JP4050124B2 - Information recording method on magnetic disk medium and magnetic disk medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic transfer master carrier having on its surface a magnetic material pattern for transferring information to a magnetic disk medium.
[0002]
The present invention also relates to a magnetic disk medium having a magnetization pattern formed by magnetic transfer using a magnetic transfer master carrier.
[0003]
[Prior art]
In general, with the increase in the amount of information, a magnetic recording medium is desired that has a large capacity for recording a large amount of information, is inexpensive, and can read out a necessary portion preferably in a short time and can perform so-called high-speed access. As an example of this, a high-density magnetic recording medium made of a flexible disk such as a hard disk or ZIP (Iomega Corporation) is known. These high-density magnetic recording media have an information recording area composed of narrow tracks. In order to reproduce a signal with a high S / N by accurately scanning a narrow track width with a magnetic head, a so-called tracking servo technique is used. It plays a big role.
[0004]
Servo information such as track positioning servo signals, track address signals, and reproduction clock signals must be recorded in advance on the magnetic recording medium as a preformat when the magnetic recording medium is manufactured. Preformatting is performed using an apparatus (servo track writer). However, the pre-formatting by this servo recording device records a single magnetic recording medium by a magnetic head, which requires a considerable amount of time and has a problem in production efficiency.
[0005]
On the other hand, as a method for performing preformatting accurately and efficiently, a method of transferring a pattern carrying servo information formed on a master carrier to a magnetic recording medium by magnetic transfer has been proposed (for example, Patent Documents 1 to 3). reference).
[0006]
In this magnetic transfer, a magnetic field for transfer is applied in a state in which a master carrier having a magnetic material pattern corresponding to information to be transferred to a magnetic recording medium (slave medium) such as a magnetic disk medium is in close contact with the slave medium. Thus, the magnetic pattern corresponding to the information (for example, servo signal) carried by the magnetic material pattern is magnetically transferred to the slave medium, and without changing the relative position between the master carrier and the slave medium. Recording is possible, accurate preformat recording is possible, and the time required for recording is extremely short.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 63-183623
[Patent Document 2]
Japanese Patent Laid-Open No. 10-40544
[Patent Document 3]
Japanese Patent Laid-Open No. 10-269566
[Problems to be solved by the invention]
Servo writing using a conventional servo track writer is performed using a magnetic head in a magnetic disk device provided with a magnetic recording medium, and both recording and reproduction of a magnetization pattern are performed by the magnetic head of the magnetic disk device. Therefore, the azimuth loss could be kept small. However, with respect to a magnetic disk medium on which a magnetic pattern is formed by magnetic transfer using a magnetic transfer master carrier, when reproducing a signal based on the magnetic pattern, there is a possibility that azimuth loss may increase due to completely different recording and reproduction processes. Is expensive. An increase in azimuth loss leads to a decrease in the quality of the reproduced signal. Furthermore, if the transfer information is a servo signal, the accuracy of the tracking servo is reduced, which is not preferable.
[0011]
The present invention has been made in view of the above circumstances, and provides a master carrier capable of obtaining a good reproduction signal with small azimuth loss in a magnetic disk medium on which a magnetic pattern is formed by magnetic transfer. It is the purpose.
[0012]
It is another object of the present invention to provide a magnetic disk medium capable of obtaining a good reproduction signal with small azimuth loss.
[0013]
[Means for Solving the Problems]
The magnetic transfer master carrier of the present invention is adapted to transfer information to a magnetic disk medium used in a magnetic disk device having a reproducing head fixed to a part of a rotating arm. A disk-shaped master carrier for magnetic transfer having a magnetic pattern arranged concentrically or spirally on its surface,
Each magnetic element constituting the magnetic pattern has a substantially parallelogram-shaped upper surface, and a pair of opposing sides of the upper surface extend along the circumferential direction of the concentric circle or the spiral, and another set The side of the cross extends in the circumferential direction,
The other set of sides of each magnetic element extends along the width direction of the head gap of the read head at a position on the magnetic disk medium corresponding to the position of the magnetic element. It is a feature.
[0014]
The “magnetic disk device having a reproducing head fixed to a part of a rotating arm” is an apparatus having a configuration in which the reproducing head moves in an arc shape across the circumference of the magnetic disk medium. And a magnetic disk device having a rotary actuator for rotating the arm.
[0015]
“Having the magnetic material pattern on the surface” means that the magnetic material is formed in a pattern on at least the part that faces (or contacts) the magnetic disk medium that is the slave medium during magnetic transfer. A pattern made of a magnetic material formed on at least the surface of a convex portion on a substrate having a concavo-convex pattern, a pattern made of a magnetic material embedded only in a concave portion on a substrate having a concavo-convex pattern, and concavo-convex Either a pattern made of a magnetic material formed in a pattern or a pattern made of a magnetic material arranged in a pattern may be used.
[0016]
Therefore, “the magnetic element constituting the magnetic layer pattern” means an individual magnetic body formed in a portion close to the magnetic disk medium. Magnetic body formed on the surface of each convex part on the substrate having a pattern, magnetic body embedded only in each concave part on the substrate having a concave / convex pattern, and part constituting the convex part of the magnetic body formed in a concave / convex pattern Each magnetic body arranged in a pattern is said.
[0017]
The “width direction of the head gap of the reproducing head” corresponds to the direction in which the width of the reproducing track defined by the reproducing head extends, and is attached to a part of a rotating arm and has an arc shape in a direction crossing a concentric circle. In the case of a moving reproducing head, the direction in which the reproducing track width extends differs depending on the distance from the disc rotation center.
[0018]
Therefore, in the magnetic transfer master carrier of the present invention, the inclination of the upper surface of the magnetic element constituting the magnetic pattern formed on the surface with respect to the circumferential direction of the other set of sides is formed by the element. It is characterized by being different for each distance from the center of the disc-shaped substrate.
[0019]
The information can be a servo signal.
[0020]
A magnetic disk medium of the present invention is a magnetic disk medium having concentric or spiral tracks, which is used in a magnetic disk device having a reproducing head fixed to a part of a rotating arm,
By magnetic transfer using the magnetic transfer master carrier, a magnetization pattern consisting of magnetic domains arranged along the track is formed,
The magnetization transition region of the magnetic section arranged along the track that constitutes the magnetization pattern extends along the width direction of the head gap of the reproducing head at the track position. It is.
[0021]
In the magnetic disk medium of the present invention, a pattern corresponding to a servo signal is suitable as the magnetization pattern.
[0022]
【The invention's effect】
In the magnetic transfer master carrier of the present invention, the upper surface of each magnetic element constituting the magnetic pattern corresponding to the information to be transferred has a substantially parallelogram shape, and extends 1 across the circumferential direction of the upper surface shape. Since the sides of the pair extend along the width direction of the reproducing head at the position on the corresponding magnetic disk medium, transfer to the magnetic disk medium subjected to magnetic transfer using the magnetic transfer master carrier of the present invention. Since the magnetization transition region of the magnetization pattern to be extended extends along the width direction of the reproducing head, azimuth loss can be suppressed and good signal reproduction can be performed.
[0023]
In the magnetic disk medium of the present invention, information is transferred using the above-described magnetic transfer master carrier of the present invention. As described above, the magnetization transition region of the magnetization pattern extends along the width direction of the reproducing head. Therefore, azimuth loss can be suppressed, and good signal reproduction is possible.
[0024]
In particular, when the information to be transferred is a servo signal, the tracking accuracy can be improved.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the basic steps of magnetic transfer for transferring information to a slave medium (magnetic disk medium) using the magnetic transfer master carrier of the present invention will be described with reference to FIGS.
[0026]
FIG. 1 is a perspective view showing the magnetic transfer master carriers 3 and 4 and the slave medium 2 that receives the transfer by the master carriers 3 and 4 according to the present invention. The slave medium 2 is, for example, a magnetic disk medium such as a high-density flexible disk or a hard disk used in a hard disk device, and recording surfaces 22 and 23 made of a magnetic material layer are provided on both surfaces of a disk-like base 21 made of a non-magnetic material. I have it.
[0027]
The master carriers 3 and 4 are disk-shaped rigid bodies having a magnetic material pattern on the surface, and are composed of disk-shaped substrates 31 and 41 and magnetic layers 32 and 42 disposed on the substrates 31 and 41. Here, the master carriers 3 and 4 are respectively formed with magnetic patterns for the lower recording surface 22 and the upper recording surface 23 of the slave medium 2. Here, the information carried by the master carriers 3 and 4 is a servo signal for positioning the head of the magnetic disk medium, and a magnetic pattern corresponding to the servo signal is formed in a plurality of radial servo areas 3a. Yes.
[0028]
When the substrates 31 and 41 are made of a ferromagnetic material such as Ni, magnetic transfer is possible only with the substrate, and the magnetic layers 32 and 42 need not necessarily be covered. However, better magnetic transfer can be performed by providing a magnetic layer with good transfer characteristics. Further, when the substrate is a nonmagnetic material, it is necessary to provide a magnetic layer. Furthermore, if a protective film such as diamond-like carbon (DLC) is coated on the uppermost layer, this protective film improves the contact durability and enables multiple times of magnetic transfer. Furthermore, a Si film may be formed by sputtering or the like under the DLC protective film in order to improve adhesion.
[0029]
The master carriers 3 and 4 of this embodiment are composed of disk-shaped substrates 31 and 41 on which concave and convex patterns corresponding to servo signals are formed, and magnetic layers 32 and 42 formed on the concave and convex patterns. As a result, a magnetic pattern is formed by a portion of the layers 32 and 42 formed on the convex portion of the concave / convex pattern (referred to as the magnetic element 3b). However, the master carrier only needs to have a magnetic material pattern on the surface, and the magnetic material is embedded only in the concave portion of the substrate on which the uneven pattern is formed, and the magnetic material pattern is formed by the embedded magnetic material. In addition, a concavo-convex pattern made of a magnetic material may be formed on a flat substrate, and a magnetic material pattern may be formed by the convex portions of the concavo-convex pattern. In the former, a magnetic element refers to a magnetic body embedded in a concave portion, and in the latter, a magnetic element refers to a convex portion of an uneven pattern. Further, it may be a master carrier in which a magnetic body (magnetic element) is formed in a pattern on a flat substrate.
[0030]
FIG. 2 is a diagram for explaining the basic steps of magnetic transfer using this magnetic transfer master carrier. FIG. 2 (a) shows the initial DC magnetization of the magnetic layer of the slave medium by applying a magnetic field in one direction. (B) shows a step of applying a transfer magnetic field by closely contacting the master carrier and the slave medium, and (c) shows a magnetization state of the magnetic layer of the slave medium after the magnetic transfer. In FIG. 2, only the lower surface recording surface 22 of the slave medium 2 is shown.
[0031]
As shown in FIG. 2A, an initial magnetic field Hin is applied to the slave medium 2 in one direction in the track direction in advance, so that the magnetization of the magnetic layer 22 is initially magnetized in one direction in the track direction. After that, as shown in FIG. 2B, the recording surface 22 of the slave medium 2 and the information carrying surface formed by coating the magnetic layer 32 on the fine uneven pattern of the substrate 31 of the master carrier 3 are brought into close contact with each other. Magnetic transfer is performed by applying a transfer magnetic field Hdu in the direction opposite to the initial magnetic field Hin in the track direction 2. As a result, as shown in FIG. 2C, information (for example, servo signals) corresponding to the magnetic pattern of the information carrier surface of the master carrier 3 is magnetically transferred and recorded on the magnetic layer 22 of the slave medium 2. The Here, the lower recording surface 22 and the lower master carrier 3 of the slave medium 2 have been described. However, the upper recording surface 23 of the slave medium 2 is also brought into close contact with the upper master carrier 4 to similarly perform magnetic transfer. However, the magnetic transfer to the upper and lower recording surfaces 22 and 23 of the slave medium 2 may be performed simultaneously or sequentially one by one.
[0032]
Even if the concave / convex pattern of the master carrier 3 is a negative pattern having a concave / convex shape opposite to the positive pattern of FIG. 2, the direction of the initial magnetic field Hin and the direction of the transfer magnetic field Hdu are reversed from the above. Similar information can be magnetically transferred and recorded. Note that the initial magnetic field and the magnetic field for transfer need to adopt values determined in consideration of the coercivity of the slave medium and the relative permeability of the master carrier and the slave medium.
[0033]
Next, the master carrier of the present invention will be described in more detail.
[0034]
FIG. 3 is an enlarged view of a part of the magnetic material pattern formed on the maximum radius concentric circle rout, the center radius concentric circle rm, and the minimum radius concentric circle rin of the servo area 3a of the master carrier 3 of the present embodiment of FIG. FIG. The top surface shape of the magnetic element 3b (the portion indicated by the slanted line in the figure) is a substantially parallelogram, one set of opposing sides extending along the circumferential direction X of the concentric circle, and the other set of sides 33 are It extends across the circumferential direction. Depending on the radial position from the inner peripheral side rin to the outer peripheral side rout, the inclination of the other set of sides 33 constituting the upper surface shape of the element 3b with respect to the radial direction Y and the radial width of the upper surface shape are different. (Win <Wm <Wout). In the present embodiment, the inner peripheral element 3b has a side 33 substantially along the radial direction Y. The side 33 of the outer peripheral element 3b has a larger inclination with respect to the radial direction Y, and the width of the element 3b. W is also larger on the outer peripheral side. The upper surface shape of the element 3b (the inclination of the side 33 with respect to the Y direction) and the radial width of the upper surface shape are the reproducing head in the magnetic disk device using the magnetic disk medium obtained by magnetic transfer using the master carrier. The other set of sides 33 on the upper surface of each magnetic element 3b is at a position on the magnetic disk medium corresponding to the position of the magnetic element 3b. It extends along the width direction of the head gap of the reproducing head.
[0035]
As the substrate of the master carrier, nickel, silicon, quartz plate, glass, aluminum, alloy, ceramics, synthetic resin or the like is used. The formation of the concavo-convex pattern is performed using a stamper method used as a method for manufacturing an optical disc master, a photolithography method used when manufacturing a semiconductor, or the like. The depth of the concavo-convex pattern (projection height) of the substrate is preferably in the range of 80 nm to 800 nm, more preferably 150 nm to 600 nm. In the case of a servo signal, the uneven pattern is formed long in the radial direction. For example, the length in the radial direction is preferably 0.05 to 20 μm, and the circumferential direction is preferably 0.05 to 5 μm, and a longer pattern in the radial direction in this range is preferable as a pattern for holding servo signal information.
[0036]
Further, the magnetic material of the magnetic layer is preferably a soft magnetic or semi-hard magnetic material, specifically, Co, Co alloy (CoNi, CoNiZr, CoNbTaZr, etc.), Fe, Fe alloy (FeCo, FeCoNi, FeNiMo, FeAlSi, FeAl, FeTaN), Ni, Ni alloy (NiFe) or the like is used. Particularly preferred are FeCo and FeCoNi. This magnetic layer is formed by depositing a magnetic material by a vacuum film forming means such as a vacuum deposition method, a sputtering method, an ion plating method, a plating method, or the like. The thickness of the magnetic layer is preferably in the range of 50 nm to 500 nm, more preferably 150 nm to 400 nm.
[0037]
FIG. 4 shows a top view of the main part of a magnetic disk apparatus equipped with a magnetic disk medium according to an embodiment of the present invention, which has been magnetically transferred using the magnetic transfer master carrier of the above embodiment.
[0038]
As shown in FIG. 4, the magnetic disk device 10 is fixed to a magnetic disk medium 2 having a magnetization pattern formed by magnetic transfer, an arm 12 that rotates about a pivot 11, and a part (tip) of the arm 12. The controller includes a magnetic head 13 for recording / reproducing data, an actuator 14 for rotating the arm 12, and a spindle motor 15 for rotating the magnetic disk medium 2. , Data processing circuit, computer interface, cover.
[0039]
One or a plurality of magnetic disk media 2 are stacked and rotated by a spindle motor 15.
[0040]
The magnetic head 13 for recording / reproducing data may be one that performs recording and reproduction with one head element, or may be one that performs recording and reproduction with separate head elements. Examples of the former head element and the latter recording head element include interactive heads such as ferrite heads and thin film heads, and examples of the latter reproducing head element include an MR head or GMR head.
[0041]
The actuator 14 rotates the arm 12, and as a result, the magnetic head 13 attached to the tip of the arm 12 moves in an arc shape on the inner and outer circumferences of the disk 2 as indicated by a dotted line in FIG. 4.
[0042]
FIG. 5 schematically shows the magnetization pattern 2a formed on each of the outer track Tout, the center track Tm, and the inner track Tin of the magnetic disk medium 2 provided in the magnetic disk device 10 shown in FIG. Is. In the drawing, the reproducing head element 20 (hereinafter simply referred to as the reproducing head 20) is also shown in order to show the inclination of each track. The magnetization pattern 2a of the magnetic disk medium 2 is formed according to the magnetic pattern of the master carrier 3 shown in FIG. 3, and the individual magnetic domains 2b and domain walls 2c correspond to the shape of the magnetic element 3b. It has become a thing. As shown in FIG. 5, the inclination of the extending direction A of the domain wall (magnetization transition region) 2c intersecting the track direction X between the magnetic domains 2b constituting the magnetization pattern 2a with respect to the radial direction Y perpendicular to the track direction X is Different for each track. A direction A in which each domain wall 2c extends in each track is formed to be substantially parallel to a direction B in which the width of the head gap of the reproducing head 20 in each track extends. Further, the recording track widths Wout, Wm, and Win of the tracks Tout, Tm, and Tin are also set according to the inclination of the reproducing head 20, and here, the track width is formed wider toward the outer peripheral side.
[0043]
Since the magnetic disk medium 2 has a magnetic pattern formed by magnetic transfer in accordance with the inclination of the reproducing head 20 of the magnetic disk apparatus provided with the magnetic disk medium 2 with respect to the track, the reproducing head 20 always has the width of the head gap. The magnetization transition region 2c substantially parallel to the extending direction B (reproduction track width direction) B can be detected, azimuth loss can be suppressed, and a good reproduction signal can be obtained.
[0044]
The magnetization pattern shown in FIG. 5 is suitable for the magnetic disk device 10 of this embodiment, but the magnetization pattern of the magnetic disk medium and the magnetic material pattern of the master carrier for forming the magnetization pattern are the same as the magnetic disk. The magnetic disk device can be configured according to the configuration of the magnetic disk device provided with the medium, that is, the length of the arm, the position of the pivot, the mounting position of the head and the like. Therefore, the magnetic pattern of the master carrier and the magnetization pattern of the magnetic disk are not limited to those shown in FIGS. 3 and 5, respectively.
[0045]
For example, the magnetization pattern of a magnetic disk medium used in a magnetic disk device in which the read head is substantially parallel to the track direction at the position of the center track Tm includes a magnetization transition region in which the magnetization pattern is parallel to the track width direction at the center track Tm. The inclinations of the magnetization transition regions of the magnetization patterns of the outer track Tout and the inner track Tin are different from each other.
[0046]
For example, as shown in FIG. 6, the magnetic transfer master carrier for forming such a magnetization pattern includes a pair of magnetic elements 103b formed in a central radius concentric circle rm along the radial direction Y. The shape is a top surface having a side 133, and the sides 133 of the magnetic element formed in the maximum radius concentric circle rout and the magnetic element formed in the minimum radius concentric circle rin are in different directions.
[0047]
In the above embodiment, the information transferred to the magnetic disk medium by the master carrier is the servo signal. However, the information is not limited to the servo signal.
[0048]
In the above description, the concave / convex patterns are arranged concentrically. However, the concave / convex patterns are not necessarily limited to concentric circles, and may be arranged spirally.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a master carrier and a magnetic disk medium according to one embodiment of the present invention. FIG. 2 shows steps of a magnetic transfer method using the master carrier according to one embodiment of the present invention. FIG. 3 is a plan view showing a part of a magnetic pattern of the magnetic transfer master carrier shown in FIG. 1. FIG. 4 schematically shows a part of a magnetization pattern in an embodiment of the magnetic disk medium of the present invention. FIG. 5 is a plan view showing a main part of a magnetic disk device. FIG. 6 is a plan view showing a part of a magnetic pattern of a master carrier according to another embodiment of the present invention.
2 Magnetic disk medium 2a Magnetization pattern 2b Magnetic domain 2c Magnetization transition region (domain wall)
3 Master carrier 3a for magnetic transfer Servo area (magnetic material pattern)
3b Magnetic element 10 Magnetic disk device 11 Pivot 12 Arm 13 Magnetic head 14 Actuator 15 Spindle motor 21 Base 22 and 23 of magnetic disk medium Magnetic layer (magnetic recording layer) of magnetic disk medium
31 Magnetic Transfer Master Carrier Substrate 32 Magnetic Layer

Claims (4)

In a method for recording information on a magnetic disk medium having concentric or spiral tracks, used in a magnetic disk device having a reproducing head fixed to a part of a rotating arm,
A disk-shaped master carrier for magnetic transfer having a magnetic material pattern formed by magnetic elements arranged concentrically or spirally in accordance with the information for transferring information to a magnetic disk medium. Each of the magnetic elements has a substantially parallelogram-shaped upper surface, a pair of opposite sides of the upper surface extend along the circumferential direction of the concentric circle or the spiral, and the other set of sides is the circumferential surface. A width of the head gap of the read head at a position on the magnetic disk medium corresponding to the position of the magnetic element, the other set of sides of the magnetic elements extending in a direction intersecting with each other Prepare a magnetic transfer master carrier that extends along the direction,
By adhering the surface of the magnetic transfer master carrier and the recording surface of the magnetic disk medium and applying a magnetic field,
A magnetic domain having a magnetization direction along the track and a magnetization transition region of the magnetic section arranged along the track, and the magnetization transition region of the head gap of the reproducing head at the track position A method of recording information on a magnetic disk medium, comprising forming a magnetization pattern extending along the width direction. Method for recording information on the magnetic disk medium of claim 1, wherein said information is a servo signal. A magnetic disk medium having concentric or spiral tracks used in a magnetic disk device having a reproducing head fixed to a part of a rotating arm,
A magnetic disk medium having a magnetization pattern formed by the information recording method on the magnetic disk medium according to claim 1,
A magnetic domain having a magnetization direction along the track and a magnetization transition region of the magnetic section arranged along the track, and the magnetization transition region of the head gap of the reproducing head at the track position A magnetic disk medium having a magnetization pattern extending along a width direction. 4. The magnetic disk medium according to claim 3 , wherein the magnetization pattern formed on the magnetic disk is a pattern corresponding to a servo signal.

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