JP2005038519A - Magnetic recording medium, its manufacturing method, and magnetic storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording medium which has excellent thermal fluctuation resistance and whose medium noise is reduced by stabilizing anti-ferromagnetic bonds acting between a plurality of magnetic layers, to provide its manufacturing method and to provide a magnetic storage device. <P>SOLUTION: The magnetic recording medium 10 is constituted of a substrate 11 and a seed layer 12, an underlayer 13, an intermediate layer 14, a first magnetic layer 15, a non-magnetic bonding layer 16, a second magnetic layer 18, a protective film 19 and a lubricant layer 20 which are successively laminated on the substrate 11 and the non-magnetic bonding layer 16 is film-deposited in an atmospheric gas containing an inert gas such as Kr and Xe having atomic weight larger than that of Ar. Lattice mismatching between the non-magnetic bonding layer 16 and the second magnetic layer 18 formed on the non-magnetic bonding layer 16 is suppressed by controlling the lattice constant of a crystal growing face of the non-magnetic bonding layer 16. As a result, anti-ferromagnetic bonds functioning to magnetization of the first and the second magnetic layers 15 and 18 are stabilized and the magnetic recording medium has excellent thermal fluctuation resistance and its medium noise is reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a magnetic recording medium and a magnetic storage device suitable for high-density recording, and more particularly to a magnetic recording medium having excellent thermal fluctuation resistance and low medium noise.

  2. Description of the Related Art In recent years, an increase in the amount of information handled with the advancement of information processing technology and the application to acoustic video equipment for moving image storage have demanded an increase in recording capacity for magnetic recording devices. One method for meeting this requirement is to improve the recording density, that is, to refine the recording bits, which are the recording unit of the magnetic recording medium for recording information.

  Since the signal output decreases when the recording bit size is reduced, it is necessary to sufficiently reduce the medium noise and ensure a sufficient signal-to-noise ratio (S / N ratio) in the high recording density region. In order to reduce the medium noise, it has been conventionally known that the reduction in the crystal grains constituting the recording layer of the magnetic recording medium is achieved. In order to reduce the size of crystal grains, a method of reducing the thickness of the recording layer and suppressing the enlargement due to crystal growth is effective.

  However, the refinement of crystal grains reduces the volume of magnetization that bears one recording bit, and thus causes a problem of loss of recorded magnetization due to thermal disturbance, that is, deterioration of thermal fluctuation resistance. In order to secure this thermal fluctuation resistance, it is an effective technique to increase the Pt composition amount of the CoCrPt-based alloy forming the magnetic recording layer and improve the coercive force. This is not preferable because it is difficult to sufficiently magnetize the magnetic head, and the writeability is deteriorated.

  In recent years, in order to avoid such a problem, a magnetic recording medium in which the magnetizations of two magnetic layers are antiferromagnetically coupled has been proposed. As shown in FIG. 1, in the magnetic recording medium 100, a second magnetic layer 103 is provided on a first magnetic layer 101 via a nonmagnetic coupling layer 102, and the thickness of the nonmagnetic coupling layer 102 is about 1 nm or less. By thinning, the magnetizations of the first magnetic layer 101 and the second magnetic layer 103 are antiferromagnetically coupled. With this configuration, the volume of magnetization that bears one recording bit is the volume of the magnetization 103A of the second magnetic layer 103 close to the recording magnetic head 104 and the magnetization 101A of the first magnetic layer 101 that is antiferromagnetically coupled. Thus, the thermal fluctuation resistance can be ensured by increasing the volume of magnetization that bears one recording unit.

JP 2001-056924 A

  By the way, when the magnitude of the antiferromagnetic coupling between the magnetizations 101A and 103A of the first and second magnetic layers 101 and 103 is not sufficiently secured, the coupling may be broken at a part of the magnetic recording medium. . When the coupling is broken, the recording magnetic head 104 magnetizes the magnetizations 101A and 103A of the first and second magnetic layers 101 and 103 in a parallel state, so that the reproduction output increases and local output fluctuations and medium noise are generated. It appears as an increase. Such an output fluctuation and an increase in medium noise cause a problem in reducing the S / N ratio and increasing the recording density.

  It is generally known that the magnitude of antiferromagnetic coupling strongly depends on the Co composition amounts of the first and second magnetic layers 101 and 103 in the vicinity of the interface with the nonmagnetic coupling layer 102. That is, it is effective to increase the Co composition amount of the first and second magnetic layers 101 and 103 in order to ensure the magnitude of antiferromagnetic coupling.

  However, when the Co composition amount of the second magnetic layer 103 is increased, the magnetostatic interaction between the magnetizations of the crystal grains constituting the second magnetic layer 103 is increased, resulting in an increase in medium noise. There is a problem of lowering.

  For this reason, it has been difficult for conventional techniques to increase antiferromagnetic coupling between magnetic layers without increasing medium noise.

  Accordingly, it is a general object of the present invention to provide a novel and useful magnetic recording medium, a method for manufacturing the same, and a magnetic storage device that solve the above-described problems.

  A more specific problem of the present invention is to provide a magnetic recording medium that stabilizes antiferromagnetic coupling acting between a plurality of magnetic layers, has excellent thermal fluctuation resistance, reduces medium noise, and enables high density recording. A manufacturing method and a magnetic storage device are provided.

According to one aspect of the present invention, a substrate, a first magnetic layer provided above the substrate,
The non-magnetic coupling layer provided on the first magnetic layer and the second magnetic layer provided on the non-magnetic coupling layer. The first magnetic layer and the second magnetic layer are exchanged. A magnetic recording medium that is coupled and antiparallel to each other, wherein the nonmagnetic coupling layer is formed in an atmospheric gas containing an inert gas having an atomic weight larger than that of Ar. Provided.

  According to the present invention, the second magnetic layer formed on the nonmagnetic coupling layer is formed by forming the nonmagnetic coupling layer in an inert gas having an atomic weight larger than that of Ar, for example, an atmospheric gas containing Kr or Xe. The crystallinity of the initial growth layer of the layer is improved, and the crystallinity of the entire second magnetic layer is improved. Accordingly, the crystallinity of the entire second magnetic layer is good, and particularly the crystallinity near the interface with the nonmagnetic coupling layer is good, so that the antiferromagnetic property between the first magnetic layer and the second magnetic layer is good. The coupling force of exchange coupling can be increased. As a result, the thermal fluctuation resistance can be improved. Furthermore, since the crystallinity of the entire second magnetic layer is good, medium noise can be reduced.

  The effect | action of this invention is considered as follows. That is, when Ar gas is used as the atmospheric gas when forming the nonmagnetic coupling layer, it is taken into the nonmagnetic coupling layer, deteriorating the crystallinity of the nonmagnetic coupling layer and increasing the lattice constant. On the other hand, when an inert gas having an atomic weight larger than that of Ar, such as Kr or Xe, is used, it becomes difficult to be incorporated into the nonmagnetic coupling layer due to the large atomic radius, thereby suppressing deterioration in crystallinity and increase in lattice constant. Therefore, the crystallinity of the initial growth layer of the second magnetic layer formed on the nonmagnetic coupling layer is improved, and the crystallinity of the entire second magnetic layer grown thereon is improved.

  The nonmagnetic coupling layer may be made of Ru or an alloy containing Ru as a main component, and the film thickness thereof may be set in the range of 0.4 nm to 1.0 nm. The antiferromagnetic coupling force between the first magnetic layer and the second magnetic layer can be stabilized.

  According to another aspect of the present invention, there is provided a magnetic storage device comprising a magnetic head having a magnetoresistive effect type reproducing head and any one of the above magnetic recording media.

  According to the present invention, since a magnetic recording medium has excellent thermal fluctuation resistance and low medium noise characteristics, a magnetic storage device capable of high-density recording can be realized by combining with a magnetoresistive effect reproducing head. .

  According to another aspect of the present invention, a substrate, a first magnetic layer provided above the substrate, a nonmagnetic coupling layer provided on the first magnetic layer, and the nonmagnetic coupling layer The first magnetic layer and the second magnetic layer are exchange-coupled with each other, and the magnetization of the first magnetic layer and the second magnetic layer are not applied with an external magnetic field. A method of manufacturing a magnetic recording medium in which the magnetizations of the magnetic layers are antiparallel to each other, the method comprising: forming the nonmagnetic coupling layer in an atmosphere containing an inert gas having an atomic weight greater than Ar A manufacturing method is provided.

  According to the present invention, as described above, the second magnetic layer formed on the nonmagnetic coupling layer by forming the nonmagnetic coupling layer in an atmospheric gas containing an inert gas having an atomic weight larger than that of Ar. The crystallinity of the initial growth layer is improved, and the antiferromagnetic exchange coupling force between the first magnetic layer and the second magnetic layer can be increased.

  The atmospheric gas may be set in a range of Ar gas partial pressure: Kr or Xe gas partial pressure = 99: 1 to 0: 100. In addition, the substrate temperature at the time of forming the nonmagnetic coupling layer may be set in a range of 200 ° C. to 270 ° C.

  According to the present invention, by reducing lattice mismatch between the nonmagnetic coupling layer and the magnetic layer formed thereon, the antiferromagnetic coupling acting between the plurality of magnetic layers is stabilized, and the thermal fluctuation resistance is improved. And a magnetic recording medium with reduced medium noise can be provided.

  Hereinafter, a magnetic recording medium according to an embodiment of the present invention will be described.

(First embodiment)
FIG. 2 is a cross-sectional view of a magnetic recording medium according to an embodiment of the present invention. Referring to FIG. 2, a magnetic recording medium 10 according to the present embodiment includes a substrate 11, a seed layer 12, an underlayer 13, an intermediate layer 14, a first magnetic layer 15, and a nonmagnetic coupling layer on the substrate 11. 16, the 2nd magnetic layer 17, the protective film 19, and the lubricating layer 20 are laminated | stacked one by one. In the magnetic recording medium 10, the magnetizations of the first magnetic layer 15 and the second magnetic layer 18 sandwiching the nonmagnetic coupling layer 16 are antiferromagnetically coupled and formed on the nonmagnetic coupling layer 16. It is characterized in that the magnitude of lattice mismatch with the second magnetic layer 18 is reduced.

  The substrate 11 can be a substrate made of a non-magnetic material, such as a disk-shaped plastic substrate, a glass substrate, a NiP plated aluminum alloy substrate, a silicon substrate, etc. Especially when the substrate 11 is in a tape shape, PET, A plastic film such as PEN or polyimide can be used. The substrate 11 may or may not be subjected to texture processing such as mechanical texture or laser texture.

  The seed layer 12 is made of a nonmagnetic material, and for example, a NiP film can be used. The seed layer 12 may or may not be textured. When the seed layer 12 is a NiP film, the surface is preferably oxidized. By this oxidation treatment, the in-plane orientation of the c-axis of the ferromagnetic material of the first magnetic layer 15 and the second magnetic layer 18 can be improved. The seed layer 12 can be used instead of the NiP film as long as it is a known material that improves the c-axis orientation.

  The underlayer 13 is made of a nonmagnetic material, for example, a Cr-based alloy having a body-centered cubic structure such as Cr, CrMo, CrW, or CrV, or an alloy having a B2 structure such as AlRu, NiAl, or FeAl. The underlayer 13 is epitaxially grown on the seed layer 12. When the underlayer 13 has a B2 structure, the (001) plane or the (112) plane shows a good orientation in the growth direction, and the underlayer 13 is a Cr film. The (002) plane shows a good orientation in the growth direction.

  The intermediate layer 14 is made of a nonmagnetic material, and is made of an alloy having a hexagonal close packed structure containing at least one element selected from Co, Cr, Ta, Mo, Mn, Re, and Ru. An alloy containing at least one element selected from Mo, Mn, Re, and Ru is preferable. The intermediate layer 14 has a thickness set in the range of 0.5 nm to 3.0 nm. The intermediate layer 14 is epitaxially grown by taking over the crystallinity and crystal grain size of the underlayer 13, and improves the crystallinity of the first magnetic layer 15 and the second magnetic layer 18 that are epitaxially grown on the intermediate layer 14. ) Reduce the size distribution width and promote c-axis orientation in the in-plane direction (direction parallel to the substrate surface).

  The first magnetic layer 15 is made of Co, Ni, Fe, a Co alloy, a Ni alloy, a Fe alloy, or the like. In particular, a material obtained by adding CoCrTa and CoCrPt and further adding B, Mo, Nb, Ta, W, and an alloy thereof to these is preferable. The thickness of the first magnetic layer 15 is set in the range of 2 nm to 10 nm. The first magnetic layer 15 is epitaxially grown in the (11-20) direction on the intermediate layer 14, the c-axis is oriented in the in-plane direction, and the easy axis of magnetization is the in-plane direction.

  The nonmagnetic coupling layer 16 is made of, for example, Ru or a Ru-based alloy. Ru has a hcp structure and is suitable because it is close to the a-axis length of 0.270 nm of Ru with respect to the a-axis length of 0.25 nm of the CoCrPt alloy. As the Ru-based alloy, Ru—Cr, Ru—Co, Ru—Pd, Ru—Re and the like are suitable.

  The thickness of the nonmagnetic coupling layer 16 is set in the range of 0.4 nm to 1.0 nm. A state in which the distance between the first magnetic layer 15 and the second magnetic layer 18 is defined, the magnetization of the first magnetic layer 15 and the second magnetic layer magnetization 18 are antiferromagnetically coupled, and no external magnetic field is applied Then they are antiparallel to each other.

  Similar to the first magnetic layer 15, the second magnetic layer 18 is made of Co, Ni, Fe, a Co alloy, a Ni alloy, a Fe alloy, or the like. In particular, a material obtained by adding CoCrTa and CoCrPt and further adding B, Mo, Nb, Ta, W, Cu, and alloys thereof to these is preferable. The thickness of the second magnetic layer 18 is set in the range of 5 nm to 30 nm.

The relationship between the product t ₁ Br ₁ of the thickness t ₁ of the first magnetic layer 15 and the residual magnetization Br ₁ and the product t ₂ Br ₂ of the thickness t ₂ of the second magnetic layer 18 and the residual magnetization Br ₂ is as follows. It is preferable that the following formula (2) is satisfied. If it exceeds 10.0 nTm, the medium noise increases and the S / N ratio decreases.

2.0 nTm ≦ t ₂ Br ₂ −t ₁ Br ₁ ≦ 10.0 nTm (2)
The protective film 19 is made of a material containing carbon as a main component, for example, hydrogenated carbon, carbon nitride, amorphous carbon, or the like, and has a thickness of 0.5 nm to 10 nm (preferably 0.5 nm to 5 nm).

  The lubricating layer 20 is made of an organic liquid lubricant having perfluoropolyether as a main chain and having an end group of —OH, a benzene ring, or the like. Specifically, ZDol having a thickness of 0.5 nm to 3.0 nm (end group: —OH) manufactured by Monte Fluos, AM3001 (end group: benzene ring manufactured by Augmont Co., Ltd.), Z25 (manufactured by Monte Fluos), etc. Can be used. The lubricant is appropriately selected according to the material of the protective film 19.

  Each of the layers described above is formed by sputtering, vacuum vapor deposition, or the like except for the lubricating layer 20, and the substrate temperature during film formation is preferably set in the range of 160 ° C to 270 ° C, and is preferably 200 ° C to 270 ° C. More preferably, it is set within the range. However, when the material of the substrate 11 is a plastic such as PET or PEN, the substrate temperature may be set to 160 ° C. or lower. As the atmospheric gas during film formation, Ar or He gas is used except when the nonmagnetic coupling layer 16 described later is formed. Furthermore, the pressure of the atmospheric gas is set in a range of 0.3 Pa to 5 Pa.

  In addition, the lubricating layer 20 uses an immersion method or a spin coater method. When the magnetic recording medium is in the form of a tape, a die coating method or the like can also be used.

  In the magnetic recording medium 10 according to the present embodiment, an inert gas having an atomic weight larger than that of Ar, for example, an atmospheric gas containing Kr or Xe is used when forming the nonmagnetic coupling layer 16. Conventionally, an inert gas, Ar gas, is used as the atmosphere gas from the seed layer to the second magnetic layer 18. As a result of various studies, the inventor of the present application made a lattice mismatch between the formed Ru film and the second magnetic layer 18 formed thereon when the nonmagnetic coupling layer 16 is formed using an Ru material in an Ar gas atmosphere. Thus, the crystallinity of the initial growth layer 18A of the second magnetic layer 18 in the vicinity of the interface of the Ru film is poor, which adversely affects the magnetic characteristics and electromagnetic conversion characteristics of the second magnetic layer 18, and as described above. It has been found that the antiferromagnetic coupling state between the first magnetic layer 15 and the second magnetic layer 18 is adversely affected. That is, the crystallinity and composition of the first magnetic layer 15 and the second magnetic layer 18 in the vicinity of the interface of the nonmagnetic coupling layer 16 affect the coupling force of antiferromagnetic coupling.

  Therefore, the inventor of the present application, when forming the nonmagnetic coupling layer 16 of the magnetic recording medium according to the present embodiment, as an atmospheric gas, an inert gas such as Kr or Xe having an atomic weight larger than that of Ar as Ar gas. Can improve the crystallinity of the initial growth layer 18A of the second magnetic layer 18 formed on the nonmagnetic coupling layer 16 and further the crystallinity over the entire second magnetic layer 18 grown thereon. It was confirmed. The atmospheric gas is preferably set in the range of Ar gas partial pressure: Kr or Xe gas partial pressure = 99: 1 to 0: 100, and the larger the partial pressure of Kr or Xe inert gas, the more It is particularly preferable that no Ar gas is contained.

  The magnetic recording medium has an in-plane orientation, that is, the c-axis of the first and second magnetic layers 15 and 18 and the nonmagnetic coupling layer 16 is oriented substantially parallel to the substrate surface. If the nonmagnetic coupling layer 16 is formed in an atmosphere containing only Ar gas, Ar gas enters the Ru film, which is the nonmagnetic coupling layer 16, and increases the lattice constant of the Ru film. On the other hand, when an inert gas such as Kr or Xe is used as the atmospheric gas, Kr or Xe has a larger atomic radius than Ar, so that it does not easily enter the Ru film and does not increase the lattice constant of the Ru film. It is guessed. Therefore, lattice mismatch between the Ru film of the nonmagnetic coupling layer 16 and the CoCr-based alloy used for the second magnetic layer 18 is reduced on the crystal growth surface at the interface between the nonmagnetic coupling layer 16 and the second magnetic layer 18. The crystallinity of the initial growth layer 18A of the second magnetic layer 18 can be improved.

  As a result, the crystallinity in the vicinity of the interface between the second magnetic layer 18 and the nonmagnetic coupling layer 16 is improved and the c-axis crystal orientation is also improved, so that the first magnetic layer 15 and the second magnetic layer 18 The antiferromagnetic coupling force of magnetization can be increased. Furthermore, since the crystallinity of the entire second magnetic layer 18 is improved, low medium noise characteristics can be maintained.

It is more preferable that the relationship regarding the lattice mismatch between the nonmagnetic coupling layer 16 and the second magnetic layer 18 satisfies the following expression (1).
| L ₀ / L ₂ -1 | ≦ 0.05 (1)
(Here, L ₀ is the spacing of the (1-100) plane of the nonmagnetic coupling layer, and L ₂ is the spacing of the (1-100) plane of the second magnetic layer.)
Furthermore, since the increase in the lattice constant of the Ru film that is the nonmagnetic coupling layer 16 is suppressed, when the first magnetic layer 15 is made of CoCr or a CoCr alloy, the first magnetic layer 15 and the nonmagnetic coupling layer 16 Lattice mismatch is reduced. Therefore, since the crystallinity of the nonmagnetic coupling layer 16 is improved, the crystallinity of the second magnetic layer 18 is further improved. As a result, a magnetic recording medium having excellent thermal fluctuation resistance and low medium noise can be realized.

[Example 1]
The magnetic recording medium of this example according to this embodiment was formed as follows. The configuration of the magnetic recording medium according to the present example is the same as that of the magnetic recording medium 10 of the present embodiment described above.

  First, a NiP film having a thickness of 1 μm was formed as a seed layer on a glass substrate by an electroless plating method. Next, the surface of the NiP film was washed with alkaline water and then a thin film was formed.

A thin film was stacked on the NiP film using a DC magnetron sputtering method. The degree of vacuum in the film formation chamber of the sputtering apparatus was evacuated to 1 × 10 ⁻⁵ Pa or less as a base pressure, and was maintained at 0.67 Pa during film formation. The substrate temperature is set to 260 ° C. to remove deposits on the NiP film, and then a 5 nm thick CrW film (16 atomic% W) is formed as an underlayer on the NiP film, and further, as an intermediate layer A 1 nm thick CoCr film (*** atomic% Cr) having a nonmagnetic hcp structure was formed.

  Next, a CoCr film (16 atomic% Cr) having a thickness of 3 nm was formed as the first magnetic layer. Next, in a Kr gas atmosphere (pressure 0.617 Pa, flow rate 100 sccm), a Ru film having a thickness of 0.8 nm was formed as a nonmagnetic coupling layer. Next, a CoCrPtBCu film (19 atomic% Cr, 12 atomic% Pt, 7 atomic% B, 4 atomic% Cu) having a thickness of 17 nm was formed as the second magnetic layer.

  Next, a carbon film having a thickness of 4.5 nm was formed as a protective layer, and a lubricating layer made of AM3001 having a thickness of 10 nm was further applied. Thus, the magnetic recording medium of this example was formed.

[Example 2]
The magnetic recording medium according to this example was formed in the same manner as the magnetic recording medium of Example 1 except that Xe was used instead of Kr as the atmospheric gas when forming the Ru film of the nonmagnetic coupling layer.

[Comparative example]
The magnetic recording medium according to this comparative example not according to the present invention is the same as the magnetic recording medium of Example 1 except that Ar is used instead of Kr as the atmospheric gas when forming the Ru film of the nonmagnetic coupling layer. Formed.

  FIG. 3 is a diagram showing the lattice spacing of the nonmagnetic coupling layer 16 and the lattice mismatch between the nonmagnetic coupling layer 16 and the second magnetic layer of the magnetic recording media according to the example and the comparative example. The Ru film of the example and the comparative example and the CoCrPtB film of the second magnetic layer have an hcp (hexagonal close packed) structure, and the crystal growth plane is the (11-20) plane. The degree of lattice mismatch between the Ru film and the CoCrPtB film was determined by measuring the spacing of the (1-100) plane, which is one of the planes perpendicular to the (11-20) plane. Incidentally, in order to measure the spacing of the Ru film by X-ray diffraction, the magnetic recording media according to the present example and the comparative example were formed except that the Ru film was formed to have a thickness of 10 nm and 20 nm. When the lattice spacing of the (1-100) plane perpendicular to the crystal growth direction (11-20) is measured by the θ-2θ method using a meter, and the Ru film is 0.8 nm The lattice spacing of the (1-100) plane was determined.

  Referring to FIG. 3, the surface of the Ru film of Example 1 using Kr gas and the surface of the Ru film of Example 2 using Xe with respect to the surface spacing of the Ru film of the comparative example formed using Ar gas. It can be seen that the interval is small. Corresponding to these spacings, the degree of lattice mismatch is smaller in Example 1 and Example 2 than in the comparative example, indicating that lattice matching is achieved. For the lattice mismatch (%), the following formula (3) was used.

Lattice mismatch (%) = {[face spacing of (1-100) face of Ru film / face spacing of (1-100) face of CoCrPtB film] -1} × 100 (3)
Here, the spacing between the (1-100) planes of the CoCrPtB film was 0.1270 nm.

  FIG. 4 is a diagram illustrating an example of a hysteresis loop of the magnetic recording medium of the present embodiment. Referring to FIG. 4, for example, when the hysteresis loop is saturated by applying a magnetic field H in the positive direction from a state saturated by applying the magnetic field H in the negative direction, and applying the magnetic field H in the original negative direction, The magnitude and direction of magnetization change in the order of point A, point B, point C, point D, and point A. As shown in FIG. 4, the magnetizations of the first and second magnetic layers are parallel to the applied magnetic field direction at points A and C, and are antiferromagnetic at points B and D. It becomes antiparallel due to the bond.

In FIG. 4, Hc is the coercive force, the magnetization at points B and D is the residual magnetization Br, the magnetization at points A and C is the saturation magnetization Bs, the slope of the hysteresis loop at Hc is the coercivity squareness ratio, and the positive magnetic field at point D The magnetic field at the center of the loop formed by the minor loop ML indicated by the broken line on the side and the major loop indicated by the solid line is the coupling magnetic field _HEX . A coupled magnetic field is also obtained on the negative magnetic field side at point B.

  FIG. 5 is a diagram showing the magnetostatic characteristics of the magnetic recording media according to the example and the comparative example. Referring to FIG. 5, it can be seen that Examples 1 and 2 have superior coercivity, saturation magnetization, and coupling magnetic field characteristics compared to the comparative example. This is because the coercive force improves the crystallinity of the second magnetic layer by reducing the above-described lattice mismatch, and the saturation magnetization improves the in-plane orientation for the same reason. Furthermore, the coupling magnetic field indicating the antiferromagnetic coupling force between the CoCr film as the first magnetic layer and the CoCrPtBCu film as the second magnetic layer is improved by about 10% or more compared to the comparative example. I understand. Furthermore, it can be seen that Example 2 is superior to Example 1 in these characteristics. That is, it can be seen that Xe is superior to Kr.

FIG. 6 is a diagram illustrating electromagnetic conversion characteristics of the magnetic recording media according to the example and the comparative example. The electromagnetic conversion characteristics were measured at a peripheral speed of 12.6 m / s, a linear recording density of 705 kFCI, and a composite magnetic head equipped with a reproducing magnetic head having a GMR reproducing element was used. Resolution is the ratio of output at 353 kFCI to output at 88 kFCI, overwrite is measured after the output V ₁ at 117 kFCI, 705 kFCI is written, the remaining output 171 kFCI V ₂ is measured, and V ₂ / V ₁ is overwritten (DB). S _iso / N _m is the ratio (dB) between the solitary wave output S _iso and the medium noise N _m, and S / N _t is the output S at 705 kFCI and its total noise N _t (= medium noise + equipment noise + And the noise of the magnetic head for reproduction). Each measured value in the figure represents a difference from a predetermined measured value of the reference disk.

Referring to FIG. 6, first, regarding the overwrite, it can be seen that Examples 1 and 2 are improved by 1.2 dB to 2.4 dB and the writeability is improved as compared with the comparative example. It is considered that the crystallinity of the CoCrPtB film is improved, the distribution of the anisotropic magnetic field is narrowed, and the magnetization is easily reversed. Next, regarding S _iso / N _m, it can be seen that Examples 1 and 2 are improved by 0.1 dB to 0.2 dB over the comparative example. It is considered that the crystallinity is good at the interface between the Ru film and the CoCrPtB film, so that the distribution of crystal grain size is narrowed and the solitary wave output is improved.
Further, when S / Nt is observed, it can be seen that Examples 1 and 2 are improved by 0.1 dB over the comparative example. The reason is considered to be similar to S _iso / N _m .

According to the present embodiment, the Ru film is formed using Kr or Xe as an atmospheric gas, thereby reducing the lattice constant of the Ru film and reducing the lattice mismatch with the CoCrPtB film as the second magnetic layer. Anti-ferromagnetic coupling between the CoCr film of the first magnetic layer and the CoCrPtB film of the second magnetic layer without increasing medium noise by improving the crystallinity of the initial growth layer 18A of the layer and increasing the coupling magnetic field You can increase your power.
(Second Embodiment)
Next, a magnetic storage device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a cross-sectional view showing the main part of the magnetic memory device. FIG. 8 is a plan view showing the main part of the magnetic memory device shown in FIG.

  With reference to FIGS. 7 and 8, the magnetic storage device 30 is generally composed of a housing 33. In the housing 33, a motor 34, a hub 35, a plurality of magnetic recording media 36, a plurality of recording / reproducing heads 37, a plurality of suspensions 38, a plurality of arms 39, and an actuator unit 31 are provided. The magnetic recording medium 36 is attached to a hub 35 that is rotated by a motor 34. The recording / reproducing head 37 is an MR element (magnetoresistive element), GMR element (giant magnetoresistive element) or TMR element (tunnel magnetic effect type) reproducing head and thin film head recording head. Consists of. The recording head is a ring type head. Each recording / reproducing head 37 is attached to the tip of a corresponding arm 39 via a suspension 38. The arm 39 is driven by the actuator unit 31. The basic configuration itself of this magnetic storage device is well known, and detailed description thereof is omitted in this specification.

  The magnetic storage device 30 of this embodiment is characterized by a magnetic recording medium 36. The magnetic recording medium 36 is, for example, a magnetic recording medium according to the first embodiment. The number of magnetic recording media 36 is not limited to three, and may be one, two, or four or more.

  The basic configuration of the magnetic storage device 30 is not limited to that shown in FIGS. The magnetic recording medium 36 used in the present invention is not limited to a magnetic disk.

  According to the present embodiment, the magnetic storage device 30 has excellent thermal fluctuation resistance and low medium noise characteristics of the magnetic recording medium 36. Therefore, high density recording is possible.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the present invention described in the claims. Is possible. For example, the present invention can be applied to a magnetic tape used as an auxiliary storage device such as a large computer.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the present invention described in the claims. Is possible.

  For example, the present invention can be applied to a linear running magnetic tape used as an auxiliary storage device such as a large computer or a helical scan type magnetic tape.

In addition, the following additional notes are disclosed regarding the above description.
(Appendix 1) a substrate,
A first magnetic layer provided above the substrate;
A nonmagnetic coupling layer provided on the first magnetic layer;
A second magnetic layer provided on the nonmagnetic coupling layer,
The first magnetic layer and the second magnetic layer are exchange coupled and are magnetic recording media that are antiparallel to each other,
A magnetic recording medium, wherein the nonmagnetic coupling layer is formed in an atmospheric gas containing an inert gas having an atomic weight larger than that of Ar.
(Supplementary note 2) The magnetic recording medium according to supplementary note 1, wherein the nonmagnetic coupling layer is made of Ru or an alloy containing Ru as a main component.
(Additional remark 3) The magnetic recording medium of Additional remark 1 or 2 characterized by the thickness of the said nonmagnetic coupling layer being set to the range of 0.4 nm-1.0 nm.
(Additional remark 4) The said atmospheric gas contains Kr or Xe gas, The magnetic recording medium as described in any one of Additional remarks 1-3 characterized by the above-mentioned.
(Additional remark 5) The relationship about the lattice mismatch of the said nonmagnetic coupling layer and a 2nd magnetic layer satisfies the following formula | equation (1), It is any one of Additional remark 1 to 4 characterized by the above-mentioned. Magnetic recording medium.
| L ₀ / L ₂ -1 | ≦ 0.05 (1)
(Here, L ₀ is the spacing of the (1-100) plane of the nonmagnetic coupling layer, and L ₂ is the spacing of the (1-100) plane of the second magnetic layer.)
(Supplementary Note 6) and the thickness t1 of the first magnetic layer and the product t1Br1 between the residual magnetization Br1, the relationship between the product t ₂ Br ₂ with the film thickness t ₂ of the second magnetic layer and residual magnetization Br ₂ is the following formula The magnetic recording medium according to any one of appendices 1 to 5, wherein (2) is satisfied.
2.0 nTm≤t2Br2-t1Br1≤10.0 nTm (2)
(Additional remark 7) It further has a base layer between the said board | substrate and a 1st magnetic layer,
Supplementary notes 1 to 6, wherein the underlayer is made of Cr or a Cr-X alloy containing Cr as a main component, X is W, V, Mo or an alloy thereof and has a body-centered cubic structure. A magnetic recording medium according to any one of the above.
(Supplementary Note 8) An intermediate layer is further provided between the underlayer and the first magnetic layer,
The magnetic recording medium according to appendix 7, wherein the intermediate layer includes at least one selected from the group consisting of Cr, Ta, Mo, Mn, Re, and Ru, and has a hexagonal close packed structure.
(Supplementary Note 9) A seed layer is further provided between the substrate and the base layer,
The magnetic recording medium according to appendix 7 or 8, wherein the seed layer is made of a NiP film.
(Additional remark 10) The magnetic storage apparatus provided with the magnetic head which has a magnetoresistive effect type reproducing head, and the magnetic recording medium as described in any one of additional marks 1-9.
(Supplementary Note 11) a substrate;
A first magnetic layer provided above the substrate;
A nonmagnetic coupling layer provided on the first magnetic layer;
A second magnetic layer provided on the nonmagnetic coupling layer,
Magnetic recording in which the first magnetic layer and the second magnetic layer are exchange-coupled and the magnetization of the first magnetic layer and the magnetization of the second magnetic layer are antiparallel to each other when no external magnetic field is applied A method for producing a medium, comprising:
A method of manufacturing a magnetic recording medium, comprising the step of forming the nonmagnetic coupling layer in an atmosphere containing an inert gas having an atomic weight larger than that of Ar.
(Supplementary Note 12) The atmospheric gas includes Kr or Xe gas and / or Ar gas,
The method for producing a magnetic recording medium according to appendix 11, wherein the partial pressure of Ar gas: the partial pressure of Kr or Xe gas = 99: 1 to 0: 100 is set.
(Additional remark 13) The substrate temperature at the time of forming the said nonmagnetic coupling layer is set to the range of 200 to 270 degreeC, The manufacturing method of the magnetic recording medium of Additional remark 11 or 12 characterized by the above-mentioned.

1 is a configuration diagram of a main part of a magnetic recording medium having an antiferromagnetically coupled magnetic layer. FIG. 1 is a cross-sectional view of a magnetic recording medium according to a first embodiment of the invention. It is a figure which shows the lattice mismatch of the nonmagnetic coupling layer and 2nd magnetic layer of the magnetic-recording medium based on the Example of this invention, and the comparative example which is not based on this invention. It is a figure which shows an example of the magnetic characteristic of the magnetic-recording medium based on 1st Embodiment. It is a figure which shows the magnetostatic characteristic of the magnetic recording medium which concerns on an Example and a comparative example. It is a figure which shows the electromagnetic conversion characteristic of the magnetic recording medium which concerns on an Example and a comparative example. It is sectional drawing which shows the principal part of the magnetic memory device based on the 2nd Embodiment of this invention. It is a top view which shows the principal part of the magnetic memory device shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Magnetic recording medium 11 Substrate 12 Seed layer 13 Underlayer 14 Intermediate layer 15 First magnetic layer 16 Nonmagnetic coupling layer 18 Second magnetic layer 18A Initial growth layer 19 Protective film 20 Lubricating layer 30 Magnetic storage device

Claims (5)

A substrate,
A first magnetic layer provided above the substrate;
A nonmagnetic coupling layer provided on the first magnetic layer;
A second magnetic layer provided on the nonmagnetic coupling layer,
The first magnetic layer and the second magnetic layer are exchange coupled and are magnetic recording media that are antiparallel to each other,
A magnetic recording medium, wherein the nonmagnetic coupling layer is formed in an atmospheric gas containing an inert gas having an atomic weight larger than that of Ar. 2. The magnetic recording medium according to claim 1, wherein a relationship regarding lattice mismatch between the nonmagnetic coupling layer and the second magnetic layer satisfies the following expression (1).
| L ₀ / L ₂ -1 | ≦ 0.05 (1)
(Here, L ₀ is the spacing of the (1-100) plane of the nonmagnetic coupling layer, and L ₂ is the spacing of the (1-100) plane of the second magnetic layer.)   A magnetic storage device comprising: a magnetic head having a magnetoresistive effect reproducing head; and the magnetic recording medium according to claim 1. A substrate,
A first magnetic layer provided above the substrate;
A nonmagnetic coupling layer provided on the first magnetic layer;
A second magnetic layer provided on the nonmagnetic coupling layer,
Magnetic recording in which the first magnetic layer and the second magnetic layer are exchange-coupled and the magnetization of the first magnetic layer and the magnetization of the second magnetic layer are antiparallel to each other when no external magnetic field is applied A method for producing a medium, comprising:
A method of manufacturing a magnetic recording medium, comprising the step of forming the nonmagnetic coupling layer in an atmosphere containing an inert gas having an atomic weight larger than that of Ar. The atmospheric gas includes Kr or Xe gas, and / or Ar gas,
11. The method of manufacturing a magnetic recording medium according to claim 10, wherein Ar gas partial pressure: Kr or Xe gas partial pressure is set in a range of 99: 1 to 0: 100.

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