JP3046846B2 - Magnetic recording media - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a top coat film of a magnetic recording medium having a continuous metal thin film type magnetic layer.

[0002]

2. Description of the Related Art Various continuous thin-film magnetic recording media having a ferromagnetic metal thin film as a magnetic layer have been put to practical use. this house,
In a hard magnetic disk used for a computer or the like, a ferromagnetic metal thin film is provided on a rigid substrate. Various floating magnetic heads are used as magnetic heads for recording and reproducing data on and from a hard magnetic disk.

In such a case, the magnetic disk is damaged by the magnetic head during a contact start / stop (CSS). In order to increase the recording density, there is a strong demand for reducing the flying height of the magnetic head as much as possible, but at this time, the damage of the disk during CSS is further increased.

[0004] In order to enhance such durability, it has been proposed to provide a top coat film using various solid lubricants on the disk surface.

For example, in JP-A-2-161612,
It has been proposed to provide a two-layer carbon sputter topcoat film by adjusting the Ar pressure on a magnetic layer. However, even if the film is formed by lowering the Ar pressure during sputtering, the lubricity is not sufficient.

On the other hand, in US Pat. No. 4,880,687, a top coat film is formed by laminating a plasma polymerized film using a hydrocarbon on a magnetic layer and a plasma polymerized film using an organic material containing fluorine on a magnetic layer. A proposal has been made to that effect. In this proposal, the fluorine content gradually decreases from the surface side toward the substrate side.

However, this top coat film is not sufficient in terms of durability and friction characteristics.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording medium having excellent friction characteristics and high durability.

[0009]

This and other objects are achieved by the present invention which is defined below as (1) to (7).

(1) In a magnetic recording medium having a magnetic layer of a ferromagnetic metal thin film on a substrate and a top coat film on the magnetic layer, the top coat film is formed of carbon or a carbon-containing hydrogen. A fluorine-containing layer obtained by laminating a second plasma polymerization film containing fluorine on the first plasma polymerization film,
A magnetic recording medium comprising two or more layers.

(2) The magnetic recording medium according to (1), wherein the thickness of the first plasma polymerization film is 50 to 300 °.

(3) The magnetic recording medium according to (1) or (2), wherein the thickness of the second plasma-polymerized film is 10 to 100 °.

(4) In a magnetic recording medium having a magnetic layer of a ferromagnetic metal thin film on a substrate and a top coat film on the magnetic layer, the top coat film is a plasma containing carbon or carbon and hydrogen. A magnetic recording medium comprising two or more fluorinated layers obtained by plasma-treating the surface of a polymer film using a fluorine-based gas.

(5) The thickness of the plasma polymerized film is 50 to 50.
The magnetic recording medium according to the above (4), which is 300 °.

(6) The magnetic recording medium according to the above (4) or (5), wherein the fluorine-containing layer contains fluorine in a range from the surface of the plasma polymerized film to a thickness of 10%.

(7) The thickness of the top coat film is 100
The magnetic recording medium according to any one of the above (1) to (6), which has an angle of up to 400 °.

[0017]

According to the present invention, the top coat film formed on the magnetic layer of the ferromagnetic metal thin film is composed of (1) a second plasma polymerization film containing fluorine on a first plasma polymerization film containing carbon or carbon and hydrogen. A film is laminated and a plurality of the laminates are laminated, or (2) a structure in which the surface of the first plasma polymerized film is plasma-treated and laminated with a fluorine-based organic gas is used as a structural unit, and a plurality of the structural units are used. Laminate.

Since the first plasma polymerized film has a high hardness, the surface of the magnetic layer can be effectively protected and the durability can be improved.

The second plasma polymerized film or the plasma-treated surface has a small surface energy, a large contact angle with water,
It shows hydrophobicity, lowers affinity with the head, shows good solid lubrication, improves friction characteristics with the magnetic head, and suppresses wear.

Further, when stress is applied, between the films, for example, between the first plasma-polymerized film and the second plasma-polymerized film containing fluorine, or between the first plasma-polymerized film and the fluorine-containing surface. The shear stress at the interface is reduced, the frictional force is reduced, and the durability is improved.

Further, on the surface of the fluorine-containing plasma polymerized film on the first plasma-polymerized film or the surface of the plasma-treated film, fluorine or carbon fluoride forms a fine uneven structure. Therefore, the true contact area of the contact surface of the magnetic head is reduced, and the friction characteristics are improved.

[0022]

[Specific Configuration] Hereinafter, a specific configuration of the present invention will be described in detail.

<Substrate> The substrate used in the present invention is not particularly limited as long as it is a non-magnetic material, and various resins, metals, ceramics, and the like that can withstand heat when depositing a ferromagnetic metal thin film can be used.

However, since the top coat film of the present invention has extremely high durability, it is particularly useful for a hard disk. In this case, a rigid substrate, particularly a rigid substrate made of resin is preferable. Since the durability of the resin substrate is reduced, the effect of the present invention is increased.

In this case, the fact that the substrate is rigid means that a flexible substrate for a so-called floppy disk is excluded. Therefore, the Young's modulus of the substrate is E, and the thickness is t.
In this case, E · t ³ ≧ 1 × 10 ⁷ dyn · cm, more preferably E · t ³ ≧ 3 × 10 ⁷ dyn · cm.

The resin used is not particularly limited, and any resin such as a thermoplastic resin, a thermosetting resin, and a radiation-curable resin may be used.

In this case, when the substrate is molded by the casting method, for example, polyurethane, epoxy resin, acrylic resin, polystyrene, polyamide, silicone resin, polyester and modified products thereof can be used.

Examples of the molding stand by the injection method include polyethylene, polypropylene, vinyl chloride resin, vinylidene chloride resin, vinylidene fluoride resin, polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, acrylic Resin, polyamide, polycarbonate, polyacetal, polyester, polysulfone, polyoxybenzylene, polyethersulfone, polyetherketone, polyetheretherketone, polyphenylenesulfide, polyphenyleneether, polyphenylene oxide, polyketonesulfide, polyimide, polyamideimide, poly Acrylic imide, polyether imide, polyolefin, amorphous polyolefin and their modified products are used Kill.

The dimensions of the resin substrate may be selected according to the purpose, but usually the thickness is about 0.8 to 1.9 mm and the diameter is 60 mm.
It is about 130 mm.

As the rigid substrate, for example, metals such as aluminum and aluminum alloy, glass, ceramics and the like can be used.

<Underlayer> An underlayer may be provided on the substrate.

The material of the underlayer is not particularly limited, and various inorganic materials, organic materials, metals and alloys may be used, and the film forming method and the film thickness may be appropriately selected according to the purpose and application. Good. Preferred examples are shown below.

A first example of the underlayer is C or C, H,
It is a plasma polymerized film containing at least one of N and O.

In this case, more preferably, C, H, and N
And / or O, more preferably C, H, N
And O are preferable.

The thickness of the underlayer of the plasma polymerized film is 100
It is preferably between 2000 and 2000, more preferably between 300 and 1000. The plasma polymerized film forms a polymerized film by contacting discharge plasma of a raw material gas with a substrate according to a known method.

In the plasma polymerized film, Japanese Patent Application No. Sho 61
As described in JP-A-207567, various metals may be contained in an amount of about 30 at% or less by depositing an electrode material on the plasma polymerized film portion or using an organic metal compound as a source gas.

Such a plasma polymerized film is preferably formed on a substrate, particularly on a substrate that has been subjected to plasma treatment.

A second example of the underlayer includes Al, Ti, Cu,
It is a continuous thin film of a nonmagnetic metal or a nonmagnetic alloy containing at least one selected from the group consisting of Zn, Ag, In, Sn and Au. The metal to be used may be a simple substance or an alloy. In the case of an alloy, the metal is preferably contained in an amount of 80% by weight or more.

In this case, the thickness of the underlayer is 100 to 30.
The angle is preferably 00 °, particularly 500 to 1500 °.

A third example of the underlayer 3 is an oxide, a nitride,
It is a continuous thin film containing at least one selected from the group consisting of carbides, silicides, borides, and carbon. In this case, one of oxide, nitride, carbide, silicide and boride
Species or more may be contained and may be oxynitride, oxycarbide, nitride carbide, oxynitride carbide, or the like.

As a continuous oxide thin film, SiOx (1
≦ x ≦ 2), ZrO ₂ , Al ₂ O ₃ , Si—Al—O—
N-based compounds, La-Si-ON-based compounds and the like are preferred.

As a continuous thin film of nitride, Si ₃ N ₄ ,
AlN, TiN and the like are preferred.

As a continuous thin film of carbide, SiC, Ti
C, h-BC, c-BC, WC and the like are preferred.

As the continuous thin film of silicide, SiOx,
_{SiC, Si 3 N 4, Si} -Al-O-N 2 compound,
La-Si-ON-based compounds and the like are preferred.

As a continuous thin film of boride, h-BN,
C-BN and the like are preferred.

As the continuous carbon thin film, amorphous carbon or the like is preferable.

In this case, the thickness of the underlayer is 100 to 30.
The angle is preferably 00 °, particularly 500 to 1500 °.

The underlayers of the second and third examples may be formed by various vapor deposition methods such as vapor deposition, sputtering, ion plating, and CVD. In particular, it is preferable that the underlayer of the third example is formed by sputtering or plasma CVD.

On the underlayer, a magnetic layer is formed directly or via an intermediate layer.

<Magnetic Layer> The magnetic layer of the present invention is a ferromagnetic metal thin film. There is no particular limitation on the material of the thin film, for example,
It may be composed of a continuous thin film containing at least one selected from Fe, Co and Ni, particularly a Co-based continuous thin film.

As a specific example of the composition of the magnetic layer, Co—N
i-alloy, Co-Ni-Cr alloy, Co-Cr alloy, Co
-Cr-B alloy, Co-Cr-Mn alloy, Co-Cr-
Mn-B alloy, Co-Cr-Ta alloy, Co-Cr-S
i-Al alloy, Co-V alloy, Co-Ni-P alloy, C
o-P alloy, Co-Zn-P alloy, Co-Ni-Pt alloy, Co-Pt alloy, Co-Ni-Mn-Re-P alloy and the like.

Incidentally, these alloys may contain O,
Elements such as N, Si, Al, Mn, and Ar may be contained in an amount of about 0.1% by weight or less.

The thickness of the magnetic layer is preferably 300 to 1000 °. Below the range, the output during recording and reproduction is insufficient, and beyond the range, the output is sufficient, but disadvantageously, the recording density decreases.

A non-magnetic intermediate layer is provided between the underlayer and the magnetic layer, if necessary. For example, if the magnetic layer is made of Co
-Ni, Co-Ni-Cr, Co-Cr, Co-Cr-
Ta, Co-Ni-P, Co-Zn-P, Co-Ni-
When the magnetic layer is made of Mn-Re-P or the like, the provision of the non-magnetic intermediate layer makes it possible to favorably perform epitaxial growth of the magnetic layer and improve magnetic properties.

The nonmagnetic intermediate layer may be composed of, for example, a continuous thin film containing at least one selected from Cr and W, particularly Cr and / or W. In this case, the metal used may be a simple substance or an alloy. However, it is preferable that the metal base contains 80% by weight or more of the metal.

The thickness of the non-magnetic intermediate layer is 500 to 5000
Å is preferred. Below this range, satisfactory magnetic properties cannot be obtained because the epitaxial growth of the cobalt alloy is not performed sufficiently. Beyond the above range, the magnetic characteristics converge to a substantially constant value, so there is no significance in the magnetic characteristics,
It is disadvantageous for mass production.

The non-magnetic intermediate layer and the magnetic layer are
Each film may be formed by various vapor deposition methods such as vapor deposition, sputtering, ion plating, and CVD, and it is particularly preferable to form the film by sputtering.

<Top Coat Film> (1) First Embodiment On such a magnetic layer 3, a top coat film 10 is provided as shown in FIG.

The top coat film 10 has the plasma polymerized film 1 containing carbon or carbon and hydrogen. As a raw material source for forming such a plasma polymerized film 1,
Although various substances containing carbon or carbon and hydrogen can be used, methane, ethane, propane, butane, pentane, and gaseous gas at ordinary temperature are usually used because of good operability.
One or more of ethylene, propylene, butene, butadiene, acetylene, methylacetylene and other saturated or unsaturated hydrocarbons are used as C and H sources. If necessary, hydrocarbons that are liquid at room temperature may be used as raw materials.

The thickness of the plasma polymerized film 1 formed by using such a raw material is 50 to 300 °, more preferably 50 to 200 °, and particularly preferably 50 to 150 °. When the film thickness exceeds this range, spacing loss increases, and
If it is less than this range, the durability is reduced.

The film thickness may be measured using an ellipsometer or the like. Such control of the film thickness may be performed by controlling the reaction time, the flow rate of the source gas, and the like when the plasma polymerization film 1 is formed.

The content of C in the film is preferably at least 30 at%, more preferably 60 to 100 at%. Further, the content of H in the film is preferably set to 40 at% or less.

With such a composition, the durability is improved. These contents are determined by Auger spectroscopy (A
ES) and the CHN coder.

The first plasma polymerized film 1 forms a polymerized film by contacting the above-mentioned discharge plasma of the raw material gas with the magnetic layer according to a known method. Electrode arrangement,
Applied current, processing time, operating pressure, etc. may be set under normal conditions.

The processing condition is W / (FM) [where,
W is the plasma input power (Jole / sec),
F is the flow rate of the organic raw material gas, M is the molecular weight of the raw material gas, and the unit of F · M is kg / sec]. The value may be 10 ⁸ Joule / kg or more, particularly 5 × 10 ⁸ to 1 × 10 ¹⁰ Joule / kg. preferable. This value is 10 ⁸ Joule /
If it is less than kg, the denseness of the plasma polymerized film 1 becomes insufficient. Note that Ar, N ₂ , H
e, it may also be used, such as _{H 2.}

As the plasma generation source, any of microwave discharge, DC discharge, AC discharge and the like can be used in addition to high frequency discharge.

In the first embodiment of the present invention, a second plasma polymer film 2 containing fluorine is laminated on the polymer film 1 containing carbon or carbon and hydrogen.

The material source for forming such a plasma polymerized film 2 includes CF ₄ , C ₂ F ₄ , C ₂ H ₃ F, C
₂ H ₂ F ₂ , C ₄ F ₈ etc., or in some cases CF
_At least one kind of carbon fluoride such as ₄ is used as a fluorine source, and C ₄ F ₈ or the like is particularly preferably used. In this case, hydrocarbons such as H ₂ and CH ₄ may be shared.

The thickness of the second plasma-polymerized film 2 formed using such a raw material is 10 to 100 °, more preferably 10 to 60 °. When the film thickness exceeds this range, the adhesiveness is reduced and the film is peeled off. In the present invention,
Since it is sufficient to obtain a surface with a low surface energy, a range from the thickness of a single atom to about 100 ° is sufficient.

The method of measuring the film thickness and the method of controlling the film thickness may be in accordance with the above-described method. The conditions for forming the polymer film are the same as described above.

The content of F in the polymer film is 30 to 60 at%.
It is preferred that The content of C is 40 to 70.
It is preferably at%. With such a composition,
The friction characteristics are improved, and the durability is improved. The method for measuring the content is the same as described above. Here, the W / (FM) value is 1
Is preferably performed at 0 ⁷ ~10 ⁹ Joule / kg.

In the first embodiment, as shown in FIG. 1, a first plasma polymerization film 1 and a second plasma polymerization film 2 are formed.
Are laminated as a structural unit, and a plurality of these are laminated.

In the top coat 10 in which such a laminate 11 is used as a constituent unit and a plurality of the laminates are laminated, slip occurs at each interface between the first plasma polymerized film 1 and the second plasma polymerized film 2. The shear stress is further reduced, and the laminate 1
Compared to the case where the top coat film was formed from only 1
The durability and friction characteristics are improved critically.

The cumulative number of laminations of a single component unit is 2 or more and up to about 4. Further, the total film thickness is preferably 100 to 400 °. This is because spacing loss increases when the film thickness exceeds 400 °. On the other hand, if the film thickness is too small, the effect of the present invention is lost.

(2) Second Aspect In the second aspect, the surface of the first plasma polymerization film 1 containing carbon or carbon and hydrogen of the above (1) is subjected to plasma treatment using a fluorine-based gas. , A fluorine-containing layer is provided on the surface.

As a processing gas used for such a plasma processing, a fluorine-based gas such as F ₂ and / or CF ₄ can be preferably used.

The principle, method, forming conditions and the like of the plasma processing method are basically almost the same as those of the above-mentioned plasma polymerization method. Further, the frequency of the plasma processing power supply is not particularly limited, and may be any of direct current, alternating current, microwave, and the like.

As described above, the first plasma-treated surface is used.
Are laminated as two or more layers to form a top coat film. Thereby, the shear stress is reduced, and the durability is critically improved.

In such a case, the thickness of the first plasma-polymerized film is 50 to 300 °, more preferably 50 to 200 °.
Å, particularly preferably 50 to 150Å. Also,
Its composition is the same as above.

Further, it is preferable that the number of laminated first plasma polymerized films subjected to the plasma treatment is 2 to 4 layers, and the total film thickness is 100 to 400 °.

The fluorine-containing layer formed by the plasma treatment preferably contains fluorine in a range of 10% or less, particularly 5% or less of the total thickness from the surface. By increasing the fluorine concentration on the surface side, the lubricity of the surface of the top coat film can be enhanced, and the shear stress can be further reduced.

The content of fluorine is preferably 30 to 60 at% on the surface of each constituent film, and 10 to 60 at% in the range of 5% (relative value) from the surface.

<Medium Structure> In the magnetic recording medium of the present invention, it is preferable to form a groove on the underlayer forming surface side of the substrate. There are no particular restrictions on the shape, pattern, dimensions, etc. of the groove, but it is preferable to form the groove in the circumferential direction of the disk.

The grooves are formed by so-called textured processing in which a polishing tape or the like is applied while rotating the substrate to form concentric irregularities on the surface of the substrate. The grooves may be regularly formed in a shape or the like, or may be both. The regular grooves can be used as grooves for tracking, and the recording density is improved.

In such a case, the groove dimensions and the groove arrangement interval are as follows: the groove width is 0.1 to 10 μm, particularly about 0.5 to 2 μm; 2 μm
Degree, groove depth 100-5000５, especially 500-1
It is preferably about 000 °.

Since no information is recorded on the groove, the groove becomes a guard band regardless of the position of the magnetic head. For this reason, if grooves are provided on the substrate, the accuracy of tracking servo can be relatively low, and the area of the recording surface used for servo signals can be reduced. Also, crosstalk from adjacent tracks is significantly reduced.

In the case of a continuous thin-film type magnetic layer, when grooves having the above dimensions are formed regularly in the circumferential direction of the disk, cracks in the magnetic layer are further prevented, and the orientation in the circumferential direction of the disk is reduced. And the coercive force in the disk circumferential direction is improved.

Incidentally, a liquid lubricating layer may be provided on the top coat film 10.

In the above description, a single-sided recording type magnetic disk has been mainly described, but the present invention may be applied to a double-sided recording type magnetic disk.

<Recording / Reproduction> The magnetic head used in combination with such a magnetic disk medium is a floating magnetic head. In this floating magnetic head, it is preferable that at least the vicinity of the gap portion is formed of a soft magnetic material having a saturation magnetic flux density of 0.7 T or more, and other configurations are not particularly limited.

As the floating magnetic head having such a configuration, a metal-in-gap (MIG) magnetic head or a thin-film magnetic head is preferable.

The MIG-type magnetic head is a magnetic head having a soft magnetic thin film having a higher saturation magnetic flux density than at least one of the pair of cores on a surface facing the gap. In the MIG type magnetic head, since a strong magnetic flux can be applied to the magnetic layer from the soft magnetic thin film, effective recording can be performed on the magnetic layer having a high coercive force. Further, in the present invention, a so-called enhanced dual gap length (EDG) type magnetic head, which is one type of MIG type magnetic head, may be used.

In the present invention, the flying height of the flying magnetic head is preferably 0.2 μm or less. When the flying height exceeds this range, the overwrite characteristics become insufficient, and it becomes difficult to obtain a high recording density. Note that a more preferable range of the flying height is 0.17 μm or less. There is no particular lower limit for the flying height, and the flying height can be reduced until the flying surface of the flying magnetic head and the surface of the magnetic disk are brought into a quasi-contact state. The flying height is the distance between the flying surface of the flying magnetic head and the surface of the magnetic disk.

The flying height can be set to various values by changing the shape of the slider, changing the load of the gimbal, suspension, etc., changing the number of revolutions of the magnetic disk, and the like.

The number of rotations of the magnetic disk at the time of recording / reproduction is not particularly limited, and may be appropriately set according to the target transfer rate, flying height, recording density, and the like.
It is about 000 rpm.

In the present invention, since a digital signal is usually recorded, saturation recording is performed. In addition, since the saturation recording is performed, overwrite recording is possible.

[0097]

The present invention will be described in more detail with reference to the following examples.

Example 1 A disc-shaped rigid substrate made of polycarbonate having an outer diameter of 3.5 inches and a thickness of 1.27 mm was manufactured by injection molding. Grooves were formed on the substrate surface.

The groove is formed in the circumferential direction of the disk.
The cross section was substantially rectangular, and the dimensions were 0.8 μm in width, 0.8 μm in land width, and 400 to 700 ° in depth. On this substrate, using CH ₄ as a source gas, a film thickness of 200 °
The underlayer of the plasma polymerized film was formed. On this underlayer, a Co-Ni-Cr magnetic layer having a thickness of 500 成膜 was formed. The magnetic layer was formed by DC-magnetron sputtering. Sputtering was performed in an Ar atmosphere with an operating pressure of 1 Pa.

The target was Co ₇₀ Ni ₂₀ C
r ₁₀ was used.

The obtained continuous thin-film magnetic disk was placed in a vacuum chamber, and once evacuated to 10 ⁻⁶ Torr, plasma polymerization was carried out under the conditions shown in Table 1 below. Was formed on the magnetic layer.

[0102]

[Table 1]

The composition of the plasma polymerized film was measured by AES.
The film thickness was measured with an ellipsometer.

The polymer film No. Using Examples 1 and 2, a top coat film having a structure shown in Table 2 below was obtained. In this case, the sample No. 4 is sample No. The thickness of the laminate of No. 3 was reduced to half, and this was laminated twice.

[0105]

[Table 2]

The sample Nos. Shown in Table 2 With respect to Nos. 1 to 4, recording and reproduction were performed using a magnetic disk device equipped with a floating magnetic head. In this case, the magnetic head has a monolithic type MI having a gap length of 0.6 μm.
Using a G head, the flying height during recording and reproduction was 0.14 μm. Sample No. The following evaluation was performed about 1-4.

(1) Coefficient of friction μ The coefficient of friction μ was measured based on ANSI standards. 1 rpm
And the values at 100 rpm are shown in Table 3.

(2) Durability Table 3 shows μ of the above (1) after running for 100 hours.

(3) Surface Roughness The surface roughness Ra at the time of running at 100 rpm in the above (2) was determined by JI.
It was determined by the method described in SB0601.

Table 3 shows the results.

[0111]

[Table 3]

From the results shown in Table 3, the effect of the present invention,
In particular, the effect of critically improving the durability and the like by the lamination of the laminate is apparent. The sample No. In No. 4, when the top coat film was set to 500 °, the output decreased to 75% or less.

Example 2 The polymer film No. of Example 1 was used. For the disk that formed 1,
CF ₄ and Ar were used as processing gases, and the CF ₄ content was 8
While maintaining gas pressure at 0.1% at 0%, 100k
Over Hz high frequency voltage to generate plasma, CH ₄
The surface of the polymer film was subjected to plasma treatment.

The fluorine content of this film is 60% on the surface,
It was 40 at% at a depth of 20 ° from the surface.

The polymer film No. Sample No. 1 having a thickness of 300 mm was prepared. 5 is assumed. In addition, the polymer film No. The thickness of 1 was set to 150 mm, and the same operation was repeated.
Sample No. No. 6 was produced.

The results are shown in Table 3.

From the results shown in Table 3, the effect of the present invention is clear.

[0118]

According to the present invention, excellent durability and friction characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a magnetic recording medium according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st plasma polymerized film 2 2nd plasma polymerized film 3 magnetic layer 10 top coat film 11 lamination unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-16028 (JP, A) JP-A-64-50235 (JP, A) JP-A-1-296429 (JP, A) JP-A-2- 15417 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B 5/72

Claims (7)

(57) [Claims] 1. A magnetic recording medium having a magnetic layer of a ferromagnetic metal thin film on a substrate and a top coat film on the magnetic layer, wherein the top coat film is carbon or a first layer containing carbon and hydrogen. A magnetic recording medium characterized in that two or more fluorine-containing layers in which a second plasma polymerization film containing fluorine is laminated on the plasma polymerization film of (1). 2. The method according to claim 1, wherein the first plasma polymerization film has a thickness of 50.
2. The magnetic recording medium according to claim 1, wherein the angle is about 300 °. 3. The film thickness of the second plasma polymerized film is 10
The magnetic recording medium according to claim 1, wherein the angle is about 100 °. 4. A magnetic recording medium having a magnetic layer of a ferromagnetic metal thin film on a substrate and a top coat film on the magnetic layer, wherein the top coat film is carbon or a plasma polymerization containing carbon and hydrogen. A magnetic recording medium comprising two or more fluorinated layers whose surfaces are plasma-treated using a fluorine-based gas. 5. The plasma polymerized film has a thickness of 50 to 30.
5. The magnetic recording medium according to claim 4, wherein the angle is 0 °. 6. The magnetic recording medium according to claim 4, wherein the fluorine-containing layer contains fluorine in a range from the surface of the plasma polymerized film to a thickness of 10%. 7. The film thickness of the top coat film is 100 to 4
7. The magnetic recording medium according to claim 1, wherein the angle is 00 °.