JPH07254146A - Magnetic disk, its production and magnetic disk device - Google Patents

Abstract

PURPOSE:To obtain a magnetic disk having an improved recording density and reliability on sliding resistance by providing the surface of a magnetic recording layer with fine projections having a skirted and substantially pyramidal shape. CONSTITUTION:This magnetic disk 71 has a nonmagnetic substrate which is the constituting element of the disk and the magnetic recording layer consisting of a ferromagnetic material disposed on the nonmagnetic substrate. The surface of the magnetic recording layer is provided with a nonmagnetic layer having the fine projections 6 having the skirted and substantially pyramidal shape directly or via a nonmagnetic layer having a smooth surface. As a result, the surface having low tacky adhesiveness is realized even with the low projections and the reliability on the sliding resistance is improved. Further, the surface of the magnetic recording layer is made smoother than the conventional projection forming surface, by which the noises at the time of recording and reproducing are decreased and a high effect is obtd. in the high-density recording of the magnetic disk.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk used in a storage device such as a computer, a method for manufacturing the same, and a magnetic disk device, and more particularly, a magnetic disk suitable for high recording density, and a method for manufacturing such a magnetic disk. The present invention relates to a magnetic disk device having such a magnetic disk.

[0002]

2. Description of the Related Art For magnetic disks used in storage devices such as computers and workstations, there has been an increasing need for smaller size and larger capacity in recent years, and in order to meet this, it is essential to dramatically improve the recording density. Has become. The first condition for this is to reduce the distance between the magnetic head for recording and reproduction and the recording layer of the magnetic disk, and specifically, to reduce the flying height of the magnetic head,
It is necessary to reduce the thickness of the protective layer that protects the recording layer and smooth the surface of the magnetic disk. But,
When the thickness of the protective layer is reduced, the strength is lowered, which causes a head crash. Further, the smoothing of the surface sometimes increases the contact area between the magnetic disk and the magnetic head, and causes a trouble such as adhesion due to sticking of a lubricant or the like. As a result, the sliding resistance deteriorates and a head crash may occur. Therefore, it is necessary to improve the strength of the magnetic disk at the same time.

In order to prevent the above-mentioned adhesion, the magnetic disk currently used is subjected to a roughening treatment called a texture treatment on the substrate surface by machining. However, such unevenness of the substrate surface increases variations in the distance between the magnetic head element surface and the recording layer, and as a result, increases the noise component of the recording / reproducing signal and hinders high-density recording. From the viewpoint of recording and reproduction, the surface of the recording layer should be as smooth and flat as possible. A protective film having irregularities for simultaneously filling such a smooth recording layer and a low-adhesion surface has been proposed, and many manufacturing methods therefor have been proposed.
For example, Japanese Patent Application Laid-Open No. 62-22241 discloses a magnetic disk in which the surface of the protective film has irregularities within a range not exceeding its thickness. As means for providing irregularities, a polishing method using sandpaper or the like, a wet etching method, A sputter etching method, an oblique vapor deposition method and the like are disclosed.

[0004]

The above-mentioned prior art is effective in reducing the adhesiveness due to the unevenness of the protective film surface, but the protective film thickness is made thinner to further improve the recording density, and the magnetic head and recording There is a problem that it is difficult to further reduce the layer spacing. In order to form a structure that can avoid sticking with an ultra-thin protective film,
For example, it is preferable that the interval between adjacent protrusions be 1 micron or less. By doing this, the number of contact points with the head increases, so a true magnetic head that sums the areas of the individual contact points,
It is necessary to make the contact area between magnetic disks as small as possible.

However, if the area of each contact point is simply reduced, it is possible to extend the prior art, but there is a problem that the area of the magnetic head itself is also reduced. That is, when the head is operated with a lower flying height than the conventional one, contact between the magnetic head and the magnetic disk is inevitable, and the magnetic head needs to have a low load in order to reduce the impact at this time. Since the magnetic head receives a levitation force due to air resistance, a low-load magnetic head floats up if the area of the slider surface is large. Therefore, for example, the air floating type needs to have an area of 1 mm ² or less, preferably 0.1 mm ² or less, and the contact type needs to have an area of 0.01 mm ² or less, preferably about 0.001 mm ² . In order to make uniform contact with such a minute area, the distribution of the protrusions on the disk surface must be very dense, the average spacing between the protrusions is 1 micron or less, and the distribution is very uniform. It must be free of space and dense. The above conventional technique has a problem that such a shape cannot be obtained.

A first object of the present invention is to provide a magnetic disk having improved recording density and sliding resistance. A second object of the present invention is to provide a method for manufacturing such a magnetic disk. A third object of the present invention is to provide a magnetic disk device having a magnetic disk with improved recording density and sliding resistance.

[0007]

In order to achieve the above first object, a magnetic disk of the present invention comprises a non-magnetic substrate, a magnetic recording layer made of a ferromagnetic material and provided on the non-magnetic substrate. The non-magnetic layer is provided on the magnetic recording layer and has minute protrusions with a substantially polygonal pyramid having a skirt.

The non-magnetic layer having fine protrusions may be provided directly on the magnetic recording layer, or a non-magnetic layer having a smooth surface may be provided on the magnetic recording layer. Good. The distance between adjacent protrusions is 100 nm to 1
It is preferably in the micron range. Further, the protrusion may be provided only in a desired region on the magnetic recording layer.

As described above, the size, height, and distribution of each of the protrusions poses a problem, but when extremely small protrusions are closely arranged, there is also a preferable shape for the protrusions. That is, in the case of a flat protrusion, the contact area at the apex portion becomes large, and the total contact area increases, and it becomes impossible to suppress adhesion. Therefore, sharp protrusions are better in this respect, but if they do so, the individual protrusions will weaken and will be destroyed. The broken pieces become foreign matters and cause a crash. That is, it is most preferable that the skirt has a wide hem and the apex has an acute angle. Further, if the distribution is sparse or dense, the running of the magnetic head becomes unstable. Therefore, it is preferable that the distribution is uniform, and it is more preferable that the distribution is regular. However, even if it is said to be regular, if it is regular in the circumferential direction, a certain portion of the head will selectively slide and shorten the life, so it is preferable to be random in the circumferential direction. Further, if the heights of the vertices vary, the heads will feel as protrusions from the viewpoint of the running performance of the head, so a uniform height is preferable.

As the non-magnetic substrate, for example, a substrate having a diameter of 1 to 10 inches is used, and the material thereof is NiP plated aluminum, glass, carbon, plastic or the like, and does not depend on the material. However, it is preferable to use glass or carbon in terms of easiness of flattening, impact strength, lightness and the like. The smoothness is an important point, and it is preferable that the surface roughness of the substrate is as smooth as possible and the waviness is small.
This is because a rough substrate or a substrate with undulations cancels the effect of the projections and depressions. At least the center line average roughness needs to be equal to or less than the height of the fine protrusions, preferably 5 nm or less, and more preferably 1 nm or less. The lower limit of the center line average roughness is not particularly limited and may be zero, but in practice, one having a thickness of 0.1 nm or more is used.

It is preferable that an underlayer is provided on the non-magnetic substrate, and a magnetic recording layer is further provided on the underlayer. As the magnetic recording layer, a ferromagnetic alloy thin film is used. For example, CoCr, CoCrTa, CoCrPt, CoCrV,
CoCr alloys such as CoCrMo, CoNi, CoNiZ
A CoNi-based alloy such as r, or a quaternary alloy in which a fourth element such as Si, P, or Ta is further added to these is used. The present invention does not depend on the material of these underlayer and magnetic recording layer, and any material can be used, but the surface roughness thereof has an influence, and it is preferable that the material is as smooth as the substrate. Specifically, it is necessary that the roughness is smaller than the height of the protrusion, and the center line average roughness is preferably in the range of 0.1 nm to 5 nm.
More preferably, it is in the range of 0.1 nm to 1 nm.

The nonmagnetic layer having a smooth surface on the magnetic recording layer may not be provided as described above, but it is preferable to provide it because it has an effect of preventing corrosion of the magnetic recording layer even if it is thin. It is preferable to select a material that prevents corrosion of the magnetic recording layer and has high strength against contact with the magnetic head, such as amorphous carbon, oxides such as SiO ₂ , TiO ₂ , and ZrO ₂ .
It can be selected from carbides such as SiC and TiC. In particular, a carbon-based material is preferable because it has both durability and lubricity. Among the carbon-based materials, what is called diamond-like carbon is the most preferable because it is dense and has high durability, and has an insulating property and a high anticorrosion effect.

In order to achieve the second object,
The method for manufacturing a magnetic disk of the present invention comprises:
At least a magnetic recording layer made of a ferromagnetic material is provided, and a particle layer composed of particles that are substantially in close contact with each other is formed on the magnetic recording layer. Using this particle layer as a mask, protrusions are formed in at least a desired region. The non-magnetic layer is formed, and then the particle layer is removed. As described above, it is preferable to provide a non-magnetic layer having a smooth surface. Therefore, after providing the magnetic recording layer, a non-magnetic layer having a smooth surface is formed on the entire surface of the magnetic recording layer, and then the particles are formed. It is preferred to form layers.

This manufacturing method will be described below by showing preferable specific steps. The cross-sectional structure of the non-magnetic substrate in each step is shown in FIG. The shape of the finally obtained magnetic disk is shown in FIG. Step 1: A step of preparing a smooth non-magnetic substrate 1 and removing contaminants and foreign substances by washing (FIG. 1A). Step 2: A step of forming the underlayer 2, the magnetic recording layer 3, and the nonmagnetic layer 4 having a smooth surface on the nonmagnetic substrate 1 (FIG. 1B). Step 3: A step of uniformly adhering particles 5 of a desired size onto the smooth surface of the non-magnetic layer 4 (FIG. 1 (c)). Step 4: A step of depositing a nonmagnetic layer made of the same or another material and having projections 6 on the surface of the nonmagnetic layer to which particles are attached (FIG. 1D). Step 5: A step of removing the particles (FIG. 1 (e)). Step 6: A step of forming a lubricating layer 7 by applying or adhering a material having lubricity on the surface of the non-magnetic layer (FIG. 1 (f)). If necessary, a step of removing the abnormal protrusion may be added after the step 5 or 6.

The cross-sectional shape of the protrusions present on the surface of the substrate is
As shown in the front view and the side view in FIGS. 3A and 3B, it has a triangular pyramid shape with a skirt. Therefore, the contact area between the protrusion and the magnetic head can be made extremely small, and the protrusion exhibits high strength against a lateral force. This shape depends on the shape of the gap of the particle mask and the film forming method, as shown in FIG.
In some cases, it may be a quadrangular pyramid or a polygonal pyramid having more vertices. The distribution depends on how the particles are arranged, but when the spherical particles are densely packed, the protrusions are regularly arranged at the positions of the regular hexagonal vertices as shown in the enlarged view of FIG. 2, which is the most preferable. It becomes an array.

The non-magnetic substrate used in step 1 is as described above. Cleaning is to prevent errors due to the presence of foreign matter or contamination, sliding accidents, corrosion, etc.The specific method differs depending on the substrate material, but for example, scrub cleaning with detergent, ultrasonic cleaning, spray cleaning, pure water It is performed by combining the steps of finishing cleaning, drying, etc.

Step 2 is preferably performed using an in-line continuous film forming apparatus, and a large number of non-magnetic substrates are arranged once in a single-wafer film forming apparatus or a holder for transporting non-magnetic substrates one by one to form a film. Any of the methods of forming a film on the substrate can be used. Immediately before film formation, a substrate heating step and a surface oxide film removal or adsorbed water removal step by plasma treatment or the like may be performed. This step may be performed on only one side. The heating of the substrate during film formation is performed to control the crystal growth of the underlayer and the magnetic recording layer, and should be set to a temperature suitable for the material used.

The underlayer controls the crystal growth of the magnetic film, and Cr or its alloy is often used. The materials for the magnetic recording layer and the non-magnetic layer having a smooth surface are as described above. The non-magnetic layer having a smooth surface can be formed by a bias plasma chemical vapor deposition (CVD) method, an ion beam deposition, an ion beam sputtering, or the like, but it is easy in terms of productivity and has a uniform film thickness. A good plasma CVD method is suitable. In this case, a desired film quality can be obtained by mainly introducing a raw material gas such as hydrocarbon into a vacuum container and forming a film under the condition that the substrate side has a large negative potential with respect to plasma. To form this film on both sides of the substrate at the same time, see, for example, JP-A-63-20647.
The electrodes described in 1 may be used. Any kind of gas may be used as long as it can form a hard protective film containing carbon, and can be selected from the following, for example.

Saturated hydrocarbons such as methane, ethane, propane and butane. Unsaturated hydrocarbons such as ethylene, acetylene, propylene and butene. Aromatic hydrocarbons such as benzene, toluene and xylene. Methanol, ethanol,
Oxygenated hydrocarbons such as acetone and ethyl ether. Nitrogen-containing hydrocarbons such as acetonitrile and methylamine. CF
Fluorocarbons such as ₄ , C ₂ F ₆ , C ₂ F ₄ , and C ₆ F ₆ . CH
Fluorinated hydrocarbons such as ₃ F and C ₂ H ₂ F ₂ . A mixed gas of two or more kinds selected from the above gases. Above gas and Ar, H
Inert gas such as e, Ne, Xe or a mixed gas with oxygen, nitrogen, hydrogen and the like. It is preferable that the particles used in the step 3 have a constant size and a constant shape as much as possible, and it is particularly preferable that spherical particles have a uniform shape when they are lined up. When the non-magnetic material constituting the above is deposited, the peaks become flat, so the average particle size is preferably 1 micron or less. However, if it is too small, it becomes difficult to remove it by adsorbing it on the surface, and the non-magnetic material forming the projections is buried when it is deposited on it, so the lower limit is about 100 nm. The most preferable range is 200 to 500 nm, and at this time, protrusions with sharp apexes are formed.

As the material of the particles, oxides such as SiO ₂ and Al ₂ O ₃ and plastics such as Teflon and polypropylene are preferable, but other materials can be used as long as spherical particles having an appropriate size can be obtained. Anything is fine. However, since these particles will be removed later by washing, it is better to avoid particles that strongly adhere to the surface of the non-magnetic layer.

The particle layer is formed by dipping the substrate in a dispersion of particles in a solvent and pulling it up at a constant speed, spraying in which the above dispersion is sprayed in a mist state, or applying an electric charge to the particles by arc discharge or the like. An electrostatic coating method or the like can be used in which the electrostatic charge is applied and attracted to the surface of the substrate by static electricity to adhere.

Step 4 is sputtering, plasma CV
Although various methods such as D, vapor deposition, ion beam deposition, and ECRCVD can be used, it is desirable that the protrusions have high wear resistance, lubricity, and are dense, and are formed by sputtering or plasma CVD. The resulting amorphous carbon layer shows good performance. The same techniques and raw materials as disclosed in step 2 can be used for this formation.

It is due to the shadow effect of the particles that the projections having a skirted shape can be obtained by such a method. In the above film deposition method, atoms, molecules, ions, etc. are incident on the surface of the substrate at various solid angles, but when a film is formed through a space in which spherical or similar particles are densely arranged, it is incident with energy. Of the components, the components that are incident perpendicularly to the substrate surface are efficiently deposited, and the components with an angle hit the particles and do not reach the substrate. On the other hand, the components that reach the substrate by diffusion wrap around to the lower side of the particles and are deposited in a shape with a tail. These are combined to form a protrusion that has a skirt and a sharp apex. This shape is of course slightly different depending on the film forming method, and in a film forming method that has many vertical components with respect to the substrate, such as the bias plasma CVD method, the spread of the hem becomes slightly narrower than that of a method that has many diffusion components such as the sputtering method.

When the film is formed only in the contact start / stop region in this step, as shown in FIG. 4, in the portion that slides on the magnetic head, the total thickness of the non-magnetic layer and the protrusion becomes thick, and the thickness is appropriate. High durability due to unevenness,
Although the head does not stick, the non-magnetic layer, which is the protective film, can be made as thin as possible on the data side, and the gap between the magnetic head and the magnetic recording layer during read / write can be reduced, which is a great improvement in recording density. effective.

In the shape as shown in FIG. 4, the flying height of the magnetic head is equal to the flying height obtained from the mechanical calculation of the shape and relative speed of the magnetic head and the support system with reference to the plane of the dotted line in the figure. When the magnetic head is sought on the data surface, the flying reference surface becomes a smooth non-magnetic film surface, and the flying height on the data surface can be made lower than the protrusion height of the contact start / stop portion. Therefore, it is very effective in improving the recording density.

The partial film formation as described above can be formed by, for example, a method of forming a film by masking a portion other than a necessary portion. Also, EC
The plasma density of the required portion may be increased by R plasma or the like, or a method of narrowing the beam by an ion beam deposition method can be used.

In step 5, it is necessary to select an appropriate cleaning method depending on the type of particles used and the properties of the protrusions. Examples of methods that can be used include ultrasonic cleaning with pure water or a solvent, jet spray cleaning, and scrub cleaning.

Step 6 is a dipping method in which a disk substrate is dipped in a solution of a lubricant and pulled up at a constant speed, a spray method in which the lubricant solution is sprayed in a mist state, a lubricant solution is dropped on the disk substrate and a spin is performed to rotate the substrate. A coating method or the like can be used. Alternatively, a dry method such as vapor deposition of lubricant molecules in vacuum may be used.

The material of the lubricating layer is preferably a fluorinated polyether polymer, and a polymer having a molecular weight of 2000 to 10,000 is preferably used. Although the present invention does not depend on the type of the lubricating layer, it is better to use a specific lubricating layer in order to improve the sliding resistance of the magnetic disk. Particularly, an ester, a carboxyl group, an amide group or an amine group is added to the terminal. , Those having a polar group such as amine salt and azide group, and those capable of reacting and adhering to the surface of the protective layer are preferable.

Furthermore, in order to achieve the third object, the magnetic recording apparatus of the present invention comprises any of the above magnetic disks, and a holder for holding the magnetic disk.
It is arranged on the magnetic recording layer of the magnetic disk to record information,
It is composed of a magnetic head for reproducing, a moving means for moving the relative position of the magnetic head and the magnetic disk, and a control means for controlling these.

[0031]

The high recording density of the magnetic disk of the present invention and the reason why such a magnetic disk can be manufactured are as follows.
As is clear from the explanation already given, the summary is as follows. (1) Since the protrusions are densely and regularly arranged, uniform contact can be realized even with respect to the minute magnetic head. (2) Since the angle formed between the head surface of the contact portion and the slope of the protrusion is an acute angle, the meniscus effect of the lubricating layer can be reduced, which is effective in preventing adhesion. (3) Since the skirt of the protrusion is wide, the protrusion is less likely to be broken when the protrusion collides with the magnetic head. (4) Since the portion other than the protrusion is a smooth flat surface and the area of this flat portion occupies a large area, it is possible to prevent the flying posture of the head from fluctuating due to the presence of the protrusion and lower the flying height limit. (5) When the protrusion is provided only in the contact start / stop region, the head flying height on the data surface can be made lower than the height of the protrusion.

In the above-mentioned manufacturing method, a particle layer is formed,
Since the projections are formed by using this as a mask, the projections having substantially the same height and the above-described shape can be easily manufactured. Further, in the above-mentioned magnetic disk device, since the protrusion is provided only in the contact start / stop region, the head flying height on the data surface can be made lower than the height of the protrusion, so that the magnetic head and the magnetic recording layer can be made closer to each other. it can.

[0033]

EXAMPLES Examples of the present invention will be described below.

Example 1 A tempered glass disk substrate having a diameter of 1.8 inches was washed, and a Cr underlayer film of 50 nm, a CoCrTa magnetic film of 30 nm as a recording layer, and a nonmagnetic layer serving as a protective film were formed by a vacuum in-line continuous film forming apparatus. As a result, a carbon film of 10 nm was sequentially formed. Next, this substrate was immersed in an alcohol solution in which ultrafine particles of SiO ₂ having an average diameter of 300 nm were dispersed, and was pulled up at a constant rate to form a single particle layer on the entire surface. After this substrate was dried, it was placed in another vacuum film forming apparatus to form a film having protrusions made of diamond-like carbon by the bias plasma CVD method. Next, when this substrate was washed to remove ultrafine particles,
Triangular pyramidal protrusions having a maximum height of 10 nm and having a hem drawn were formed on the entire surface. Furthermore, by immersing this substrate in a solution of perfluoropolyether lubricant and pulling it up at a constant speed,
A lubricating layer having an average thickness of 1 nm was formed.

A magnetic head having a slider portion with a length of 1 mm is loaded on the magnetic disk substrate manufactured as described above under a load of 2 gf.
And the relative speed between the magnetic disk and the magnetic head is 2
The magnetic disk was rotated so as to be m / s (drag test). When the rotation was maintained up to 5,000,000 rotations, the rotation was stopped and the surface of the magnetic disk and the head slider surface were observed. In both cases, there was no damage or adhesion of dirt, and the change in the dynamic friction coefficient was stable at a low level as shown by a in FIG. Further, when the limiting flying height was measured with the same combination of the magnetic disk and the magnetic head, it was 15 nm.

Further, contact start stop (CS
When the S) test was conducted, the friction coefficient was about 0.2 even after CSS of 100,000 times, and neither the magnetic disk nor the magnetic head was damaged. After that, the head was left standing for 24 hours, and the frictional force (adhesive force) at the start of rotation of the magnetic disk after that was 1 gf or less.
I found it was not sticky.

Comparative Example 1 A crystallized glass substrate having irregularities with an average roughness of 10 nm on the substrate surface was used, and after an underlayer, a magnetic film, and a carbon film were formed by the same process as in Example 1 to the same thickness, A lubricating layer having an average thickness of 1 nm was formed by immersing in a solution of perfluoropolyether lubricant and pulling it up at a constant speed.

When the same evaluation as in Example 1 was carried out on the magnetic disk thus manufactured, a crash occurred at 200,000 rotations in the drag test. Also,
The friction coefficient at that time begins to increase as shown in FIG. 6B due to the increase in the contact area due to the abrasion of the magnetic disk surface from the early stage after rotation, and becomes 1 immediately before the crash.
Increased to near. The limit flying height of this disk was 30 nm. 1,500 in CSS test
It crashed in a number of times and the dynamic friction coefficient fluctuated significantly.

<Examples 2 to 9> In the same manner as in Example 1,
However, magnetic disks were manufactured by changing the diameter of particles to be attached, the material, and the height of protrusions, and the same evaluation was performed. The results are summarized in Table 1. In Examples 2, 3 and 4, the size of the triangular pyramid is different, but the height is the same. In addition, Example 5,
In Nos. 6 and 7, the height of protrusions was changed by changing the processing time of bias plasma CVD. All showed good characteristics.

[0040]

[Table 1]

<Comparative Examples 2 and 3> In the same manner as in Example 1,
However, magnetic particles were manufactured by making the size of the particles to be adhered extremely large or small, and the same evaluation as in Example 1 was performed. The results are shown in Table 1 by Roman numerals II and III. When the particles were large like this, sticking occurred, and when the particles were small, the particles crashed. This is because the latter case makes it difficult to wash the particles.

<Comparative Example 4> As in Example 1, a base film and a magnetic film having the same thickness are provided, a carbon film having a thickness of 20 nm is formed, and then a particle layer is not used. The surface was scratched by mechanical polishing with a diamond abrasive to form fine irregularities. After applying the lubricant, the same evaluation as in Example 1 was performed. The result was an instantaneous crash, and the initial friction coefficient was about 0.5, which was very large.

<Example 10> In the same manner as in Example 1, a magnetic disk was manufactured by changing the method of forming a film having projections to sputtering or reactive sputtering, and the shape of the projections was observed with an electron microscope. The same evaluation as 1 was performed. The shape of the protrusion was almost the same as in Example 1, and the results were all good as in Example 1.

<Embodiment 11> In the same manner as in Embodiment 1, except that plasma C is passed through a mask in which only the inner peripheral portion is opened.
By performing VD, a magnetic disk having protrusions with a height of 20 nm provided only on the inner peripheral portion was manufactured. This inner circumference is CS
S area. FIG. 7 is a schematic diagram of an embodiment of a magnetic recording device using such a magnetic disk. The magnetic disk 71 is held by a holder rotated by a motor, and a magnetic head 72 for writing and reading information is arranged corresponding to each magnetic film. The position of the magnetic head 72 with respect to the magnetic disk 71 is moved by an actuator 73 and a voice coil motor 74. Further, in order to control these, the recording / reproducing circuit 7
5, a positioning circuit 76, and a control circuit 77 are provided.

By this control circuit, the magnetic head 72 is stopped in the CSS area of the magnetic disk 71. When the magnetic head 72 was levitated, the head flying height on the CSS region was 5 nm from the tip of the protrusion. In this state, after the magnetic head was sought and moved to the data surface, the head flying height was measured and found to be 14 nm. When CSS and seek are repeated under these conditions, 100, 0
There was no crash even after the repetition of 00 times, and the signals could be read and written normally.

Example 12 A magnetic disk was manufactured in the same manner as in Example 1 except that the size of the particles to be adhered was 100 nm and the projections with a height of 10 nm were provided using this as a mask. On the other hand, a thin film magnetic head element was formed on the side surface, and the bottom surface was polished into a spherical shape with a radius of 10 mm.
A block made of C was fixed to a support spring, placed on the above disc, and rotated at a relative speed of 10 m / s with a load of 0.1 gf. When the disk and the head were observed after 1000 hours of rotation, there were slight sliding marks on the disk surface, but there was no damage, and the friction coefficient during this was also 0.15 or less. In addition, it was confirmed that signals were read and written during this period to operate normally. Therefore, it was found that the magnetic disk of the present invention can be applied to contact recording. A schematic diagram when this magnetic disk is applied to contact recording is shown in FIG. <Comparative Example 5> The magnetic disk disk used in Comparative Example 1 was combined with the magnetic head used in Example 12 to obtain Example 12.
When tested under the same contact recording conditions as above, the friction coefficient increased to 0.5 after 15 hours of rotation, and an output signal could not be obtained normally. When the magnetic disk and the magnetic head were observed, scratches were visually observed on the head surface, and when the disk surface was examined with an optical microscope, many abrasion marks and deposits were found.

In each of the above embodiments, the 1.8-inch disk substrate has been described as an example, but 1, 1.3, 2.5,
Substrate of other size such as 3.5 inch, NiP plated aluminum substrate, carbon substrate, plastic substrate, Ti, S
It is needless to say that the same effect can be obtained with substrates made of other materials such as i and other ceramic substrates. Further, although the film having the protrusions is formed on the carbon film, it may be directly formed on the magnetic film without forming the carbon film. Also in this case, the limit flying height, the number of CSSs, the amount of adhesion, etc. were good.

[0048]

As described above, according to the present invention, it is possible to realize a surface having a low adhesiveness even with a low protrusion, and it is possible to reduce noise during recording and reproduction by smoothing the surface of the magnetic recording layer. It has a great effect on increasing the recording density of the magnetic disk. Further, such a magnetic disk can be easily manufactured by using the particle layer as a mask. Further, in the magnetic disk device using the magnetic disk in which the projection is provided only in the contact start / stop zone and the data surface is smooth, the distance between the magnetic recording layer and the magnetic head can be made closer on the data surface.

[Brief description of drawings]

FIG. 1 is a sectional view of a magnetic disk in each step of a method of manufacturing a magnetic disk according to an embodiment of the present invention.

FIG. 2 is a front perspective view of a magnetic disk according to an embodiment of the present invention.

3A and 3B are a sectional view and a perspective view showing a shape of a protrusion of a magnetic disk according to an embodiment of the present invention.

FIG. 4 is a schematic diagram showing a positional relationship between a magnetic disk having protrusions provided only in a contact start / stop region and a magnetic head according to an embodiment of the present invention.

FIG. 5 is a schematic view of an example in which the magnetic disk of one embodiment of the present invention and a magnetic head for contact recording are combined.

FIG. 6 is a diagram showing a change in friction coefficient for explaining a drag test of a magnetic disk according to an embodiment of the present invention and a conventional magnetic disk.

FIG. 7 is a schematic diagram of a magnetic disk device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Nonmagnetic substrate 2 ... Underlayer 3 ... Magnetic recording layer 4 ... Nonmagnetic layer 5 ... Particles 6 ... Protrusion 7 ... Lubrication layer 12, 72 ... Magnetic head 13 ... Element 71 ... Magnetic disk 73 ... Actuator 74 ... Voice coil motor 75 ... Recording / reproducing circuit 76 ... Positioning circuit 77 ... Control circuit

Front Page Continuation (72) Inventor Hiroshi Matsumoto 2880, Kozu, Odawara, Kanagawa Prefecture, Hitachi Storage Systems Division (72) Inventor Takao Nakamura, 2880, Kozu, Odawara, Kanagawa Hitachi Storage Systems Division (72) Inventor Yoshishige Endo 502 Jinritsucho, Tsuchiura-shi, Ibaraki Machinery Research Institute, Hiritsu Manufacturing Co., Ltd. (72) Inventor Heigo Ishihara 2880, Kokuzu, Odawara-shi, Kanagawa Hitachi Storage Systems Division (72) Invention Keigo Ikechika 2880 Kozu, Odawara-shi, Kanagawa Stock Company, Hitachi Ltd. Storage Systems Division

Claims (5)

[Claims] 1. A first step of providing at least a magnetic recording layer made of a ferromagnetic material on a non-magnetic substrate, and forming a particle layer composed of particles substantially adhered to each other on the magnetic recording layer. A second step of forming a non-magnetic layer having a projection in at least a desired region by using the particle layer as a mask, and a fourth step of removing the particle layer. Disk manufacturing method. 2. The method for manufacturing a magnetic disk according to claim 1, wherein after the first step and before the second step, a nonmagnetic layer having a smooth surface is formed on the entire surface of the magnetic recording layer. A method of manufacturing a magnetic disk, comprising the step of forming a magnetic disk. 3. A nonmagnetic substrate, a magnetic recording layer made of a ferromagnetic material provided on the nonmagnetic substrate, and on the magnetic recording layer,
A magnetic disk comprising a non-magnetic layer having fine projections of a substantially polygonal pyramid which is provided directly or through a non-magnetic layer having a smooth surface. 4. The magnetic disk according to claim 3, wherein the protrusions have an interval between adjacent ones of 100 nm to 1 micron. 5. A magnetic disk according to claim 3 or 4, a holder for holding the magnetic disk, a magnetic head arranged on the magnetic recording layer of the magnetic disk for recording and reproducing information, and a magnetic head. A magnetic recording device comprising a moving means for moving the relative position of the magnetic disk and a control means for controlling these.