WO2004051630A1 - Polycrystalline structure film, magnetic recording medium and magnetic storage - Google Patents

Abstract

A polycrystalline structure film (32) comprises a seed layer (36) lying over a surface of a substrate (31). A multilayered crystal layer (37) is over the surface of the seed layer (36). The seed layer (36) comprises crystal grains which grow in the vertical direction (V) that is perpendicular to the surface of the substrate (31). The normal (N) of each crystal grain, which is perpendicular to a predetermined face of the crystal lattice, is inclined to the vertical direction (V). The characteristics of the crystal layer can be controlled by the action of the seed layer (36). Namely, the anisotropy of the crystal layer can be heightened even when the surface of the substrate (31) is not provided with a texture structure.

Description

 Polycrystalline structure film, magnetic recording medium, and magnetic storage device

 The present invention relates to a polycrystalline structure film that can be used for a magnetic recording medium such as a hard disk (HD). Background art

 In the field of hard disks, for example, the texture structure established on the surface of an aluminum substrate is widely known. An underlayer and a recording magnetic layer, that is, a crystal layer, are laminated on the surface of the substrate having the established texture structure. In the recording magnetic layer, the so-called circumferential magnetic anisotropy is enhanced by the function of the texture structure. With hard disks, the magnetic properties can be enhanced.

 Recently, glass substrates are widely used for hard disks. A texture structure is not easily formed on the surface of a hard glass substrate. In such a glass substrate, it is required to increase the magnetic anisotropy without forming a texture structure. For example, Patent Document 1 proposes a technique for forming an obliquely grown crystal layer on the surface of a substrate. In the obliquely grown crystal layer, the crystal grains grow obliquely from a normal line perpendicular to the substrate surface. A crystal layer is formed on the surface of the obliquely grown crystal layer. According to the obliquely grown crystal layer, circumferential magnetic anisotropy can be increased in the crystal layer. Patent Document 1

 Japanese Unexamined Patent Publication No. 2000-200203

Patent Document 2

 Japanese Patent Application Laid-Open No. 08-72050

Patent Document 3

Japanese Unexamined Patent Publication No. 58-128280 Disclosure of the invention

 The present invention has been made in view of the above situation, and an object of the present invention is to provide a polycrystalline structure film capable of controlling the characteristics of a crystal layer with a structure different from the conventional structure. At the same time, an object of the present invention is to provide a magnetic recording medium that has a different structure from the above and can increase the magnetic anisotropy of the recording magnetic layer.

 To achieve the above object, according to the present invention, there is provided a seed layer including crystal grains extending along a surface of an object and growing in a vertical direction perpendicular to the surface of the object; The present invention provides a polycrystalline structure film comprising: a crystal layer that extends; and a normal perpendicular to a crystal lattice plane preferentially oriented in a predetermined direction of a crystal grain is inclined from a vertical direction.

 In such a polycrystalline structure J3, the seed layer crystal grains grow in the vertical direction perpendicular to the surface of the object. In the crystal grains of the seed layer, a normal line perpendicular to a predetermined crystal lattice plane is inclined from a vertical direction. The properties of the crystal layer can be controlled by the function of the crystal grains of the seed layer.

 When the crystal lattice plane of the crystal grain of the shield layer is preferentially oriented in a predetermined direction, in each crystal grain, the normal of the predetermined crystal lattice plane is inclined from the vertical direction to the predetermined direction. Thus, a groove is formed on the surface of the shield layer between crystal grains adjacent to each other in a predetermined direction. When a crystal layer is formed on the surface of such a seed layer, the anisotropy of the crystal layer can be increased without establishing a texture structure on the surface of the object. In such a polycrystalline structure film, the crystal grains may be composed of an alloy containing Cr and Nb. In such a polycrystalline structure film, the shield layer may be formed in an atmosphere containing nitrogen based on an oblique incidence film formation method.

 Such a polycrystalline structure film can be used, for example, in a magnetic recording medium incorporated in a magnetic storage device. A magnetic recording medium is, for example, a support, a seed layer that extends along the surface of the support and includes crystal grains that grow in a perpendicular direction perpendicular to the surface of the support, and a magnetic layer that spreads along the surface of the seed layer. And a crystal layer including the layer. At this time, the normal perpendicular to the crystal lattice plane preferentially oriented in a predetermined direction of the crystal grains may be inclined from the vertical direction.

In a magnetic recording medium such as a magnetic disk, the support is formed in a disk shape. The normal perpendicular to the crystal lattice plane of the crystal grains may be inclined in an upright plane including the diameter line of the support. The normal to the crystal lattice plane may be inclined toward the outer periphery of the support.

 In the magnetic recording medium described above, the crystal grains of the seed layer grow in the vertical direction perpendicular to the surface of the support. In each crystal grain, the normal to the predetermined crystal lattice plane is inclined from the vertical direction to the outer periphery in an upright plane including the diameter of the support. That is, a predetermined crystal lattice plane is inclined in each crystal grain. Thus, a groove is formed on the surface of the seed layer between crystal grains adjacent in the radial direction of the support. When a crystal layer is formed on the surface of such a seed layer, the axis of easy magnetization of the magnetic layer included in the crystal layer can be reliably aligned in the circumferential direction of the support. Even if the texture structure is not established on the surface of the support, the magnetic properties in the circumferential direction can be enhanced. In a magnetic recording medium, the circumferential magnetic anisotropy and electromagnetic conversion characteristics can be enhanced.

 On the other hand, in such a magnetic recording medium, a texture structure may be established on the surface of the support. The texture structure may be composed of a plurality of grooves extending in the circumferential direction. By the action of the groove, the magnetic properties and electromagnetic conversion properties in the circumferential direction of the magnetic recording medium can be further enhanced. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a plan view schematically showing a specific example of a magnetic recording medium drive, that is, an internal structure of a hard disk drive (HDD).

 FIG. 2 is an enlarged vertical sectional view showing the structure of the magnetic disk.

 FIG. 3 is an enlarged vertical sectional view showing the structure of the magnetic disk in detail.

 FIG. 4 is a vertical partial cross-sectional view of a substrate conceptually showing a step of forming a first seed layer. FIG. 5 is a vertical partial cross-sectional view of a substrate conceptually showing a process of forming a second seed layer. FIG. 6 is an end view of the substrate and the evening gate schematically showing a process of forming the second seed layer.

 FIG. 7 is a perspective view of a substrate and an evening get schematically showing a process of forming a second shield layer J3.

 FIG. 8 is a vertical partial cross-sectional view of a substrate conceptually showing a process of forming an underlayer.

FIG. 9 is a vertical partial cross-sectional view of a substrate conceptually showing a process of forming an intermediate layer. FIG. 10 is a vertical partial cross-sectional view of a substrate conceptually showing a process of forming a recording magnetic layer. FIG. 11 is a graph showing verification results based on X-ray diffraction.

 FIG. 12 is a graph showing the relationship between the thickness of the second seed layer and the coercive force of the recording magnetic layer.

 FIG. 13 is a graph showing the relationship between the thickness of the second seed layer and the magnetic anisotropy of the recording magnetic layer.

 FIG. 14 is a graph showing the relationship between the thickness of the second seed layer and the S / N ratio of the recording magnetic layer.

 FIG. 15 is a graph showing the relationship between the J3 thickness of the second seed layer and the reproduction output resolution of the recording magnetic layer. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

 FIG. 1 schematically shows a specific example of a magnetic recording medium drive, that is, an internal structure of a hard disk drive (HDD) 11. The HDD 11 includes, for example, a box-shaped casing main body 12 that defines a flat rectangular parallelepiped internal space. One or more magnetic disks 13 as recording media are accommodated in the accommodation space. The magnetic disk 13 is mounted on a rotating shaft of a spindle motor 14. The spindle motor 14 can rotate the magnetic disk 13 at a high speed of, for example, 720 rpm or 100 rpm. A lid or a cover (not shown) that seals the accommodation space between the housing body 12 and the housing body 12 is connected to the housing body 12.

The accommodating space further accommodates Head Actuyue 15th. The head actuating unit 15 includes an actuator unit block 17 rotatably supported by a vertically extending support shaft 16. In the actuator block 17, a rigid actuator arm 18 extending horizontally from the support shaft 16 is defined. The actuator arm 18 is arranged on each of the front and back surfaces of the magnetic disk 13. The work block 17 may be molded from aluminum, for example, based on the structure. A head suspension 19 is attached to the tip of the arm 18. Head suspension 19, the front of the arm 18 Extending towards. As is well known, a flying head slider 21 is supported at the front end of the head suspension 19. Thus, the flying head slider 21 is connected to the actuator block 17. The flying head slider 21 faces the surface of the magnetic disk 13.

 A so-called magnetic head, that is, an electromagnetic transducer (not shown) is mounted on the flying head slider 21. These electromagnetic transducers include, for example, a giant magnetoresistive element (GMR) and a tunnel junction magnetoresistive element (TMR) that read information from a magnetic disk 13 by using the resistance change of a spin valve film or a tunnel junction film. And a write element (not shown) such as a thin-film magnetic head that writes information on the magnetic disk 13 using a magnetic field generated by a thin-film coil pattern. Just fine.

 A pressing force is applied to the flying head slider 21 from the head suspension 19 toward the surface of the magnetic disk 13. Buoyancy acts on the flying head slider 21 by the action of airflow generated on the surface of the magnetic disk 13 based on the rotation of the magnetic disk 13. Due to the balance between the pressing force of the head suspension 19 and the buoyancy, the flying head slider 21 can keep flying with relatively high rigidity while the magnetic disk 13 is rotating.

 A power source 22 such as a voice coil motor (VCM) is connected to the actuator block 17. With the power source 22, the actuator block 17 can rotate around the support shaft 16. The swing of the actuator arm 18 and the head suspension 19 is realized based on the rotation of the actuator block 17. When the actuator arm 18 swings around the support shaft 16 while the flying head slider 21 is flying, the flying head slider 21 can cross the surface of the magnetic disk 13 in the radial direction. As is well known, when a plurality of magnetic disks 13 are incorporated in the housing main body 12, two actuators 18 between adjacent magnetic disks 13 or two heads are required. Head suspension 19 is placed.

FIG. 2 shows the cross-sectional structure of the magnetic disk 13 in detail. This magnetic disk 13 includes a substrate 31 as a support and a polycrystalline structure film 32. The substrate 31 is, for example, glass Force, etc. should be configured. However, the substrate 31 may be made of silicon or sapphire, or may be made of aluminum. A smooth surface is established on the surface of the substrate 31. Magnetic information is recorded on the polycrystalline structure film 32. The surface of the polycrystalline structure film 32 is covered with a protective film 33 such as diamond-like carbon (DLC) and a lubricating film 34 such as perfluoropolyether (PFPE).

 As shown in FIG. 3, the polycrystalline structure film 32 includes a first side layer 35 extending along the surface of the substrate 31 and a second side layer extending along the surface of the first seed layer 35. A second crystal layer 37 extending along the surface of the second seed layer 36. The first seed layer 35 is formed of, for example, an amorphous layer. The amorphous layer may be made of, for example, an alloy containing Cr and Ti. Here, for example, a CrTi film having a thickness of about 25 nm is used.

 The second seed layer 36 may be made of, for example, an alloy containing Cr and Nb. Here, for example, a CrNb film having a thickness of about 25 nm is used. As shown in FIG. 3, the second seed layer 36 is composed of crystal grains that grow in the vertical direction V perpendicular to the surface of the substrate 31. Moreover, the normal line N perpendicular to the crystal lattice plane preferentially oriented in the predetermined direction of the crystal grains is inclined from the vertical direction V toward the outer periphery at a predetermined inclination angle. The multilayer crystal layer 37 includes an underlayer 38 extending along the surface of the second seed layer 36. In the underlayer 38, crystal grains having a bec (body-centered cubic) structure are established. The underlayer 38 may be made of, for example, Cr or an alloy containing Cr. Here, for example, a CrMo film having a thickness of about 4 nm is used.

The intermediate layer 39 spreads on the surface of the underlayer 38. In the middle layer 39, crystal grains with the hcp (hexagonal fine crystal) structure are established. The intermediate layer 39 may be made of, for example, an alloy containing Co. Here, for example, a C0CrTa film having a thickness of about 1 nm is used. The recording magnetic layer 41 spreads on the surface of the intermediate layer 39. Magnetic information is recorded on the recording magnetic layer 41. In the recording magnetic layer 41, crystal grains having the hcp structure are established. The recording magnetic layer 41 may be made of, for example, an alloy containing Co. Here, for example, a CoCrPtBCu film having a thickness of about 15 nm is used. However, the recording magnetic layer 41 may be composed of, for example, a laminate of a plurality of magnetic layers. In this case, a Ru layer having a thickness of, for example, about 0.7 nm may be interposed between the magnetic layers. According to such a polycrystalline structure film 32, even if a texture structure is not established on the surface of the substrate 31, the magnetic axis of the recording magnetic layer 41 in the circumferential direction is easily controlled by the second seed layer 36. Can be aligned. In the magnetic disk 13, Hec / Hcr (the ratio of the coercive force Hec in the circumferential direction to the coercive force Her in the radial direction) and the electromagnetic conversion characteristics can be improved.

 Next, an example of a method for manufacturing the magnetic disk 13 will be briefly described. First, a disk-shaped substrate 31 is prepared. The surface of the substrate 31 is smoothed. The substrate 31 is mounted on, for example, a magnetron sputtering apparatus. At the time of mounting, the substrate 31 is heated to 220 degrees Celsius based on the condition of the carbon dioxide. A polycrystalline structure film 32 is formed on the surface of the substrate 31 in the magnetron sputtering device. Details of the forming method will be described later. After that, a protective film 33 is formed on the surface of the polycrystalline structure film 32. For example, a CVD (chemical vapor deposition) method is used for forming a layered structure. A lubricating film 34 is applied on the surface of the protective film 33. In the application, the substrate 31 may be immersed in a solution containing perfluoropolyether, for example.

 As shown in FIG. 4, in forming the polycrystalline structure film 32, a first seed layer 35, that is, a CrTi film 42 is formed on the surface of the substrate 31 based on the vertical incidence sputtering method. At the time of film formation, a CrTi i-get is installed in the sputtering device. When the Cr and Ti atoms are released from the C r T i get, the Cr and T i atoms fall in the vertical direction V perpendicular to the surface of the substrate 31. That is, the incident angle α is set to 0 degrees. Thus, an amorphous CrTi film 42 is formed on the surface of the substrate 31. The 〇1 "1 ^ film 42 contains 50 [at%] Cr and 50 [at%] Ti.

Subsequently, as shown in FIG. 5, a second seed layer 36, that is, a CrNb film 43 is formed on the surface of the CrTi film 42 based on the oblique incidence sputtering method. In film formation, a CrNb target is attached to the sputtering apparatus. Ar gas is introduced into the chamber of the sputtering apparatus. Ar gas is mixed with N ₂ gas. That is, the CrTi film 42 is formed in an atmosphere containing nitrogen. N ₂ gas may be mixed at a partial pressure ratio of about 10 to 60 [%]. Here, for example, the partial pressure ratio is set to 20 [%]. The gas pressure in the chamber is set to about 1.6 [Pa]. Just do it.

 When the Cr and Nb atoms are released from the Cr Nb target, the Cr and Nb atoms fall at a predetermined angle of incidence with respect to the vertical direction V. The Cr atoms and Nb atoms may be poured from the outer periphery of the substrate 31 toward the center. Thus, a CrNb film 43 is formed on the surface of the CrTi film 42. The CrNb film 43 contains 67 [at%] Cr and 33 [at%] Nb.

 The C r Nb target 44 is formed, for example, in a disk shape. The diameter of the CrNb target 44 is set to be larger than the diameter of the substrate 31, for example, as shown in FIG. In the C r Nb first get 44, the erosion position 44 a is set outside the outer peripheral edge of the substrate 31. In response to the supply of electric current, Cr atoms and Nb atoms fall down on the substrate 31 from the erosion position 44a. In the substrate 31, the atoms enter from the outer periphery toward the center.

A shield 45 is interposed between the CrNb target 44 and the substrate 31. As shown in FIG. 7, a disk member 45a is formed at the center of the shield 45. In the shield 45, a shielding plate 45b is formed radially around the disk member 45a. The disk member 45a is positioned at the center of the substrate 31. When the shield 45 is set on the substrate 31, the shielding plate 45 b stands upright from the surface of the substrate 31. According to the shielding plate 45b, the incident direction of atoms is restricted to a predetermined direction. That is, atoms that enter the substrate 31 from the circumferential direction can be excluded. When a sufficiently wide flight path of atoms is secured between the CrNb getter 44 and the substrate 31 in this way, a sufficient amount of Cr and Nb atoms can reach the substrate 31. The deposition rate of Cr atoms and Nb atoms, that is, the deposition rate of the Cr Nb film 43 does not decrease. On the substrate 31, crystal grains grow in the vertical direction V, although Cr atoms and Nb atoms fall down at the predetermined incident angle α. However, in each crystal grain, the normal Ν of the crystal lattice plane preferentially oriented in a predetermined direction is inclined from the vertical direction V at a predetermined inclination angle α. Based on the rotation of the substrate 31, Cr atoms and Nb atoms are uniformly deposited on the substrate 31. On the other hand, in the related art, a predetermined shield covers the substrate when the CrNb film 43 is formed. An annular slit is formed in the shield. Only the atoms passing through the slit enter the substrate. The flight path of the atoms is significantly narrowed. C rN bCr and Nb atoms emitted from the evening gate accumulate on the shield. The deposition rate of the CrNb film 43 decreases. In such a conventional manufacturing method, the crystal grains grow in an inclined direction inclined from the vertical direction V.

If the N ₂ gas is not mixed with the Ar gas in the chamber in forming the CrNb film, the CrNb film is formed of an amorphous material. That is, no crystal grains are formed in the CrNb film. As will be described in detail later, a groove is formed on the surface of the CrNb film. Fine grooves are formed in the CrNb film composed of an amorphous material. In such a CrNb film, the effect of increasing the magnetic anisotropy of the recording magnetic layer is significantly reduced.

 Subsequently, the surface of the CrNb film 43 is oxidized. During the oxidation, the surface of the CrNb film 43 may be exposed to the atmosphere, or a gas containing oxygen may be introduced into the chamber. Next, as shown in FIG. 8, an underlayer 38, that is, a CrMo film 46 is formed on the surface of the CrNb film 43 based on the normal incidence sputtering method. During film formation, a CrMo target is attached to the sputtering apparatus. Cr and Mo atoms descend in the vertical direction V from the CrMo sunset. That is, the incident angle α may be set to 0 degrees. Thus, a CrMo film 46 is formed on the surface of the CrNb film 43. The CrMo film 46 contains 75 [at%] of Cr and 25 [at%] of Mo. A crystal structure of the CrMo film 46, that is, the underlayer 38, establishes a bcc structure.

Subsequently, as shown in FIG. 9, an intermediate layer 39, that is, a CoCrTa film 47 is formed on the surface of the CrMo film 46 based on the normal incidence sputtering method. For film formation, a CoCrTa evening gate is installed in the sputtering system. From the CoCrTa target, Co atom, Cr atom and Ta atom descend in the vertical direction V. That is, the incident angle α may be set to 0 degrees. Thus, a CoCrTa film 47 is formed on the surface of the CrMo film 46. The CoC rTa film 47 contains Co of 82 [at%], Cr of 13 [at%], and Ta of 5 [at%]. An hc ρ structure is established in the crystal grains of the CoC rTa film 47, that is, the intermediate layer 39. Subsequently, as shown in FIG. 10, a recording magnetic layer 41, that is, a CoCrPtBCu film 48 is formed on the surface of the CoCrTa film 47 based on the normal incidence sputtering method. When forming the film, the sputtering equipment must have a CoCrPtBCu target. The bird is attached. Co atoms, Cr atoms, Pt atoms, B atoms, and Cu atoms descend from the CoC r P t BCu target in the vertical direction V. That is, the incident angle α may be set to 0 degrees. Thus, a CoCrPtBCu film 48 is formed on the surface of the CoCrTa film 47. The CoC r Pt BCu film 48 includes 58 [at%] Co, 19 [at%] Cr, 12 [at] Pt, 7 [at%] B, and 4 [at%] Cu. Is included. The hcp structure is established in the CoCrPtBCu film 48, that is, the crystal grains of the recording magnetic layer 41.

 In the manufacturing method as described above, the crystal grains of the CrNb film 43 grow in the vertical direction V orthogonal to the surface of the substrate 31. In each crystal grain, the normal line N of the crystal lattice plane preferentially oriented in a predetermined direction is inclined from the vertical direction V toward the outer periphery in an upright plane including the diameter line of the substrate 31. Thus, a groove is formed on the surface of the CrNb film 43 between crystal grains adjacent to each other in the radial direction of the substrate 31. When a CrMo film 46, a CoCrTa film 47, and a CoCrPtBCu film 48 are formed on the surface of the CrNb film 43 based on the epitaxial growth, the CoCrPtBCu film 48 The easy axis of magnetization of the magnetic layer 41 can be reliably aligned in the circumferential direction of the substrate 31. Even if a texture structure is not established on the surface of the substrate 31, the magnetic anisotropy of the recording magnetic layer 41 can be increased. In the magnetic disk 13, Hec / Hcr and electromagnetic conversion characteristics can be enhanced.

 The inventor has observed the cross section of the second shield layer 36, that is, the CrNb film 43. A transmission electron microscope (TEM) was used for observation. Here, on the surface of the disk-shaped substrate 31, a CrTi film 42 having a thickness of about 25 nm was formed by lamination based on the above-described manufacturing method. On the surface of the CrTi film 42, a CrNb film 43 having a thickness of about 100 nm was laminated. In the CrNb film 43, one cross section along the radial direction and one cross section along the circumferential direction of the substrate 31 were observed. It has been confirmed that the crystal grains of the CrNb film 43 grow in the vertical direction perpendicular to the surface of the substrate 31. In addition, it was confirmed that the normal line perpendicular to the predetermined crystal lattice plane of the crystal grain was inclined from the vertical direction in the upright plane including the diameter line of the substrate 31. A groove extending along the circumferential direction was confirmed on the surface of the CrNb film 43 based on the inclination of the crystal lattice plane.

Next, the present inventor based on the X-ray diffraction, the second seed layer 36, that is, the CrNb film 43. Was observed. The rocking curve was measured based on the preferred orientation plane of the crystal grains (plane spacing: 2.077 Å). As described above, a CrTi film 42 having a thickness of about 25 nm and a CrNb film 43 having a thickness of about 100 nm were formed on the surface of the disk-shaped substrate 31. Similarly, a comparative example was prepared. However, in the comparative example, the incident angles α of the Cr atoms and the Nb atoms on the substrate 31 were set to 0 degrees when the CrNb film 43 was formed. X-rays entered from the outer periphery of the substrate 31 toward the center. In the crystal grains of the CrNb film 43, the inclination angle of the normal to the crystal lattice plane with respect to the direction perpendicular to the substrate 31 was measured. As a result, as shown in FIG. 11, in the CrNb film 43 according to the present embodiment, an X-ray diffraction peak of the preferential orientation plane was confirmed at a point deviated to the outer peripheral side. That is, it was confirmed that the normal of the crystal lattice plane was inclined toward the outer peripheral side in most of the crystal grains. However, Φ in FIG. 11 indicates the X-ray incident angle on the substrate 31. On the other hand, in the CrNb film 43 according to the comparative example, the X-ray diffraction peak of the preferred orientation plane was confirmed at the point where the tilt angle was 0 degree. That is, it was confirmed that the normal of the crystal lattice plane was almost parallel to the vertical direction of the substrate 31 in most crystal grains.

 Subsequently, the present inventors verified the coercive force of the recording magnetic layer 41 in the circumferential direction. For verification, several specific examples were manufactured based on the manufacturing method described above. In each specific example, different film thicknesses were set for the CrNb film 43. A comparative example was prepared for verification. The comparative example was manufactured in the same manner as the specific example. However, in the comparative example, when forming the CrNb film 43, the incident angles α of Cr atoms and Nb atoms on the substrate 31 were set to 0 degrees. The coercive force H c c was measured along the circumferential direction of the magnetic disk 13. As a result, as shown in FIG. 12, in the magnetic disk 13 according to the present embodiment, it was confirmed that the coercive force in the circumferential direction had substantially the same value as the coercive force of the magnetic disk 13 according to the comparative example. Was.

Subsequently, the present inventors verified the magnetic anisotropy of the magnetic recording layer 41. In verification, a specific example was manufactured based on the above-described manufacturing method. In each specific example, a different film thickness was set for the CrNb film 43. A comparative example was prepared for verification. The comparative example was manufactured in the same manner as the specific example. However, in the comparative example, when the CrNb film 43 was formed, the angle of incidence a of Cr atoms and Nb atoms on the substrate 31 was set to 0 degree. The coercive force He c was measured along the circumferential direction of the magnetic disk 13. At the same time, the magnetic disk 13 The coercivity Her was measured along the radial direction of. As a result, as shown in FIG. 13, the value of He cZHcr of the magnetic disk 13 according to the present embodiment exceeds the value of H cc / H cr of the magnetic disk 13 according to the comparative example regardless of the film thickness. This was confirmed. The establishment of magnetic anisotropy was confirmed.

 The present inventors have verified the S / N ratio of the recording magnetic layer 41. For verification, the same specific examples and comparative examples as described above were prepared. The playback output was measured at a linear recording density of 82.5 [kFC I]. At the same time, medium noise was measured at a linear recording density of 330.2 [kFC I]. As a result, as shown in FIG. 14, it was confirmed that the SZN ratio of the magnetic disk 13 according to the present embodiment exceeded the S / N ratio of the magnetic disk 13 according to the comparative example regardless of the film thickness. . In particular, it was confirmed that a high SZN ratio was obtained when the film thickness was set in the range of 5 nm to 25 nm.

 The present inventors have verified the reproduction output resolution of the recording magnetic layer 41. For verification, the same specific examples and comparative examples as described above were prepared. The playback output was measured at a linear recording density of 82.5 [kFC I]. At the same time, the reproduction output was measured at a linear recording density of 330.2 [kFC I]. The reproduction output resolution was calculated from the ratio of these reproduction outputs. As a result, as shown in FIG. 15, it was confirmed that the reproduction output resolution of the magnetic disk 13 according to the present embodiment exceeded the reproduction output resolution of the magnetic disk 13 according to the comparative example regardless of the film thickness. . In particular, it was confirmed that high reproduction output resolution was obtained when the film thickness was set in the range of 5 nm to 25 nm.

In the magnetic disk 13 as described above, a texture structure may be established on the surface of the substrate 31. The texture structure may be composed of multiple scratches extending in the circumferential direction. The present inventors have verified Hec / Her of the specific example and the comparative example in which the texture structure was established. In the above specific example and comparative example, a texture structure was established on the surface of the substrate 31. As a result, the magnetic disk 13 according to the present embodiment recorded Hcc ZHcr of 1.11. On the other hand, the magnetic disk 13 according to the comparative example recorded Hcc ZHcr of 1.06. It was confirmed that the value of Hcc / Hcr was sufficiently increased in the magnetic disk 13 according to the present embodiment as compared with the comparative example. At the same time, the inventor verified the SZN ratio of the specific example and the comparative example in which the texture structure was established. The reproduction output was measured at a linear recording density of 82.5 [kFC I]. same At times, media noise was measured at a linear recording density of 330.2 [kFC I]. As a result, the value of the SZN ratio of the magnetic disk 13 according to the present embodiment was 24.9 [dB]. On the other hand, the value of the SZN ratio of the magnetic disk 13 according to the comparative example was 24.7 [dB]. It has been confirmed that the SZN ratio can be increased in the magnetic disk 13 according to the present embodiment.

Claims

The scope of the claims 1. A seed layer including crystal grains extending along the surface of the object and growing in a vertical direction perpendicular to the surface of the object, and a crystal layer extending along the surface of the seed layer. A normal line perpendicular to a crystal lattice plane preferentially oriented in a direction is inclined from the vertical direction. 2. The polycrystalline structure film according to claim 1, wherein the seed layer is formed based on an oblique incidence film forming method. 3. The polycrystalline structure film according to claim 2, wherein the crystal grains are made of an alloy containing Cr and Nb. 4. The polycrystalline structure film according to claim 3, wherein the seed layer is formed in an atmosphere containing nitrogen. 5. A support, a seed layer that extends along the surface of the support and includes crystal grains that grow in a vertical direction perpendicular to the surface of the support, and a crystal layer that extends along the surface of the seed layer and includes a magnetic layer. A magnetic recording medium comprising: a normal line perpendicular to a crystal lattice plane preferentially oriented in a predetermined direction of a crystal grain is inclined from the perpendicular direction. 6. The magnetic recording medium according to claim 5, wherein the support is formed in a disk shape, and a normal perpendicular to a crystal lattice plane of the crystal grain is in an upright plane including a diameter line of the support. A magnetic recording medium characterized by being inclined. 7. The magnetic recording medium according to claim 6, wherein the crystal lattice plane of the crystal grain is inclined toward the outer periphery of the support. 8. The magnetic recording medium according to claim 7, wherein the crystal grains are Cr and A magnetic recording medium comprising an alloy containing Nb. 9. The magnetic recording medium according to claim 8, wherein the seed layer is formed by an oblique incidence film forming method. 10. The magnetic recording medium according to claim 9, wherein the seed layer is formed in an atmosphere containing nitrogen. 11. The magnetic recording medium according to claim 10, wherein a texture structure is established on a surface of the support. 12. A magnetic storage device incorporating the magnetic recording medium according to any one of claims 5 to 11.