JPH08221736A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE: To obtain a magnetic recording medium suppressing the peeling of the protective layer and excellent in wear resistance by forming a protective layer having a rugged surface shape by a sputtering method using an alloy of Al with a carbide forming metal. CONSTITUTION: A Cr layer 2 and a magnetic layer 3 of a CoCrPr alloy are formed on an amorphous carbon substrate 1 by DC magnetron sputtering. A 1st protective layer 4 and a 2nd protective layer 5 are formed on the magnetic layer 3 by DC magnetron sputtering. A lubricative layer 6 is further formed by dip coating with a soln. of 'FOMBLIN Z03 (R)'. At least one of the protective layers 4, 5 is a layer having a rugged surface shape formed using an alloy of Al with one or more kinds of carbide forming metals selected from among Si, Cr, Ta, Ti, Zr, Y, Mo, W and V. The center line average roughness Ra of the surfaces of the protective layers 4, 5 is 1-10nm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium having a magnetic layer and a protective layer provided on a substrate, and particularly to a magnetic recording medium excellent in low noise, high reliability, durability and abrasion resistance. It relates to a manufacturing method.

[0002]

2. Description of the Related Art In recent years,
Along with the high-density recording of hard disks used as external recording devices for computers, the rotation speed of the disks has been increased and the flying height of the magnetic head has been reduced, and the wear resistance required for magnetic recording media used as disks. Is required a high level year by year.

In order to improve the wear resistance of conventional magnetic recording media, 1) irregularities are formed on a substrate by a process such as tape, sputtering, CVD, etc. 2) Dry etching, ion milling, ion bombardment An uneven shape is formed on the magnetic layer or the protective layer formed by, for example,
2-267924, JP-A-6-139561), and 3) forming an island-shaped protective layer on the magnetic layer (JP-A-1-273219). However, if unevenness is formed on the substrate as in 1), noise is increased due to a change in spacing (a gap between the magnetic head and the magnetic layer), and as in 2), the process is complicated in forming unevenness by etching. In addition, as in 3), the surface is not entirely covered with the island-shaped protective layer, so that the abrasion resistance is slightly inferior.

In order to solve these drawbacks, 4) an unevenness forming layer is formed between the magnetic layer and the protective layer by a sputtering method (sputtering method) using Al as a sputtering target (Japanese Patent Publication No. 4-62414), 5 It has been proposed that a non-magnetic cluster is formed on the surface of a magnetic recording layer (magnetic layer) by a physical vapor deposition method, and a protective layer made of carbon or the like is further formed (JP-A-5-20659).
4) and 5) overcome the drawbacks of 1), 2), and 3) above, but 4) uses Al as a sputter target, so there is concern about wear resistance.
Has a problem that the cluster or the protective layer may be peeled off due to poor adhesion between the non-magnetic cluster and carbon.

Therefore, an object of the present invention is to provide a magnetic recording medium having excellent abrasion resistance, low noise and high reliability, and a method for manufacturing the same, in order to solve the above problems.

[0006]

As a result of intensive studies aimed at achieving the above-mentioned object, the present inventors have found that in a magnetic recording medium comprising a magnetic layer on a substrate and a protective layer on the magnetic layer, The protective layer is provided on a substantially smooth magnetic layer,
And by forming an uneven shape on the surface of the protective layer by a sputtering method using an alloy of Al and a carbide forming metal, it was found that the wear resistance is improved, it is possible to suppress the peeling of the protective layer, the present invention, It came to completion.

That is, the gist of the present invention is (1) a magnetic recording medium comprising a magnetic layer on a substrate and a protective layer on the magnetic layer, wherein the protective layer is a substantially smooth magnetic layer. A magnetic recording medium, wherein the protective layer is formed on the surface by an sputtering method using an alloy of Al and a metal forming a carbide,
(2) The magnetic recording medium according to (1) above, wherein the protective layer comprises one or more layers, and (3) at least one layer of the two or more layers comprises an alloy of Al and a carbide forming metal. (4) The magnetic recording medium as described in (2) above, wherein an uneven shape is formed on the surface by a sputtering method.
Carbide forming metal is Si, Cr, Ta, Ti, Z
The magnetic recording medium according to any one of (1) to (3) above, which is one or more selected from the group consisting of r, Y, Mo, W, and V. (5) An alloy in which the protective layer is Al and a carbide-forming metal. (6) The magnetic recording medium according to any one of (1) to (4), wherein the magnetic recording medium contains the oxide according to any one of (1) to (4).
Ra (center line average roughness) of the surface of the protective layer is 1 to 10 n.
m, the magnetic recording medium according to any one of (1) to (5), (7) the substrate is a carbon substrate, (1) to
(6) The magnetic recording medium according to any one of the above, (8) The magnetic recording medium according to any one of the above (1) to (7), wherein a lubricating layer is provided on the surface, (9) 1 between the substrate and the magnetic layer. (1) The magnetic recording medium according to any one of (1) to (8) above, wherein the thin film is formed, and (10) a magnetic recording medium comprising a magnetic layer on a substrate and a protective layer on the magnetic layer. The method for producing a magnetic recording medium according to claim 1, wherein an alloy of Al and a carbide-forming metal is used to provide a protective layer on the surface of which unevenness is formed by a sputtering method on a substantially smooth magnetic layer. Is related to. Less than,
The present invention will be described in detail.

The substrate used for manufacturing the magnetic recording medium in the present invention may be magnetic or non-magnetic, but generally a non-magnetic one is used. The non-magnetic substrate is not particularly limited, and may be a commonly used non-magnetic substrate. Specifically, carbon such as amorphous carbon (Japanese Patent Publication No. 63-46004, Japanese Patent Laid-Open No. 3-11005, etc.), glass (tempered glass, crystallized glass, etc.), Al, Al alloy, titanium, titanium alloy, Ceramics (Al ₂ O ₃ , SiC, etc.), resin, or a composite material of these materials is used. Among these, amorphous carbon is preferably used because it has heat resistance and generates less gas due to heating when a magnetic layer or the like is formed by sputtering.

That is, since the carbon substrate is black, the surface arrival temperature of the substrate becomes higher than that of the conventional NiP / A1 substrate even when heated under the same conditions. Further, since carbon is a non-magnetic material, it does not magnetically affect the magnetic layer even when heated to a high temperature. In addition, since carbon has high heat resistance, 25
It does not easily deform even when heated to a temperature of 0 ° C or higher. Furthermore,
Since carbon is a conductor, it is possible to form a magnetic layer while applying a bias voltage. Therefore, it is possible to form a magnetic layer made of a Co-based alloy on a substrate having a surface temperature higher than that of the prior art and having a negative bias voltage applied. This makes it possible to obtain a magnetic layer having a higher coercive force than the conventional one. Further, the hardness of carbon is high, and the smoothness is excellent as compared with the aluminum alloy or NiP that has been conventionally used as a substrate of a magnetic recording medium. Furthermore, the specific gravity of carbon is 1.5 to 2.0.
Since it is lighter than aluminum (specific gravity 2.7) and has a high bending strength of about 180 MPa, the magnetic recording medium can be made lighter and the load on the drive motor can be reduced. As described above, the carbon substrate is lightweight, has high strength, is excellent in smoothness, can apply a negative bias voltage when forming the magnetic layer, and further reduces the surface temperature of the substrate. Since it can be heated to a high temperature, it is extremely excellent as a substrate for a magnetic recording medium.

The physical properties of the substrate used in the present invention are not particularly limited, but the hardness is Shore hardness of 120 to 180 (HS), and the surface roughness is Ra (center line average roughness) of 0. The range of 3 to 1.5 nm is preferable from the viewpoint of impact resistance, reduction in flying height, and noise characteristics.

The magnetic layer in the present invention is provided on the substrate as a metal thin film type magnetic layer by PVD means. The material forming the magnetic layer is not particularly limited, and may be a commonly used known material. For example, CoCr, CoC
Examples thereof include Co-based magnetic alloys containing Co as a main component, such as rX, CoNiX, and CoW. Here, X is Ta, Pt, Au, Ti, V, Cr, Ni, W, L.
a, Ce, Pr, Nd, Pm, Sm, Eu, Li, S
i, B, Ca, As, Y, Zr, Nb, Mo, Ru, R
One or more elements selected from the group consisting of h, Ag, Sb and Hf can be mentioned. Among these, CoCr and CoCrPt can be mentioned as preferable ones from the viewpoint of high output and corrosion resistance. Further, the weight ratio of each element in the alloy may be a commonly used known level. The thickness of such a magnetic layer is preferably 30 to 100 nm,
50 nm is particularly preferred. From the viewpoint of output, the film thickness is 30n
m or more is preferable, and 100 nm or less is preferable from the viewpoint of noise.

The present invention is characterized in that a protective layer is provided on a substantially smooth magnetic layer, where "substantially smooth" means Ra (center line average roughness) of the surface of the magnetic layer. ) Is 0.5 to 3 nm, preferably 0.5 to 1.5 nm
Means Since the surface of the magnetic layer is smooth in this way, a change in spacing is suppressed, and low noise can be achieved without being affected by the surface roughness of the magnetic recording medium. That is, in the conventional method, since the uneven shape is formed under the magnetic layer, the surface roughness of the magnetic layer increases, but as the surface roughness increases, noise due to changes in spacing increases. Problems have been pointed out.
However, in the present invention, such a problem can be solved.

Next, the protective layer will be described. A protective layer made of an alloy of Al and a metal forming a carbide (hereinafter sometimes abbreviated as "Al-M alloy") is provided on the magnetic layer formed as described above. In the present specification, "carbide forming metal" means heat or physical adsorption,
It means a metal that can form carbide by chemisorption. Since Al-M alloy has better adhesion to carbon and higher hardness than Al, use of Al-M alloy in at least one protective layer improves wear resistance and protects other materials. The effect of suppressing peeling of carbon, which is commonly used as a layer, can be expected.

The number of protective layers formed is not particularly limited, but is preferably 1 to 3, and more preferably 1 to 2 from the viewpoint of output and noise. When the protective layer has two or more layers, the desired effect can be obtained as long as at least one layer has an uneven shape formed on the surface by sputtering using an Al-M alloy. The thickness of the protective layer is 5 to 50 nm, preferably 5 to 5 nm as a whole, regardless of the number of layers.
It is 30 nm. Here, the thickness is preferably 5 nm or more from the viewpoint of wear resistance and corrosion resistance, and is preferably 50 nm or less from the viewpoint of electromagnetic conversion characteristics. Further, the roughness Ra (center line average roughness) of the irregularities on the surface after forming the protective layer is not particularly limited, but is preferably 1 to 10 nm, more preferably 1 to 5 nm. Further, the unevenness may be the whole surface or a part thereof. Here, from the viewpoint of wear resistance, 1n
m or more is preferable, and 10 nm or less is preferable from the viewpoint of electromagnetic conversion characteristics.

As a concrete example of this Al-M alloy, the carbide forming metals are Si, Cr, Ta, Ti, Zr, Y,
Examples include alloys containing at least one selected from the group consisting of Mo, W, V, and the like. More specifically, the alloys shown in Table 1 are listed.

[0016]

[Table 1]

Further, Al-5 wt% Si-5 wt% C
r-based alloy, Al-5 wt% Si-3 wt% Mo-based alloy,
An Al-M alloy of a ternary or higher system such as an Al-5 wt% Si-3 wt% W-based alloy can also be used. Further, oxides of these alloys can also be used. The oxide of the alloy may be a part of the protective layer, or all may be the oxide. Among the above alloys, particularly preferable are Al—Si alloys and Al—Cr alloys from the viewpoint of controlling the surface shape and adhering to the magnetic layer.

The protective layer made of an Al-M alloy and having an uneven surface is provided by the sputtering method. The sputtering method in the present invention may be a commonly used known method, and examples thereof include DC magnetron sputtering and RF magnetron sputtering.
C magnetron sputtering is preferred. That is, D
Compared to RF magnetron sputtering, C magnetron sputtering has a simpler power supply and is less expensive. In addition, DC magnetron sputtering is easy to operate (in RF magnetron sputtering, impedance matching is required to effectively apply power), and it is easy to apply large power, which is suitable for high-speed film formation. There is.

The sputtering conditions are not particularly limited, but in the case of DC magnetron sputtering, the substrate temperature is preferably 80 to 500 ° C, more preferably 120 to 350 ° C. Here, the substrate temperature is preferably 80 ° C. or higher from the viewpoint of forming the uneven shape, and 50 from the viewpoint of film forming conditions.
It is preferably 0 ° C or lower. The sputtering time is preferably 0.5 to 2 minutes, and the input power is preferably 0.5 to 3 kW. An inert gas such as Ar is kept at 1 to 10 mTorr in the sputtering chamber. Here, by introducing a small amount of oxygen into the chamber, the protective layer obtained can be made of an oxide of the alloy. By performing the sputtering under such conditions, Al within the above-mentioned thickness of the protective layer is formed.
-M alloy layer can be provided. Within this range, A
The 1-M alloy layer is formed in a continuous film shape having unevenness or in the form of scattered islands, and both of them can form a protective layer having unevenness on the surface.

Next, the relationship between the number of layers and the shape of the protective layer in the present invention will be described. When the number of layers is one, the protective layer is only the Al-M alloy layer having the uneven shape of the thickness of the protective layer described above. At this time, from the viewpoint of obtaining sufficient wear resistance, the protective layer is preferably a continuous film having an uneven shape. When the number of layers is two or more, at least one Al-M alloy layer having an uneven shape may be present in the protective layer. The Al-M alloy layer may be located anywhere in the protective layer, that is, it may be the lowermost layer of the protective layer, the uppermost layer of the protective layer, or the intermediate layer of the protective layer. Also,
The total thickness of the protective layer may be within the above range. The shape of the Al-M alloy layer may be a continuous film shape having an uneven shape, or may be a dotted island shape.
Even if a layer other than the Al-M alloy is provided on the layer on which the unevenness is formed, the unevenness is inherited as it is as long as the protective layer is within the above-mentioned thickness range. The desired effect can be obtained regardless of the position and shape inside.

Further, as a component of layers other than the Al-M alloy used when the protective layer has two or more layers, amorphous carbon; amorphous carbon partially having a diamond-like structure (hereinafter referred to as "diamond-like carbon") Abbreviated as)); Al, Si, Ti, V, Cr, Zr, N
b, Mo, Sn, Ta, Zn, In, and one or more substances selected from the group consisting of oxides thereof; Si, T
One or more substances selected from the group consisting of i, Ta, carbides thereof, and nitrides thereof; sulfides such as MoS _{2 and the} like. Of these, amorphous carbon and diamond-like carbon are preferable from the viewpoint of lubricity and durability. As a method for providing these layers, a commonly used known PVD means can be used. For example,
In the case of an amorphous carbon layer, it can be achieved by a sputtering method using carbon as a sputtering target. The thickness of these layers can also be provided within the range of the thickness of the protective layer described above by changing the conditions of the PVD means. As described above, in any of the embodiments falling within the scope of the present invention, the surface of the magnetic recording medium is appropriately roughened, so that the magnetic recording medium of the present invention can prevent adsorption of the magnetic head and It has excellent wear properties and a small friction coefficient, resulting in excellent running properties.

In the present invention, a lubricating layer may be provided on the surface of the medium in order to improve the running property of the magnetic head. The lubricating layer can be provided by a known method, and for example, a layer having a desired thickness can be provided by a coating method or the like. The lubricant to be used is not particularly limited, and a commonly used known lubricant can be used. For example, a perfluoropolyether type having a molecular weight of 2000 to 10,000 can be mentioned. Specific examples include Fomblin AM2001, Fomblin Z03 (both manufactured by Montecatini), and Demnum SP (manufactured by Daikin Industries, Ltd.). The lubricant may be applied alone, a plurality of lubricants may be mixed and applied, or another lubricant may be applied after the lubricant is applied. When applying by such a method, the thickness of the lubricating layer is 0.5 to 4 nm, especially 1 to 3 n.
It is preferably m. Here, the thickness of the lubricating layer is preferably 0.5 nm or more from the viewpoint of obtaining a lubricating effect, and is preferably 4 nm or less from the viewpoint of suppressing spacing loss.

In the present invention, particularly preferably, the lubricating layer is formed of a polymer obtained by gas phase polymerization,
Further, it comprises a fixed layer fixed on the protective layer and a free layer formed on the fixed layer. In this case, the lubricating layer is preferably formed by vapor phase polymerization of a fluorocarbon compound and oxygen. The fluorocarbon compound has the following general formula (I):
Preferably selected from the group consisting of compounds represented by

CF ₂ ═CFR _f ¹ (I) (In the formula, R _f ¹ is a fluorine atom, a perfluoroalkyl group, a perfluoroalkenyl group, a partially fluorinated alkyl group, a partially fluorinated alkenyl group, a perfluoroaryl group. Or represents a partially fluorinated aryl group.)

CF ₂ ═C (R _f ² ) (R _f ³ ) (II) (wherein R _f ² and R _f ³ are the same or different hydrogen atom, fluorine atom, perfluoroalkyl group, perfluoro). An alkenyl group, a partially fluorinated alkyl group, a partially fluorinated alkenyl group, a perfluoroaryl group or a partially fluorinated aryl group is shown.)

CF ₂ ═CFO (R _f ⁴ ) (III) (In the formula, R _f ⁴ is a fluorine atom, a perfluoroalkyl group, a perfluoroalkenyl group, a partially fluorinated alkyl group, a partially fluorinated alkenyl group, a perfluoroalkyl group. Indicates a fluoroaryl group, a partially fluorinated aryl group or a perfluoroalkoxyalkyl group.)

The polymer obtained by vapor phase polymerization of a fluorocarbon compound and oxygen is a polymer mainly having a-(CF ₂ O)-structural unit, and its molecular weight is preferably 1500 to 30000. Is.

Although the structure of the above-mentioned polymer is not always clear, for example, a polymer represented by the following structural formula is estimated. X- (CF ₂ O) _1- (CF ₂ CF ₂ CF ₂ O) _m- (CF (C
F ₃ ) CFO) _n X '(wherein 1, m and n are positive integers (provided that 1
>> m, 1 >> n), X and X'represent end portions containing the same or different alcohol, ether bond, ester bond, urethane bond or the like. ) Above in the polymer - (CF ₂ O) - the content of the structural units, is preferably at least 70% in the total structural units, for example, in polymer represented by the structural formula [1 / It is preferable that (1 + m + n)] × 100 is 70% or more.

The fixed layer means a layer which is chemically or physically firmly fixed to the protective layer, and is washed off even if it is washed with a fluorine-based solvent such as a trade name "Freon 113". It refers to the layer that does not exist. On the other hand, the free layer means a layer that is washed away when washed with a fluorine-based solvent.

When the lubricating layer is composed of a fixed layer and a free layer, the weight ratio of the free layer / fixed layer is 1/10 to 10/1,
It is preferably 2/5 to 5/1. If the lubricating layer is too thick, spacing loss will be large, and if it is too thin, the lubricating effect will be poor. Therefore, the thickness of the lubricating layer is 0.2-20 nm
Is preferred, 1-10 nm is more preferred, and 2-8 nm
Is more preferable, and 2 to 5 nm is particularly preferable.

The gas phase polymerization is carried out under a vacuum condition, and the first polymerization step in which a fluorocarbon compound and oxygen are polymerized to form a lubricating layer, and after introducing steam, the gas phase polymerization is carried out under a vacuum condition. And a second polymerization step of polymerizing the fluorocarbon compound and oxygen to form a lubricating layer is sequentially performed. At this time, it is particularly preferable to introduce the water vapor by returning the vacuum condition in the first polymerization step to the atmospheric pressure condition after the completion of the first polymerization step.

The gas phase polymerization means a polymerization method in which a fluorocarbon compound and oxygen are polymerized in a gas phase in a gas state and a polymerization reaction is caused only in the gas phase. As a method that can be adopted for the polymerization, for example, CVD such as plasma polymerization or photochemical vapor deposition (hereinafter referred to as “CVD”) can be adopted. Light CV from the point of simple things
D is preferably adopted.

Regarding the above first and second polymerization steps,
This will be described with reference to FIG. Here, FIG. 4 is a schematic diagram showing a photoreaction chamber that can be used when forming the lubricating layer. Chamber 11 for photoreaction shown in FIG.
Is a laser transmission window 12 provided on both left and right side surfaces above the laser transmission window 12 for transmitting laser light, and a magnetic disk 13 as a magnetic recording medium provided below (a base layer on a support,
A medium setting member 14 capable of vertically arranging a magnetic layer and a protective layer) and a valve for decompressing the inside of the chamber provided above the chamber 11 and releasing to the atmosphere. 15 and.

In the first polymerization step, first, the valve 15 is connected to a vacuum pump (not shown) to temporarily reduce the pressure in the chamber 11 to vacuum (for example, 1 × 1).
After the 0 ^-5 ~1Torr), the vacuum conditions described later by introducing a fluorocarbon-based compound and oxygen. Next, an excimer laser beam or the like from the excimer laser 16 is applied in the direction of the arrow shown in FIG. 4 so as to pass through the center between the upper part of the magnetic disk 13 and the chamber ceiling and not hit the magnetic disk 13. The vacuum condition means a state in which a fluorocarbon compound and oxygen are introduced into the chamber 11 in a vacuum state, and the pressure in the chamber 11 in this state is preferably 5 to 200 Torr. Also,
In order for the lubrication layer to be formed uniformly over the entire surface of the magnetic disk 13, the medium setting member 14 can rotate each magnetic disk 13 in the circumferential direction. The first polymerization step may be repeated several times.

Then, in the second polymerization step, the first
After the completion of the polymerization step, the valve 15 is opened to the atmosphere, and the first
After returning the vacuum condition in the polymerization step to atmospheric pressure and introducing water vapor into the chamber 11, after depressurizing and vacuuming as in the first polymerization step, introducing a fluorocarbon compound and oxygen. Then, a vacuum condition is set and irradiation with excimer laser light or the like is performed. Here, the "vacuum condition" in the second polymerization step is the same as the "vacuum condition" in the first polymerization step.

In the present invention, the introduction of water vapor is
As described above, it is preferable to introduce the atmosphere by setting the chamber 11 under atmospheric pressure. At this time, the relative humidity of the air introduced is preferably 30 to 90%, more preferably 40 to 80%. In addition,
The second polymerization step may also be repeated several times. Furthermore, the first polymerization step can be performed again after the second polymerization step.

In the above description, with respect to points not particularly described, the same method as the conventionally known method for manufacturing a magnetic recording medium can be used without particular limitation.

Further, in the present invention, one or more thin films may be formed between the substrate and the magnetic layer in order to obtain the effect of improving the orientation of the magnetic layer. Thin film thickness,
The material and the like are not particularly limited, and may be a commonly used known thickness and material. Specifically, a non-magnetic Cr-based layer made of Cr or a Cr alloy is used for 10 to 10 times by PVD means.
The thickness is preferably 100 nm.

In the method of manufacturing a magnetic recording medium of the present invention, the protective layer having the irregular surface formed by the sputtering method using the Al-M alloy in the step of forming the protective layer as described above is substantially smooth. It is characterized by being provided on the magnetic layer. In this case, when the magnetic layer is formed by the sputtering method, the film can be formed in a single step, which is advantageous. The performance of the magnetic recording medium of the present invention thus obtained is measured by measuring the friction coefficient between the magnetic head and the magnetic recording medium as shown in the following examples, durability test of the magnetic recording medium, and film formation stability. It is an excellent medium which shows excellent abrasion resistance and no peeling of the protective layer by a property test. Here, the friction coefficient is to measure the friction coefficient of the magnetic recording medium after CSS (contact start stop) is performed a predetermined number of times. Further, the durability test is evaluated by visually inspecting the magnetic recording medium after performing the CSS a predetermined number of times and observing for the presence of scratches. Furthermore, the film formation stability is
The purpose of this study is to determine whether or not a film having the same properties can be stably manufactured by forming the film multiple times under the same conditions.

[0040]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the examples, the protective layer closest to the magnetic layer is referred to as the first protective layer, and the layer above it is referred to as the second protective layer.

Examples 1 to 10 A substrate was prepared using an amorphous carbon substrate having a density of 1.5 g / cm ³ and a Shore hardness of 150 (HS) (described in Japanese Patent Publication No. 60-33333). This substrate has Ra of 0.8 nm (evaluation by a stylus type surface roughness meter). On this substrate, a 40 nm-thick Cr layer was formed by DC magnetron sputtering under the conditions of Ar gas pressure of 2 mTorr, substrate temperature of 250 ° C., sputtering time of 1 minute, and input power of 2 kW, and then 40 nm-thick CoCrP under the same conditions.
A t-based alloy magnetic layer was provided. Furthermore, Ar gas pressure 2 mTorr
r, substrate temperature 250 ° C., sputtering time 1 minute, input power 1
The first protective layer in Table 2 was provided by DC magnetron sputtering under the condition of up to 2 kW, and the Ar gas pressure was 2 mTorr, the substrate temperature was 250 ° C. and the sputtering time was 1 on the first protective layer.
The second protective layer shown in Table 2 was provided by DC magnetron sputtering under the condition that the input power was 1 kW. Here, the surface roughness Ra after forming the protective layer was measured by a stylus type surface roughness meter. The results are shown in Table 2. In addition, the measurement of Ra in Examples and Comparative Examples was performed by a stylus surface roughness meter (Tencor).
It was measured under the following conditions using Model P2 manufactured by Co., Ltd. Stylus diameter: 0.6 μm (needle curvature radius) Stylus pressing pressure: 7 mg Measuring length: 250 μm x 8 places Tracing speed: 2.5 μm / sec Cut-off: 1.25 μm (low pass filter)

Thereafter, a Fomblin Z03 solution was applied by a dip coating method to form a lubricating layer having the thickness shown in Table 2 to obtain the magnetic recording medium shown in FIG. The thickness of the protective layer depends on the fluorescent X-ray analyzer (manufactured by Rigaku: System 327).
2), the thickness of the lubricating layer was measured by FT-IR (Fourier transform infrared spectrometer, manufactured by Perkin Elmer).

Example 11 An Ar gas pressure of 2 mTorr was applied on the amorphous carbon substrate prepared in Example 1 on which the Cr layer and the magnetic layer were formed.
Substrate temperature 250 ° C, sputtering time 1 minute, input power 1kW
The first protective layer shown in Table 3 was provided by DC magnetron sputtering under the conditions described above, and an Ar gas pressure of 2 was provided on the first protective layer.
mTorr, substrate temperature 250 ° C., sputtering time 0.5
The second protective layer shown in Table 3 was provided in an island shape by DC magnetron sputtering under the condition that the input power was 1 kW. Here, the surface roughness Ra after forming the protective layer was measured. The results are shown in Table 3. Thereafter, a Fomblin Z03 solution was applied by a dip coating method to form a lubricating layer having the thickness shown in Table 3 to obtain the magnetic recording medium shown in FIG.

Example 12 An Ar gas pressure of 2 mTorr was applied on the amorphous carbon substrate having the Cr layer and the magnetic layer formed in Example 1.
Substrate temperature 250 ° C, sputtering time 1.5 minutes, input power 2
The first protective layer in Table 3 was provided by DC magnetron sputtering under the condition of kW. Here, the surface roughness Ra after forming the protective layer was measured. The results are shown in Table 3. After that, a Fomblin Z03 solution was applied by a dip coating method to provide a lubricating layer having the thickness shown in Table 3 to obtain the magnetic recording medium shown in FIG.

Example 13 An Al substrate was plated with NiP to prepare a substrate. The Shore hardness of this substrate is 20 (HS), and Ra is 0.8 nm. On this substrate, a 40 nm-thick Cr layer was formed by DC magnetron sputtering under the conditions of Ar gas pressure of 2 mTorr, substrate temperature of 250 ° C., sputtering time of 1 minute, and input power of 2 kW, and then 40 nm-thick CoCrP under the same conditions.
A t-based alloy magnetic layer was provided. Furthermore, Ar gas pressure 2 mTorr
r, substrate temperature 250 ° C., sputtering time 1 minute, input power 2
The first protective layer shown in Table 3 was provided by DC magnetron sputtering under the condition of kW, and the Ar gas pressure was 2 mTorr, the substrate temperature was 250 ° C., and the sputtering time was 1 on the first protective layer.
The second protective layer shown in Table 3 was provided by DC magnetron sputtering under the condition that the input power was 1 kW. Here, the surface roughness Ra after forming the protective layer was measured. The results are shown in Table 3. Thereafter, a Fomblin Z03 solution was applied by a dip coating method to provide a lubricating layer having the thickness shown in Table 3 to obtain the magnetic recording medium shown in FIG.

Example 14 A substrate was prepared using tempered glass. The Shore hardness of this substrate is 135 (HS), and Ra is 0.8 nm. Ar gas pressure 2 mTorr, substrate temperature 250 on this substrate.
A 40 nm thick Cr layer was formed by DC magnetron sputtering under the conditions of a temperature of 1 minute, a sputtering time of 1 minute, and an applied power of 2 kW, and subsequently a 40 nm thick CoCrPt-based alloy magnetic layer was formed under the same conditions. Further, the first protective layer in Table 3 was provided by DC magnetron sputtering under the conditions of Ar gas pressure of 2 mTorr, substrate temperature of 250 ° C., sputtering time of 1 minute, and input power of 2 kW, and Ar gas pressure of 2 mT was provided on the first protective layer.
The second protective layer shown in Table 3 was provided by DC magnetron sputtering under the conditions of orr, substrate temperature of 250 ° C., sputtering time of 1 minute, and input power of 1 kW. Here, the surface roughness Ra after forming the protective layer was measured. The results are shown in Table 3. Thereafter, a Fomblin Z03 solution was applied by a dip coating method to provide a lubricating layer having the thickness shown in Table 3 to obtain the magnetic recording medium shown in FIG.

Examples 15 to 17 Ar gas pressure was 2 mTorr, on the amorphous carbon substrate prepared in Example 1 and having the Cr layer and the magnetic layer formed thereon.
O ₂ partial pressure 10%, substrate temperature 250 ° C., sputtering time 1.
The first protective layer in Table 3 was provided by DC magnetron sputtering under the conditions of 5 minutes and input power of 2 kW, and Ar gas pressure of 2 mTorr, substrate temperature of 250 ° C., sputtering time of 1 minute, and input power of 1 kW on the first protection layer. Under the conditions, the second protective layer shown in Table 3 was provided by DC magnetron sputtering. Here, the surface roughness Ra after forming the protective layer was measured.
The results are shown in Table 3. Thereafter, a Fomblin Z03 solution was applied by a dip coating method to provide a lubricating layer having the thickness shown in Table 3 to obtain the magnetic recording medium shown in FIG.

Example 18 A magnetic recording medium shown in FIG. 1 was obtained in the same manner as in Example 1 except that the alloy shown in Table 3 was used as the material of the first protective layer.

Examples 19 and 20 A protective layer was prepared in the same manner as in Examples 1 and 2, and a lubricating layer was prepared as follows. That is, the substrates on which the protective layer is formed are arranged in parallel as shown in FIG. 4 in the photoreaction chamber 11 shown in FIG. 4 which is a CVD device, and the inside of the chamber 11 is 5 × 10 5. After exhausting to ^-2 Torr, hexafluoropropene (CF ₃ CF = CF ₂ ) with a partial pressure of 10 Torr and oxygen with a partial pressure of 60 Torr are introduced, and an ArF excimer laser (wavelength 193 nm) is introduced.
A laser beam from 16 (power 150 mJ, repetition rate 2 Hz) was irradiated for 1500 pulses over 12.5 minutes, and the first polymerization step was performed once.

Next, the chamber 11 was leaked, and an atmosphere having a humidity of 60% was introduced to make atmospheric conditions. After this, the chamber 11 was again evacuated to 5 × 10 ^-2 Torr, and then hexafluoropropene with a partial pressure of 10 Torr and oxygen with a partial pressure of 60 Torr were introduced to make the laser light 1
The second polymerization step was performed once by irradiating 1500 pulses for 2.5 minutes. As a result, the thickness of the protective layer is 2.5 nm.
Was provided with a lubricating layer. The laser light was irradiated in the direction of the arrow shown in FIG. 4 so that the substrate was not directly irradiated.
Also, the temperature of the substrate is room temperature (22 ° C.) during photo-CVD.
And In this way, a fixed layer (1.7 nm) in which polymer molecules are fixed to the surface of the protective layer by a chemical bond.
And a free layer (0.8 nm) formed on the fixed layer was formed.

Comparative Examples 1 to 4 On the glass substrate having the Cr layer and the magnetic layer prepared in Example 14, the Ar gas pressure was 2 mTorr and the substrate temperature was 180.
The first protective layer shown in Table 4 was provided by DC magnetron sputtering under the conditions of ℃, sputtering time of 1 minute, and input power of 2 kW, and Ar gas pressure of 2 mTorr, substrate temperature of 250 ° C., sputtering time of 1 minute on the first protective layer. The second protective layer shown in Table 4 was provided by DC magnetron sputtering under the condition that the input power was 2 kW. Here, the surface roughness R after forming the protective layer
a was measured. The results are shown in Table 4. Thereafter, a Fomblin Z03 solution was applied by a dip coating method to form a lubricating layer having the thickness shown in Table 4 to obtain the magnetic recording medium shown in FIG.

Comparative Examples 5 to 7 NiP prepared in Example 13 having a Cr layer and a magnetic layer
Ar gas pressure 2 mTorr, substrate temperature 250 ° C., sputtering time 1 minute, input power 0.5-2 k on plated Al substrate
Table 4 was obtained by DC magnetron sputtering under the condition of W.
A first protective layer is provided inside, and an Ar gas pressure of 2 is provided on the first protective layer.
The second protective layer in Table 4 was provided by DC magnetron sputtering under the conditions of mTorr, substrate temperature of 250 ° C., sputtering time of 1 minute, and input power of 0.8 kW. Here, the surface roughness Ra after forming the protective layer was measured. The results are shown in Table 4. Thereafter, a Fomblin Z03 solution was applied by a dip coating method to form a lubricating layer having the thickness shown in Table 4 to obtain the magnetic recording medium shown in FIG.

Comparative Example 8 NiP having a Cr layer and a magnetic layer prepared in Example 13
Ar gas pressure of 2 mTorr, O on the plated Al substrate
₂ partial pressure 10%, substrate temperature 250 ° C, sputtering time 1 minute,
The first protective layer shown in Table 4 was provided by DC magnetron sputtering under the condition of input power of 1 to 2.5 kW, and Ar gas pressure was 2 mTorr, substrate temperature was 250 ° C. on the first protective layer.
The second protective layer in Table 4 was provided by DC magnetron sputtering under the conditions of a sputtering time of 1 minute and an input power of 0.8 kW. Here, the surface roughness Ra after forming the protective layer was measured. The results are shown in Table 4. Thereafter, a Fomblin Z03 solution was applied by a dip coating method to form a lubricating layer having the thickness shown in Table 4 to obtain the magnetic recording medium shown in FIG.

Comparative Example 9 An Ar gas pressure of 2 mTorr was applied on the amorphous carbon substrate prepared in Example 1 and having the Cr layer and the magnetic layer formed thereon.
O ₂ partial pressure 10%, substrate temperature 250 ° C., sputtering time 1
The first protective layer shown in Table 4 is provided by DC magnetron sputtering under the conditions of a power input of 2 kW, an Ar gas pressure of 2 mTorr, a substrate temperature of 250 ° C., a sputtering time of 1 minute, and a power of 0.8 kW on the first protective layer. The second protective layer shown in Table 4 was provided by DC magnetron sputtering under the above conditions. Here, the surface roughness Ra after forming the protective layer was measured.
The results are shown in Table 4. Thereafter, a Fomblin Z03 solution was applied by a dip coating method to form a lubricating layer having the thickness shown in Table 4 to obtain the magnetic recording medium shown in FIG.

The test conditions are as follows. (About abrasion resistance) As for abrasion resistance, CSS is 10,000
The magnetic recording medium after 0 times was visually inspected under a halogen light source and judged by the presence or absence of scratches. 1000 times of CSS
If the coefficient of friction exceeded 1 before reaching 00, CSS was terminated at that point and the magnetic recording medium was visually inspected.

CSS was performed under the following conditions. As the head, a thin film head manufactured by Yamaha Corporation was used. Head load is 3.5g,
The head flying height is 2.8 μ inches, and the rotation speed is 4500 r.
p. m. The cycle of 5 seconds of operation for 5 seconds and 1 second of stop was once, and 100,000 times. The static friction coefficient (friction coefficient) was measured at any time using a strain gauge.

(Regarding film formation stability) Regarding film formation stability, a magnetic recording medium was produced 10 times under the same conditions, and the same thing was reproduced in all cases ⊚, and an example in which abnormal one or two times was made ○
And Tables 2 to 4 show these evaluations.

[0058]

[Table 2]

[0059]

[Table 3]

[0060]

[Table 4]

From Tables 2 to 4, it was found that all the magnetic recording media of the present invention were excellent in abrasion resistance and had no peeling of the protective layer because no scratch was observed by visual inspection. Further, it was possible to obtain a medium having excellent durability in which the rate of increase in the friction coefficient was suppressed (Examples 1 to 20). on the other hand,
It was found that the magnetic recording media produced without using the Al-M alloy for the protective layer were all scratched, and were inferior in wear resistance and the like to those of the products of the present invention (Comparative Examples 1 to 9).

[0062]

According to the present invention, it is possible to manufacture a magnetic recording medium having excellent abrasion resistance, in which peeling of the protective layer is suppressed. Further, according to the present invention, since the magnetic recording medium can be produced only by the film forming process, it is advantageous that the film can be formed in a single step when the magnetic layer is formed by the sputtering method.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of a magnetic recording medium of the present invention.

FIG. 2 is a cross-sectional view of essential parts of a magnetic recording medium of the present invention.

FIG. 3 is a cross-sectional view of essential parts of a magnetic recording medium of the present invention.

FIG. 4 is a schematic configuration diagram of a CVD apparatus used for forming a lubricating layer in the present invention.

[Explanation of symbols]

 1 Substrate 2 Thin Film 3 Magnetic Layer 4 First Protective Layer 5 Second Protective Layer 6 Lubrication Layer 11 Chamber 12 Laser Transmission Window 13 Magnetic Disk 14 Medium Setting Member 15 Valve 16 Excimer Laser 17 Power Meter

Claims (10)

[Claims] 1. A magnetic recording medium comprising a magnetic layer provided on a substrate and a protective layer provided on the magnetic layer, wherein the protective layer is provided on a substantially smooth magnetic layer, and the protective layer is provided on the magnetic layer. A
A magnetic recording medium having an uneven surface formed by a sputtering method using an alloy of 1 and a metal forming a carbide. 2. The magnetic recording medium according to claim 1, wherein the protective layer is composed of one or more layers. 3. Of the two or more layers, at least one layer is A
The magnetic recording medium according to claim 2, wherein an uneven shape is formed on the surface by a sputtering method using an alloy of 1 and a metal forming a carbide. 4. The carbide forming metal is Si, Cr, T.
The magnetic recording medium according to any one of claims 1 to 3, which is one or more selected from the group consisting of a, Ti, Zr, Y, Mo, W, and V. 5. The magnetic recording medium according to claim 1, wherein the protective layer contains an oxide of an alloy of Al and a carbide forming metal, or all of the oxide is an oxide. 6. Ra (center line average roughness) of the surface of the protective layer
Is 1 to 10 nm, the magnetic recording medium according to claim 1. 7. The carbon substrate as the substrate according to claim 1.
The magnetic recording medium according to any one of the above. 8. A lubricating layer is provided on the surface of the device.
The magnetic recording medium according to any one of the above. 9. The magnetic recording medium according to claim 1, wherein one or more thin films are formed between the substrate and the magnetic layer. 10. A method of manufacturing a magnetic recording medium comprising a magnetic layer on a substrate and a protective layer on the magnetic layer, wherein an uneven shape is formed on the surface by sputtering using an alloy of Al and a metal forming a carbide. A method of manufacturing a magnetic recording medium, comprising: providing a protective layer on which is formed a substantially smooth magnetic layer.