JP2007200395A - Magnetic recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording medium capable of shortening a period of time required for manufacture iand eliminating noise caused by distortion of an easily-magnetized axis. <P>SOLUTION: The magnetic recording medium wherein magnetic force is received and information is recorded according to the magnetic force is provided with a substrate, a soft magnetic layer 11 formed on the substrate, a first intermediate layer 12 formed as an upper layer of the soft magnetic layer 11 and turning crystal orientation of a directly upper non-magnetic layer in a direction vertical to the substrate by a layer consisting of a single layer or a plurality of layers, a second intermediate layer 13 formed as an upper layer of the first intermediate layer 12 and comprising a non-magnetic body crystal, a recording layer 14 which is formed as an upper layer of the second intermediate layer 13 and wherein magnetic force is received and magnetic domains whose magnetization directions are changed in a direction vertical to the substrate are recorded and a protective layer 15 formed on an upper layer of the recording layer 14 and protecting the recording layer 14. The first intermediate layer 12 is discretely formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic recording medium on which information is recorded in response to a magnetic force.

  In recent years, with an increase in the amount of information processed by computers, there is a demand for an increase in capacity of magnetic recording media used for external storage devices and the like.

  In order to meet the above demands, so-called perpendicular magnetic recording, in which a magnetic domain whose magnetization direction changes in a direction perpendicular to the substrate surface of the magnetic recording medium is recorded on the recording layer as a magnetic recording medium capable of increasing the capacity in principle. A scheme has been proposed. (For example, refer to Patent Document 1).

  In this perpendicular magnetic recording system, as the recording density increases, it is necessary to narrow the track width of the data writing track in the magnetic recording medium.

  However, along with the narrowing of the track width, a leakage magnetic field generated from the side surface of the magnetic head at the time of writing causes a write (cross-write) operation to an adjacent track, which tends to cause recording failure and reproduction failure. There is a problem.

  In order to solve the above problem, a discrete track type magnetic recording medium has been proposed in this perpendicular magnetic recording system. This discrete track type magnetic recording medium magnetically separates a magnetic film for each track by processing, thereby preventing writing (cross-write) to adjacent tracks and realizing high-density recording (for example, (See Patent Document 2, Patent Document 3, and Patent Document 4).

According to Patent Document 2, Patent Document 3, and Patent Document 4, which are conventional examples of such a discrete track type magnetic recording medium, a groove is formed in a soft magnetic layer to form a discrete track structure. By preventing leakage of the magnetic flux density of the magnetic field, writing to adjacent tracks is prevented and recording density is improved.
JP 2004-259306 A JP 2003-16621 A JP 2003-16622 A JP 2003-16623 A

  The structures of perpendicular magnetic recording discrete track magnetic recording media disclosed in Patent Documents 2 and 4 are laminated on a substrate in the order of a soft magnetic layer, a recording layer, and a protective layer, and disclosed in Patent Document 3 The structure of the perpendicular magnetic recording type discrete track type magnetic recording medium is formed by laminating a soft magnetic layer, an intermediate layer, a recording layer, and a protective layer in this order on a substrate.

  Here, the soft magnetic layer has an easy axis of magnetization parallel to the substrate surface and in the radial direction. The recording layer is a layer in which a magnetic domain having a magnetization direction changed in a direction perpendicular to the substrate by receiving a magnetic force is recorded on the track, and the protective layer protects the recording layer. The intermediate layer controls the crystal orientation of the recording layer.

  Here, in the manufacture of the magnetic recording media disclosed in Patent Documents 2, 3, and 4, in order to form a groove in the soft magnetic layer, the time required for etching is larger because the film is thicker than the other layers. There is a problem that it takes. Therefore, a method of reducing the thickness of the soft magnetic layer as much as other layers in order to shorten the time required for etching is conceivable, but this causes a problem because it may affect the magnetization action. In addition, when the soft magnetic layer is etched, the easy magnetization axis may be distorted, and as a result, noise may be generated.

  In view of the above circumstances, an object of the present invention is to provide a magnetic recording medium in which a time required for manufacturing is shortened and a device for eliminating noise generation due to distortion of an easy magnetization axis is provided.

The magnetic recording medium of the present invention that achieves the above object provides:
In a magnetic recording medium that receives magnetic force and records information according to the magnetic force,
A substrate,
A soft magnetic layer formed on the substrate;
A first intermediate layer on the soft magnetic layer, the first intermediate layer directing the crystal orientation of the upper layer in a direction perpendicular to the substrate;
A second intermediate layer made of a non-magnetic crystal formed on the first intermediate layer;
A recording layer formed in an upper layer of the second intermediate layer, in which a magnetic domain having a magnetization direction changed in a direction perpendicular to the substrate by receiving a magnetic force is recorded;
A protective layer for protecting the recording layer formed on the recording layer,
By forming the first intermediate layer discretely in the disk radial direction, the crystal axis of the second intermediate layer formed on the upper layer of the first intermediate layer is perpendicular to the substrate, and there is no first intermediate layer. The crystal axis of the second intermediate layer formed in the part faces the direction parallel to the substrate, and the direction of the easy magnetization axis of the recording layer having the same crystal axis direction as the second intermediate layer is discretized depending on the presence or absence of the first intermediate layer And forming an isolation region that isolates the magnetic recording region in the width direction.

  Adopting the above structure eliminates the need to etch the soft magnetic layer, shortens the time required for manufacturing, and magnetic recording has been devised to eliminate noise caused by distortion of the easy axis of the soft magnetic layer A medium can be provided.

  Further, by applying the discretization not only in the width direction but also in the recording traveling direction, the density can be further increased.

  The substrate is preferably selected from the group consisting of glass, Si, and Al.

  Since the substrate is made of a non-magnetic material, the soft magnetic layer can be prevented from being affected by the magnetic field when supplied with the magnetic field.

  The soft magnetic layer is preferably composed of any one of CoZrNb, FeC, and FeNi.

  Further, it is preferable that the first intermediate layer is made of at least one element selected from the group consisting of Ta, Pt, Ni, Fe, Ti, W, Mo, B, C, Si, and Ge. .

  The non-magnetic crystal is preferably a Ru crystal having a hexagonal close-packed structure.

  Here, the Ru crystal having a hexagonal close-packed structure can match the Co crystal lattice, and can direct the Co crystal axis in the same direction as Ru.

The recording layer is preferably made of CoCrPt—SiO ₂ , CoCr—SiO ₂ , and CoPt—SiO ₂ .

  These can precisely record magnetic domains generated with magnetization.

  The protective layer is preferably diamond-like carbon having carbon as a main component and having an amorphous structure.

  The hardness of diamond-like carbon is suitable as a film material for protecting the recording layer, and can prevent deterioration of the magnetic recording medium.

  As described above, it is possible to provide a magnetic recording medium that has been devised to reduce the time required for manufacturing and to eliminate the occurrence of noise due to distortion of the easy magnetization axis.

  Hereinafter, embodiments of the present invention will be described.

  First, the configuration of the magnetic recording medium according to the embodiment of the present invention will be described.

  FIG. 1 is a diagram showing a cross-sectional structure of a magnetic recording medium according to an embodiment of the present invention.

  In this magnetic recording medium 1, a soft magnetic layer 11, a first intermediate layer 12, a second intermediate layer 13, a recording layer 14, and a protective layer 15 are laminated on a substrate 10 in this order.

  The substrate 10 is a disk-shaped glass substrate, but may be an Al substrate or a Si substrate.

  The soft magnetic layer 11 is CoZrNb, and has an easy axis of magnetization in the radial direction parallel to the substrate surface. A crystal containing FeC and FeNi may be used as the soft magnetic layer 11. This FeC also has an easy axis in the radial direction parallel to the substrate surface. CoZrNb and FeC are suitable materials for the soft magnetic layer 11 because they have the physical property of easily forming an easy magnetization axis.

  The first intermediate layer 12 is formed by concentrically arranging Ta 121 in the in-plane radial direction of the substrate. The first intermediate layer 12 directs the crystal orientation of the second intermediate layer 13 immediately above in a direction perpendicular to the substrate 10. Further, Ta 121 forms a magnetic recording region 141 in which information is recorded in the portion of the recording layer 14 immediately above the magnetic crystal, and the region 122 in which the first intermediate layer is not formed is a recording layer. An isolation region 142 that isolates the magnetic recording region 141 in the width direction is formed immediately above the layer 14. The region may be filled with a non-metallic material such as SiO2. The arrows in the magnetic recording area 141 shown in FIG. 2 explicitly indicate that the magnetization direction of the recording layer 14 is a direction perpendicular to the substrate 10.

  In addition, Ta121 may be a crystal made of at least one element selected from the group consisting of Ni, Fe, Ti, W, Mo, B, C, Si, and Ge.

  The second intermediate layer 13 is a Ru crystal having a hexagonal close-packed structure. This Ru crystal has the effect of directing the direction of the crystal axis of Co contained in the material of the recording layer 14 in the same direction.

  The second intermediate layer 13 is a Ru crystal having a hexagonal close-packed structure. This Ru crystal has the effect of directing the direction of the crystal axis of Co contained in the material of the recording layer 14 in the same direction.

  The recording layer 14 records a magnetic domain whose magnetization direction has changed due to an external magnetic field.

The recording layer 14 is a CoCrPt—SiO ₂ crystal. Note that CoCr—SiO ₂ , CoPt—SiO _2, or the like may be used as the material of the recording layer 14.

  The protective layer 15 protects the recording layer 14. The protective layer 15 is made of diamond-like carbon having carbon as a main component and having an amorphous structure. The hardness of the diamond-like carbon is suitable as a material for the film that protects the recording layer 14, and can prevent deterioration of the magnetic recording medium.

  Then, the manufacturing method of the magnetic recording medium 1 which is one Embodiment of this invention is demonstrated.

  FIG. 2 is a diagram showing the steps of the first manufacturing method of the magnetic recording medium according to the embodiment of the present invention.

  First, a soft magnetic layer 11 made of CoZrNb is formed on a glass substrate 10 by sputtering, and then a first intermediate layer 12 made of Ta is formed on the soft magnetic layer 11 by sputtering (FIG. 2 ( a)). At this stage, the thickness of the soft magnetic layer 11 is 100 nm, and the thickness of the first intermediate layer 12 is 1 nm.

  Next, PMMA (polymethyl methacrylate) is spin-coated on the first intermediate layer 12, and a resist layer 16 is laminated. A 100 nm resist layer 16 is formed on the first intermediate layer 12 (FIG. 2B).

  Next, an imprint process is performed using the mold 17 patterned concentrically (FIGS. 2C and 2D).

  In this imprint process, the resist layer 16 is processed into a concavo-convex shape. PMMA remains as a residue in the recess. Here, the thickness of the residue is indicated by L in FIG.

  Next, the PMMA residue is removed by oxygen plasma etching (FIG. 2E).

  Subsequently, patterning is performed on the first intermediate layer 12 using Ar ion milling (FIG. 2F). Thereafter, the resist layer 16 is removed by oxygen plasma (FIG. 2G).

Further, in FIG. 2H, Ru is sputtered to form the second intermediate layer 13. In the second intermediate layer 13, as shown in FIG. In this state, CoCrPt—SiO ₂ is sputtered to form the recording layer 14. Subsequently, a protective layer 15 is formed by depositing diamond-like carbon on the recording layer 14 using a CVD method (FIG. 2H).

  Through these steps, the magnetic recording medium of one embodiment of the present invention can be manufactured.

  Next, a second method for manufacturing a magnetic recording medium according to an embodiment of the invention will be described.

  FIG. 3 is a diagram showing the steps of the second manufacturing method of the magnetic recording medium according to the embodiment of the present invention.

  First, a soft magnetic layer 11 made of CoZrNb is formed on a glass substrate 10 by a sputtering method, and then a first intermediate layer 12 made of Ta is formed on the soft magnetic layer 11 by a sputtering method (FIG. 3 ( a)). At this stage, the thickness of the soft magnetic layer 11 is 100 nm, and the thickness of the first intermediate layer 12 is 1 nm.

  Next, PMMA is spin-coated on the first intermediate layer 12, and a resist layer 16 is laminated. A resist layer 16 having a thickness of 100 nm is formed on the first intermediate layer 12 (FIG. 3B).

  Next, these are exposed concentrically by electron beam drawing (FIG. 3C), and a plurality of strip-like resist masks along the circumference of the substrate are formed by development (FIG. 3D).

  Subsequently, patterning is performed on Ta of the first intermediate layer 12 by Ar ion milling (FIG. 3E). Thereafter, the resist layer 16 is removed by oxygen plasma (FIG. 3F).

Next, a second intermediate layer 13 is formed by forming a hexagonal dense structure Ru on the substrate from which the resist layer 16 has been removed by sputtering. Subsequently, CoCrPt—SiO ₂ is formed on the second intermediate layer 13 by sputtering to form the recording layer 14. The thickness of the second intermediate layer is 25 nm, and the thickness of the recording layer 14 is 15 nm.

  Finally, diamond-like carbon is formed on the recording layer 14 by the CVD method to form the protective layer 15 (FIG. 3G).

  As described above, the magnetic recording medium of one embodiment of the present invention can be manufactured through the steps of the second manufacturing method.

  Next, a third method for manufacturing a magnetic recording medium according to an embodiment of the invention will be described.

  FIG. 4 is a diagram showing the steps of the third manufacturing method of the magnetic recording medium according to the embodiment of the present invention.

Compared to the first manufacturing method, the third manufacturing method is subjected to the planarization process. Here, in the third manufacturing method of the magnetic recording medium according to the embodiment of the present invention, FIG. The steps from a) to FIG. 4G are the same as those in the first method of manufacturing a magnetic recording medium according to an embodiment of the present invention, and are therefore omitted, and will be described from the step in FIG.

  In FIG. 4H, a hexagonal fine structure Ru is sputtered to form a planarization layer 18 for planarization. As shown in FIG. 4H, the flattened layer 18 has uneven portions in the surface layer.

Next, SiO ₂ is laminated to about 5 nm by sputtering. Subsequently, SiO ₂ is etched back by Ar ion etching to planarize the first intermediate layer 12 (FIGS. 4H and 4I). After planarizing the first intermediate layer 12, a second intermediate layer 13 is formed by forming a hexagonal fine structure Ru by sputtering. Subsequently, CoCrPt—SiO ₂ is formed on the second intermediate layer 13 by sputtering to form the recording layer 14. The thickness of the second intermediate layer is 25 nm and the thickness of the recording layer 14 is 15 nm. Finally, diamond-like carbon is formed on the recording layer 14 by the CVD (Chemical Vapor Deposition) method, and the protective layer 15 is formed. Is formed (FIG. 4 (j)).

  The magnetic recording medium according to one embodiment of the present invention can be manufactured through the steps of the third manufacturing method.

  In the manufacturing method described above, since it is not necessary to etch the soft magnetic layer, it is possible to provide a magnetic recording medium in which the time required for manufacturing is shortened.

  Next, an example in which a magnetic recording medium according to an embodiment of the present invention is incorporated in a magnetic disk device will be described.

  FIG. 5 is a top view of a magnetic disk device in which a magnetic recording medium according to an embodiment of the present invention is used.

  The magnetic disk device 100 shown in FIG. 5 is used by being connected to or built in a device such as a large computer or a personal computer.

  A spindle motor 2 for rotationally driving the magnetic recording medium 1 is mounted on the magnetic disk 100 on a base plate 3 that supports components of the magnetic disk device 100.

  A magnetic recording medium 1 is mounted on the rotation shaft of the spindle motor 2 and is rotated at a predetermined rotation speed by the spindle motor 2.

  In this magnetic disk device 100, an arm 4 for approaching the surface of the magnetic recording medium 1 is rotatably attached to an arm shaft 5 and is driven by an arm driving device 6.

  A magnetic head 7 is provided at the tip of the arm 4. The magnetic head 7 is provided with a single magnetic pole type writing element and a GMR (Giant Magnet-Resistive) reading element (not shown). The single magnetic pole type writing element of the magnetic head 7 applies a magnetic field according to data to be recorded on the magnetic recording medium during information recording, and forms a magnetic domain having magnetization in a direction perpendicular to the substrate surface of the magnetic recording medium. To record.

  On the other hand, the GMR reading element of the magnetic head 7 detects a change in the leakage magnetic field from the magnetic recording medium 1 and reproduces information recorded on the magnetic recording medium 1. The magnetic disk device 100 encodes data to be recorded on the magnetic recording medium 1 and transmits a recording signal to the single magnetic pole type writing element of the magnetic head 7. Further, the magnetic disk device 100 decodes a reproduction signal from the magnetic recording medium 1 detected by the GMR reading element of the magnetic head 7.

  As described above, in the magnetic recording medium 1, recording can be performed without providing a groove in the soft magnetic layer, so that noise generation due to distortion of the easy magnetization axis can be eliminated.

  As described above, according to the present invention, it is possible to provide a magnetic recording medium that has been devised to reduce the time required for manufacturing and eliminate the occurrence of noise caused by distortion of the easy magnetization axis.

It is a figure which shows the cross-section of the magnetic recording medium of one Embodiment of this invention. It is a figure which shows the process of the 1st manufacturing method of the magnetic recording medium which is one Embodiment of this invention. It is a figure which shows the process of the 2nd manufacturing method of the magnetic-recording medium which is one Embodiment of this invention. . It is a figure which shows the process of the 3rd manufacturing method of the magnetic recording medium which is one Embodiment of this invention. 1 is a top view of a magnetic disk device in which a magnetic recording medium according to an embodiment of the present invention is used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic recording medium 2 Spindle motor 3 Base plate 4 Arm 5 Arm shaft 6 Arm drive device 7 Magnetic head 10 Substrate 11 Soft magnetic layer 12 First intermediate layer 121 Ta
122 Nonmagnetic Crystal 13 Second Intermediate Layer 14 Recording Layer 141 Magnetic Recording Area 142 Isolation Area 15 Protective Layer 16 Resist Layer 17 Mold 18 Flattening Layer 100 Magnetic Disk Device

Claims (7)

In a magnetic recording medium in which information is recorded in response to a magnetic force,
A substrate,
A soft magnetic layer formed on the substrate;
A first intermediate layer on the soft magnetic layer, the first intermediate layer directing the crystal orientation of the nonmagnetic layer immediately above by a single layer or a plurality of layers in a direction perpendicular to the substrate;
A second intermediate layer made of a non-magnetic crystal formed on the first intermediate layer;
A recording layer formed in an upper layer of the second intermediate layer, on which a magnetic domain having a magnetic direction changed in a direction perpendicular to the substrate by receiving a magnetic force;
A protective layer formed on the recording layer and protecting the recording layer;
The magnetic recording medium, wherein the first intermediate layer is formed discretely.   2. The magnetic recording medium according to claim 1, wherein the substrate is selected from the group consisting of glass, Si, and Al.   2. The magnetic recording medium according to claim 1, wherein the soft magnetic layer is composed of any one of CoZrNb, FeNi, and FeC.   The first intermediate layer is made of at least one element selected from the group consisting of Ta, Pt, Ni, Fe, Ti, W, Mo, B, C, Si, and Ge. The magnetic recording medium according to claim 1.   2. The magnetic recording medium according to claim 1, wherein the non-magnetic crystal is a hexagonal close-packed Ru crystal. The magnetic recording medium according to claim 1, wherein the recording layer is a compound selected from the group consisting of CoCrPt—SiO ₂ , CoCr—SiO ₂ , and CoPt—SiO ₂ .   2. The magnetic recording medium according to claim 1, wherein the protective layer is diamond-like carbon composed mainly of carbon and having an amorphous structure.

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