JPH0485725A - Magnetic disk device and magnetic recording medium - Google Patents

Abstract

PURPOSE:To prevent the modulation of an electrical output and to stably maintain floating even if the floating quantity of a magnetic head is decreased by orienting a magnetic layer in a circumferential direction. CONSTITUTION:Only the hill part directly faces the head and the area ratio of the magnetic recording medium in contact with a head can be decreased and, therefore, the friction force and attraction force to the head are lowered. In addition, the fluctuation in the floating quantity of the head is decreased if the formed hills are regularly disposed. The stability of the floating of the head is assured over the entire surface of the magnetic recording medium and the fluctuation in the output by the fluctuation in the floating quantity is prevented. Further, the microgrooves formed along the circumferential direction in the hill and groove parts contribute to the shape magnetic anisotropy of the magnetic layer. The coercive force in the circumferential direction with respect to a radial direction and the squareness ratio are large and the fluctuation in the output by the modulation is lessened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording device and a magnetic recording medium used therein.

[Conventional technology]

In recent years, the importance of magnetic recording devices as external storage devices for computer systems has been increasing, and the recording density thereof has been significantly improved year by year. Thin-film magnetic recording media that use magnetic thin films are attracting attention as magnetic recording media that can support such high recording densities, instead of the conventional coated media that coats a substrate with magnetic paint that is a mixture of magnetic powder and binder. ing.

Thin-film magnetic recording media (hereinafter referred to as
The optical structure of the magnetic recording medium (simply referred to as a magnetic recording medium) is as follows. The substrate consists of an aluminum alloy disk and a hard underlayer formed thereon.

If a disk material with high hardness, such as glass, is used instead of aluminum alloy, the base layer may be omitted. 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 the characteristics of the magnetic layer. A protective layer and, if necessary, a lubricating layer are formed on the magnetic layer to constitute a magnetic recording medium.

A magnetic recording device consists of a magnetic recording medium and a recording/reproducing magnetic head (
The main components are a magnetic recording medium rotation control mechanism, a head positioning mechanism, and a recording/reproduction signal processing circuit.

In this recording and reproducing method, the head and the magnetic recording medium are in contact before the start of operation, but by rotating the magnetic recording medium, a space is created between the head and the magnetic recording medium, and recording and reproducing is performed in this state. Let's do it.

At the end of the operation, the magnetic recording medium stops rotating and the head and magnetic recording medium are in contact again.

(Contact start-stop method, hereinafter referred to as C8S method) In order to improve the recording density of a magnetic recording device, the smaller the flying height of the head during recording and reproduction, the better.
In order to ensure the flying stability of the head at this time, the surface of the magnetic recording medium is required to be as flat as possible.

Incidentally, the frictional force generated between the head and the magnetic recording medium when the apparatus is started and stopped causes wear of both, causing characteristic deterioration.

Furthermore, if moisture is present between the head and the magnetic recording medium while the magnetic recording medium is stationary, the two will be strongly attracted to each other, and if the head is started in this state, a large force will be generated between the head and the magnetic recording medium. This may cause damage to the head or magnetic recording medium. Such frictional force and adsorption force tend to increase as the surface of the magnetic recording medium becomes flatter, which conflicts with the above-mentioned requirement for flying stability of the head accompanying the increase in recording density.

In order to reduce such frictional force and adsorption force, a method of forming minute irregularities on the surface of a magnetic recording medium is usually used.

Various methods have been proposed in the past, including, for example, forming fine irregularities on a nonmagnetic substrate using an abrasive tape and forming fine irregularities on the surface of a protective layer. For example, on the surface of a magnetic recording medium on which a protective layer is formed,
A method of forming irregularities on the surface of a protective layer by irradiating gaseous ions is proposed in JP-A-58-53026.

In addition, polishing,
A method of forming irregularities within a range not exceeding the thickness of the protective layer by wet etching or dry etching is disclosed in Japanese Patent Laid-Open No. 62-22.
This is proposed in Publication No. 241. Furthermore, Japanese Patent Laid-Open No. 1.3227/1983 proposes a method of polishing the surface of the protective layer while rotating the magnetic recording medium to form concentric irregularities.

Another purpose of forming circumferential microgrooves on the surface of a magnetic recording medium is to prevent so-called modulation, which is described in the literature (for example, IEEE Trans.
, Nag, MAG-22,579(1,986),
IEEE Trans, Nag, MAG-23,3
402 (1987), IEEE Trans.

Mag, Mag-20,821 (1984) and USP
4,735,840, JP-A-63-42027, JP-A-63-191312, JP-A-63-197030
It is stated in the No.

[Problem to be solved by the invention]

All of the above conventional technologies aim to reduce the frictional force and adsorption force of the magnetic head against the magnetic recording medium to prevent the magnetic head supporting slider from adhering to the magnetic recording medium, or to prevent modulation. The purpose of this method is to satisfy both of these objectives and do not consider maintaining the flying stability of the magnetic head over a long period of time.

The purpose of the invention is to prevent modulation and to
An object of the present invention is to provide a magnetic recording medium in which the frictional force and attraction force of a magnetic head are reduced, and the flying stability of the magnetic head can be maintained for a long period of time.

Another object of the present invention is to provide a magnetic disk device and system equipped with a magnetic recording medium.

Still another object of the present invention is to reduce the flying height of the magnetic head to 0.1.
It is an object of the present invention to provide a magnetic disk device, a system, and a magnetic recording medium therefor that can be made to have a diameter of 5 μm or less and maintain flying stability for a long period of time.

[Means to solve the problem]

The magnetic disk device of the present invention essentially includes at least one magnetic disk having a magnetic layer and a surface protective layer on a substrate, opposed to the rotating magnetic disk with a small gap, and supported by a slider. A magnetic disk device comprising a magnetic head that rotates the magnetic disk, a rotating means that rotates the magnetic disk, and a magnetic head positioning means that moves and positions the magnetic head to a predetermined position on the magnetic disk. A magnetic disk device characterized in that a structure comprising the following (a) and (b) is formed below a magnetic layer.

(b) A plurality of continuous or discontinuous hills and grooves are provided, the width of the hill is 1 to 100 μm, the width of the groove is 1 to 100 μm, the height of the hill and the groove is 10 to 50 nm, and the pitch is 2 to 1
00 μm with substantially regular hills and grooves.

(b) Substantially irregular microgrooves with an average roughness of 10 nm or less are provided on the surface of the regular hills and grooves to control the orientation of the magnetic layer along the circumferential direction.

The present invention provides the above (a) on the surface of a magnetic recording medium.

By meeting the requirement (b), it is possible to orient the magnetic layer in the circumferential direction and prevent the modulation of the eight electrical forces, and it is possible to maintain stable levitation even if the flying height of the magnetic head is reduced. It is based on an investigation of the facts.

The effects based on (a) and (b) promote the orientation of the magnetic layer in the circumferential direction, thereby preventing modulation, and making it possible to set the flying height of the magnetic head to be extremely small. Furthermore, the flying height of the magnetic head can be maintained approximately constant.

None of the prior art has proposed a structure that satisfies both of the above requirements. In particular, the importance of the above-mentioned technique becomes particularly significant as the flying height of the head is reduced to increase the recording density of a magnetic disk device, for example, when the flying height is set to 0.15 μm or less.

It is effective to form the grooves having the shape (a) above on the surface of the nonmagnetic substrate or the surface of the protective layer constituting the magnetic recording medium.

Here, the nonmagnetic substrate is a substrate formed by forming a NiP layer on an Al alloy substrate, or a substrate made of glass, ceramics, hard plastics, or the like. The protective layer is carbon (
C film formed by sputtering, diamond-like C film, etc.)
, silicon dioxide, metal carbides, metal nitrides, metal oxides.

A metal boride film or a mixed film thereof can be applied.

Further, the groove having the shape (b) above needs to be formed on the substrate surface before forming the magnetic layer. The surface of the substrate before forming the magnetic layer refers to the N
This is the surface of the iP layer, and is preferably formed on the surface of the substrate made of glass, ceramics, hard plastics, etc.

Furthermore, a layer containing chromium as a main component, for example, may be formed between the substrate surface on which the grooves of (a) and/or (b) are formed and the magnetic layer.

[Effect]

According to the present invention, firstly, only the hill portion directly faces the head, and the area ratio of the magnetic recording medium in contact with the head can be reduced, so that the frictional force and attraction force with the head can be reduced. . Second, by regularly arranging the hills that are formed, there is little variation in the flying height of the head, and the flying stability of the head can be ensured over the entire surface of the magnetic recording medium.
It is possible to prevent output fluctuations due to fluctuations in flying height. Thirdly, the minute grooves along the circumferential direction formed in the hills and grooves contribute to the shape magnetic anisotropy of the magnetic layer, and the coercive force and square shape in the circumferential direction relative to the radial direction. The ratio is large, and output fluctuations due to modulation are extremely small.

As described above, according to the present invention, the frictional force and adsorption force with the head can be reduced, output fluctuations can be prevented, and stable flying of the head can be ensured, resulting in high recording and reproducing accuracy. It is possible to obtain a magnetic recording medium that can cope with a reduction in the flying height of a head and a magnetic recording device using the same.

Furthermore, fourthly, if the formed hills are arranged regularly so that fine dust attached to the head or magnetic recording medium can be quickly removed, head crashes due to fine dust are less likely to occur, and the head can be maintained for a long time. It is possible to ensure floating stability.

The present invention provides a magnetic recording medium and a magnetic recording medium that can ensure stable flying of the head over a long period of time, have high recording/reproducing accuracy, can cope with the reduction in the flying height of the head due to higher recording density, and have long-term durability. A magnetic recording device using the same can be obtained.

〔Example〕

The present invention will be explained in detail below.

The present inventors investigated the surface microstructure that contributes to the shape magnetic anisotropy of the magnetic layer, or the groove shape (groove width, groove depth, groove angle, etc.).
The present invention was achieved by discovering that the pitch, etc.) and the groove shape, which contributes to reducing the adhesive force and frictional force between the magnetic head and the magnetic recording medium, are different. In other words, the basic idea of the present invention is to create magnetic recording with different shapes of the surface microstructure that contributes to the magnetic anisotropy of the magnetic film, the adhesive force between the magnetic head and the magnetic recording medium, and the grooves that contribute to the reduction of the frictional force. The purpose is to form it on the surface of the medium.

In order to increase the coercive force and squareness ratio in the circumferential direction with respect to the radial direction of the magnetic recording medium, the magnetic film is, for example,
It is known that when forming by sputtering, it is effective to form grooves along the circumferential direction on the surface of the underlying substrate. The most common method is to deposit NiP on the Al alloy substrate surface.
This is a method in which a layer is formed, and circumferential grooves are formed on the layer by mechanical processing using abrasive grains and tape.

The grooves may be irregular and discontinuous in shape.

The magnetic recording medium formed by this method could be used without any problem in magnetic recording devices with a magnetic head flying height on the order of 0.2 μm, but it is possible to use it in high-density magnetic recording devices with a magnetic head flying height on the order of 0.1 μm. The inventors of the present invention have found that there are problems when used in a recording device. In other words, by a mechanical processing method using abrasive grains and tape, a groove shape is formed that satisfies both the magnetic anisotropy of the magnetic film in the circumferential direction and the adhesion and friction reduction of the magnetic head. It has been found that when the magnetic recording medium is exposed to a certain frequency, protrusions are formed on the surface of the magnetic recording medium, and the magnetic head comes into contact with the protrusions, causing a crash accident. For example, even when forming grooves with an average roughness of 10 nm measured with a stylus-type surface roughness meter,
A portion with a protrusion height (Rp) of 30 to 40 nm is always formed, and when the flying height of the magnetic head 1 is on the order of 0.1 μm, it is difficult to contact that portion when the flying height of the magnetic head changes. confirmed.

Figure 4 shows the relationship between the surface roughness of the magnetic recording medium, the minimum flying circumferential speed of the head, which is an index of the flying ability of the head, and the standard value of the frictional force between the head and the magnetic recording medium (based on the frictional force when Rp is 50 nm). Show relationships. From this figure, it can be seen that the frictional force and the flying ability of the head are in a contradictory relationship, and it is difficult to satisfy both characteristics with a single groove machining method.

Therefore, the present inventors reduced the adhesive force and frictional force between the magnetic head and the magnetic recording medium while maintaining the shape magnetic anisotropy of the magnetic film, and at the same time lowered the flying height of the magnetic head, for example, 0.
It was concluded that the shape between the magnetic recording media that can stably float even when the thickness is 1 μm satisfies the following (a) and (b).

(b) It has a plurality of continuous or discontinuous hills and grooves, and the width of the hill is 1 to 100 μm, the width of the groove is 1 to 100 μm, the height of the hill and groove is 10 to 50 nm, and the pitch is 2 to 100 μm. Provide regular hills and grooves.

(b) On the surface of regular hills and grooves, substantially irregular micro grooves with an average roughness of 1° nm or less are provided along the circumferential direction.

The effect of the structure (a) above is to reduce the adhesive force and frictional force between the magnetic head and the magnetic recording medium, and to make the magnetic head fly stably. The effect is to impart shape magnetic anisotropy in the circumferential direction to the magnetic layer.

The shape of the structure in (a) can be formed on the protective layer of a magnetic recording medium or on the surface of a non-magnetic substrate, but it must be arranged regularly and its height must be controlled within a specified value. It is important that As a result, the area ratio of the hills facing the head can be arbitrarily controlled over the entire surface, so that the flying height of the 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 rotation center of the magnetic recording medium, if the area ratio of the hill is kept constant within the size range of the Hent slider, the head can be moved to a certain track. When the magnetic recording medium is rotated while remaining at a fixed position, the head always faces the hill at approximately the same area ratio within the size range of the slider, making it possible to suppress fluctuations in flying height. In addition, if the area ratio of the hills is made to be almost constant over the entire surface of the hill forming part within the size range of the head slider, even when the magnetic recording medium is rotated and the head is moved, the head will not move along the slider. Within the range of the size of , the area ratio of the plane to the hill is always the same, and fluctuations in the flying height can be kept low over the entire surface. However, depending on the rotation of the magnetic recording medium, the linear velocity differs between the inner circumference and the outer circumference, so if necessary, the area ratio of the hills may be continuously changed little by little from the inner circumference to the outer circumference.

In addition, the hills formed on the surface of the protective layer and the nonmagnetic substrate are
It is desirable that it is discontinuous at least on the same circumference of the magnetic recording medium. This is because when the head is stationary and the magnetic recording medium is rotated, the head will intermittently move against a hill when viewed from one point, so even if minute dust adheres to the head, it will be easily removed. It is.

Further, the hills formed on the surface of the protective layer and the non-magnetic substrate are in the form of discontinuous lines or pits, and at least a part of the hill-free portion is within the movement area of the head, and the magnetic recording medium It is desirable that there is a smooth continuity from the inner circumference to the outer circumference. This is because even if fine dust enters between the head and the magnetic recording medium, the fine dust is likely to be removed toward the outer circumferential side by centrifugal force along the hill-free portion.

A specific hill arrangement that satisfies all of the above conditions is as follows. For example, linear or pit-shaped hills formed from part of a concentric circle or a spiral arc are regularly arranged over the entire surface of the magnetic recording medium with respect to the center of rotation or the center of a pattern intentionally shifted from the center of rotation. Therefore, it is preferable that the hills are arranged so that at least a part of the hill-free portion is smoothly continuous from the inner circumference to the outer circumference of the magnetic recording medium within the movement area of the head. For example, on an arc concentric with the rotation center of the magnetic recording medium with a width of 2 μm and a pitch of 60 μm, an arc-shaped convex portion with a central angle of 0.02 degrees is placed.
Convex portions are formed on the entire surface of the magnetic disk by sequentially shifting them toward the inner circumference by 2 μm in the direction of rotation of the magnetic disk. It is desirable that the arc rows on the spiral are offset by at least 4 degrees with respect to the concentric circles. The reason for this is to avoid overlapping with the magnetic recording trunk and affecting the recording/reproduction signal.

Next, the groove having the shape (b) needs to be formed on the surface of the nonmagnetic substrate before forming the magnetic layer. The grooves may be irregular and discontinuous, but must be entirely along the circumferential trunk direction. The average roughness (Ra) of the groove measured with a stylus-type surface roughness meter is 10 nm or less, preferably 3-3
8 nm, the height between the hills and grooves is less than 20 nm, preferably 5-15 nm. Furthermore, the pitch of the grooves is on average 0.0
The thickness is preferably 1 to 0.1 μm. Groove pitch is 0
．． If the thickness is 1 μm or more, the effect on the shape magnetic anisotropy of the magnetic film is small.

In the case of an Al alloy substrate, the groove in the shape of (b) is a NjP layer,
Further, in the case of a substrate made of glass, ceramics, hard plastic, etc., it can be formed directly on the surface of the substrate. In one embodiment of the present invention, a substrate can be obtained by forming grooves in the shape of the substrate (A).

If necessary, apply a layer containing chromium, etc. to these substrates.
After forming a 500 nm thick magnetic layer, for example, after forming a 10 to 50 nm magnetic layer containing cobalt as a main component, a 5 to 50 nm protective layer and a 5 to 20 nm lubricating layer can be formed to obtain a magnetic recording medium. . For the protective layer, carbon, silicon dioxide, metal carbide, metal nitride, metal boride, metal oxide, etc. are used.

Furthermore, another embodiment of the present invention includes NjP on an Al alloy substrate.
A layered substrate or glass.

After forming only grooves in the shape of (b) in ceramics, hard plastics, etc., if necessary, after forming a layer containing chromium, etc. to a thickness of 50 to 500 nm on these substrates, for example, a layer containing cobalt as the main component is formed. A magnetic layer is formed to a thickness of 10 to 50 nm. After forming a 10-50 nm protective layer on it,
A magnetic recording medium can be obtained by forming grooves in the shape of (A) on the surface of the protective layer and forming a lubricating layer thereon.

A specific method for forming the grooves (a) and (b) according to the present invention is as follows.

To form grooves in the shape of (a) on a mirror-finished non-magnetic disk, or to form hills on the surface of the protective layer, use lithography technology to form a desired mask pattern on the non-magnetic disk or the surface of the protective layer. A preferred method is to perform etching after formation, selectively and uniformly etching only the portions not covered by the mask pattern to a certain depth, and then removing the mask pattern. The etching method used here is selected from b-ly etching such as ion milling, reactive plasma treatment, wet etching, and the like.

Another method for forming hills is to form a film of a substance that can be hardened by beam irradiation with light, laser, or charged particles on a nonmagnetic disk or the surface of a protective layer, and then irradiate the film surface with light, laser, or charged particle beams. Alternatively, it can be similarly formed by regularly irradiating a beam of charged particles to a desired position to partially cure it, and then removing the uncured portion.

Note that other methods than this method may be used as long as the final shape of the hill obtained is desired. For example, a photodegradable organometallic gas is introduced onto a mirror-finished nonmagnetic disk with a magnetic layer and a protective layer formed thereon, and a laser beam is periodically and regularly irradiated onto the disk. do,
A similar shaped hill can also be formed by a method of selectively depositing metal (laser CVD method).

To form a groove in the shape of (b), for example, a micro groove in the circumferential direction is formed on the substrate surface while rotating the substrate using a cutting fluid containing diamond particles with an average particle diameter of 1 μm and a polishing tape. be able to.

FIG. 3 shows an outline of the magnetic disk device. The magnetic disk drive includes components 8 to 15 in FIG. 3 and a voice coil motor control circuit. 8 is a base, and 9 is a spindle. A plurality of disc-shaped magnetic disks 11 are attached to one spindle as shown in the figure. Although FIG. 3 shows an example in which five magnetic disks 11 are provided on one spindle, the number is not limited to five. Further, a plurality of magnetic disks 11 may be installed on one spindle 9 in this way. 10 is spindle 9
This is a motor for driving the magnetic disk and rotating the magnetic disk, that is, a magnetic disk rotation control means. 12 represents a data magnetic head, and 12a represents a positioning magnetic head.

13 is a carriage, 14 is a voice coil, and 15 is a magnet. The voice coil 14 and the magnet 15 constitute a voice coil motor. And 13, 14.
Head positioning is performed by 15 elements. Therefore, the components 13, 1, 4, and 15 are collectively referred to as the magnetic head positioning mechanism. Voice coil 14 and magnetic heads 12 and 1
．． 2a is connected via a voice coil motor control circuit.

In FIG. 3, the host device indicates, for example, a computer system, which has a function of processing information recorded on a magnetic disk device.

In this recording and reproducing method, the magnetic head and the magnetic recording medium are in contact before the start of operation, but by rotating the magnetic recording medium, a space is created between the magnetic head and the magnetic recording medium, and recording is performed in this state. Perform playback. At the end of the operation, the rotation of the magnetic recording medium stops, and the magnetic head and the magnetic recording medium are brought into contact again. This is called the contact start/stop method, hereinafter referred to as the C8S method.

<Example 1> A 15 μm thick N1-P base film was formed on the surface of an aluminum alloy disk having an outer diameter of 5.25 inches by electroless plating, and the base film was polished to 10 μm.

Mirror finishing was performed so that the average roughness (Ra) was 2 nm or less and the maximum roughness (Rmax) was 5 nm or less as measured with a stylus surface roughness meter.

Next, using a polishing liquid containing diamond abrasive grains with an average grain size of 1 μm and a polishing tape, grooves were formed in the NiP surface along the circumferential direction while rotating the substrate. The groove shape was evaluated using a stylus-type surface roughness meter (for example, Talystep) and a scanning tunneling microscope (STM). The average roughness (Ra) measured in the radial direction was 8 nm, the average pitch was 0.08 μm, and the maximum roughness (R++ax) was less than 12 nm.

A positive resist (Tokyo Ohka, 0FPR800) was applied to the surface of the NiP layer on the substrate thus obtained to a thickness of about 0.5 μm, and a photo resist was formed in the shape shown in Figure 1 so that only the hill portions did not transmit light. After exposure with a mask in close contact, development was performed to form a mask pattern on the surface of the NiP layer in the shape shown in FIG. 1, with resist remaining only in the hill portions.

The entire surface of this disk was irradiated with an argon ion beam for 60 seconds using an ion milling device to uniformly etch the areas where no mask pattern was formed, and then the mask pattern was removed using a resist removal solution. Regularly arranged hills were formed on the surface of the NiP layer.

On the thus obtained substrate, a 0.2 μm thick intermediate layer mainly composed of Cr, a 4.0 nm thick CoNiCr magnetic layer, and a 20 nm thick C protective layer were formed by sputtering, and then a perfluoropolyether based lubricant layer was formed. of lubricant about 5
A magnetic recording medium was fabricated by coating the film. Here, the thinner the thickness of the intermediate layer mainly composed of Cr, the more faithfully it will reflect the groove shape formed on the NiP layer, but this layer will affect not only the orientation of the magnetic layer but also the magnetic head. Since it also contributes to sliding resistance, the film thickness is preferably 0.05 to 0.5 μm. Here, the intermediate layer mainly composed of Cr is
Metallic chromium or chromium alloy (e.g. Cr and Ti)
, Mo, V, etc.).

FIG. 2 shows a schematic diagram of the cross-sectional structure in the radial direction of the magnetic recording medium of this example. In this example, the area ratio of the hills is 25% over the entire surface.

As the sputtering method, a DC sputtering method, an RF sputtering method, etc. can be applied, but a DC sputtering device is often used as a mass production device from the viewpoint of device cost. Further, for the handling of the substrate, a stationary facing film forming method using a single wafer method, a conveying film forming method using a substrate carriage, etc. are applied. In particular, it is effective to form microgrooves in the circumferential direction on the NiP surface in order to reduce modulation.
In order to prevent the formation of protrusions required for magnetic recording media that can be used in magnetic disk devices with magnetic head flying heights on the order of 0.1 μm, the average roughness must be at least 10 nm.
It is important to note the following.

The Ar pressure during sputtering is, for example, 3 to 10 m
Torr, but the ultimate pressure of the sputtering equipment is to reduce impurity gases such as moisture as much as possible.

Desirably, it is 3×10 −7 Torr or less. Further, although the type of magnetic layer is not essential to the present invention, it can be formed using a target containing cobalt as a main component. For example, when a magnetic layer is formed using a CoaoNix5Cr5 target, the coercive force and squareness ratio in the circumferential direction and radial direction are 1600, 10000e, and 0.9, 0, respectively.
．． 85, and the fluctuation (modulation) of the recording signal in the circumferential direction was within ±5%.

Furthermore, the minimum guaranteed flying height of the magnetic head of the magnetic recording medium formed in this example is 0.045 μm or less, and a highly reliable magnetic recording device can be obtained even with a flying height of the magnetic head on the order of 0.1 μm. Ta.

<Example 2> As in Example 1, a 15 μm thick N1-P base film was formed on the surface of an aluminum alloy disk with an outer diameter of 5.25 inches by electroless plating, and the base film was polished to 10 μm. Mirror finishing was performed so that the average roughness (Ra) was 2 nm or less and the maximum roughness (R-a, x) was 5 nm or less as measured with a stylus surface roughness meter.

Next, using a polishing liquid containing diamond abrasive grains with an average grain size of 1 μm and a polishing tape, grooves were formed in the NiP surface along the circumferential direction while rotating the substrate. The groove shape was evaluated using a stylus-type surface roughness meter (for example, Talystep) and a scanning tunneling microscope (STM). The average roughness (Ra) measured in the radial direction is 8 nm, the average pitch is 0.08 μm,
The maximum roughness (R+may) was 12 nm or less.

On the substrate thus obtained, a 0.2 μm thick CoNiCr magnetic layer and a 30 nm C protective layer were formed as an intermediate layer containing Cr by the same sputtering method as in Example 1.

A positive resist (
Apply approximately 0.5 μm of Tokyo Ohka, 0FPR800),
After exposure with a photomask formed in the shape shown in Figure 1 so that only the hill portions do not pass through, the photomask is developed, and the hill part in the shape shown in Figure 1 is placed on the surface of the C protective layer. A mask pattern was formed in which only some parts of the resist remained.

The entire surface of this disk was irradiated with an argon ion beam for 30 seconds using an ion milling device to uniformly etch the areas where no mask pattern was formed, and then the mask pattern was removed using a resist removal solution. Regularly arranged hills were formed on the surface of the C protective layer.

The height of the hill was measured at ten arbitrary points on the surface of the magnetic recording medium using an STM and a stylus surface roughness meter, and the height of the hill was 15 nm at every measurement point.

After forming grooves on the surface of the protective film in this way.

A magnetic recording medium was obtained by applying a lubricant. The flying ability and modulation characteristics of the magnetic head of this medium were as excellent as in Example 1.

<Example 3> A magnetic recording medium was produced in the same manner as in Example 2, except that SiC was formed to a thickness of 20 nm by sputtering as a protective layer, and the etching time by ion milling to form hills was 20 seconds. . The height of the hill was measured at ten arbitrary points on the surface of the magnetic recording medium using a stylus type surface roughness meter. As a result, the height of the hill was 10 nm at every measurement point.

The flying ability and modulation characteristics of the magnetic head of this medium were as excellent as in Example 1.

<Example 4> As a protective layer, a C film (so-called 1-C
), and a magnetic recording medium was produced in the same manner as in Example 2, except that the etching time by ion milling to form hills was 1 minute. The height of the hill was measured at ten arbitrary points on the surface of the magnetic recording medium using a stylus type surface roughness meter. As a result, the height of the hill was 10 nm at every measurement point.

The flying ability and modulation characteristics of the magnetic head of this medium were as excellent as in Example 1.

<Example 5> As a substrate, the average roughness (R
a) A magnetic recording medium was produced in the same manner as in Example 1, except that a tempered glass disk with an outer diameter of 5.25 inches that was mirror-finished to have a roughness of 3 nm or less and a maximum roughness (Rmax) of 8 nm or less was used. did. The height of the hill was measured at ten arbitrary points on the surface of the magnetic recording medium using a stylus type surface roughness meter. As a result, the height of the hill was 10 nm at every measurement point.

The flying ability and modulation characteristics of the magnetic head of this medium were as excellent as in Example 1.

<Comparative Example 1> While rotating the same substrate as in Example 1, the surface of the NiP layer was polished by pressing a puff containing abrasive grains to form grooves and grooves along the circumferential direction.

The thus obtained substrate surface was measured with a stylus surface roughness meter to have an average roughness (Ra) of 10 nm and a maximum roughness (Rmay).
It was 35 nm.

An intermediate layer was formed on this substrate in the same manner as in Example 1.

A magnetic layer and a protective layer were formed by a sputtering method, and a perfluoropolyether lubricant was applied as a lubricant layer to a thickness of about 5 nm on the protective layer to prepare a magnetic recording medium.

The magnetic recording medium prepared in this comparative example had excellent orientation characteristics in the circumferential direction of the magnetic film as in Example 1, had almost no modulation, and was a medium with excellent electrical properties. However, when we measured the flying characteristics using the magnetic head of the A, QzOs-TiC composite ceramic slider, we found that
The limit flying height is approximately 0.0 because the slider contacts the convex part.
8 μm, and could only be applied to magnetic disk drives with a flying height on the order of 0.15 μm.

<Comparative Example 2> As in Example 1, an N1-P base film of 15 μm was formed on the surface of an aluminum alloy disk with an outer diameter of 5.25 inches by electroless plating, the base film was polished to 10 μm, and the base film was polished to a thickness of 10 μm. Mirror finishing was performed so that the average roughness (Ra) was 2 nm or less and the maximum roughness (R, a,) was 5 nm or less as measured by a needle-type surface roughness meter. On this substrate, an intermediate layer containing Cr 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 film was formed as a protective layer to a thickness of 40 nm by sputtering. While rotating this disk, the C protective layer was polished by about 10 nm by pressing a puff containing abrasive grains to form grooves along the circumferential direction. A magnetic recording medium was prepared by applying a perfluoropolyether lubricant to a thickness of about 5 nm as a lubricant layer on the surface of the disk thus obtained.

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

The medium produced in this comparative example had output fluctuations of 15% or more due to modulation, and its electrical properties were of poor quality. Additionally, the critical flying height of the magnetic head is approximately 0.07μ.
m, and it was found that a high-performance magnetic disk device could not be applied.

〔Effect of the invention〕

According to the present invention, a magnetic recording medium with small 8-force fluctuations due to modulation, low frictional force and adsorption force with the head, guaranteeing flying stability of the head even at a low flying height, and with little characteristic deterioration over a long period of time can be created. It can be manufactured with good reproducibility, and furthermore, a high-performance magnetic disk device using the present magnetic recording medium can be provided.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment showing the arrangement of hills formed on a non-magnetic substrate of the present invention, and FIG. 2 is a radial cross-sectional structure of the magnetic recording medium of FIG. 1 of the present invention. FIG. 3 is a block diagram of the magnetic disk device, and FIG. 4 is a characteristic diagram showing the relationship between surface roughness, minimum flying circumferential speed of the magnetic head, and frictional force. Agent Patent attorney Katsuma Ogawa ・1) ＼No. 8 Diagram Diagram

Claims (1)

[Claims] 1. At least one magnetic disk having a magnetic layer and a surface protective layer on a substrate, facing the rotating magnetic disk with a small gap,
A magnetic disk device comprising: a magnetic head 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. In the above, the magnetic disk is provided with substantially irregular microgrooves along the circumferential direction and substantially regular grooves having a period larger than an average pitch of the microgrooves and the valleys. A magnetic disk device featuring: 2. At least one magnetic disk having a magnetic layer and a surface protective layer on a substrate, facing the rotating magnetic disk with a minute gap of 0.03 to 0.2 μm, and supported by a slider. A magnetic disk drive comprising: a magnetic head that rotates the magnetic disk; and a magnetic head positioning device that moves and positions the magnetic head to a predetermined position on the magnetic disk. The following (a) and (
A magnetic disk device characterized in that a structure comprising (b) is formed. (b) A plurality of continuous or discontinuous hills and grooves are provided, the width of the hill is 1 to 100 μm, the width of the groove is 1 to 100 μm, the height of the hill and the groove is 10 to 50 nm, and the pitch is 2 to 1
00 μm substantially regular structure. (b) Substantially irregular microgrooves having an average roughness of 10 nm or less and extending along the circumferential direction on the surface of the regular hills and grooves. 3. A magnetic disk device, wherein a layer containing chromium is formed to a thickness of 50 to 500 nm on the magnetic disk according to claim 2, and a magnetic layer is formed on the layer. 4. A magnetic disk device using a substrate having a NiP layer of 8 to 30 μm on the surface of the Al alloy substrate as the nonmagnetic substrate according to claim 3. 5. A magnetic disk device using a substrate selected from tempered glass, crystallized glass, hard plastic, and ceramic substrates as the nonmagnetic substrate according to claim 3. 6. At least one magnetic disk having a magnetic layer and a surface protective layer on a substrate, a magnetic head facing the rotating magnetic disk with a small gap and supported by a slider, rotating the magnetic disk. and a magnetic head positioning means for moving and positioning the magnetic head to a predetermined position on the magnetic disk, wherein the magnetic disk has a non-magnetic substrate surface with an average roughness of 10 nm.
After forming a surface fine shape that is substantially irregular and controls the orientation of the magnetic layer along the circumferential direction in the circumferential direction,
A magnetic disk device, wherein after forming a magnetic layer and a protective layer, the groove according to claim 2 (a) is formed on the surface of the protective layer. 7. A magnetic disk device using an Al alloy substrate on which a NiP layer is formed as the nonmagnetic substrate according to claim 6. 8. As the non-magnetic substrate according to claim 6, tempered glass;
A magnetic disk device using a substrate selected from crystallized glass, hard plastic, and ceramic substrates. 9. The magnetic disk according to claims 1 to 8,
50-500 nm layer containing at least chromium, 20-500 nm
A magnetic disk device comprising a 50 nm cobalt-containing magnetic layer, a 10 to 40 nm carbon protective film layer, and a lubricating layer. 10. The magnetic disk device according to claim 1, wherein the ratio (Hcθ/Hcr) between the circumferential holding force Hcθ and the radial holding force Hcr is 1.1 or more.