the thickness of the perpendicular magnetic recording layer 8. Specifically, the thickness of the intermediate layer 7 is desirably 6 nm or more thinner than the depth of the recess formed on the surface of the metal glass 6. When the difference between the thickness of the intermediate layer 7 and the depth of the recess formed on the surface of the metal glass 6 is less than 6 nm, the thickness of the perpendicular magnetic recording layer 8 magnetically separated by the planarization process described later is insufficient. Therefore, there is a possibility that the thickness is not sufficient to obtain an output necessary for recording and reproduction.

  Next, as shown in FIG. 2 (d), a film 8b to be the perpendicular magnetic recording layer 8 is formed on the intermediate layer 7, and the surface of the film 8b to be the perpendicular magnetic recording layer 8 is flattened so that the perpendicular magnetic recording is performed. The film 8b to be the recording layer 8 is magnetically separated to form a magnetic recording pattern 8a (planarization step) as shown in FIG. By performing the planarization step, as shown in FIG. 2E, the convex portions of the metallic glass film 6 are exposed between the magnetic recording patterns 8a.

  A method for planarizing the film 8b to be the perpendicular magnetic recording layer 8 is not particularly limited. For example, a dry method can be an ion milling method, and a wet method can be a polishing method using CMP (Chemical Mechanical Polishing). In the present invention, any method can be suitably used.

After forming the perpendicular magnetic recording layer 8 having the magnetic recording pattern 8a in this way, a protective layer 9 (see FIG. 1) and a lubricating film (not shown) are formed on the perpendicular magnetic recording layer 8 by a conventionally known method. Are formed in this order.
Through the above steps, the magnetic recording medium 10 shown in FIG. 1 is obtained.

  In the method of manufacturing the magnetic recording medium 10 according to the present embodiment, a plurality of antiferromagnetically coupled soft magnetic alloy films 3 and 5 laminated on the nonmagnetic substrate 1 with the nonmagnetic coupling film 4 interposed therebetween. A backing layer forming step for forming the soft magnetic backing layer 11 and a perpendicular magnetic recording layer 8 having a magnetic recording pattern 8a magnetically separated on the soft magnetic backing layer 11 using a thermal imprint method; And the strain relief films A and B are provided between the soft magnetic alloy films 3 and 5 and the nonmagnetic coupling film 4 in the backing layer formation process, respectively. Thus, distortion of the soft magnetic backing layer 11 due to thermal imprinting is prevented, and diffusion of elements at the interface between the soft magnetic alloy films 3 and 5 and the nonmagnetic coupling film 4 is prevented. As a result, according to the present embodiment, the magnetic recording medium 10 having high electromagnetic conversion characteristics can be obtained.

  Further, in the method for manufacturing the magnetic recording medium 10 of the present embodiment, the magnetic recording pattern 8a is formed by using the thermal imprint method, and therefore, when the magnetic layer is subjected to physical unevenness processing using the mask layer. As compared with the above, the productivity of the magnetic recording medium 10 can be remarkably increased.

  Further, in the method for manufacturing the magnetic recording medium 10 according to the present embodiment, the patterning step provides the metal glass film 6 on the soft magnetic backing layer 11, and uses the thermal imprint method on the surface of the metal glass film 6. An imprint process for forming irregularities 6a corresponding to the magnetic recording pattern 8a, and a film 8b to be the perpendicular magnetic recording layer 8 are formed on the metallic glass film 6, and the surface of the film 8b to be the perpendicular magnetic recording layer 8 is formed. Since the film 8b to be the perpendicular magnetic recording layer 8 is magnetically separated by flattening to form a magnetic recording pattern 8a, the magnetic recording can be performed without forming a mask layer. The magnetic recording layer 8 having the pattern 8a can be easily formed at low cost, and the magnetic characteristics are not deteriorated due to the removal of the mask layer.

  In the method for manufacturing the magnetic recording medium 10 of the present embodiment, the metallic glass film 6 is any one selected from the group consisting of PdCuNiP, PdCuPtP, ZrAlNiCu, ZrAlNiCu, ZrAlAgCu, TiCuNiSi, ZrCuNiSi, HfCuNiSi, CuZrTi, and NiNbTiZr. Alternatively, when it is made of an alloy thereof, in the imprint process, it is gradually cooled after heating when the irregularities 6a corresponding to the magnetic recording pattern 8a are formed on the surface of the metallic glass film 6 (for example, 1 ° C. or 1 Even if it is cooled to 0.02 ° C. per second), the metallic glass film 6 is not crystallized, and the same structure as that of the amorphous state can be maintained. For this reason, the orientation of the perpendicular magnetic recording layer 8 (and the intermediate layer 7) formed on the metallic glass film 6 becomes favorable, and the magnetic recording medium 10 having much higher electromagnetic conversion characteristics can be obtained.

(Magnetic recording / reproducing device)
Next, the magnetic recording / reproducing apparatus of the present invention will be described. FIG. 4 is a perspective view showing an example of the magnetic recording / reproducing apparatus of the present invention. The magnetic recording / reproducing apparatus shown in FIG. 4 includes a magnetic recording medium 50, a medium driving unit 51 that rotationally drives the magnetic recording medium 50, a magnetic head 52 that records and reproduces information on the magnetic recording medium 50, and the magnetic head 52. Is provided with a head drive unit 53 for moving the recording medium relative to the magnetic recording medium 50 and a recording / reproducing signal processing system 54.

  The magnetic recording / reproducing apparatus shown in FIG. 4 includes the magnetic recording medium 10 shown in FIG. Also, the recording / reproduction signal processing system 54 shown in FIG. 4 processes data input from the outside and sends the recording signal to the magnetic head 52, and processes the reproduction signal from the magnetic head 52 and sends the data to the outside. Is possible. The magnetic head 52 may be a magnetic head 52 having a GMR element using a giant magnetoresistive effect (GMR) as a reproducing element and suitable for high recording density.

  Hereinafter, the effects of the present invention will be made clearer by examples. In addition, this invention is not limited to a following example, In the range which does not change the summary, it can change suitably and can implement.

Example 1
In this example, first, a 60Cr-40Ti film having a thickness of 8 nm was formed as a barrier layer on a glass substrate (amorphous substrate MEL3 manufactured by MYG, diameter 2.5 inches) by a DC magnetron sputtering method. Next, on the barrier layer, a 76Co-4.9Fe-14.7B-2.4Si-2Nb film having a thickness of 20 nm as the first soft magnetic alloy film (average interatomic distance of 0.206 nm, saturation magnetization (Ms) 1 0.0T), a Co film (average interatomic distance 0.25 nm, saturation magnetization (Ms) 1.7T) as a first strain relaxation film, and a Ru film (a thickness 0.5 nm as a nonmagnetic coupling film). An average interatomic distance of 0.27 nm), a Co film having a thickness of 2 nm as the second strain relaxation film, and a 76Co-4.9Fe-14.7B-2.4Si-2Nb film having a thickness of 20 nm as the second soft magnetic alloy film. It formed in order by DC magnetron sputtering method.

A 42.5 Pd-30Cu-7.5Ni-20P film having a thickness of 30 nm was formed thereon as a metallic glass film by a DC magnetron sputtering method. Thereafter, the substrate is heated to 340 ° C., and a nickel stamp having a positive pattern corresponding to the magnetic recording pattern is pressed against the metal glass film at a pressure of 60 MPa (about 600 kgf / cm ² ) for 10 seconds to heat the metal glass film. After imprinting, the stamp was separated from the metallic glass film, and irregularities corresponding to the magnetic recording pattern were transferred to the surface of the metallic glass film, which was used as an evaluation sample.

  The uneven pattern transferred to the metal glass film has a shape corresponding to a magnetic recording pattern of 2 terabits (Tbpsi) per square inch, and the convex portion of the data area of the magnetic recording medium is a cylinder (dot) having a diameter of 10 nm. The track is formed by arranging the projections at equal intervals along the circumference with the interval between the projections adjacent to each other in the circumferential direction being 17.96 nm. In addition, the uneven pattern was provided with 256 servo areas so as to cross the track in the circumferential direction. In addition, as for the layer thickness of the metal glass film in which the unevenness | corrugation was formed, the convex part was 35 nm and the recessed part was about 10 nm.

(Comparative Example 1)
After the substrate was heated to 340 ° C., a sample for evaluation was produced in the same manner as in Example 1 except that the thermal imprint processing of the metal glass film was not performed.

(Comparative Example 2)
Instead of the soft magnetic underlayer of Example 1, a 76Co-4.9Fe-14.7B-2.4Si-2Nb film having a thickness of 20 nm is used as the first soft magnetic alloy film, and a thickness of 0. 0 is used as the nonmagnetic coupling film. A Ru film of 5 nm and a 76 Co-4.9Fe-14.7B-2.4Si-2Nb film having a thickness of 20 nm as a second soft magnetic alloy film are sequentially formed by a DC magnetron sputtering method. No strain relaxation film was provided. The other steps were the same as in Example 1, and an evaluation sample was produced.
(Comparative Example 3)
After the substrate was heated to 340 ° C., a sample for evaluation was produced in the same manner as in Comparative Example 2 except that the thermal imprinting of the metal glass film was not performed.

  The samples for evaluation manufactured in Example 1 and Comparative Examples 1 to 3 were annealed until the substrate temperature reached 400 ° C., and the bias of the soft magnetic backing layer was measured using a sample vibration type magnetometer (VSM) (Vibrating Sample Magnetometer). The magnetic field (Hbias) was measured. The result is shown in FIG.

  FIG. 5 is a graph showing the relationship between the annealing temperature of the evaluation samples manufactured in Example 1 and Comparative Examples 1 to 3, and the bias magnetic field (Hbias) acting between the two soft magnetic alloy films. As shown in FIG. 5, the soft magnetic underlayer of Example 1 has less change in magnetic properties due to heating and pressurization due to thermal imprinting than Comparative Example 2, and does not perform thermal imprinting. It was confirmed that the magnetic properties were equivalent to those of Comparative Example 1. Further, as shown in FIG. 4, it was confirmed that the soft magnetic underlayer of Example 1 had a larger bias magnetic field than that of Comparative Example 3, and that there was little decrease in magnetic properties due to heating.

(Example 2)
In Example 2, first, in the same manner as in the evaluation sample of Example 1, a process was performed until the unevenness corresponding to the magnetic recording pattern was transferred to the surface of the metal glass film.
Next, a NiW film having a thickness of 5 nm is formed by DC magnetron sputtering using a 94Ni-6W target as the first intermediate layer of the intermediate layer on the metal glass film having the irregularities, and the first intermediate layer is formed. A Ru film having a thickness of 5 nm was formed by DC magnetron sputtering using a Ru target as the second intermediate layer.

Next, a film serving as a perpendicular magnetic recording layer on the intermediate layer, a magnetic layer having a granular structure comprising an oxide comprising 60Co-10Cr-20Pt-10SiO ₂ thickness 8 nm, a thickness of 10nm 65Co-18Cr- A magnetic layer made of 14Pt-3B that does not contain an oxide was sequentially formed.

Next, the surface of the film to be the perpendicular magnetic recording layer was processed and planarized with an ion beam from an oblique direction until the upper surface of the convex portion of the metal glass was exposed. Thus, the film to be the perpendicular magnetic recording layer was magnetically separated to form a magnetic recording pattern to obtain a perpendicular magnetic recording layer.
The ion beam conditions were as follows: Ar gas was 5 sccm, pressure was 0.05 Pa, high-frequency plasma power was 200 w, acceleration voltage was 1000 V, extraction voltage was −500 V, and processing time was 90 seconds.

  Next, a 4 nm protective layer was formed on the perpendicular magnetic recording layer by a CVD method. Finally, a lubricating film made of perfluoropolyether was formed on the protective layer by dipping, and the patterned medium of Example 2 was obtained.

The recording / reproduction characteristics of the patterned medium of Example 2 obtained in this way were evaluated. The recording / reproduction characteristics were evaluated by measuring the signal / noise ratio (S / N ratio) and the recording characteristics (OW) using a read / write analyzer RWA1632 and spin stand S1701MP manufactured by GUZIK.
As a result, the S / N ratio of the patterned medium of Example 2 was 14.1 dB, and OW was 50.2 dB.

(Example 3)
As a material for the first soft magnetic alloy film and the second soft magnetic alloy film of the soft magnetic underlayer, a 79Co-5Fe-14.5B-1.5Nb film (average interatomic distance of 0.205 nm, saturation magnetization (Ms). 1T), and 70Co-30Fe (average interatomic distance of 0.256 nm, saturation magnetization (Ms) 2.0T) was used as the material of the strain relaxation film, in the same manner as in Example 1, the metallic glass film A sample for evaluation was manufactured by performing a process until the irregularities corresponding to the magnetic recording pattern were transferred to the surface of the film.

Example 4
A sample for evaluation was produced in the same manner as in Example 1 except that 42Cu-42Zr-8Al-8Ag was used as the material of the metal glass film, and the substrate was heated to 455 ° C. to heat imprint the metal glass film. did.

(Example 5)
A sample for evaluation was produced in the same manner as in Example 1 except that 55Zr-10Al-5Ni-30Cu was used as the material of the metal glass film, and the substrate was heated to 440 ° C. to thermally imprint the metal glass film. did.

For the evaluation samples of Examples 3 to 5, the bias magnetic field of the soft magnetic backing layer was measured using a sample vibration magnetometer VSM.
As a result, the evaluation sample of Example 3 was 114 Oe, the evaluation sample of Example 4 was 75 Oe, and the evaluation sample of Example 5 was 83 Oe.

Further, the pattern of Example 3 to Example 5 was performed by performing the same steps as in Example 2 until a lubricating film was formed on the metal glass film having the unevenness of Example 3 to Example 5. Media was obtained.
For the patterned media of Examples 3 to 5 thus obtained, the recording / reproduction characteristics were evaluated in the same manner as the patterned medium of Example 2.
As a result, the S / N ratio of the patterned medium of Example 3 was 14.4 dB, OW was 52.0 dB, the S / N ratio of the patterned medium of Example 4 was 13.8 dB, and OW was 49.0 dB. The S / N ratio of the patterned medium of Example 5 was 14.0 dB, and OW was 49.5 dB.

(Comparative Example 4)
A patterned medium of Comparative Example 4 was prepared in the same manner as in Example 2 except that the first strain relaxation film and the second strain relaxation film were not provided.
The recording / reproduction characteristics of the patterned medium of Comparative Example 4 obtained were evaluated in the same manner as the patterned medium of Example 2.
As a result, the S / N ratio of the patterned medium of Comparative Example 4 is 12.9 dB and OW is 48.2 dB, and the electromagnetic conversion characteristics are remarkably lowered as compared with the patterned media of Examples 2 to 5. It was.

  INDUSTRIAL APPLICABILITY The present invention can manufacture a magnetic recording medium having excellent electromagnetic conversion characteristics used in a hard disk drive (HDD) that is a kind of magnetic recording / reproducing apparatus, and can significantly increase the productivity.

  DESCRIPTION OF SYMBOLS 1 ... Nonmagnetic board | substrate, 2 ... Barrier layer, 3 ... 1st soft magnetic alloy film, 4 ... Nonmagnetic coupling film, 5 ... 2nd soft magnetic alloy film, 6 ... Metallic glass film, 6a ... Concavity and convexity, 7 ... Middle 8 ... perpendicular magnetic recording layer, 8a ... magnetic recording pattern, 9 ... protective layer, 10 ... magnetic recording medium, 11 ... soft magnetic backing layer, 24 ... stamper, 50 ... magnetic recording medium, 51 ... rotational drive unit, 52 DESCRIPTION OF SYMBOLS ... Magnetic head, 53 ... Head drive part, 54 ... Recording / reproducing signal processing system, A ... 1st distortion relaxation film, B ... 2nd distortion relaxation film.

Claims (9)

A backing layer forming step of forming a soft magnetic backing layer having a plurality of antiferromagnetically coupled soft magnetic alloy films laminated on a nonmagnetic substrate with a nonmagnetic coupling film interposed therebetween;
A patterning step of forming a perpendicular magnetic recording layer having a magnetic recording pattern magnetically separated using a thermal imprint method on the soft magnetic backing layer,
A method of manufacturing a magnetic recording medium, comprising: providing a strain relaxation film between the soft magnetic alloy film and the nonmagnetic coupling film in the backing layer forming step. An imprinting step in which the patterning step includes providing a metallic glass film on the soft magnetic backing layer and forming irregularities corresponding to the magnetic recording pattern on the surface of the metallic glass film using a thermal imprinting method; ,
A film to be a perpendicular magnetic recording layer is formed on the metal glass film, and the film to be the perpendicular magnetic recording layer is magnetically separated by planarizing a surface of the film to be the perpendicular magnetic recording layer. The method of manufacturing a magnetic recording medium according to claim 1, further comprising a planarization step of forming the magnetic recording pattern.   The magnetic glass film according to claim 2, wherein the metallic glass film is made of any one selected from the group consisting of PdCuNiP, PdCuPtP, ZrAlNiCu, ZrAlAgCu, TiCuNiSi, ZrCuNiSi, HfCuNiSi, CuZrTi, NiNbTiZr, or an alloy thereof. A method for manufacturing a recording medium.   The method for manufacturing a magnetic recording medium according to claim 1, wherein the nonmagnetic coupling film is made of Ru or a Ru alloy.   The average interatomic distance of the strain relaxation film is between the average interatomic distance of the soft magnetic alloy film and the average interatomic distance of the nonmagnetic coupling film, or the soft magnetic alloy film and / or the above 5. The method of manufacturing a magnetic recording medium according to claim 1, wherein the distance is the same as the average interatomic distance of the nonmagnetic coupling film.   6. The method of manufacturing a magnetic recording medium according to claim 1, wherein a saturation magnetization (Ms) of the strain relaxation film is equal to or greater than a saturation magnetization of the soft magnetic alloy film.   The soft magnetic alloy film contains Co, Fe, B, and Nb, and the contents of these elements are Co at a atomic%, Fe at b atomic%, B at x atomic%, and Nb at y atomic%. In some cases, the following relationships are satisfied: 80 ≦ a + b ≦ 84, 14 ≦ a / b ≦ 17, 14 ≦ x ≦ 17, and 0.5 ≦ y ≦ 3. A method for producing a magnetic recording medium according to any one of the above.   8. The magnetic recording medium according to claim 1, wherein the strain relaxation film is made of any one selected from the group consisting of Co, Ni, and Fe or an alloy thereof. 9. Production method.   A magnetic recording medium manufactured by using the method for manufacturing a magnetic recording medium according to claim 1, and a magnetic head for recording and reproducing information on the magnetic recording medium. A magnetic recording / reproducing apparatus.

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