Method for manufacturing a magnetic recording medium, magnetic recording medium, and magnetic storage device

Abstract

To provide a method of manufacturing a magnetic recording medium capable of having a magnetic layer with high crystal orientation and few defections.SOLUTION: A method of manufacturing a magnetic recording medium according to the present invention includes: forming a magnesium oxide base layer on a surface of a substrate by a sputtering method by using a target containing magnesium oxide; and forming a magnetic layer on the surface side of the magnesium oxide base layer. When forming the magnesium oxide base layer, the target containing the magnesium oxide is heated to 600°C or higher.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a magnetic recording medium, a magnetic recording medium, and a magnetic storage device. [Background technology]

[0002] A magnetic recording medium is generally manufactured by laminating an underlayer, a magnetic layer, and a protective layer in that order on a substrate. One method for recording magnetic information on a magnetic recording medium is the thermally assisted recording method, in which the magnetic recording medium is irradiated with a laser beam or the like to locally heat the surface of the magnetic layer, thereby reducing the coercive force of the magnetic layer and recording magnetic information. The thermally assisted recording method has a data rate of 1 Tbit / inch 2 Since it is possible to realize an areal recording density of up to 1000 times the size of a magnetic recording medium, it is being considered as a next-generation magnetic recording method that can increase storage capacity as magnetic recording media become smaller and their recording densities increase.

[0003] As a magnetic recording medium that can be used in the thermally assisted recording method, for example, a substrate, a plurality of underlayers formed on the substrate, and L1 0 A magnetic recording medium has been disclosed that is composed of a magnetic layer mainly composed of an alloy having a BCC structure, and multiple underlayers include a NiO underlayer and an orientation control layer (see, for example, Patent Document 1). In this magnetic recording medium, the orientation control layer includes an underlayer made of an alloy having a BCC structure and an underlayer such as MgO having a NaCl structure, and causes the NiO underlayer to have a (100) orientation.

[0004] As the magnetic layer of the magnetic recording medium, L1 0When using an FePt alloy having the structure, the (001) plane is used as the crystal orientation plane of the magnetic layer. In order to orient the FePt alloy in (001), MgO with (100) orientation is generally used as the underlayer. That is, since the (100) plane of MgO has high lattice matching with the (001) plane of the FePt alloy, the FePt alloy is easily oriented in (001) by forming a magnetic layer containing the FePt alloy above the MgO layer. In addition, in the magnetic recording medium of Patent Document 1, the NiO underlayer is also oriented in (100), so MgO is used as the underlayer of the orientation control layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-026368 A Summary of the Invention [Problem to be solved by the invention]

[0006] When MgO is used to form the orientation control layer, the MgO layer is generally formed by sputtering, but MgO has a high melting point and therefore has poor sinterability. When the MgO layer is formed by sputtering using a target with poor sinterability, there is a problem that sputter dust is easily generated due to abnormal discharge (arcing) occurring on the target surface, which melts and scatters the target surface. This sputter dust reduces the crystal orientation of the MgO layer and makes it more likely that defects will occur in the MgO layer. As a result, the crystal orientation of the magnetic layer formed on the MgO layer is reduced and the possibility of defects occurring in the magnetic layer increases.

[0007] An object of one aspect of the present invention is to provide a method for producing a magnetic recording medium that can have a magnetic layer with high crystal orientation and few defects. [Means for solving the problem]

[0008] One embodiment of a method for manufacturing a magnetic recording medium according to the present invention includes the steps of forming a magnesium oxide underlayer on a surface of a substrate by a sputtering method using a target containing magnesium oxide, and forming a magnetic layer on the surface side of the magnesium oxide underlayer, and when forming the magnesium oxide underlayer, the target containing magnesium oxide is heated to 600°C or higher.

[0009] The magnetic recording medium according to one embodiment of the present invention includes a magnesium oxide underlayer and an L1 0 and a magnetic layer containing an FePt alloy having a structure, the magnesium oxide underlayer containing magnesium oxide, which has an O1s spectrum peak of 531 eV to 533 eV when measured by XPS. Effect of the Invention

[0010] According to one aspect of the present invention, it is possible to provide a magnetic layer with high crystal orientation and few defects. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing an example of a configuration of a magnetic recording medium according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an explanatory diagram showing one step of a method for producing a magnetic recording medium according to an embodiment of the present invention. [Diagram 3] 5A to 5C are explanatory diagrams showing other steps of the method for producing a magnetic recording medium according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing an example of the relationship between the target temperature of an MgO target and the amount of sputter dust generated in a chamber. [Diagram 5] This is an O1s spectrum of a magnesium oxide film measured by XPS. [Figure 6] 5A to 5C are explanatory diagrams showing other steps of the method for producing a magnetic recording medium according to an embodiment of the present invention. [Figure 7] 1 is a perspective view showing an example of a magnetic storage device using a magnetic recording medium according to an embodiment of the present invention. [Figure 8]FIG. 2 is a schematic diagram showing an example of a magnetic head. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail. In order to facilitate understanding of the description, the same components in each drawing are given the same reference numerals, and duplicated descriptions will be omitted. In addition, the scale of each member in the drawings may differ from the actual scale. In this specification, "~" indicating a numerical range means that the numerical values ​​before and after it are included as the lower and upper limits, unless otherwise specified.

[0013] A method for producing a magnetic recording medium according to the present embodiment will be described. Before describing a method for producing a magnetic recording medium according to the present embodiment, a magnetic recording medium obtained by the method for producing a magnetic recording medium according to the present embodiment will be described.

[0014] [Magnetic recording media] 1 is a cross-sectional view showing an example of the configuration of a magnetic recording medium according to the present embodiment. As shown in FIG. 1, the magnetic recording medium 1 includes a substrate 10, an underlayer 20, and an L1 0 The magnetic layer 30 includes an alloy having the structure, and is laminated in this order from the substrate 10 side.

[0015] In this specification, the thickness direction (vertical direction) of the magnetic recording medium 1 is defined as the Z-axis direction, and the lateral direction (horizontal direction) perpendicular to the thickness direction is defined as the X-axis direction. The magnetic layer 30 side in the Z-axis direction is defined as the +Z-axis direction, and the substrate 10 side is defined as the -Z-axis direction. In the following description, for convenience of explanation, the +Z-axis direction is referred to as the top or upper direction, and the -Z-axis direction is referred to as the bottom or lower direction, but this does not represent a universal up-down relationship.

[0016] Although FIG. 1 shows the underlayer 20 and the magnetic layer 30 only above the substrate 10, the magnetic recording medium 1 also includes an underlayer 20 and a magnetic layer 30 laminated in this order from the substrate 10 side below the substrate 10.

[0017] The magnetic recording medium 1 has an underlayer 20 and a magnetic layer 30 on both the top and bottom surfaces of the substrate 10, and information can be recorded on both the top and bottom surfaces of the substrate 10 (double-sided recording). However, the magnetic recording medium 1 may have an underlayer 20 and a magnetic layer 30 on only one of the top and bottom surfaces of the substrate 10, and information can be recorded on only one side of the substrate 10 (single-sided recording).

[0018] The material constituting the substrate 10 is not particularly limited as long as it is a material that can be used for a magnetic recording medium. Examples of materials constituting the substrate 10 include Al alloys such as AlMg alloys, soda glass, aluminosilicate glass, amorphous glasses, silicon, titanium, ceramics, sapphire, quartz, resins, etc. Among these, Al alloys and glasses such as crystallized glass and amorphous glass are preferred.

[0019] The underlayer 20 includes a magnesium oxide (MgO) underlayer 21 which is a first underlayer, and may include a second underlayer 22. The underlayer 20 includes an MgO underlayer (first underlayer) 21 and a second underlayer 22 which are laminated in this order from the substrate 10 side, the second underlayer 22 and the MgO underlayer 21.

[0020] The MgO underlayer 21 is provided above the second underlayer 22. The MgO underlayer 21 is preferably the uppermost layer of the underlayer 20 (the layer farthest from the substrate 10), and preferably contains MgO, or consists essentially of MgO, and more preferably consists only of MgO. "Substantially" means that, in addition to MgO, it may contain inevitable impurities that may be inevitably contained during the manufacturing process.

[0021] In this embodiment, the MgO underlayer 21 is in contact with the first magnetic layer 31, and therefore the (100) plane of MgO and the L1 0 Since the (001) plane of the magnetic alloy having the structure is easily lattice matched, the crystal orientation of the magnetic alloy can be improved.

[0022] The MgO underlayer 21 is formed by deposition under predetermined conditions using a sputtering method, as described below. The MgO underlayer 21 has a peak of the O1s spectrum of MgO at 531 eV to 533 eV, as detected when measured by X-ray photoelectron spectroscopy (XPS). The manufacturing conditions and characteristics of the MgO underlayer 21 will be described in detail below.

[0023] The second underlayer 22 is provided above the substrate 10 .

[0024] The material constituting the second underlayer 22 is not particularly limited as long as it is capable of orienting the first magnetic layer 31 in (001) orientation, and examples thereof include (100) oriented W, Cr, a Cr alloy having a BCC structure, an alloy having a B2 structure, etc.

[0025] Examples of Cr alloys having a BCC structure include CrMn alloys, CrMo alloys, CrW alloys, CrV alloys, CrTi alloys, and CrRu alloys.

[0026] Examples of alloys having the B2 structure include RuAl alloys and NiAl alloys.

[0027] The number of layers of the underlayer 20 is not particularly limited, and may be three or more.

[0028] When the number of laminated layers of the underlayer 20 is three or more, the underlayers other than the MgO underlayer 21 can be formed using the same material as the second underlayer 22.

[0029] The magnetic layer 30 includes a first magnetic layer 31 and a second magnetic layer 32 laminated in this order from the MgO underlayer 21 side.

[0030] The first magnetic layer 31 is the bottom layer of the magnetic layer 30 (the layer closest to the substrate 10), but L1 0 It is preferred that the alloy has the structure.

[0031] L1 constituting the first magnetic layer 31 0The alloy having the structure preferably further contains Fe or Co and Pt. 0 Specifically, the alloy having the structure is preferably an FePt alloy or a CoPt alloy. The crystal magnetic anisotropy constant (Ku) of the FePt alloy is 7×10 6 J / m 3 The Ku content of the CoPt alloy is 5×10 6 J / m 3 The following are all 1×10 6 J / m 3 The FePt alloy or the CoPt alloy is a material with a high Ku value (high Ku material). Therefore, by using the FePt alloy or the CoPt alloy as the material constituting the first magnetic layer 31, the magnetic layer 30 can maintain its thermal stability while the magnetic particles constituting the magnetic layer 30 can be finely divided to a grain size of, for example, 6 nm or less.

[0032] The first magnetic layer 31 may further contain a grain boundary segregation material and have a granular structure, which makes the first magnetic layer 31 more likely to be (001) oriented and improves lattice matching with the MgO underlayer 21 that is (100) oriented.

[0033] Examples of the grain boundary segregation material contained in the first magnetic layer 31 include nitrides such as VN, BN, SiN, and TiN, carbides such as C and VC, and borides such as BN, and two or more of these may be used in combination.

[0034] The second magnetic layer 32, like the first magnetic layer 31, has an L1 0 It is preferable that the second magnetic layer 32 contains an alloy having a structure, which improves the (001) orientation of the magnetic layer 30. That is, the second magnetic layer 32 can be a magnetic film that is epitaxially grown along the orientation of the first magnetic layer 31.

[0035] L1 constituting the second magnetic layer 32 0 Like the first magnetic layer 31, the alloy having the structure preferably contains Fe or Co, and Pt.

[0036] The second magnetic layer 32, like the first magnetic layer 31, may further contain a grain boundary segregation material and have a granular structure.

[0037] The grain boundary segregation materials contained in the second magnetic layer 32 include nitrides such as VN, BN, SiN, and TiN, carbides such as C and VC, borides such as BN, and SiO 2 , TiO 2 , Cr 2 O 3 , Al 2 O 3 , Ta 2 O 5 , ZrO 2 , Y 2 O 3 , CEO 2 Examples of the oxides include oxides such as MnO, TiO, and ZnO, and two or more of them may be used in combination.

[0038] The number of layers of the magnetic layer 30 is not particularly limited, and may be three or more.

[0039] When the number of stacked layers of the magnetic layer 30 is three or more, the magnetic layers other than the first magnetic layer 31 can be formed using the same material as the second magnetic layer 32.

[0040] The magnetic recording medium 1 preferably includes a protective layer 40 on the magnetic layer 30 .

[0041] The protective layer 40 has the function of protecting the magnetic recording medium 1 from damage caused by contact with a magnetic head or the like.

[0042] The thickness of the protective layer 40 is preferably 1 nm to 6 nm. If the thickness of the protective layer 40 is 1 nm to 6 nm, the flying characteristics of the magnetic head are improved, the magnetic spacing is reduced, and the SNR of the magnetic recording medium 1 is improved.

[0043] The magnetic recording medium 1 may further include a lubricant layer 50 on the protective layer 40 .

[0044] Examples of materials constituting the lubricant layer 50 include fluororesins such as perfluoropolyether.

[0045] The magnetic recording medium 1 according to this embodiment includes an MgO underlayer 21 containing MgO and a magnetic layer 30. The MgO contained in the MgO underlayer 21 has a peak of an O1s spectrum detected by XPS measurement at 531 eV to 533 eV. Since the MgO underlayer 21 has high crystal orientation and few defects, the magnetic layer 30 formed above the MgO underlayer 21 can also be formed with high crystal orientation and few defects, similar to the MgO underlayer 21. Therefore, the magnetic recording medium 1 can have a magnetic layer 30 with high crystal orientation and few defects above the MgO underlayer 21.

[0046] [Method of manufacturing magnetic recording media] The method for manufacturing the magnetic recording medium according to this embodiment includes a step of forming an MgO underlayer (first underlayer) and a step of forming a magnetic layer, and may also include other steps such as a step of forming a second underlayer, a step of forming a protective layer, and a step of forming a lubricant layer.

[0047] The method for manufacturing the magnetic recording medium according to this embodiment includes the steps of forming a second underlayer, a MgO underlayer (first underlayer), a magnetic layer, a protective layer, and a lubricant layer.

[0048] In the method for producing a magnetic recording medium according to this embodiment, first, as shown in FIG. 2, an MgO underlayer 21 may be formed on the surface of the substrate 10 (first underlayer forming step).

[0049] Next, as shown in FIG. 3, the MgO underlayer 21 is formed on the surface of the second underlayer 22 by sputtering using a target containing MgO (MgO underlayer forming step).

[0050] When forming the MgO underlayer 21, a target containing MgO is heated to 600° C. or higher, preferably 800° C. or higher, and more preferably 1000° C. or higher.

[0051] MgO has a high melting point and is therefore poorly sinterable. As a result, it is difficult to manufacture an MgO target containing MgO with a sufficiently high density as a sputtering target. The relative density of a normal MgO target is about 65% to 98%, so abnormal discharge (arcing) is likely to occur on the target surface during sputtering. This arcing causes the target surface to melt and scatter, resulting in sputter dust that adheres to the deposition surface, which is the upper surface of the MgO underlayer 21, thereby reducing the crystallinity of the MgO underlayer 21 and making the MgO underlayer 21 more susceptible to defects. These problems are also inherited by the magnetic layer 30 formed on the upper surface of the MgO underlayer 21, reducing the crystallinity of the magnetic layer 30, and introducing defects into the magnetic layer 30 may result in unreadable and unwritable areas on the data surface of the magnetic recording medium 1, which may cause a decrease in product yield.

[0052] The present inventors have thoroughly investigated the deterioration of the crystallinity of the magnetic layer 30 and the occurrence of defects in the magnetic layer 30, and as a result have focused on the deposition conditions when forming the MgO underlayer 21, in particular the heating temperature of the MgO target containing MgO. They have found that by sputtering while heating the MgO target to an extremely high temperature of 600° C. or more, it is possible to suppress the generation of sputtering dust and form an MgO underlayer 21 with high crystal orientation and few defects, and that the magnetic layer 30 formed above the MgO underlayer 21 can also have improved crystal orientation and fewer defects.

[0053] FIG. 4 is a diagram showing an example of the relationship between the target temperature of the MgO target and the amount of sputter dust generated in the chamber of the sputtering device. FIG. 4 shows the result of performing sputtering for 2 hours using an RF sputtering method with a relative density of 85% and a diameter of 120 mm, an input power of 1 kW, a sputter gas pressure of 3 Pa, and Ar gas as the sputter gas. The amount of sputter dust was measured by counting dust particles adhering within a radius of 16 mm to 48 mm on one side of a substrate for magnetic recording media with a diameter of 3.5 inches. The deposition time of the MgO film during the manufacture of magnetic recording media is usually about 10 seconds. As shown in FIG. 4, if the MgO target is sputtered at a target temperature of 600° C. or higher, the amount of sputter dust can be reduced to 1 / 2 or less compared to the case of sputtering at a target temperature of 400° C. or lower.

[0054] In addition, the MgO film produced by sputtering using an MgO target at a heating temperature of 600°C or higher differs in physical properties from MgO films produced by conventional methods. The conventional method refers to the case where the film is formed without heating the MgO target, specifically, the case where the temperature of the MgO target is 400°C or lower. In this case, the back side of the MgO target is usually water-cooled.

[0055] Fig. 5 shows the O1s spectrum of a magnesium oxide film measured by X-ray photoelectron spectroscopy (XPS). In Fig. 5, (a) shows the spectrum of a magnesium oxide film formed by a conventional method, and (b) shows the spectrum of a magnesium oxide film produced by the method for producing a magnetic recording medium according to this embodiment. As shown in Fig. 5, (a) has an O1s spectrum peak at about 530 eV. In contrast, (b) has an O1s spectrum peak that is shifted by about 1 eV to the high energy side, falling within the range of 531 eV to 533 eV.

[0056] According to the investigations of the present inventors, such a peak shift becomes more prominent on the surface side of the MgO film, and is believed to occur as a result of a portion of the oxygen in MgO being replaced by OH.

[0057] This substitution results in the formation of a MgO(100) surface and a L1 0 This can be said to increase the lattice matching with the (001) plane of the FePt alloy having the structure, thereby increasing the (001) orientation of the FePt alloy film.

[0058] Since the sputtering target containing MgO used in the sputtering method is usually an insulator, it is preferable to use RF sputtering as the sputtering method, whereas when the sputtering target has conductivity, DC sputtering or DC magnetron sputtering can be used.

[0059] Next, as shown in FIG. 6, the magnetic layer 30 is formed on the surface of the MgO underlayer 21 (magnetic layer forming step).

[0060] In the magnetic layer forming step, the first magnetic layer 31 is formed on the surface of the MgO underlayer 21 (first magnetic layer forming step).

[0061] The first magnetic layer 31 can be formed by a sputtering method using a target containing a material for forming the first magnetic layer 31.

[0062] The target containing the material for forming the first magnetic layer 31 is L1 0 It is preferable to use a target containing an alloy having the structure L1. 0 As the alloy having the structure, an alloy containing Fe or Co and Pt or the like can be used, and for example, an FePt alloy, a CoPt alloy, or the like can be used.

[0063] As the sputtering method, a film formation method such as a DC magnetron sputtering method or an RF sputtering method can be used.

[0064] When forming the first magnetic layer 31, an RF (Radio Frequency) bias, a DC bias, a pulsed DC, a pulsed DC bias, or the like may be used as necessary.

[0065] Reactive gas: O 2 Gas, H 2 O gas, N 2 A gas or the like may also be used.

[0066] The sputtering gas pressure is appropriately adjusted so as to optimize the characteristics of each layer, but is usually within the range of about 0.1 Pa to 30 Pa.

[0067] Thereafter, the second magnetic layer 32 is formed on the surface of the first magnetic layer 31 (second magnetic layer forming step).

[0068] The second magnetic layer 32 can be formed by a sputtering method using a target containing a material for forming the second magnetic layer 32, similarly to the method for forming the first magnetic layer 31.

[0069] As a target containing a material for forming the second magnetic layer 32, a target similar to the target containing a material for forming the first magnetic layer 31 can be used.

[0070] The sputtering conditions may be the same as those for the first magnetic layer 31.

[0071] Next, as shown in FIG. 1, a protective layer 40 is formed on the surface of the magnetic layer 30 (protective layer forming step).

[0072] The method for forming the protective layer 40 is not particularly limited, but examples thereof include the RF-CVD (Radio Frequency-Chemical Vapor Deposition) method in which a film is formed by decomposing a raw material gas consisting of a hydrocarbon using high frequency plasma, the IBD (Ion Beam Deposition) method in which a film is formed by ionizing a raw material gas using electrons emitted from a filament, and the FCVA (Filtered Cathodic Vacuum Arc) method in which a film is formed using a solid carbon target without using a raw material gas.

[0073] Furthermore, the lubricant layer 50 may be formed on the surface of the protective layer 40 by using a general coating method or the like (lubricant layer forming step).

[0074] The method for manufacturing a magnetic recording medium according to the present embodiment includes a step of forming an MgO underlayer and a step of forming a magnetic layer. In the step of forming the MgO underlayer, an MgO target containing MgO is heated to 600° C. or higher to form the MgO underlayer 21. This makes it possible to suppress the generation of sputter dust due to the MgO target in the chamber of the sputtering device during the formation of the MgO underlayer 21. This makes it possible to form the MgO underlayer 21 with high crystal orientation and few defects. As a result, when the MgO contained in the obtained MgO underlayer 21 is measured by XPS, the peak of the O1s spectrum is detected in the range of 531 eV to 533 eV. From the measurement results by this XPS, the obtained MgO underlayer 21 is (100) oriented and has high crystal orientation. When an FePt alloy is used as the magnetic layer 30, the (001) plane is used as the crystal orientation plane of the magnetic layer 30. Therefore, by improving the crystal orientation of the MgO underlayer 21, it is possible to improve the crystal orientation of the magnetic layer 30 formed on its surface. Furthermore, by improving the crystal orientation, it is possible to reduce defects occurring in the magnetic layer 30. Therefore, according to the method for manufacturing a magnetic recording medium according to this embodiment, it is possible to manufacture a magnetic recording medium 1 having a magnetic layer 30 with high crystal orientation and few defects.

[0075] That is, when the first magnetic layer 31 or the second magnetic layer 32 included in the magnetic layer 30 includes an FePt alloy, the (001) plane is used as the crystal orientation plane of the magnetic layer 30. The MgO included in the MgO underlayer 21 is oriented in the (100) plane. The (100) plane of the MgO included in the MgO underlayer 21 is oriented in the L1 plane included in the magnetic layer 30. 0Since the MgO has high lattice matching with the (001) plane of the FePt alloy having the structure, the magnetic layer 30 containing the FePt alloy can be easily oriented in the (001) direction by forming the magnetic layer 30 containing the FePt alloy on the MgO underlayer 21. Therefore, by increasing the crystal orientation of the MgO underlayer 21 and reducing defects, the crystal orientation of the magnetic layer 30 formed on the surface of the MgO underlayer 21 can also be increased and defects reduced.

[0076] The method for manufacturing a magnetic recording medium according to this embodiment can form an MgO underlayer 21 with improved crystal orientation and reduced defect generation, without manufacturing a target containing MgO at a high density as a sputtering target in the step of forming the MgO underlayer. Therefore, according to the method for manufacturing a magnetic recording medium according to this embodiment, an MgO underlayer 21 with high crystal orientation and few defects can be formed using a target containing MgO as previously used.

[0077] In the method for producing a magnetic recording medium according to this embodiment, in the step of forming the MgO underlayer, a target containing MgO can be heated to 800° C. or higher to form the MgO underlayer 21. This can more reliably improve the crystal orientation of the MgO underlayer 21 and reduce defects, so that the crystal orientation of the magnetic layer 30 formed on the surface of the MgO underlayer 21 can also be more reliably improved and defects occurring in the magnetic layer 30 can be reduced. Thus, according to the method for producing a magnetic recording medium according to this embodiment, the magnetic recording medium 1 can have a magnetic layer 30 with higher crystal orientation and fewer defects.

[0078] In the method for producing the magnetic recording medium according to the present embodiment, the magnetic layer 30 is 0 The FePt alloy and the CoPt alloy each have a structure of 1×10 6 J / m 3It is a high Ku material of the order of 1000. Therefore, by using at least one of the FePt alloy and the CoPt alloy as the material constituting the magnetic layer 30, the magnetic particles constituting the magnetic layer 30 can be finely divided, for example, to a particle size of 6 nm or less while maintaining thermal stability. Therefore, when the thermally assisted recording method is used as the recording method, the magnetic layer 30 can have a coercive force of several tens of kOe at room temperature, and magnetic information can be easily recorded in the magnetic layer 30 by the recording magnetic field of the magnetic head.

[0079] Furthermore, the magnetic layer 30 containing at least one of an FePt alloy and a CoPt alloy can use the (001) plane as the crystal orientation plane. Since the MgO underlayer 21 is (100) oriented, the lattice matching between the (100) plane of MgO or CoPt and the (001) plane of the FePt alloy is high, so the crystal orientation of the magnetic layer 30 can be easily improved. Therefore, according to the manufacturing method of the magnetic recording medium according to this embodiment, the magnetic recording medium 1 can have a magnetic layer 30 with higher crystal orientation and fewer defects.

[0080] [Magnetic storage device] A magnetic storage device using the magnetic recording medium according to the present embodiment will be described. The magnetic storage device according to the present embodiment is not particularly limited in form as long as it has the magnetic recording medium according to the present embodiment. Here, a case will be described in which the magnetic storage device uses a thermally assisted recording method to record magnetic information on the magnetic recording medium.

[0081] The magnetic storage device of this embodiment may have, for example, a magnetic recording medium driving unit for rotating the magnetic recording medium of this embodiment, a magnetic head having a near-field light generating element at its tip, a magnetic head driving unit for moving the magnetic head, and a recording / playback signal processing unit.

[0082] The magnetic head also has, for example, a laser light generating unit for heating the magnetic recording medium, and a waveguide for guiding the laser light generated from the laser light generating unit to the near-field light generating element.

[0083] Fig. 7 is a perspective view showing an example of a magnetic storage device using the magnetic recording medium according to this embodiment. As shown in Fig. 7, the magnetic storage device 100 can have a magnetic recording medium 101, a magnetic recording medium driving unit 102 for rotating the magnetic recording medium 101, a magnetic head 103 having a near-field light generating element at its tip, a magnetic head driving unit 104 for moving the magnetic head 103, and a recording and reproducing signal processing unit 105. The magnetic recording medium 1 according to this embodiment described above is used as the magnetic recording medium 101.

[0084] 8 is a schematic diagram showing an example of the magnetic head 103. As shown in FIG. 8, the magnetic head 103 has a recording head 110 and a reproducing head 120.

[0085] The recording head 110 has a main magnetic pole 111, an auxiliary magnetic pole 112, a coil 113 that generates a magnetic field, a laser diode (LD) 114 which is a laser light generating unit, and a waveguide 116 which transmits the laser light L generated from the LD 114 to a near-field light generating element 115.

[0086] The reproducing head 120 has a shield 121 and a reproducing element 122 sandwiched between the shield 121 .

[0087] As shown in FIG. 3, in the magnetic storage device 100, the center of a magnetic recording medium 101 is attached to the rotating shaft of a spindle motor, and information is written to or read from the magnetic recording medium 101 while a magnetic head 103 floats and runs above the surface of the magnetic recording medium 101, which is rotated by the spindle motor.

[0088] In the magnetic storage device 100 according to this embodiment, by using the magnetic recording medium 1 according to this embodiment as the magnetic recording medium 101, the recording density of the magnetic recording medium 101 can be increased, and therefore the recording density can be increased. EXAMPLES

[0089] Hereinafter, the embodiment will be specifically described with reference to examples and comparative examples, but the embodiment is not limited to these examples and comparative examples.

[0090] <Example 1> [Magnetic recording media manufacturing] A magnetic recording medium was manufactured by the following method.

[0091] A 50 nm thick 50 atomic % Cr-50 atomic % Ti alloy film (third underlayer) and a 25 nm thick 75 atomic % Co-20 atomic % Ta-5 atomic % B alloy film (soft magnetic underlayer) were deposited in this order on a heat-resistant glass substrate. Next, the substrate was heated to 250°C, and then a 10 nm thick Cr film (second underlayer) was deposited. A DC magnetron sputtering device (C-3040, manufactured by Anelva Corporation) was used to deposit the third underlayer, the soft magnetic underlayer, and the second underlayer.

[0092] Next, an RF sputtering device was used to deposit a first underlayer, an MgO underlayer. Specifically, an MgO target with a relative density of 85% and a diameter of 120 mm was used, and discharge was performed for 12 seconds at a target temperature of 1000°C, input power of 1 kW, sputtering gas of Ar, and sputtering gas pressure of 3 Pa to deposit an MgO film with a thickness of 2 nm.

[0093] Next, the substrate was heated to 520°C, and then a 3 nm thick 60 mol% (52 at% Fe-48 at% Pt)-40 mol% C film (first magnetic layer) and a 5 nm thick 82 mol% (52 at% Fe-48 at% Pt)-18 mol% SiO 2 A DC magnetron sputtering device (C-3040, manufactured by Anelva Corporation) was used to deposit the first magnetic layer and the second magnetic layer.

[0094] Next, a 3 nm thick carbon film was formed as a protective layer by using an ion beam method, and then a perfluoropolyether film was formed as a lubricant layer by a coating method, thereby obtaining a magnetic recording medium.

[0095] ((001) orientation of magnetic layer) Using an X-ray diffractometer (manufactured by Philips), the X-ray diffraction spectrum of the substrate after the second magnetic layer was formed was measured, and the half-value width of the (200) peak of the FePt alloy was obtained.

[0096] The (001) orientation of the second magnetic layer is determined by the L1 0 The half-width of the (200) peak of the FePt alloy having the structure was used for evaluation. Here, the appearance angle 2θ of the (001) peak of the FePt alloy is not sufficiently large. Therefore, even if the low angle side is expanded to the measurement limit when measuring the rocking curve, the intensity of the (001) peak of the FePt alloy is not stable compared to the case where the peak does not exist, and it is difficult to analyze the half-width. For such measurement reasons, it is difficult to evaluate the (001) orientation of the magnetic layer using the half-width of the (001) peak of the FePt alloy. On the other hand, the (200) peak of the FePt alloy appears when the FePt alloy is (001) oriented, but since the appearance angle 2θ is sufficiently large, it is suitable for evaluating the (001) orientation of the magnetic layer.

[0097] The evaluation results of the half-width of the (200) peak of the FePt alloy are shown in Table 1. In addition, the yield when 1000 magnetic recording media were manufactured under the same conditions as above was evaluated using an error tester. The evaluation results are shown in Table 1.

[0098] <Examples 2 to 3, Comparative Example 1> The procedure of Example 1 was repeated, except that the heating temperature of the MgO target during deposition of the MgO underlayer was changed to the temperatures shown in Table 1. Table 1 shows the evaluation results of the half-width of the (200) peak of the FePt alloy, and the yield when 1,000 magnetic recording media were manufactured under the same conditions in each of the examples and comparative examples.

[0099] [Table 1]

[0100] As can be seen from Table 1, the yield when 1000 magnetic recording media were manufactured was 98.7% or more in Examples 1 to 3. On the other hand, in Comparative Example 1, the yield when 1000 magnetic recording media were manufactured was 98.1%.

[0101] In Examples 1 to 3, unlike Comparative Example 1, it was confirmed that the orientation of the second magnetic layer can be improved and the yield can be improved by forming the MgO underlayer at an MgO target temperature of 600° C. or higher during the formation of the MgO underlayer and then manufacturing the magnetic recording medium. Therefore, it can be said that the magnetic recording medium manufacturing method according to this embodiment can manufacture magnetic recording media with high efficiency.

[0102] Although the embodiment has been described above, the above embodiment is presented as an example, and the present invention is not limited to the above embodiment. The above embodiment can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0103] 1, 101 Magnetic recording media 10 Substrate 20 Base layer 21 Magnesium oxide (MgO) underlayer (first underlayer) 22 Second Undercoat Layer 30 Magnetic layer 31 First magnetic layer 32 Second magnetic layer 100 Magnetic storage device

Claims

1. A step of forming a magnesium oxide underlayer by a sputtering method using a target containing magnesium oxide on the surface of a substrate; and A step of forming a magnetic layer on the surface side of the magnesium oxide underlayer; comprising A method for manufacturing a magnetic recording medium, wherein when forming the magnesium oxide underlayer, the target containing magnesium oxide is heated to 600 °C or higher.

2. The method for manufacturing a magnetic recording medium according to claim 1, wherein the target containing magnesium oxide is heated to 800 °C or higher.

3. The magnetic layer is L1 ０ The method for manufacturing a magnetic recording medium according to claim 1 or 2, comprising at least one of an FePt alloy and a CoPt alloy having a L1

Images