JPH1091945A - Magnetic disk device, magnetic recording medium and production of magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain low frictional force and sucking force with a magnetic head and to obtain stable property with small floating height by forming an intermediate layer, magnetic layer, and protective layer on a substrate in such a manner that the protective layer consists of a corrosion-resistant first protective layer and a second protective layer where a projecting part is formed. SOLUTION: A base layer 2, intermediate layer 3, magnetic layer 4 and protective layer 5 are formed on a nonmagnetic disk substrate 1 which is preliminarily processed into a mirror surface. The protective layer 5 consists of a SiC first protective layer 5a having corrosion resistance and a C second layer 5b where a projecting part is formed. The projecting part is produced by forming a master pattern on the surface of the second protective layer 5b and etching to remove the master pattern to form a projecting part of specified height on the first protective layer 5a. Further, a lubricant layer 6 is formed on the protective layer 5. Thereby, frictional force and sucking force with a magnetic head can be decreased while stable property with small floating height can be obtd. Moreover, the obtd. magnetic recording medium shows little deterioration in characteristics for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive, a magnetic recording medium used therein, and a method of manufacturing a magnetic recording medium.

[0002]

2. Description of the Related Art In recent years, a magnetic disk device as an external storage device of a computer system has been increasingly important.
The recording density has been significantly improved year by year.

In order to improve the recording density of a magnetic disk drive, the flying height of a magnetic head during recording / reproducing is preferably reduced. In order to ensure the flying stability of the magnetic head at that time, a magnetic recording medium is required. Is required to be as flat as possible.

[0004] The frictional force generated between the magnetic head and the magnetic recording medium when the magnetic disk device is started and stopped causes wear of the magnetic head and the magnetic recording medium, and causes deterioration of characteristics such as write characteristics or read characteristics. Furthermore, if moisture or the like is interposed between the magnetic head and the magnetic recording medium while the magnetic recording medium is stationary, the two strongly adsorb,
When started in this state, a large force is generated between the magnetic head and the magnetic recording medium, which may cause damage to the magnetic head and the magnetic recording medium. Such a frictional force and an attractive force tend to increase as the surface of the magnetic recording medium becomes flat, which conflicts with the requirement for the flying stability of the magnetic head accompanying the improvement in the recording density.

It has been known to form minute irregularities on the surface of a magnetic recording medium in order to reduce such frictional force and attraction force.

As an example, Japanese Patent Application Laid-Open No. 1-134720 discloses that a magnetic recording medium is provided with island-shaped protrusions on the surface thereof.

Japanese Patent Application Laid-Open No. 1-122028 discloses that a metal alkoxide solution is applied to the surface of a magnetic layer of a magnetic recording medium, and the surface is rapidly heated to form a protective layer having irregularities on the surface of the magnetic layer. .

Japanese Patent Application Laid-Open No. 57-20925 discloses that a cylindrical projection having a diameter of 0.03 to 0.1 mm and a height of about 0.05 μm is provided on the surface of a magnetic layer or a protective layer. Have been.

[0009]

In each of the above-mentioned prior arts, the flying height of the magnetic head with respect to the magnetic recording medium is reduced, and in this case, the slider for supporting the magnetic head is prevented from being attracted to the magnetic recording medium. I want to do it.

No consideration is given to maintaining the flying stability of the magnetic head for a long period of time.

An object of the present invention is to provide a magnetic recording medium capable of maintaining the flying stability of a magnetic head. Another object is to improve the corrosion resistance of the magnetic recording medium.

Another object of the present invention is to provide a magnetic disk drive having a magnetic recording medium that achieves the above object.

Still another object of the present invention is to provide a magnetic disk drive capable of reducing the flying height of a magnetic head to 0.2 μm or less and maintaining flying stability for a long period of time.
And a magnetic recording medium therefor.

[0014]

According to the present invention, there is provided a magnetic disk drive having at least one magnetic disk having a magnetic layer and a surface protective layer on a substrate, and having a small gap with the rotating magnetic disk. A magnetic disk device comprising: a magnetic head facing and supported by a slider; rotating means for rotating the magnetic disk; and magnetic head positioning means for moving and positioning the magnetic head to a predetermined position on the magnetic disk. Wherein the surface of the magnetic disk has a large number of flat portions having the following features (a) and (b).

(A) A convex portion is divided on the same circumference and the same radius of the magnetic disk, has a concave portion between the convex portions, and is provided between the convex portions closest to the magnetic disk. The interval is 0.2 to 50 μm.

(B) The convex portion is arranged at an arbitrary position on the magnetic disk such that the convex portion contacts the entire surface of the slider when the magnetic disk is rotated once by using the slider. .

According to the present invention, a magnetic recording medium is provided with a number of convex portions having a flat surface on the surface thereof, and
Based on the fact that the requirement (b) is satisfied, the flying height of the magnetic head can be reduced and the flying stability can be maintained.

By providing the above requirement (b),
Dust adhering to the magnetic head and the slider can be scraped off by the projection.

By providing the above requirement (a),
Dust scraped from the magnetic head and slider
The slider can be discharged to the outside of the slider using the recess between the protrusions on the surface of the magnetic recording medium.

With the effects based on (a) and (b),
The flying height of the magnetic head can be set extremely small, and the flying height of the magnetic head can be kept almost constant.

In this specification, a magnetic disk and a magnetic recording medium are the same.

The inventors of the present invention have studied various irregularities formed on a magnetic recording medium. As a result, in order to secure the flying stability of a magnetic head for a long period of time, a magnetic layer and a surface protective layer were formed on a substrate. However, it has been found that it is extremely important that, when providing the surface of the surface protective layer with irregularities, the arrangement of the irregularities has an effect of quickly removing the fine dust attached to the magnetic head or the magnetic recording medium. Was.

In any of the prior arts of JP-A-1-134720, JP-A-1-122028 and JP-A-57-20925, it is not possible to impart a dust removing effect due to unevenness of the surface of a magnetic recording medium. Not listed. Further, the protrusions and recesses do not have a concave-convex shape or a concave-convex arrangement having a dust removing action.

In the present invention, the projections on the surface of the magnetic recording medium are desirably flat, and in particular, all the projections are desirably maintained at a substantially constant height.

If the surface of the projection is sharp or if there is a partly sharp projection on the surface of the flat projection, the flying stability of the magnetic head is deteriorated. In the worst case, the magnetic head and the magnetic recording medium come into contact with each other. Doing so may cause damage to the magnetic recording medium or the magnetic head.

Further, the unevenness of the unevenness affects the flying stability of the magnetic head, and there is a problem that the flying height tends to change even if the magnetic head does not contact the magnetic recording medium. Therefore, it is desirable that the protrusions are arranged regularly or almost regularly.

Fluctuations in the flying height of the magnetic head cause fluctuations in output during recording and reproduction, and contribute to a reduction in the S / N ratio.
Furthermore, since the output of the servo signal for positioning the magnetic head also fluctuates depending on the fluctuation of the flying height, there is a problem that the accuracy of the positioning of the magnetic head is reduced. Such a problem due to the fluctuation of the flying height of the magnetic head becomes particularly remarkable when the flying height is reduced to increase the recording density of the magnetic disk device, for example, when the flying height is set to 0.2 μm or less.

As an indication that the surface of the convex portion is flat,
An arbitrary length in the circumferential direction of the surface of the magnetic disk, for example, a height of 100 μm of the convex portion (a height from the center line of the upper surface of the convex portion to the center line of the adjacent concave portion) was measured by a stylus type roughness meter. Sometimes, it is desirable not to have a protrusion having a height exceeding 30% of the maximum protrusion height on the surface of the protrusion.

When the height of the protrusion is measured at an arbitrary length, for example, 100 μm using a stylus-type roughness meter, with the height of the protrusion being almost constant, 50% of the maximum height of the protrusion is measured. 30% with respect to the average value of the height of the convex portion having the above height
It is desirable that there is no convex part having a height exceeding 30% or a height below 30%.

It is desirable that the interval between the closest protrusions of the magnetic disk, that is, the magnetic recording medium, is 0.2 to 50 μm.

The number of projections is 400 / mm 2 or more, and preferably does not exceed 250,000 / mm 2.

If the projections are sparse, the air flow tends to be turbulent, and the flying height of the magnetic head tends to fluctuate. On the other hand, if the protrusions are too dense, dust is difficult to be discharged.

It is desirable that the size of each projection is 0.1 μm or more and 10 μm or less in the radial width of the magnetic disk, and 0.5 μm or more and 1 mm or less in the circumferential width of the magnetic disk.

If the width in the radial direction is smaller than 0.1 μm, when the dust collides with the projection, the projection may not be strong and may be damaged. The width of the radial projection is 10
If it is larger than μm, it is difficult for the dust to move to the left and right sides of the projection, and there is a possibility that the dust may be trapped.

If the width of the circumferential protrusion is smaller than 0.5 μm, the strength is weak when dust collides, and if it is larger than 1 mm, the dust may not be easily discharged in the radial direction of the magnetic disk. .

The height of the projections is higher than 5 nm and 40 nm.
It is desirable to have a substantially lower height within that range.

Further, the projections are provided so that the area ratio of the total area of the projections per square millimeter is 0.1% or more and 80% or less in the projection forming region on the surface of the magnetic disk. Is desirable.

The projections are regularly or almost regularly arranged on the surface of the magnetic disk such that the deviation of the area ratio of the projections on the same circumference is within 20% per square millimeter. Is desirable.

If the distribution of the projections varies significantly, the flying height of the magnetic head may fluctuate.

It is desirable that the bottom surface of the concave portion be as flat as possible in order to make it easier to discharge dust to the outside of the magnetic disk by utilizing the concave portion between the convex portions on the magnetic disk surface.

As an indication that the bottom surface of the concave portion is a flat surface, an arbitrary length measured with a stylus type roughness meter, for example, 100 μm
It is preferable that the concave portion has no convex portion having a height exceeding 30% of the maximum convex portion height in the length of m.

Further, in order to facilitate the discharge of dust toward the outer periphery of the magnetic disk, it is desirable that the convex portions are sequentially shifted to the outer peripheral side with respect to the magnetic head when the magnetic disk is rotated. .

According to the present invention, the interval between the magnetic disk and the magnetic head can be set to an unprecedented minute interval of 0.02 to 0.2 μm, and the flying height can be maintained stably. .

The projections on the surface of the magnetic disk can be formed, for example, by the following methods.

Protrusions are formed directly on the surface of the substrate or on the surface of the substrate having an underlayer, protrusions are formed on the surface of the magnetic layer, and protrusions are formed on the surface of the protective layer.

The flying height of the magnetic head is set to 0.02 to 0.2 μm.
In the case of extremely small m, if the surface of the magnetic layer has irregularities, it tends to affect the reduction of the S / N ratio. Therefore,
In the case where the flying height of the magnetic head is made extremely small in this way, it is desirable to make the magnetic layer a flat surface and form a projection on the surface protective layer thereon.

However, even when the projections are formed on the surface of the substrate or the surface of the magnetic layer as described in (1) and (2), if the shape of the formed projections is substantially maintained up to the surface of the magnetic disk, the flying height is reduced. It is sufficiently effective for maintaining stability.

The substrate of a general magnetic recording medium comprises an aluminum alloy disk and a hard underlayer formed thereon. When a disc material having a high hardness such as glass or ceramics is used instead of the aluminum alloy, the underlayer may be omitted. In the present invention, these are collectively referred to as a substrate. A magnetic layer is formed on the substrate, and an intermediate layer may be formed between the two for the purpose of improving adhesion and improving characteristics of the magnetic layer. A protective layer and, if necessary, a lubricating layer are formed on the magnetic layer to form a magnetic recording medium.

In the present invention, the protective layer and the lubricating layer are collectively referred to as a surface protective layer.

The protective layer is not limited to a single layer and may be formed in multiple layers.

As a method of manufacturing the magnetic recording medium, the following methods (a) to (d) are preferable.

(A) In a method of manufacturing a magnetic recording medium having a lubricating layer and a lower protective layer as a surface protective layer, a mask pattern is formed on the surface of the protective layer, and the protective layer is formed within a range of its thickness. After etching according to the mask pattern, the mask pattern is removed to form a projection having a desired shape and dimensions, and then the lubricating layer is formed thereon.

(B) In a method of manufacturing a magnetic recording medium having a lubricating layer and a lower protective layer as a surface protective layer, a mask pattern is formed on the surface of the protective layer by a lithography technique, and the protective layer is coated with the film. After etching according to the mask pattern within the thickness range, the mask pattern is removed to form a projection having a desired size and shape, and then the lubricating layer is formed thereon.

(C) In a method of manufacturing a magnetic recording medium having a lubricating layer and a lower protective layer as a surface protective layer, a material curable by irradiation of light, laser, or a beam of charged particles on the surface of the protective layer. The surface is selectively irradiated with a beam of light, a laser, or a charged particle to partially cure the surface, and then the uncured portion is removed to form a projection having a desired size and shape. Then, the lubricating layer is formed thereon.

(D) In a method of manufacturing a magnetic recording medium by forming a lubricating layer and two protective layers as a surface protective layer, a mask pattern is formed on the surface after forming the two protective layers, and the upper layer is formed. After the second protective layer is etched according to the mask pattern, the mask pattern is removed to form a projection having a desired size and shape on the surface of the first protective layer. Form a layer.

As a prior art in which irregularities are formed on the surface of a magnetic recording medium, there are the following in addition to the above three published patent publications.

JP-A-55-84045: A protective layer having a surface roughness of 20 to 50 nm is formed on a mirror substrate.

JP-A-58-53026: The surface of a protective layer is irradiated with gaseous ions and etched to a surface roughness of 50 to 100 n.

Japanese Unexamined Patent Publication (Kokai) No. 62-22241: Irregularities are formed on the protective layer so as not to exceed the film thickness. JP-A-62-2314
No. 27: Concentric grooves are formed on a protective surface.

JP-A-62-222435: Irradiation is partially applied to a protective layer of a cured metal alkoxide layer with a laser to form irregularities.

JP-A-63-188821: A silicon oil film is formed on a protective layer and is partially cured by excimer laser to form a spiral, concentric or spot-like unevenness.

JP-A-1-13227: A concentric protective layer having a thickness larger than the thickness of the lubricating layer and smaller than the thickness of the protective layer is formed.

JP-A-62-107427: A lubricating film (protective layer) mainly composed of carbon is roughened by polishing.

JP-A-63-191312: The surface of a protective layer is polished in the circumferential direction to form irregularities. JP-A-61-120344: After forming a protective layer containing a substance harder than the magnetic head, a part thereof is sputter-etched to form minute projections.

JP-A-63-29320: An island-like hard substance is fixed on a magnetic layer.

JP-A-61-216114: Irregularities are formed on a protective layer of a plasma polymerization of an acidic compound. JP-A-62-2442
No. 3: Unevenness is formed on the protective layer within a range not exceeding its thickness. JP-A-63-168830: Irregularities are formed by plasma etching the surface of a protective layer having a two-layer structure.

Japanese Unexamined Patent Publication (Kokai) No. 1-109527: Unevenness is formed on a low hardness protective layer on the surface of a magnetic recording medium by a stamp.

None of these techniques discloses forming irregularities so that dust adhering to the slider for supporting the magnetic head is discharged to the outside of the magnetic disk.
Also, it does not have such a function.

According to the present invention, first, by providing a convex portion on the surface of the surface protective layer, only the convex portion directly faces the magnetic head and the area ratio of the magnetic recording medium in contact with the magnetic head is reduced. Therefore, the frictional force and the attraction force with the magnetic head can be reduced. Second, by regularly or almost regularly arranging the protrusions formed on the surface protective layer, the fluctuation of the flying height of the magnetic head is small, and the flying stability of the magnetic head is reduced over the entire surface of the magnetic recording medium. Can be secured,
Output fluctuations due to flying height fluctuations can be prevented. Third, when a magnetic layer is formed on a flat processed substrate, the magnetic layer is also substantially flat, and output fluctuations during recording and reproduction due to unevenness of the magnetic layer can be reduced.

As described above, according to the present invention, the frictional force and the attraction force with the magnetic head are reduced, the output fluctuation is prevented, and the stable floating of the magnetic head can be ensured. Further, it is possible to obtain a magnetic recording medium capable of coping with a low flying height of a magnetic head accompanying a high recording density, and a magnetic disk device using the same.

Fourth, by arranging the projections provided on the surface protective layer so as to quickly remove the fine dust adhering to the magnetic head or the magnetic recording medium, a magnetic head crash due to the fine dust may occur. And the flying stability of the magnetic head can be ensured for a long period of time.

As described above, according to the present invention, stable flying of the magnetic head can be ensured for a long period of time, so that it has a high recording / reproducing accuracy and can cope with a low flying height of the magnetic head accompanying a high recording density. A magnetic recording medium having long-term durability and a magnetic disk device using the same can be obtained.

[0073]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below.

It is desirable that the projections provided on the surface of the surface protective layer satisfy the requirements (A) and (B) described in the claims and are arranged regularly. Thus, the flying height of the magnetic head can be stably controlled over the entire surface of the magnetic recording medium, and output fluctuations due to fluctuations in the flying height can be suppressed. In particular, at least at any point on the same circumference with respect to the center of rotation of the magnetic recording medium, if the area ratio of the projections per unit area, for example, per square millimeter is made substantially constant, the magnetic head can be moved to a certain track. When the magnetic recording medium is rotated while stopped at the position,
The magnetic head always has almost the same area ratio to the protrusion within the range of the size of the slider, so that the flying height variation can be suppressed low. In addition, if the area ratio of the protrusions per unit area, for example, per square millimeter, is made substantially constant over the entire surface of the protrusion formation portion, even when the magnetic head is moved by rotating the magnetic recording medium, The magnetic head always has substantially the same area ratio with respect to the protrusions within the range of the size of the slider, so that the flying height variation can be suppressed low over the entire surface. However, depending on the rotation of the magnetic recording medium, the linear velocity differs between the inner peripheral portion and the outer peripheral portion, so that the area ratio of the convex portion may be continuously changed little by little from the inner peripheral side to the outer peripheral side as necessary. .

The projections provided on the surface of the surface protective layer are discontinuous at least on the same circumference of the magnetic recording medium. This is because, when the magnetic head is stopped and the magnetic recording medium is rotated, the magnetic head intermittently contacts the convex portion from a certain point, so that even when minute dust adheres to the magnetic head, it can be easily formed. This is because it is removed.

The projections provided on the surface of the surface protective layer are:
It is desirable that at least a part of the discontinuous linear or bit-shaped portion having no protrusion is smoothly continuous from the inner circumference to the outer circumference of the magnetic recording medium in the moving area of the magnetic head. This is because even when minute dust enters between the magnetic head and the magnetic recording medium, the minute dust is easily removed to the outer peripheral side by the centrifugal force along the portion where the protrusion is not formed.

The above conditions are all satisfied. The most preferable arrangement of the convex portions is as follows. For example, a linear or bit-shaped convex portion composed of a part of a concentric or helical arc is regularly arranged over the entire surface with respect to the rotation center of the magnetic recording medium or the pattern center intentionally shifted from the rotation center. The protrusions are arranged such that at least a part of the portion without the protrusions is smoothly continuous from the inner circumference to the outer circumference of the magnetic recording medium in the moving area of the magnetic head. More specifically, for example, a width of 2 μm, a pitch of 6 μm, and a concentric arc with respect to the rotation center of the magnetic recording medium, for example, a center angle of 0.02
The arc-shaped convex portions corresponding to the degrees are formed on the entire surface by shifting the inner peripheral side by 2 μm in order toward the rotation direction of the magnetic disk every 0.03 degrees in center angle. FIG. 4 schematically shows an example of the arrangement pattern of the protrusions shown here. In this specific example, when the slider is placed on the magnetic disk and the magnetic disk is rotated, the protrusions are sequentially shifted toward the outer peripheral side and extend over the entire surface of the slider, so that the effect of removing dust attached to the slider is great. In addition, since the cut portion of the convex portion 7 is linearly continuous from the inner circumference to the outer circumference of the magnetic recording medium (magnetic disk) 14, even if minute dust enters between the magnetic head and the magnetic recording medium, the minute dust is generated by centrifugal force. Dust is easily removed to the outer peripheral side. It should be noted that, as shown in FIG. 4, the shape is such that a large number of arc-shaped protrusions are arranged on the entire surface. FIG. 9 shows the arrangement of the protrusions of this example on a real scale at a radius of 50 mm of the magnetic disk for an area of 200 μm square.

In this example, the area ratio of the projections per square millimeter is about 22% over the entire surface of the magnetic disk, and the number of projections per square millimeter is 50 mm in radius.
The number is about 6,500 at the position of mm.

As a modification of this embodiment, there is an arrangement shown in FIG. 5 in which the size and pitch of the projections are changed, and an example shown in FIG. 10 in which the arrangement of the projections is shifted.

As another example, it is preferable that bit-shaped protrusions are regularly arranged over the entire surface at portions corresponding to vertices of a regular lattice pattern. More specifically, for example, a bit-shaped convex portion having a diameter of 2 μm is arranged on the entire surface at a portion corresponding to an intersection of a square lattice having a pitch of 4 μm, for example. FIG. 6 schematically shows an example of the arrangement pattern of the projections shown here. In practice, a bit-shaped convex portion 7 as shown in FIG. The lattice pattern used here may be any regular pattern such as a triangular lattice or a hexagonal lattice other than the square lattice described above. When the magnetic recording medium is rotated while the slider is stationary when the convex portions are arranged as described above, the convex portions intermittently cover the entire surface of the slider, so that there is a great effect of removing minute dust attached to the slider. In this case, the gap between the convex portions is linearly continuous from the inner circumference to the outer circumference of the magnetic recording medium. Therefore, even when minute dust enters between the magnetic head and the magnetic recording medium, centrifugal force is applied. Thereby, minute dust is easily removed to the outer peripheral side.
In this example, the area ratio of the protrusions per square millimeter is about 20% over the entire surface of the magnetic disk, and the number of protrusions per square millimeter is 62.500 over the entire surface of the magnetic disk.

In addition to the above, the arrangement is made so as to have the function of removing the fine dust attached to the magnetic head and the function of removing the fine dust interposed between the magnetic recording medium and the magnetic head in the outer circumferential direction of the magnetic recording medium. If the convex part is
Other arrangements are acceptable.

It is desirable that the height of the projection provided on the surface of the surface protective layer is substantially constant in the range of 5 nm to 40 nm. If the height of the projections is less than 5 nm, the effect of reducing the frictional force and the attraction force between the magnetic head and the magnetic recording medium decreases. If the height of the convex portion is higher than 40 nm, the output decreases because the distance between the magnetic head and the magnetic layer in the concave portion between the convex portions increases during recording and reproduction, and the flying stability of the magnetic head is impaired. Further, if the height of the convex portion is not uniform, the high portion becomes a projection, which is not preferable for the floating stability.

The width of the projection provided on the surface of the surface protective layer in the radial direction is preferably from 0.1 μm to 10 μm, more preferably from 0.3 μm to 3 μm. If the width of the convex portion is smaller than 0.3 μm, accuracy in forming the convex portion may be difficult to obtain. If the width of the protrusion is larger than 3 μm, the effect of reducing the frictional force and the attraction force between the magnetic head and the magnetic recording medium may be reduced.

The area ratio of the protrusions provided on the surface of the surface protective layer is 0.1% or more and 80% or less, preferably 0.5% or less.
At least 70% is desirable. The area ratio of the convex part is 0.5
%, The magnetic head is supported by a small area, so that the protruding portion is easily worn, and the long-term vibration durability is reduced. In addition, when the area ratio of the projections is reduced, the flying stability of the head may be impaired. When the area ratio of the protrusions is larger than 70%, the effect of reducing the frictional force and the attraction force between the magnetic head and the magnetic recording medium decreases.

The projection of the surface protective layer may be formed on the entire surface of the magnetic recording medium. However, depending on the specifications of the magnetic disk drive in which the magnetic recording medium is incorporated, the contact area may be changed.
If a start / stop (CSS) zone is provided exclusively, it may be formed only in that portion. The reason for this is that, as described above, the frictional force and the attraction force with the magnetic head, the effects of minute dust, etc. are mainly problems when starting and stopping the magnetic disk device, and the magnetic head stably floats. This is because the effect of forming the protruding portion is relatively small in the state in which it is performed.

It is desirable that the material of the protective layer has high hardness from the viewpoint of abrasion resistance. Such materials include, for example, Al, Si, Ti, V, Cr, Zr, Nb, Mo, H
It is desirable to use oxides, nitrides, carbides of metals such as f, Ta, W, etc., and C, BN or the like, alone or in combination of two or more. When viewed as a magnetic disk drive, it is desirable that the hardness of the protective layer material of the magnetic recording medium be equal to or higher than the hardness of the slider material of the magnetic head to be combined. This is because, when abrasion occurs due to sliding, if the protective layer is worn, the characteristics of the magnetic recording medium are likely to deteriorate, but the slight wear on the slider side has relatively little effect on the characteristics of the magnetic head. Specific examples of such a combination include, for example, the protective layer material described above and M
A combination of n-Zn ferrite sliders and the like are conceivable.

The specific method for forming the magnetic recording medium according to the present invention is as follows. A magnetic layer and a protective layer are formed on a mirror-finished nonmagnetic disk-shaped substrate. An intermediate layer may be formed between the substrate and the magnetic layer. As a method of forming a convex portion on the surface of the protective layer, a desired mask pattern is formed on the surface of the protective layer by, for example, lithography technology, and then etching is performed to selectively uniform only those portions not covered by the mask pattern. It is preferable to remove the mask pattern after etching to remove the protective layer to a certain depth or less. The etching method used here is selected from dry etching such as ion milling and reactive plasma treatment, wet etching, and the like according to the material of the protective layer. Further, the protective layer used here is made of a material of the upper protective layer having a constant height on the lower protective layer having a constant thickness, if the above-described pattern formation is performed under the condition that only the upper layer is etched as a uniform single layer structure. Protrusions can be formed.

As another method of forming the convex portion, a material curable by irradiation of a beam of light, laser or charged particles is formed on the surface of the protective layer into a film, and light, laser or charged particles are formed on the film surface. The beam can be similarly formed by regularly irradiating a desired position on a desired position and partially curing the same, and then removing the uncured portion.

In addition, other than the above method, other methods may be used as long as the shape of the finally obtained convex portion is desired. For example, a photodegradable organometallic gas is introduced on a disk on which a magnetic layer and a protective layer are formed on a mirror-finished non-magnetic disk, and a laser beam is periodically and regularly irradiated on the disk. A projection having a similar shape can be formed by a method of irradiating and selectively depositing metal (laser CVD method) or the like.

A lubricating layer is formed, if necessary, on the protective layer having the projections formed on the surface as described above, to provide a magnetic recording medium.

In the above-described manufacturing method, a method of forming a convex portion on the surface of the protective layer has been described. However, after forming a convex portion on a mirror-finished substrate by a similar method, for example, an intermediate layer and a magnetic layer are formed. If the protective layer and the lubricating layer are each formed to have a constant thickness, the shape of the projections formed on the substrate is substantially maintained up to the surface of the magnetic disk, so that a magnetic recording medium having a similar surface shape can be obtained. it can.

FIG. 8 is a schematic diagram showing the configuration of a magnetic disk drive according to one embodiment of the present invention.

The magnetic disk drive has a reference numeral 1 shown in FIG.
It includes components 1 to 18 and a voice coil motor control circuit.

Reference numeral 11 denotes a base, and reference numeral 12 denotes a spindle.

A plurality of disk-shaped magnetic disks 14 are mounted on one spindle as shown in the figure.

FIG. 8 shows an example in which five magnetic disks 14 are provided on one spindle, but the number is not limited to five.

A plurality of magnetic disks 14 provided on one spindle 12 may be provided.

Reference numeral 13 denotes a motor for driving the spindle 12 and rotating the magnetic disk, that is, magnetic disk rotation control means.

Reference numeral 15 denotes a data magnetic head, and reference numeral 15a denotes a positioning magnetic head.

Reference numeral 16 denotes a carriage, reference numeral 17 denotes a voice coil, and reference numeral 18 denotes a magnet.

The voice coil 17 and the magnet 18 constitute a voice coil motor. Then, the head is positioned by the elements denoted by reference numerals 16, 17, and 18. Accordingly, the magnetic head positioning mechanism including the reference numerals 16, 17, and 18 is collectively referred to as a magnetic head positioning mechanism. The voice coil 17 and the magnetic heads 15 and 15a are connected via a voice coil motor control circuit.

In FIG. 8, the host device is, for example, a computer system and has a function of processing information recorded on a magnetic disk device. In the recording / reproducing method, the magnetic head and the magnetic recording medium are in contact with each other before the operation starts, but a space is created between the magnetic head and the magnetic recording medium by rotating the magnetic recording medium, and the recording / reproducing is performed in this state. Perform At the end of the operation, the rotation of the magnetic recording medium stops, and the magnetic head and the magnetic recording medium come into contact again. This is referred to as a contact start / stop system, hereinafter a CSS system.

FIG. 9, FIG. 10 and FIG. 11 are plan views of the surface of the magnetic recording medium, showing examples of the arrangement of the projections. 9 and 10 show the present invention, and FIG. 11 shows a comparative example.

The square frame is 200 μm on the surface of the magnetic recording medium.
The range of m square is shown.

The comparative example shown in FIG. 11 shows an example in which convex portions continuous in the circumferential direction are formed.

Hereinafter, the present invention will be described in more detail with reference to more specific examples.

[Example 1] An aluminum alloy having an outer diameter of 5.25 inches was Ni-coated on the surface of an alloy disk by electroless plating.
A P underlayer was formed to a thickness of 15 μm, the underlayer was polished to 10 μm, and the average roughness (R
a) Mirror finishing was performed so that the maximum roughness (Pmax) was 3 nm or less.

On the substrate thus obtained, a Cr intermediate layer was formed to a thickness of 0.2 μm, a Co—Ni magnetic layer was formed to a thickness of 40 nm, and a C protective layer was formed to a thickness of 20 nm by sputtering. C
Positive resist (Tokyo Ohka, OFPR800) on the surface of the protective layer
Is applied to a thickness of about 0.5 μm, and a photomask formed in the shape shown in FIG. 4 so that only the protruding portions do not transmit light is brought into close contact with the photomask and developed, and then developed on the surface of the C protective layer. 4
A mask pattern was formed in the shape shown in FIG.

The disk was irradiated with an argon ion beam over the entire surface for 30 seconds using an ion milling device to uniformly etch portions where no mask pattern was formed, and then the mask pattern was removed with a resist removing solution. Thus, regularly arranged projections were formed on the surface of the protective layer.

On the surface of the disk thus obtained, a lubricant of a perfluoropolyether type was applied as a lubricating layer to a thickness of about 5 nm to produce a magnetic recording medium. The height of the formed convex portion is adjusted at any 10 points on the surface of the magnetic recording medium by a scanning tunneling microscope (ST).
As a result of measurement using M) and a tactile surface roughness meter, the height of the projection was 10 nm at any measurement point. When the surface of the magnetic recording medium obtained by Auger electron spectroscopy was measured, Co and Ni were not detected, and it was confirmed that there was no exposed portion of the magnetic layer. The size of the protrusions and the spacing between the protrusions are as shown in FIG.

FIG. 1 is a schematic diagram showing a cross-sectional structure in the radial direction of the magnetic recording medium of this embodiment. In FIG.
Is an aluminum alloy disk, 2 is an underlayer, 3 is a width layer, 4
Denotes a magnetic layer, 5 denotes a protective layer, and 6 denotes a lubricating layer. The disk 1 and the underlayer 2 constitute a substrate. In this embodiment,
The area ratio of the projections is about 22% over the entire surface.

Example 2 A photomask having the shape shown in FIG. 5 and formed so that only the projections do not transmit light was used. The thickness of the C protective layer was 30 nm, and the photomask was used for forming the projections. A magnetic recording medium was manufactured in the same manner as in Example 1, except that the etching time by ion milling was 1 minute. The height of the protrusions was measured at any 10 points on the surface of the magnetic recording medium using a scanning tunneling microscope and a stylus-type surface roughness meter. As a result, the height of the protrusions was 20 nm at any of the measurement points. The size of the projections and the spacing between the projections are as shown in FIG. FIG. 7 shows an example of the results obtained by measuring the protrusions on the surface of the magnetic recording medium according to the present embodiment in the radial direction with a stylus type surface roughness meter. In this embodiment, the area ratio of the convex portion is about 19% over the entire surface.

Example 3 A magnetic recording medium was manufactured in the same manner as in Example 1 except that a photomask having the shape shown in FIG. 6 and formed such that only the projections did not transmit light was used. did. As a result of measuring the height of the hill at any 10 points on the surface of the magnetic recording medium by STM and a stylus type surface roughness meter,
At each measurement point, the height of the projection was 10 nm.
The size of the projections and the spacing between the projections are as shown in FIG.

FIG. 2 is a schematic diagram showing a cross-sectional structure in the radial direction of the magnetic recording medium of this embodiment. In this embodiment, the area ratio of the convex portion is about 20% over the entire surface.

Example 4 A method similar to that of Example 1 was used except that SiC was formed as a protective layer to a thickness of 20 nm by sputtering, and the etching time by ion milling for forming the projections was 20 seconds. The magnetic recording medium was produced by the above.
Any 10 points on the surface of the magnetic recording medium can be measured using a stylus type surface roughness meter.
As a result of measuring the height of the protrusion at each point, the height of the protrusion was 10 nm at any measurement point.

Example 5 As a protective layer, a C film (so-called iC) having a thickness of 20 nm formed by a plasma CVD method using a methane-hydrogen mixed gas as a raw material was used. A magnetic recording medium was manufactured in the same manner as in Example 1 except that the etching time by milling was 1 minute. As a result of measuring the height of the protrusion at any ten points on the surface of the magnetic recording medium by using a stylus type surface roughness meter, the height of the protrusion was 10 nm at any measurement point.

[Embodiment 6] A Ni-P underlayer 2 is formed on a substrate 1 in the same manner as in Embodiment 1, and a Cr intermediate layer 3 having a thickness of 0.2 μm is formed thereon by sputtering to form a Co-Ni magnetic layer. 4 is 40 nm thick and SiC is 10 nm as the first protective layer 5a.
C was formed to a thickness of 10 nm as the second protective layer 5b. A mask pattern was formed on the surface of the C second protective layer 5b in the same manner as in Example 1, exposed to oxygen plasma for one minute using an oxygen asher device, and then the mask pattern was removed with a resist removing solution. When the obtained disk surface was analyzed, in the portion where there was no mask pattern, C disappeared due to the etching of the oxygen plasma to expose SiC, and C remained only in the mask pattern portion and the convex portion 7 remained. Was formed. As a result of measuring the height of the projections 7 at any 10 points on the disk surface using a stylus-type surface roughness meter, the height of the projections 7 was 10 nm at any measurement point. It can be seen that SiC is hardly etched. That is, the protrusion 7 is formed on the second protective layer 5b. Also, the first protective layer 5
SiC used as a has corrosion resistance.

The lubricating layer 6 was formed on the surface of the disk thus obtained.
About 5nm perfluoropolyether lubricant
The magnetic recording medium 14 was produced by applying the film to a thickness.

[Embodiment 7] On the same substrate as in Embodiment 1,
The Cr intermediate layer was formed to a thickness of 0.2 μm by sputtering,
The thickness of the Ni magnetic layer is 40 nm and the thickness of the protective layer is 10% of SiC.
It was formed to a thickness of nm. After spin-coating a solution of tetrahydroxysilane to a thickness of about 15 nm on the surface of the SiC protective layer, an Ar laser condensed to a spot diameter of 2 μm was applied as shown in FIG.
After selectively irradiating only the protruding portions in the pattern shown in (1) to change the irradiated portion of tetrahydroxysilane to SiO2 and curing, the uncured portion of tetrahydroxysilane was washed and removed, as shown in FIG. On the surface of the protective layer, regularly arranged projections were formed.

On the surface of the disk thus obtained, a lubricant of perfluoropolyether was applied as a lubricating layer to a thickness of about 5 nm to produce a magnetic recording medium. The height of the formed protrusions was measured at any 10 points on the surface of the magnetic recording medium using a stylus-type surface roughness meter. As a result, the height of the protrusions was 10 nm at any of the measurement points.

In this embodiment, the area ratio of the convex portion is about 22% over the entire surface.

Example 8 The substrate was mirror-finished to an average diameter (Ra) of 2 nm or less and a maximum roughness (Rmax) of 5 nm or less, as measured by a stylus type surface roughness meter, and had an outer diameter of 5.25. A magnetic recording medium was manufactured in the same manner as in Example 1 except that a tempered glass disk of inches was used. As a result of measuring the height of the protrusion at any ten points on the surface of the magnetic recording medium by using a stylus type surface roughness meter, the height of the protrusion was 10 nm at any measurement point.

[Embodiment 9] On the same substrate as in Embodiment 1,
A mask pattern is formed directly in the same manner as in Example 1,
Argon ion beam 10 by ion milling device
After irradiating the entire surface for 2 seconds, the mask pattern was removed to form regularly arranged projections on the substrate surface. As a result of measuring the height of the protrusion at any 10 points on the substrate surface using a stylus type surface roughness meter, the height of the protrusion was 10 nm at any measurement point.
Met.

On this substrate, an intermediate layer, a magnetic layer and a protective layer are formed by the sputtering method in the same manner as in Example 1, and a perfluoropolyether-based lubricant of about 5 nm is used as a lubricating layer on the protective layer as it is. It was applied to a thickness to produce a magnetic recording medium. As a result of measuring the height of the protrusion at any 10 points on the surface of the magnetic recording medium using a stylus type surface roughness meter, the height of the protrusion was 10 nm at any of the measurement points, and the protrusion formed on the substrate was measured. It was confirmed that the shape was substantially maintained up to the surface of the magnetic recording medium.

FIG. 3 is a schematic diagram showing a cross-sectional structure in the radial direction of the magnetic recording medium of this embodiment.

[Comparative Example 1] On the same substrate as in Example 1,
An intermediate layer, a magnetic layer, and a protective layer were formed by a sputtering method in the same manner as in Example 1, and a perfluoropolyether-based lubricant was applied as a lubricating layer on the protective layer to a thickness of about 5 nm to form a magnetic layer. A recording medium was produced. No convex portion was formed.

Comparative Example 2 While rotating the same substrate as in Example 1, a buff containing abrasive grains was pressed against and polished to form a continuous groove substantially along the circumferential direction. The substrate surface thus obtained was measured with a stylus-type surface roughness meter to have an average roughness (Ra) of 10 nm and a maximum roughness (Rmax) of 35 nm.
Met.

On this substrate, an intermediate layer, a magnetic layer, and a protective layer were formed by a sputtering method in the same manner as in Example 1, and a perfluoropolyether-based lubricant was used as a lubricating layer on the protective layer as it was. It was applied to a thickness of 5 nm to produce a magnetic recording medium.

[Comparative Example 3] In the same manner as in Example 1,
The Cr intermediate layer was formed to a thickness of 0.2 μm by sputtering,
Ni magnetic layer is 40 nm thick, and C is 40 nm as a protective layer.
The thickness was formed. While rotating the disk, a buff containing abrasive grains was pressed against it to polish the C protective layer to a thickness of about 10 nm, thereby forming a groove substantially along the circumferential direction. Then, a perfluoropolyether-based lubricant was applied as a lubricating layer to a thickness of about 5 nm on the disk surface to produce a magnetic recording medium.

The surface of the magnetic recording medium thus obtained was measured with a stylus type surface roughness meter to have an average roughness (Ra) of 10 nm,
The maximum roughness (Rmax) was 30 nm.

[Comparative Example 4] On the same substrate as in Example 1,
The Cr intermediate layer was formed to a thickness of 0.2 μm by sputtering,
40 nm thick Ni magnetic layer, 30 nm C as protective layer
It was formed to a thickness. This disk was reverse sputtered in a sputtering apparatus to etch the C protective layer to a thickness of about 10 nm.

On the surface of the obtained disk, a perfluoropolyether-based lubricant was applied as a lubricating layer to a thickness of about 5 nm to produce a magnetic recording medium.

The surface of the magnetic recording medium thus obtained had an average roughness (Ra) of 8 nm and a maximum roughness (Rmax) of 15 nm as measured by a stylus type surface roughness meter.

[Comparative Example 5] A photomask having a width of 2 μm
A magnetic recording medium was manufactured in the same manner as in Example 1 except that a concentric part having a pitch of m and a pitch of 10 μm was formed so as not to transmit light. By observing the surface of the magnetic recording medium with an electron microscope, it was confirmed that concentric convex portions having a width of 2 μm and a pitch of 10 μm were formed on the entire surface. ST
As a result of measuring the height of the protrusion at any 10 points on the surface of the magnetic recording medium using M and a stylus type surface roughness meter, the height of the protrusion was 10 nm at any of the measurement points. The arrangement of the protrusions in this comparative example is as shown in FIG.

In this embodiment, the area ratio of the convex portion is 20% over the entire surface.

Using the magnetic recording media obtained in the above Examples and Comparative Examples, a magnetic disk drive shown in FIG.
After about 30,000 tests, a visual inspection in the CSS area, a measurement of the attraction force and frictional force with the magnetic head, a measurement of the minimum flying height of the magnetic head, and a recording / reproducing test were performed. The flying height of the magnetic head during steady rotation is 0.1 μm.
m. The test results are shown in FIG.

As shown in FIG. 12, in Comparative Example 1 in which no irregularities were formed, the initial attraction force and frictional force were large, and CSS
Later increases are also large. For this reason, linear sliding marks are generated on the surface after CSS, and due to this damage, the characteristic deterioration in the flying characteristic test and the recording / reproducing test is remarkable.

Comparative Example 2 in which irregularities were formed on a substrate by a polishing method
In Comparative Example 1, the characteristic degradation after CSS was small, but the characteristic degradation was still considerable, the flying characteristics were poor even in the initial stage, and an error occurred in the recording / reproduction test. This is considered to be because local protrusions are easily generated in the polishing process in Comparative Example 2, and it is considered that this portion caused bit-like peeling after CSS. In Comparative Example 2, since the unevenness is formed on the substrate, the magnetic layer formed thereon also has the unevenness, and the S / N ratio is low even in the initial stage.

In Comparative Example 3 in which the concavities and convexities were formed on the protective layer by the polishing method, as in Comparative Example 2, a defect in the floating characteristics and an error, which are considered to be caused by local projections in the polishing process, occurred at the initial stage. I have. In Comparative Example 3, since the magnetic layer was almost flat, the initial S / N ratio was higher than that in Comparative Example 2, but it was still insufficient. This is because the floating stability of the magnetic head is not sufficient because the unevenness formed on the protective layer is not uniform. Further, the characteristic deterioration after CSS was large, which is considered to be because the flying stability of the magnetic head was further impaired due to the occurrence of a peeled portion or the like.

In Comparative Example 4, in which irregularities were formed on the protective layer by reverse sputtering, no error was initially observed, but the floating characteristics were still insufficient, and the S / N ratio was also slightly lower. This is because the floating stability of the magnetic head is not sufficient because the shape of the unevenness formed on the protective layer is non-uniform as in Comparative Example 3. In addition, although there is considerable deterioration in characteristics after CSS, analysis of the peeled portion after CSS to clarify the cause revealed that peeling occurred due to penetration of fine dust. For this reason, in Comparative Example 4, it is considered that the floating stability of the magnetic head was further impaired and the characteristics were deteriorated due to the occurrence of a peeling portion due to the presence of minute dust between the magnetic head and the magnetic recording medium. In the case of Comparative Examples 2 and 3, the peeled portion after CSS was analyzed.
Similarly, a portion where the fine dust penetrated and peeled off was found.

In Comparative Example 5, in which concentric observing convex portions were formed on the protective layer, the initial characteristics were good, but the CSS
Subsequent characteristic deterioration is large. CSS to clarify the cause
Analysis of the later peeled portion revealed that fine dust had accumulated around the peeled portion, and a portion of the dust had penetrated to cause peeling. Therefore, in Comparative Example 5, it is considered that the flying stability of the magnetic head was impaired and the characteristics were degraded.

On the other hand, the magnetic recording medium according to the present embodiment shows good characteristics before CSS and has little deterioration in characteristics after CSS. This is because the regular concave-convex shape formed in this embodiment does not have local protrusions, so that the flying stability of the magnetic head is good.

In particular, as in the case of Embodiments 1 to 8, an intermediate layer, a magnetic layer and a protective layer are formed on a flat substrate, and fine dust adhering to a head or a magnetic recording medium is formed on the surface of the protective layer. In the case of providing a regularly arranged micro unevenness so that it can be removed quickly and forming a lubricating layer on the protective layer, the frictional force and adsorption force with the magnetic head are low, and the recording / reproducing characteristics are good. Thus, the flying stability of the magnetic head is guaranteed, and a magnetic recording medium with small deterioration in characteristics over a long period of time can be obtained.

Further, as in the ninth embodiment, a fine unevenness having the above-mentioned effect is provided on the substrate, and an intermediate layer, a magnetic layer,
Even when the protective layer and the lubricating layer are formed, although the S / N ratio is slightly reduced as compared with Examples 1 to 8 due to the magnetic layer having irregularities, the size of the irregularities is small. The decrease in the S / N ratio is small, and the other characteristics are good.

As described above, according to this embodiment, the surface of the magnetic recording medium is provided with regularly arranged fine irregularities so that the fine dust adhered to the magnetic head or the magnetic recording medium can be quickly removed. This makes it possible to obtain a magnetic recording medium that has low frictional force and attraction force with the magnetic head, good recording / reproducing characteristics, guarantees the flying stability of the magnetic head, and has little characteristic deterioration over a long period of time.

[0146]

According to the present invention, there is provided a magnetic recording medium which has a low frictional force and an attractive force with the magnetic head, guarantees the floating stability of the magnetic head even at a low flying height, and has a small characteristic deterioration over a long period of time. It can be provided with good reproducibility. Further, the protective layer constituting the magnetic recording medium is divided into a first protective layer and a second protective layer, and the convex portion is formed on the second protective layer, and a first protective layer having corrosion resistance is formed below the second protective layer. By forming
A magnetic recording medium having corrosion resistance in addition to the above effects can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a cross-sectional structure in a radial direction of a magnetic recording medium according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a radial cross-sectional structure of a magnetic recording medium according to an embodiment of the present invention.

FIG. 3 is a perspective view showing a sectional structure in a radial direction of a magnetic recording medium according to an embodiment of the present invention.

FIG. 4 is a partial plan view showing the arrangement of protrusions formed on the surface of a magnetic recording medium according to one embodiment of the present invention.

FIG. 5 is a partial plan view showing the arrangement of convex portions formed on the surface of the magnetic recording medium according to one embodiment of the present invention.

FIG. 6 is a partial plan view showing the arrangement of protrusions formed on the surface of a magnetic recording medium according to one embodiment of the present invention.

FIG. 7 is a graph showing an example of a result obtained by measuring a convex portion of a magnetic recording medium according to an embodiment of the present invention in a radial direction with a stylus type surface roughness meter.

FIG. 8 is a schematic configuration diagram showing an embodiment of the magnetic disk drive of the present invention.

FIG. 9 is a plan view showing an example of the shape and distribution of convex portions on the surface of a magnetic recording medium.

FIG. 10 is a plan view showing an example of the shape and distribution of convex portions on the surface of a magnetic recording medium.

FIG. 11 is a plan view showing an example of the shape and distribution of protrusions on the surface of a magnetic recording medium.

FIG. 12 shows a magnetic recording medium according to an embodiment of the present invention.
FIG. 3 is a perspective view showing a cross-sectional structure in a radial direction.

FIG. 13 is a diagram showing a result of a CSS test.

[Explanation of symbols]

1: Aluminum alloy disk, 2: Underlayer, 3: Intermediate layer,
DESCRIPTION OF SYMBOLS 4 ... Magnetic layer, 5 ... Protective layer, 5a ... First protective layer, 5b ... Second protective layer, 6 ... Lubricating layer, 7 ... Convex part, 13 ... Magnetic disk rotation control means, 14 ... Magnetic recording medium (magnetic disk ),
15 ... magnetic head.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Maki Kondo 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Yoshihiko Miyake 2880 Kozu, Odawara City, Kanagawa Prefecture Hitachi, Ltd.Odawara City Plant (72) Inventor Yoshiki Kato 2880, Kozu, Odawara City, Kanagawa Prefecture Hitachi, Ltd.Odawara City Factory, Ltd. 72) Inventor Toyoharu Okwaki 1-280 Higashi Koigabo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. (72) Inventor Noriaki Okamoto 502, Kandate-cho, Tsuchiura-shi, Ibaraki Pref. Nobuo Nakagawa 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi Production Engineering in the Institute

Claims (9)

[Claims] 1. A magnetic disk having a magnetic layer and a protective layer on a substrate, wherein the protective layer has a first protective layer covering the magnetic layer and a number of protrusions provided on the first protective layer. A magnetic disk comprising a second protective layer. 2. A magnetic disk having a magnetic layer and a protective layer on a substrate, wherein the protective layer comprises a first protective layer covering the magnetic layer and a second protective layer forming a projection on the first protective layer. A magnetic disk, comprising: 3. The method according to claim 1, wherein the first protective layer is made of SiC, and the second protective layer is made of C.
The magnetic disk as described. 4. The magnetic disk according to claim 1, wherein the magnetic disk has a contact start / stop area and a recording / reproducing area on a surface thereof, and has the projection in the contact start / stop area. 5. A method for manufacturing a magnetic disk having a magnetic layer and a protective layer on a substrate, comprising: forming a magnetic layer on the substrate; forming a first protective layer on the magnetic layer; Forming a second protective layer, forming a mask pattern on at least a partial region of the surface of the second protective layer, etching the surface of the second protective layer through the mask pattern, and removing the mask pattern Thereby forming a large number of convex portions. 6. A method of manufacturing a magnetic disk having a magnetic layer and a protective layer on a substrate, comprising: forming a magnetic layer on the substrate; forming a first protective layer on the magnetic layer; Forming a plurality of projections by selectively irradiating an energy beam to at least a part of the surface of the second protection layer. . 7. At least one magnetic disk, rotating means for rotating the magnetic disk, a magnetic head facing the rotating magnetic disk at a small interval, and moving the magnetic head to a predetermined position on the magnetic disk In a magnetic disk drive provided with a magnetic head positioning means for performing positioning, the magnetic disk includes a magnetic layer and a protective layer formed on a substrate, and the protective layer includes a first protective layer covering the magnetic layer and a protective layer. A magnetic disk drive comprising a second protective layer having a large number of projections provided on the first protective layer. 8. At least one magnetic disk, rotating means for rotating the magnetic disk, a magnetic head facing the rotating magnetic disk at a small interval, and moving the magnetic head to a predetermined position on the magnetic disk In a magnetic disk drive provided with a magnetic head positioning means for performing positioning, the magnetic disk includes a magnetic layer and a protective layer formed on a substrate, and the protective layer includes a first protective layer covering the magnetic layer and a protective layer. A magnetic disk drive comprising a second protective layer forming a projection on the first protective layer. 9. The flying height of the magnetic head with respect to the magnetic disk is 0.2 μm or less.
Or the magnetic disk drive according to 8.