JP2009199652A - Magnetic recording medium, method of manufacturing the same, and magnetic storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bit patterned medium that increases a write timing margin. <P>SOLUTION: In the bit patterned medium in which isolated magnetic bodies 300 are arranged with regularity, a magnetic recording layer set on the upper part of a non magnetic substrate is constructed such that the isolated magnetic bodies 300 are arranged on a slant to the radial direction, and the shape of the magnetic bodies 300 is elliptic or rectangular. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic recording medium such as a hard disk, a manufacturing method thereof, and a magnetic storage device that records or reproduces information using the magnetic recording medium.

  In recent years, with the demand for an increase in capacity of a magnetic storage device, an improvement in recording density in a magnetic recording medium has been demanded. To increase the recording density, it is necessary to substantially reduce the crystal grains (magnetic particles) of the magnetic material in the data recording area. However, as the magnetic particles become finer, the magnetization direction of the magnetic particles is likely to change due to thermal energy, which may cause a problem of data loss called so-called thermal fluctuation. Bit patterned media (BPM) is known as a preferable medium for enhancing the resistance to the thermal fluctuation and increasing the recording density.

  In the BPM, for example, a plurality of recording dots made of a magnetic region are arranged in a dot shape along the disk circumferential direction and the disk radial direction in a nonmagnetic layer to be a recording layer. Here, each recording dot is physically isolated by the nonmagnetic layer and magnetically isolated. Therefore, in BPM, it is possible to reduce magnetic interference between recording dots as compared with a conventional magnetic disk. Further, since the recording unit of BPM is composed of one magnetic dot, the magnetic dot can be reduced to a point where the thermal fluctuation resistance is satisfied, which is preferable for increasing the recording density.

  In BPM, recording dots on which data is recorded are separated even in the same track, and their positions are absolutely determined. For this reason, at the time of data recording in BPM, it is necessary to accurately synchronize the timing of applying the recording magnetic field from the magnetic head to the recording dots. As a synchronization method, a method of recording and reproducing while shifting the phase of the clock signal and selecting a phase with the lowest error rate has been proposed (see Patent Document 1 below).

  In this way, various methods have been proposed to accurately synchronize clock signals. However, any method will cause variations in dot size and position, so synchronization timing will be very short, and margins will be increased. There is a problem that there are few. This problem becomes more prominent as the recording density is increased.

JP 2006-164349 A

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a bit patterned medium capable of increasing a write timing margin (a magnetic recording medium in which isolated magnetic materials are regularly arranged). An object of the present invention is to provide a manufacturing method thereof and a magnetic storage device using the same.

  In order to achieve the above object, according to the present invention, a nonmagnetic substrate and a magnetic recording provided on the upper layer side of the substrate, in which isolated magnetic bodies are arranged in a direction inclined with respect to the radial direction. And a magnetic recording medium comprising a layer.

  In one suitable aspect, the shape of the said magnetic body is an ellipse or a rectangle.

  Further, according to the present invention, a step of providing a magnetic recording layer on the upper layer side of the nonmagnetic substrate, and a plurality of isolated magnetic elements arranged such that the magnetic recording layer faces in a direction inclined with respect to the radial direction. There is provided a method of manufacturing a magnetic recording medium comprising: patterning into a body.

  In one preferred embodiment, the patterning step uses an electron beam exposure method.

  In addition, according to the present invention, there is provided a magnetic storage device comprising the above-described magnetic recording medium and means for writing or reading information on the magnetic recording medium.

  According to the disclosed magnetic recording medium and magnetic storage device, it is possible to increase the write timing margin when magnetic information is recorded on an isolated magnetic material, as compared with the prior art.

  First, a schematic structure of a magnetic disk device to which an embodiment of a bit patterned medium (a magnetic recording medium in which isolated magnetic materials are regularly arranged) is applied will be described with reference to FIG. The magnetic disk device is a kind of information storage device in a form in which a head slider mounted with a reproducing head and a recording head floats on a rotary recording medium to read (write) and write (write) magnetic information, FIG. 1 is shown with the cover attached from the direction indicated by the arrow A removed for explaining the internal structure.

  In FIG. 1, a bit patterned medium (BPM) 100 as a magnetic recording medium (magnetic disk) is fixed to a spindle motor by a clamp 102 and is continuously driven to rotate at a predetermined rotational speed by being driven by the spindle motor during operation. The head slider 104 floats on the BPM 100 in the order of nm. The reproducing head and recording head mounted on the head slider 104 operate with a predetermined interval with respect to the BPM 100.

  The slider 104 is connected to the drive arm 108 via a suspension 106 that applies a constant pressing force to the slider 104. The drive arm 108 is driven by the voice coil motor 110 and scans the BPM 100, thereby realizing reading and writing of data at a desired position. These components are attached to the base 112.

  FIG. 2 shows a general example of the arrangement of magnetic dots in a conventional BPM. In the figure, an ellipse denoted by reference numeral 200 represents a magnetic dot (an isolated magnetic body). A trapezoid indicated by reference numeral 210 represents the shape of the recording head viewed from above. Further, a dotted line area indicated by reference numeral 220 represents an area where the perpendicular magnetization direction of the bit can be reversed by the magnetic field applied from the recording head. In this case, the allowable width or margin as the write timing is “a” in FIG.

  On the other hand, FIG. 3 shows an arrangement of the magnetic dots 300 in the BPM 100 according to the present embodiment. As shown in the figure, in this embodiment, magnetic dots (isolated magnetic bodies) 300 are arranged in a direction inclined by an angle “θ” with respect to the radial direction. For this reason, the allowable width, ie, margin, as the write timing is “b” in FIG. As can be seen by comparing FIG. 2 and FIG. 3, “a <b” is satisfied, and the dot arrangement in FIG. 3 increases the write timing margin.

  FIG. 4 is a diagram showing the arrangement of magnetic dots when an attempt is made to increase the write timing margin on the extension of the prior art. That is, when the dot arrangement similar to the dot arrangement in FIG. 2 is obtained and the write timing margin “c” (b = c) having the same size as the write timing margin “b” in FIG. The shape of the dot is indicated by reference numeral 400 in FIG. Even though this increases the write timing margin, the width of the groove between the magnetic dots 400 becomes narrower than in the case of FIGS.

  FIG. 5 is a sectional view showing the structure of the bit patterned medium (BPM) 100 according to the present embodiment together with the recording head. As shown in the figure, the BPM 100 in the present embodiment has a soft magnetic backing layer 504, a nonmagnetic intermediate layer 506, a magnetic recording layer 508, and a protective film 510 laminated on a base material (nonmagnetic substrate) 502. It has a structure. The magnetic recording layer 508 may be stacked in multiple layers. When stacked in multiple layers, a nonmagnetic layer for controlling exchange coupling may be stacked between the magnetic recording layers. The soft magnetic backing layer 504 may also have a multilayer structure.

  The substrate 502 is made of, for example, plastic, crystallized glass, Si, aluminum alloy, or the like.

  The soft magnetic backing layer 504 is made of, for example, CoNbZr, CoTaZr, FeCoB, FeTaC, FeAlSi, NiFe, etc., and has a thickness of 10 to 500 nm. This layer is not limited to being composed of a single layer, and may be composed of a plurality of layers. In the case of lamination, for example, a Ru film or the like may be laminated between the soft magnetic backing layers.

  The nonmagnetic intermediate layer 506 is made of, for example, NiCr, NiCu, Ru, RuCo, RuCoCr, RuCoB, RuCoCrTa, and the thickness thereof is 1 to 20 nm. Further, a layer of a nonmagnetic material containing, for example, Ta, W or Mo as a main component may be laminated between the nonmagnetic intermediate layer 506 and the soft magnetic backing layer 504. The thickness of the layer is 1-10 nm.

  The magnetic recording layer 508 is made of, for example, CoCrPt or a composition of the same and an oxide such as Sio 2 or MgO. The thickness of the magnetic recording layer 508 is 3 to 20 nm. The magnetic recording layer 508 has a structure in which isolated dots are arranged in the circumferential direction and the radial direction, and the dot shape is, for example, an ellipse or a rectangle as shown in FIG. Or

  The protective film 510 is a layer that protects the surface when the magnetic head (reproducing head and recording head) scans, and is made of, for example, a carbon film. The thickness of the protective film 510 is 5 nm or less. From the above, the basic structure of the magnetic recording medium according to this embodiment is completed.

  Next, a method for manufacturing the bit patterned media (BPM) 100 according to the present embodiment will be described. First, a soft magnetic backing layer 504 is formed on a glass substrate 502 by depositing a soft magnetic material having a thickness of about 100 nm by sputtering or the like.

  Next, a nonmagnetic intermediate layer 506 is formed on the soft magnetic backing layer 504 by depositing a nonmagnetic material having a thickness of about 20 nm by sputtering or the like.

  Next, a magnetic recording layer 508 having a thickness of about 10 nm is formed on the nonmagnetic intermediate layer 506 by sputtering or the like. Next, the magnetic recording layer 508 is patterned. As a patterning method, an electron beam (EB) exposure method, a nanoimprint method, or the like is used.

  Here, a case where the EB exposure method is used will be described as an example. Consider a case where exposure is performed on a dot-forming part. When a beam is applied to the magnetic recording layer, exposure according to the beam diameter becomes possible. However, as it is, the dot shape is circular as shown in FIG. When creating a long dot in the radial direction, change the position where the beam is applied and irradiate again. For example, if irradiation is performed three times, a long dot in the radial direction is formed as shown in FIG. If the position where the beam is applied not only in the radial direction but also in the circumferential direction at the same time is changed, dots in an oblique direction are formed as shown in FIG. Here, as a method for changing the position to which the beam is applied, electrostatic deflection or the like for deflecting the beam by applying a static magnetic field having a component perpendicular to the beam direction is used.

  Finally, a protective film 510 is formed on the patterned magnetic recording layer 508, thereby completing the bit patterned medium (BPM) 100.

  Next, a writing (recording) operation to the bit patterned medium (BPM) 100 according to the present embodiment will be described with reference to FIG. First, the main magnetic pole 552 of the recording head 550 is excited. As an excitation method, for example, there is a method in which a current is passed through a coil (not shown) and excitation is performed using a magnetic flux generated thereby. Examples of the arrangement of the coils include a method of placing the coil on one side of the main magnetic pole 552 (single coil), placing it on both of the main magnetic poles 552 (double coil), and winding the coil on the main magnetic pole 552 (helical coil). .

  The magnetic flux generated thereby gathers at the tip of the main magnetic pole 552, and a magnetic field toward the BPM 100 is generated. By applying a magnetic field on one dot constituting the magnetic recording layer 508, the direction of perpendicular magnetization in the dot can be reversed. The magnetic field that has passed through the magnetic recording layer 508 flows to the soft magnetic backing layer 504, passes through it, and flows to the return yoke 554 of the recording head 550.

  The recording operation described above has been conventionally performed on bit patterned media. However, since the bit patterned media 100 according to the present embodiment has the dot arrangement shown in FIG. 3, as described above. The write timing margin is increased as compared with the prior art.

1 is a diagram illustrating a schematic structure of a magnetic disk device to which an embodiment of a bit patterned medium is applied. It is a figure which shows the general example of the dot arrangement | sequence in the conventional bit patterned media. It is a figure which shows the arrangement | sequence of the magnetic dot in the bit patterned media by this embodiment. It is a figure which shows the arrangement | sequence of a magnetic dot at the time of trying to increase a write timing margin on extension of a prior art. It is sectional drawing which shows the structure of the bit patterned media by this embodiment with a recording head. (A), (b) and (c) is a figure for demonstrating formation of the magnetic dot by an electron beam exposure method.

Explanation of symbols

100 bit patterned media 102 clamp 104 head slider 106 suspension 108 drive arm 110 voice coil motor 112 base 200 magnetic dot (isolated magnetic material)
210 Shape of the recording head viewed from above 220 Region in which the perpendicular magnetization direction of the bit can be reversed by a magnetic field applied from the recording head 300 Magnetic dot (isolated magnetic material)
400 Magnetic dots (Isolated magnetic material)
502 Base material (non-magnetic substrate)
504 Soft magnetic backing layer 506 Nonmagnetic intermediate layer 508 Magnetic recording layer 510 Protective film 550 Recording head 552 Main magnetic pole 554 Return yoke

Claims (5)

A non-magnetic substrate;
A magnetic recording layer provided on an upper layer side of the substrate, in which isolated magnetic bodies are arranged in a direction inclined with respect to the radial direction;
A magnetic recording medium comprising:   The magnetic recording medium according to claim 1, wherein a shape of the magnetic body is an ellipse or a rectangle. Providing a magnetic recording layer on the upper layer side of the nonmagnetic substrate;
Patterning the magnetic recording layer into a plurality of isolated magnetic bodies arranged in a direction inclined with respect to a radial direction;
A method of manufacturing a magnetic recording medium comprising:   The method of manufacturing a magnetic recording medium according to claim 3, wherein the patterning step uses an electron beam exposure method. A magnetic recording medium according to claim 1;
Means for writing or reading information to or from the magnetic recording medium;
A magnetic storage device comprising:

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