Magnetic recording medium and magnetic storage device

Abstract

To provide a method for producing a magnetic recording medium capable of having a magnetic layer with high crystal orientation and few defects, a magnetic recording medium, and a magnetic storage device.SOLUTION: A method of producing a magnetic recording medium 1 includes: a step of forming a magnesium oxide underlayer 20 on a surface of a substrate 10 by a sputtering method with using a target containing magnesium oxide; and a step of forming a magnetic layer 30 on the surface side of the magnesium oxide underlayer 20, in which the target containing the magnesium oxide is heated to more than 600°C when forming the magnesium oxide underlayer 20.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] Magnetic recording media are generally manufactured by laminating an underlayer, a magnetic layer, and a protective layer in this 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 achieves a data rate of 1 Tbit / inch. 2 Since it is possible to achieve an areal recording density of this class, it is being considered as a next-generation magnetic recording method that can increase storage capacity as magnetic recording media become smaller and have higher recording densities.

[0003] As a magnetic recording medium that can be used in the thermally assisted recording system, for example, a magnetic recording medium has been disclosed that includes a substrate, multiple underlayers formed on the substrate, and a magnetic layer whose main component is an alloy having an L10 structure, the multiple underlayers including 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] When an FePt alloy having an L10 structure is used as the magnetic layer of a magnetic recording medium, the (001) plane is used as the crystal orientation plane of the magnetic layer. To orient the FePt alloy in (001), MgO with a (100) orientation is generally used as the underlayer. That is, the (100) plane of MgO has high lattice matching with the (001) plane of the FePt alloy. Therefore, by forming a magnetic layer containing the FePt alloy on the MgO layer, the FePt alloy is easily oriented in (001). Furthermore, in the magnetic recording medium of Patent Document 1, the NiO underlayer is also oriented in (100), so MgO is used as the underlayer for the orientation control layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-026368 Summary of the Invention [Problem to be solved by the invention]

[0006] When MgO is used to form the orientation control layer, the sputtering method is generally used to form the MgO layer, but MgO has poor sinterability due to its high melting point. When an MgO layer is formed by sputtering using a target with poor sinterability, abnormal discharge (arcing) occurs on the target surface, causing the target surface to melt and scatter, resulting in the generation of sputter dust. This sputter dust reduces the crystalline orientation of the MgO layer and makes it more likely to develop defects in the MgO layer. This reduces the crystalline orientation of the magnetic layer formed on the MgO layer and increases the likelihood of defects developing in the magnetic layer.

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

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

[0009] A magnetic recording medium according to one embodiment of the present invention comprises a magnesium oxide underlayer and a magnetic layer containing an FePt alloy having an L10 structure, the magnesium oxide underlayer containing magnesium oxide, which has an O1s spectrum peak at 531 eV to 533 eV when measured by XPS. [Effects of the Invention]

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

[0011] [Figure 1] 1 is a cross-sectional view showing an example of the configuration of a magnetic recording medium according to an embodiment of the present invention. [Figure 2] 1 is an explanatory diagram showing one step of a method for manufacturing a magnetic recording medium according to an embodiment of the present invention. [Figure 3] 5A to 5C are explanatory diagrams showing other steps in the method for manufacturing a magnetic recording medium according to an embodiment of the present invention. [Figure 4] FIG. 10 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. [Figure 5] This is the O1s spectrum of a magnesium oxide film measured by XPS. [Figure 6] 5A to 5C are explanatory diagrams showing other steps in the method for manufacturing 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. 1 is a schematic diagram illustrating an example of a magnetic head. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail. To facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals, and duplicate descriptions will be omitted. The scale of each component in the drawings may differ from the actual scale. In this specification, unless otherwise specified, "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits.

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

[0014] [Magnetic recording media] Fig. 1 is a cross-sectional view showing an example of the configuration of a magnetic recording medium according to this embodiment. As shown in Fig. 1, the magnetic recording medium 1 includes a substrate 10, an underlayer 20, and a magnetic layer 30 containing an alloy having an L10 structure, stacked in this order from the substrate 10 side.

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

[0016] Although FIG. 1 shows the underlayer 20 and 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). Alternatively, 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 surface 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 magnetic recording media. 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, resin, etc. Among these, Al alloys and glass 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, stacked in this order from the substrate 10 side, with 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, consists essentially of MgO, and more preferably consists only of MgO. "Substantially" means that in addition to MgO, the layer may also contain unavoidable 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, which facilitates lattice matching between the (100) plane of MgO and the (001) plane of the magnetic alloy having the L10 structure contained in the first magnetic layer 31, thereby improving the crystal orientation of the magnetic alloy.

[0022] As will be described later, the MgO underlayer 21 is formed by sputtering under predetermined conditions. The MgO underlayer 21 has a peak in 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 later.

[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 can orient the first magnetic layer 31 in (001), and examples include (100) oriented W, Cr, Cr alloys with a BCC structure, and alloys with a B2 structure.

[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 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 stacked in this order from the MgO underlayer 21 side.

[0030] The first magnetic layer 31, which is the bottom layer of the magnetic layer 30 (the layer closest to the substrate 10), preferably includes an alloy having an L10 structure.

[0031] The alloy having the L10 structure constituting the first magnetic layer 31 preferably further contains Fe or Co and Pt. Specifically, the alloy having the L10 structure is preferably an FePt alloy or a CoPt alloy. The magnetocrystalline anisotropy constant (Ku) of the FePt alloy is 7×10 6 J / m 3 The Ku of the CoPt alloy is 5×10 6 J / m 3 and all of them are 1×10 6 J / m 3The FePt alloy or the CoPt alloy is a material with a high base Ku (high Ku material). Therefore, by using an FePt alloy or a CoPt alloy as the material for forming the first magnetic layer 31, the magnetic grains forming the magnetic layer 30 can be made fine to a grain size of, for example, 6 nm or less while maintaining the thermal stability of the magnetic layer 30.

[0032] The first magnetic layer 31 may further contain a grain boundary segregation material and have a granular structure, which facilitates the (001) orientation of the first magnetic layer 31 and improves lattice matching with the (100)-oriented MgO underlayer 21.

[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 preferably contains an alloy having an L10 structure, similar to the first magnetic layer 31. This improves the (001) orientation of the magnetic layer 30. That is, the second magnetic layer 32 can be formed as a magnetic film that is epitaxially grown along the orientation of the first magnetic layer 31.

[0035] As with the first magnetic layer 31, the alloy having the L10 structure that constitutes the second magnetic layer 32 preferably contains Fe or Co and Pt.

[0036] Like the first magnetic layer 31, the second magnetic layer 32 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 oxides such as SiO2, TiO2, Cr2O3, Al2O3, Ta2O5, ZrO2, Y2O3, CeO2, MnO, TiO, and ZnO, and two or more of these 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 magnetic layers 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 due to 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 that can be used to form 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 an O1s spectrum peak at 531 eV to 533 eV when measured by XPS. The MgO underlayer 21 has high crystalline orientation and few defects, so the magnetic layer 30 formed above the MgO underlayer 21 can also be formed with high crystalline orientation and few defects, similar to the MgO underlayer 21. Therefore, the magnetic recording medium 1 can have a magnetic layer 30 with high crystalline orientation and few defects above the MgO underlayer 21.

[0046] [Magnetic recording medium manufacturing method] The method for manufacturing a 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 a magnetic recording medium according to this embodiment includes the steps of forming a second underlayer, an MgO underlayer (first underlayer), a magnetic layer, a protective layer, and a lubricant layer.

[0048] In the method for manufacturing 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, an 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, the 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 poor sinterability. Therefore, it is difficult to manufacture an MgO target containing MgO with a sufficiently high density for use as a sputtering target. The relative density of a typical MgO target is approximately 65% ​​to 98%, making it prone to abnormal discharge (arcing) on ​​the target surface during sputtering. This arcing melts and scatters the target surface, generating sputter dust, which then adheres to the deposition surface (the upper surface of the MgO underlayer 21). This reduces the crystallinity of the MgO underlayer 21 and increases the likelihood of defects in the MgO underlayer 21. These defects are carried over to the magnetic layer 30 formed on top of the MgO underlayer 21, reducing the crystallinity of the magnetic layer 30. Furthermore, the introduction of defects in the magnetic layer 30 can result in unreadable and unwritable areas on the data surface of the magnetic recording medium 1, potentially reducing product yield.

[0052] The present inventors conducted extensive research into the deterioration of the crystallinity of the magnetic layer 30 and the occurrence of defects in the magnetic layer 30, and as a result, they focused on the film-forming conditions when forming the MgO underlayer 21, in particular the heating temperature of the MgO target containing MgO. They then discovered that by sputtering while heating the MgO target to an extremely high temperature of 600°C or higher, 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 also has improved crystal orientation and fewer defects.

[0053] Figure 4 shows an example of the relationship between the target temperature of the MgO target and the amount of sputter dust generated in the chamber of a sputtering apparatus. Figure 4 shows the results of RF sputtering performed for two hours using an MgO target with a relative density of 85% and a diameter of 120 mm, with 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 3.5-inch diameter magnetic recording medium substrate. The deposition time for an MgO film during magnetic recording medium manufacturing is typically about 10 seconds. As shown in Figure 4, sputtering at a target temperature of 600°C or higher reduces the amount of sputter dust by more than half compared to sputtering at a target temperature of 400°C or lower.

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

[0055] Figure 5 shows the O1s spectrum of a magnesium oxide film measured by X-ray photoelectron spectroscopy (XPS). In Figure 5, (a) is the spectrum of a magnesium oxide film formed by a conventional method, and (b) is the spectrum of a magnesium oxide film produced by the method for producing a magnetic recording medium according to this embodiment. As shown in Figure 5, (a) has an O1s spectrum peak at around 530 eV. In contrast, (b) has the O1s spectrum peak shifted by about 1 eV to the higher 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 pronounced on the surface side of the MgO film, and is thought to occur when part of the oxygen in the MgO is replaced by OH.

[0057] This substitution improves the lattice matching between the MgO (100) plane and the (001) plane of the FePt alloy having the L10 structure, thereby enhancing the (001) orientation of the FePt alloy film.

[0058] Since the sputtering target containing MgO used in the sputtering method is usually an insulator, RF sputtering is preferably used as the sputtering method, whereas when the sputtering target is conductive, 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 sputtering using a target containing the material for forming the first magnetic layer 31.

[0062] It is preferable to use a target containing an alloy having an L10 structure as the target containing the material for forming the first magnetic layer 31. As the alloy having the L10 structure, an alloy containing Fe or Co and Pt or the like can be used, such as an FePt alloy or a CoPt alloy.

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

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

[0065] As the reactive gas, O2 gas, H2O gas, N2 gas, or the like may be used.

[0066] The sputtering gas pressure is adjusted appropriately to optimize the properties 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] As a method for forming the second magnetic layer 32, similar to the method for forming the first magnetic layer 31, the second magnetic layer 32 can be formed by sputtering using a target containing the material for forming the second magnetic layer 32.

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

[0070] The sputtering conditions can 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 RF-CVD (Radio Frequency-Chemical Vapor Deposition), which forms a film by decomposing a raw material gas consisting of hydrocarbons using high-frequency plasma; IBD (Ion Beam Deposition), which forms a film by ionizing a raw material gas with electrons emitted from a filament; and FCVA (Filtered Cathodic Vacuum Arc), which forms a film using a solid carbon target without using a raw material gas.

[0073] Furthermore, a 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 this 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 prevents sputtering dust from being generated in the chamber of the sputtering apparatus due to the MgO target during the formation of the MgO underlayer 21. This allows the MgO underlayer 21 to be formed with high crystal orientation and few defects. When the MgO contained in the resulting MgO underlayer 21 is measured by XPS, the O1s spectrum peak is detected in the range of 531 eV to 533 eV. The XPS measurement results indicate that the resulting MgO underlayer 21 has a (100) orientation and high crystal orientation. When an FePt alloy is used for the magnetic layer 30, the (001) plane is used as the crystal orientation plane of the magnetic layer 30. Therefore, by improving the crystalline orientation of the MgO underlayer 21, it is possible to improve the crystalline orientation of the magnetic layer 30 formed on its surface. Furthermore, improving the crystalline orientation reduces defects that occur in the magnetic layer 30. Therefore, the method for manufacturing a magnetic recording medium according to this embodiment makes it possible to manufacture a magnetic recording medium 1 having a magnetic layer 30 with high crystalline 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 contains 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 (100) oriented. The (100) plane of the MgO included in the MgO underlayer 21 has high lattice matching with the (001) plane of the FePt alloy having an L10 structure included in the magnetic layer 30. Therefore, by forming the magnetic layer 30 including the FePt alloy on the MgO underlayer 21, the magnetic layer 30 including the FePt alloy is easily oriented in the (001) plane. Therefore, by increasing the crystal orientation of the MgO underlayer 21 and reducing defects, the crystal orientation of the magnetic layer 30 formed on its surface can also be increased and defects can be 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, even without manufacturing a target containing high-density MgO as a sputtering target in the step of forming the MgO underlayer. Thus, 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 conventional target containing MgO.

[0077] In the method for manufacturing a magnetic recording medium according to this embodiment, in the step of forming the MgO underlayer, a target containing MgO is heated to 800°C or higher to form the MgO underlayer 21. This more reliably improves the crystalline orientation of the MgO underlayer 21 and reduces defects, which more reliably improves the crystalline orientation of the magnetic layer 30 formed on its surface and reduces defects that occur in the magnetic layer 30. Therefore, according to the method for manufacturing a magnetic recording medium according to this embodiment, the magnetic recording medium 1 can have a magnetic layer 30 with higher crystalline orientation and fewer defects.

[0078] In the method for manufacturing a magnetic recording medium according to this embodiment, the magnetic layer 30 contains at least one of an FePt alloy and a CoPt alloy having an L10 structure. 6 J / m 3 It is a high Ku material in the order of magnitude. Therefore, by using at least one of an FePt alloy and a CoPt alloy as the material for the magnetic layer 30, the magnetic particles that make up the magnetic layer 30 can be miniaturized to a particle size of, for example, 6 nm or less while maintaining thermal stability. Therefore, when a 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 a 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. Because the MgO underlayer 21 is (100) oriented, there is high lattice matching between the (100) plane of MgO or CoPt and the (001) plane of the FePt alloy, making it easier to improve the crystal orientation of the magnetic layer 30. Therefore, according to the method for manufacturing 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.

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

[0081] The magnetic storage device according to this embodiment may have, for example, a magnetic recording medium driving unit for rotating the magnetic recording medium according to 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 include a magnetic recording medium 101, a magnetic recording medium drive unit 102 for rotating the magnetic recording medium 101, a magnetic head 103 equipped with a near-field light generating element at its tip, a magnetic head drive unit 104 for moving the magnetic head 103, and a recording / reproducing signal processing unit 105. The magnetic recording medium 101 is the magnetic recording medium 1 according to this embodiment described above.

[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 that is a laser light generating unit, and a waveguide 116 that transmits the laser light L generated from the LD 114 to a near-field light generating element 115.

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

[0087] As shown in Figure 3, in the magnetic storage device 100, the center of the magnetic recording medium 101 is attached to the rotating shaft of a spindle motor, and the magnetic head 103 writes or reads information to or from the magnetic recording medium 101 while floating and running 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 magnetic recording medium 101 can have a high recording density, and therefore the recording density can be increased. [Example]

[0089] Hereinafter, the embodiments will be specifically described with reference to examples and comparative examples, but the embodiments are 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 that order on a heat-resistant glass substrate. The substrate was then heated to 250°C, after which a 10 nm thick Cr film (second underlayer) was deposited. A DC magnetron sputtering system (C-3040, manufactured by Anelva Corporation) was used to deposit the third underlayer, soft magnetic underlayer, and second underlayer.

[0092] Next, an RF sputtering system was used to deposit a first 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 under the conditions of a target temperature of 1000°C, input power of 1 kW, sputtering gas pressure of Ar, and sputtering gas pressure of 3 Pa to deposit a 2 nm thick MgO film.

[0093] Next, the substrate was heated to 520°C, and 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% SiO2 film (second magnetic layer) were deposited in that order. A DC magnetron sputtering system (C-3040, manufactured by Anelva Corporation) was used to deposit the first and second magnetic layers.

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

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

[0096] The (001) orientation of the second magnetic layer was evaluated using the half-width of the (200) peak of the FePt alloy with an L10 structure contained in the second magnetic layer. Here, the (001) peak of the FePt alloy does not have a sufficiently large appearance angle 2θ. Therefore, even when the low-angle side of the rocking curve is extended to the measurement limit, the intensity of the (001) peak of the FePt alloy is not stable compared to when the peak is not present, making it difficult to analyze the half-width. For these 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 because the appearance angle 2θ is sufficiently large, it is suitable for evaluating the (001) orientation of the magnetic layer.

[0097] The evaluation results for the half-width of the (200) peak of the FePt alloy are shown in Table 1. In addition, the yield when 1,000 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 and 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 temperature 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 Example and Comparative Example.

[0099] [Table 1]

[0100] As can be seen from Table 1, the yield when 1000 magnetic recording media were manufactured was 98.7% or higher 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 by manufacturing a magnetic recording medium by depositing an MgO underlayer at an MgO target temperature of 600°C or higher during deposition of the MgO underlayer, it is possible to enhance the orientation of the second magnetic layer and improve the yield. Therefore, it can be said that the method for manufacturing a magnetic recording medium according to this embodiment allows for highly efficient production of magnetic recording media.

[0102] Although the embodiments have been described above, they are presented as examples and the present invention is not limited to the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as set forth 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 base layer 30 Magnetic layer 31 First magnetic layer 32 Second magnetic layer 100 Magnetic storage device

Claims

1. a magnesium oxide underlayer containing magnesium oxide; L1 ０ a magnetic layer including an FePt alloy having a structure; Equipped with The magnesium oxide has an O1s spectrum having at least one of a peak maximum value and a peak half width of 532 eV to 533 eV when measured by X-ray photoelectron spectroscopy, the magnesium oxide underlayer has a (100) orientation; The magnetic layer of the magnetic recording medium is (001) oriented.

2. A magnetic storage device comprising the magnetic recording medium according to claim 1.

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