JPH1116149A - Magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to improve the corrosion resistance and to improve traveling property by incorporating hydrogen H into a magnetic layer of a metallic thin-film type having a structure of a column and specifying the ratio (H/M) of the hydrogen H to the magnetic metal H in the magnetic layer to atomic % of a specific range. SOLUTION: The magnetic layer 11 is formed by using a vacuum diagonal vapor deposition apparatus on a PET film (base) 1 and further, a protective layer 12, a back layer 13 and layers 14, 15 of lubricants are formed. At the time of forming the magnetic layer 11, a molecular sieve is placed in order to remove H2 and H2 O in the vacuum chamber of the vacuum diagonal vapor deposition apparatus. The ratio (H/M) of the hydrogen H to the magnetic metal M in the magnetic layer 11 is regulated to 0 to 7 atm.% by increasing the active carbon quantity of a cryo-vacuum pump. The softness of the magnetic layer 11 is made adequate, the traveling property is improved and since the amt. of the hydrogen H is small, the corrosion by oxidation is hardly occured and the corrosion resistance is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a magnetic recording medium.

[0002]

2. Description of the Related Art Heretofore, there has been a metal thin-film type magnetic recording medium (magnetic tape, magnetic disk, etc.) having a magnetic layer formed by oblique evaporation. When a metal thin film type magnetic layer is formed in a vacuum, a method using PVD (physical vapor deposition) or CVD (chemical vapor deposition) can be considered, but a large coercive force can be obtained simply by employing PVD or CVD. No magnetic layer can be obtained. still,
Among these methods, the magnetic layer formed by the oblique deposition method has a relatively large coercive force due to the orientation of the particles in the magnetic layer, but is not satisfactory.

Therefore, it has been proposed to obliquely deposit metal magnetic particles while supplying oxygen gas. That is, the coercive force was improved by oxidizing and separating the metal magnetic particles, magnetically separating the columnar metal magnetic particles that are obliquely oriented, and reducing the occupancy of the magnetic particles per unit volume. It is. The columns of obliquely grown columnar particles that are separated and oriented are called columns. And Japanese Patent Laid-Open No. 8-
According to Japanese Patent Publication No. 203057 (Japanese Patent Application No. 7-9947), it is said that a column having a tilt angle of 40 to 50 ° is preferable.

[0004] In the conventional magnetic recording medium, the corrosion resistance of the magnetic layer is not good, and the running property is not good. In order to improve these characteristics, various methods have conventionally been adopted. For example, improvements in the degree of oxidation of the magnetic layer, improvements in the protective layer, and improvements in the lubricant have been made.

[0005]

SUMMARY OF THE INVENTION The present inventor has sought to improve the above characteristics by defining the amount of H in the magnetic layer while intensively studying corrosion resistance and running properties. I came to find it. Therefore, an object of the present invention is to provide a magnetic recording medium having excellent corrosion resistance and running properties.

[0006]

The object of the present invention is to provide a magnetic recording medium in which a metal thin film type magnetic layer is provided on a support, wherein the metal thin film type magnetic layer has a column structure, Hydrogen H is contained in the metal thin film type magnetic layer, and the ratio (H / M) of the hydrogen H to the magnetic metal M in the magnetic layer satisfies 0 <H / M ≦ 7 atomic%. The problem is solved by a magnetic recording medium.

That is, hydrogen H is contained in the metal thin film type magnetic layer.
When the ratio (H / M) of the hydrogen H to the magnetic metal M in the magnetic layer is set to 0 to 7 atomic%, the magnetic layer contains hydrogen H at 8 atomic% or more. The softness becomes moderate as compared with, and the traveling performance is improved. In addition, since the amount of hydrogen H is small, corrosion due to oxidation hardly occurs and corrosion resistance is improved. The preferred range of H / M was 0 <H / M ≦ 5 at%.

In the above magnetic recording medium, the metal thin-film type magnetic layer has a column structure, the inclination angle of the column is 40 ° to 55 °, and the thickness of the magnetic layer is 0.1 μm.
It is preferably about 0.2 μm. That is, when the magnetic layer had such a structure, a higher output was obtained. The magnetic layer preferably has a column structure (a structure in which the center is a ferromagnetic metal and the periphery is an oxide of a ferromagnetic metal) because a high coercive force can be obtained while maintaining high saturation magnetization. Because you can. That is, in order to obtain a high coercive force while maintaining a high saturation magnetization, it is necessary to isolate the magnetic material from the magnetic material, and this can be achieved by oxidizing around the magnetic material.

The ferromagnetic metal is preferably, for example, Co or a Co alloy (the Co alloy is particularly preferably a Co alloy containing Co as a main component). It is preferable that a protective layer made of carbon having diamond bonding, particularly diamond-like carbon, is provided on the metal thin film type magnetic layer. That is, if the protective layer made of carbon having diamond bonding is provided, the durability is further improved. The protective layer has a thickness of 8 ×
A it is preferably 10 ^-3 μm~13 × 10 ^-3 μm. The reason for this is that if the protective layer is too thick, the spacing loss with the head is correspondingly large, and if the protective layer is too thin, the function as the protective layer is correspondingly deteriorated.

Further, a liquid at 25 ° C. is formed on the metal thin film type magnetic layer (on the protective layer when the protective layer is provided),
It is preferable that a lubricant layer made of an organic compound having an aliphatic alkenyl group having 8 to 32 carbon atoms is provided at a molecular terminal. The aliphatic alkenyl group has 8 to 2 carbon atoms.
It is particularly preferable to use one having 6. More preferred are lubricants represented by the following general formula [I].

The general formula [I]

[0012]

Embedded image

That is, when the above lubricant is used as a lubricant, the dynamic friction coefficient is low in a wide temperature range,
It has good running properties, is excellent in still durability, and has a high output, especially in a short wavelength region where the recording wavelength is 0.5 μm or less. The lubricant layer has a thickness of 1 × 1.
It is preferably from 0 ⁻³ μm to 4 × 10 ⁻³ μm. This is because if the lubricant layer is too thick, the spacing loss with the head is correspondingly increased, and conversely, if the lubricant layer is too thin, the lubrication function is correspondingly reduced.

It is preferable that a layer made of a material selected from the group consisting of metal, metalloid, and ceramic is provided on the surface opposite to the magnetic layer. In particular, the thickness is 0.1 ~
A layer provided with a layer (a so-called back layer) made of a material selected from the group consisting of 0.2 μm metal, metalloid, and ceramic is preferable. Thereby, a balance can be achieved between the magnetic layer provided on one surface side of the support and the back layer provided on the other surface side of the support, and deformation such as curling hardly occurs. Between them (so-called head touch) is improved, and the electromagnetic conversion characteristics are improved.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The magnetic recording medium according to the present invention
Magnetic recording medium having metal thin film type magnetic layer provided on support
In the above, the metal thin film type magnetic layer has a column structure.
Hydrogen H in the metal thin film type magnetic layer.
Containing hydrogen relative to the magnetic metal M in the magnetic layer
H ratio (H / M) satisfying 0 <H / M ≦ 7 atomic%
It is. The H / M is particularly preferably 0 <H / M ≦ 5 atomic%.
It is. The magnetic layer of the metal thin film type particularly has a column structure.
And the column has an inclination angle of 40 ° to 55 °.
And the thickness of the magnetic layer is 0.1 μm to 0.2 μm.
You. A diamond bond is formed on the metal thin-film type magnetic layer.
From carbon, especially diamond-like carbon
Is provided. This protective layer has a thickness of 8 × 1
0^-3μm to 13 × 10 ^-3μm. Metal thin film type magnetism
On the layer (or over the protective layer if a protective layer is provided)
Is a liquid that is liquid at 25 ° C. and has 8 to 32 carbon atoms at the molecular end.
Of a lubricant comprising an organic compound having an aliphatic alkenyl group
A layer is provided. Incidentally, the carbon number of the aliphatic alkenyl group is
In particular, those of 8-26. Particularly preferred are al
The kenyl group is an aliphatic alkenyl group represented by the above general formula [I].
It is a lubricant that is used. The lubricant layer has a thickness of 1 × 10^-3
μm to 4 × 10^-3μm. Also, the surface opposite to the magnetic layer
Is selected from the group of metals, metalloids, and ceramics
A layer (back layer) made of a material is provided. Especially the thickness
A back layer having a thickness of 0.1 to 0.2 μm is provided.

The details will be described below. [Support] As the support on which the magnetic layer is provided, a known support in the technical field can be used without particular limitation. Specifically, polyethylene terephthalate (PET), polyethylene naphthalate (PE)
N), known resins such as polyphenylene sulfide, polycarbonate, polyamide, polyimide, polyamide imide, polysulfone, aramid, and aromatic polyamide; metals such as aluminum and copper; paper; and ceramics. The form may be any of film, tape, sheet, disk, drum and the like. Before providing the magnetic layer, the surface of the support may be subjected to a corona discharge treatment, a plasma treatment, an easy adhesion treatment, a heat treatment, a dustproof treatment, a bombardment treatment, or the like in the air and / or in a vacuum. The thickness of the support is 1 to 300
μm, preferably 2 to 100 μm.

[Magnetic Layer] For the formation of the magnetic layer, a known metal thin film forming means can be used. In particular, an oblique evaporation method is used. That is, as shown in FIG. 1, a vacuum oblique deposition apparatus is used. In FIG. 1, 1 is a support, 2 is a cooling can roll, 3a is a supply-side roll of the support 1, 3b is a take-up roll of the support 1, 4 is a crucible, and 5 is a crucible filled in the crucible 4. Magnetic metal, 6 is an electron gun, 7 is a magnet, 8 is a shielding plate, and 9 is an oxygen gas supply nozzle. These are arranged in a vacuum chamber.

The oblique deposition conditions are set so that the inclination angle of the column constituting the magnetic layer is 40 ° to 55 °. The setting of these conditions cannot be determined uniquely, but the angle of incidence when the metal particles adhere to the support greatly affects. For example, the maximum incident angle is set to 70 ° to 90 °, and the minimum incident angle is set to 40 ° to 70 °. Also, 1 ×
The chamber is evacuated to 10 ^-4 to 1 × 10 ^-6 Torr. Support 1
Traveling speed is 1 to 200 m / min and the output of the electron gun 6 is 5 to 200 m / min.
The supply amount of oxygen gas from the oxygen gas supply nozzle 9 at 300 kw is 10 to 3000 sccm. As a result, a magnetic layer (a metal thin film type magnetic layer) having a column structure and having a column inclination angle of 40 ° to 55 ° is formed.

Further, in order to reduce the amount of hydrogen H contained in the magnetic layer (including the oxide portion) to 7 atomic% or less, a hydrogen atom generating substance such as H ₂ or H ₂ O in a vacuum chamber is used. Limit the quantity. Incidentally, in order to reduce the amount of hydrogen H contained in the magnetic layer to 7 atomic% or less, generally, the conditions at the time of film formation are set as follows. If the vacuum chamber contains a large amount of H atom generating substances such as H ₂ or H ₂ O, the degree of evacuation in the vacuum chamber is increased to reduce the amount of H atom generating substances, substituted with an inert gas, activated carbon, etc. Adsorption using the adsorbent
The removal of water by baking the vacuum chamber or the removal of moisture adhering to the support by ion bombardment or heat treatment are appropriately performed. That is, by employing these techniques, the amount of hydrogen H contained in the magnetic layer is reduced to 7 atomic% or less. The specific conditions are determined by setting a certain condition to form a magnetic layer. At this time, if H / M is out of the range of the present invention, one of the film forming conditions is changed. A film is formed, and it is checked whether the H / M at this time is out of the range of the present invention, and the trial and error are repeated until the H / M falls under the content of the present invention. Specific conditions found as a result of these are given in the examples below.

As a method for examining the amount of hydrogen H contained in the magnetic layer, for example, SIMS (Secondary I
on Mass Spectrometer) method, GD
S (Glow Discharge Spectrom)
eter) method, HFS (Hydrogen Forwarda)
rdscattering Spectrometer
y, hydrogen forward recoil method). In this specification, H
The hydrogen (H) content in the magnetic layer was examined by the FS method.
In this method, ions heavier than hydrogen are obliquely incident on the sample surface, the hydrogen H inside the sample is flipped off, and the energy and yield of recoil hydrogen are examined and quantified. The principle diagram is shown in FIG.

The inclination angles of the columns are as shown in FIG. That is, the angle θ between the straight line connecting the lower end and the upper end of the column C in the magnetic layer 11 and the support 1 is the inclination angle of the column, and the magnetic recording medium is cut along the longitudinal direction of the support. The surface is observed with an electron microscope, the inclination angles θ are obtained for some columns C, and the average thereof is obtained to obtain the column inclination angles θ.

The metal forming the metal thin film type magnetic layer is, for example, Co. Further, a Co alloy containing Co as a main component, for example, a Co-Ni-based alloy, a Co-Pt-based alloy, a Co-Ni-Pt-based alloy, a Co-Fe-based alloy,
-Fe-Ni alloy, Co-Fe-B alloy, Co-N
An i-Fe-B-based alloy, a Co-Cr-based alloy, or an alloy containing a metal such as Al is used.

The magnetic layer may be composed of a single metal thin film or a laminate of two or more metal thin films. When the magnetic layer is composed of two or more metal thin films,
The material of each metal thin film may be the same or different.
The metal thin film type magnetic layer has an overall thickness of 0.3 mm.
It is 1 μm to 0.2 μm. [Protective Layer] A protective layer 12 is provided on the magnetic layer 11. As the protective layer, for example, boron carbide, silicon carbide,
Examples include boron nitride, silicon nitride, silicon oxide, chromium oxide, and aluminum oxide. However, in the present invention,
It is preferable that the protective layer is formed of carbon having diamond bonding. For example, the protective layer is formed of diamond-like carbon such as amorphous carbon having diamond bonds or amorphous carbon having diamond bonds and graphite bonds. The thickness of the protective layer is ^{8 × 10 -3 μm~13 × 10 -3} μm. As a method for forming the protective layer, either a CVD method or a PVD method may be used. In the CVD method, ECR (Electron
Cyclotron Resonance) Plasma C
The VD method and a method using high frequency (RF) are particularly effective. For example, an ECR plasma CVD apparatus shown in FIG. 4 is used. In FIG. 4, reference numeral 21 denotes a support provided with the magnetic layer 11, 22 denotes a cooling can roll, and 23a denotes a support 21.
Supply roll, 23b is a take-up roll of the support 21;
24 is a vacuum chamber, 25 is a plasma reaction tube, 26 is a magnet, 27 is a material supply nozzle, 28 is a microwave waveguide, 29
Is a filament. When the protective layer is formed by a CVD method, any of a gas, a liquid, and a solid may be used as a raw material.

[Back layer] A metal layer, a semi-metal layer, or a metal layer, on the surface of the support opposite to the surface on which the magnetic layer is formed, in order to improve the running properties and durability of the magnetic recording medium. A ceramic layer such as an oxide, a so-called back layer 13 is provided. The back layer may be a coating type or a metal thin film type, but is preferably a metal thin film type.
The metal thin film type back layer is generally made of Al, Cu, Si,
Nonmagnetic metals such as Fe, Mo, Mn, and Zn; Co, N
It is formed by depositing a magnetic metal such as i or Fe, a semimetal such as Si or Ge, or a ceramic such as an oxide, nitride or carbide of the metal or semimetal by PVD means such as vapor deposition. The thickness of the back layer is 0.1 μm to 0.2 μm as in the case of the magnetic layer.

[Lubricant] The lubricant of the present invention is an organic compound which is liquid at 25 ° C. and has an aliphatic alkenyl group having 8 to 32 carbon atoms at a molecular terminal. In particular, the above general formula [I]
Is a fluorine-containing compound represented by The fluorine-containing compound has a structure in which a fluoroalkyl group represented by Rf and an alkenyl group represented by R are connected by an alkylene group R ′ having a polar group Z.

In the general formula [I], Rf represents 5 carbon atoms.
Preferred are -20 linear or branched fluoroalkyl groups. The fluoroalkyl group does not need to be a perfluoroalkyl group. Further, the compound may have an ether bond in the molecule. R in the general formula [I] is an aliphatic alkenyl group having 8 to 32 carbon atoms. Preferably, it is a linear or branched aliphatic alkenyl group having 8 to 26, more preferably 9 to 25, carbon atoms. The alkenyl group R may have two or more double bonds.

It is preferable that the number of carbon atoms C _{1 of} Rf and the number of carbon atoms C _{2 of} R satisfy the relationship of C ₁ <C ₂ from the viewpoint of compatibility with an organic solvent. Further, m and n in the portion of R ′ in the general formula [I] are each an integer of 0 to 30. It is preferably an integer of 0 to 10. More preferably, it is an integer of 0 to 5. If it exceeds 30, the effect of the polar group becomes weaker,
Lubricity decreases. The sum of n and m is preferably an integer of 0 to 40. More preferably, it is an integer of 0 to 25. 1 in the general formula [I] is an integer of 0 to 30. It is preferably an integer of 0 to 10. If it exceeds 30, the effect of the polar group will be weakened and lubricity will be reduced.

X in the general formula [I] has one or no -O-. In the latter case, it means that Rf and R 'and / or R' and R are directly bonded. The lubricant of the general formula [I] contains the polar group Z as an essential component, but the alkenyl group R may further contain the polar group Z ₂ . When it has the polar group Z ₂ , it may be the same or different from the polar group Z, and the position may be the terminal or the end of the alkenyl group. Here, as described in the Chemical Dictionary (Tokyo Kagaku Doujinshi), the polar group refers to a substituent of an organic compound that causes the polarity of the compound. An atom having a different electronegativity than a carbon atom becomes a polar group. Examples of the polar groups Z and Z ₂ are shown below, but are not limited thereto.

-CH ₂ OH, -CH ₂ COOH, -CO
_{OH, -SO 3 M, -PO 3} M 2, -OPO 3 M ( where, M is a hydrogen atom, an alkali metal, ammonium), -
_{NCO, -OH, -NH 2, -NO} 2, -CHO, -C
N,

[0030]

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The lubricant of the present invention comprises toluene, methanol,
Since it is soluble in various general-purpose organic solvents such as ethanol, tetrahydrofuran (THF), chloroform, methyl ethyl ketone (MEK), dimethylformamide (DMF), and cyclohexanone, it is advantageous in terms of cost and use. The layer of the lubricant of the present invention can be formed by, for example, a wet coating method using a sprayer equipped with an ultrasonic oscillator. or,
After forming the lubricant layer, the magnetic recording medium may be washed with a solvent. The lubricant is provided by the above method after being diluted with a suitable solvent at the time of use.

The amount of the lubricant attached (layer thickness of the lubricant) can be appropriately adjusted according to the form of the magnetic recording medium (tape, disk) and the like. The thickness as a general range is 1
× 10 ⁻³ μm to 4 × 10 ⁻³ μm. That is, if the amount of adhesion is too small, sufficient lubricity of the magnetic recording medium cannot be obtained, and the head and the magnetic recording medium may be damaged.
Conversely, if the amount is too large, the surface of the magnetic recording medium becomes sticky, frictional resistance with the guide pins increases during running, running stops, and debris from the magnetic recording medium adheres to the head gap. Recording may not be possible.

In the present invention, in addition to the above lubricant, a lubricant generally used for a magnetic recording medium may be used in combination. For example, AUSIMONT K. K. FOMB
LIN (trade name), JP-A-7-220267,
A lubricant described in JP-A-62-103838 can be used in combination. Also, if necessary, other additives such as phenols, quinones, naphthols, and a nitrogen atom,
It may be used in combination with a heterocyclic compound containing an oxygen atom or a sulfur atom. In these cases, other lubricants and additives can be added in an amount of 1 to 500 parts by weight based on 100 parts by weight of the lubricant of the present invention.

Next, a synthesis example of the lubricant represented by the general formula [I] will be described. [Synthesis Example 1 of Lubricant (Fluorine-Containing Compound) Represented by General Formula [I]] A fluorine-containing compound was produced according to the following reaction formula.

[0035]

Embedded image

16 g of compound b was dissolved in 160 ml of DMF, and 1.2 equivalents of NaH was added thereto.
Heated. After aging for 1.5 hours, compound a was gradually added dropwise, and the mixture was further stirred at 110 ° C. for 1 hour. After cooling, the mixture was neutralized with dilute hydrochloric acid, extracted with chloroform, and concentrated under reduced pressure.
3.3 g of compound c was obtained (86% yield). 1. Dissolve 55 g of compound c in 600 ml of Diglyme;
78 g of 4 equivalents of NaBH ₄ and 29.8 g of 0.4 equivalents of LiBr were added and heated at 110 ° C. for 2 hours. After cooling,
Dilute hydrochloric acid was added, extracted with chloroform, and concentrated under reduced pressure.
8.2 g of compound (A) was obtained (yield 78%).

26.8 g of compound d were converted to 270 ml of TH
F in 11.9 g of pyridine in 1.5 equivalents
At 0 ° C. with 1.5 equivalents of Ts-Cl.
6 g was gradually added dropwise. After 1 hour, the temperature was raised to room temperature, extracted with water-hexane, and concentrated under reduced pressure to obtain 40.5 g of compound (B) (96% yield). 34.3 g of the compound (A) was dissolved in 350 ml of DMF, and at 0 ° C., 7.2 g of 0.5 equivalent of NaH was added. One hour later, 25.3 g of 1 equivalent of the compound (B) was added, and the mixture was gradually added dropwise. After the addition, the temperature was slowly raised to room temperature. Extraction with water-hexane and concentration under reduced pressure gave 36.5 g of the target compound (C) (yield 74%).

[Synthesis Examples 2 to 5 of Lubricants (Fluorine-Containing Compounds) Represented by General Formula [I]] The compounds a, b, and d used in the above synthesis examples are shown below.

[0039]

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The target compound (C) obtained in Synthesis Examples 1 to 5
Is shown below.

[0041]

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The reaction product was confirmed by infrared absorption spectroscopy (IR), nuclear magnetic resonance (NMR), and mass spectrometry (MS). Was confirmed. Table 1 Target compound IR (cm ^-1 ) MS (M + H) ⁺ 1 1200 to 1390 823 3400 2920 710 2 1200 to 1390 795 3400 2920 710 3 1200 to 1390 823 3400 2920 710 4 1200 to 1390 795 3400 29920 10710 Hereinafter, the present invention will be described with reference to specific examples.

[0043]

Example 1 A magnetic layer 11 was formed on a 6.3 μm-thick PET film 1 using the vacuum oblique vapor deposition apparatus shown in FIG. The PET film 1 was subjected to ion bombardment at a position before the formation of the magnetic layer 11.

The conditions for forming the magnetic layer 11 are as follows: the output of the electron gun 6 is 30 kW, the running speed of the PET film 1 is 5 m / min,
The magnetic metal 6 is Co, and the maximum incident angle of the magnetic metal particles is 88.
°, the minimum incident angle is 57 °, the supply amount of oxygen gas from the nozzle 9 is 55 sccm, and the temperature in the vacuum chamber is 80 ° C.
In order to remove H ₂ and H ₂ O, a molecular sieve was placed in the vacuum chamber. When the degree of vacuum at the time of film formation was measured with a partial pressure gauge, it was 5 × 10 ⁻⁶ Torr, and the partial pressure of H ₂ was 1 ×.
The partial pressure of 10 ^-7 Torr and H ₂ O was 1 × 10 ^-7 Torr.

When the magnetic layer 11 is formed under the above conditions, the magnetic layer 11 is a magnetic layer having a column structure in which the center is Co and the periphery is Co—O.
1 has a thickness of 0.15 μm and a column inclination angle θ of 4
5 °. The coercive force Hc was 1600 Oe and the saturation magnetic flux density Bs was 6200 G. Next, the PET film 1 on which the magnetic layer 11 is formed is shown in FIG.
The protective layer 12 was formed on the magnetic layer 11 by mounting the film in a CR plasma CVD apparatus.

It is to be noted that benzene gas is supplied from the raw material supply nozzle 27 into the plasma reaction tube 25, and the amount thereof is 50 sccm. The running speed of the PET film 1 is 8 m / min. The filament 29 is made of tungsten, and is supplied with a current of 40 A. The output of the μ wave is 600 w. Protective layer 1 thus formed
2 was made of diamond-like carbon and had a thickness of 12 × 10 ⁻³ μm.

On the surface opposite to the magnetic layer 11, a metal (Ni) thin film layer (back layer) 13 having a thickness of 0.15 μm was formed by vapor deposition. Then, the fluorine-containing compound obtained in Synthesis Example 1 was diluted with toluene so as to be 0.01 wt% to prepare a lubricant coating solution. And this is 30k
4 × 10 ^-3 after drying with an ultrasonic sprayer
It was applied on the protective layer 12 and the back layer 13 to have a thickness of μm (measured by ESCA) to form lubricant layers 14 and 15.

The raw material of the magnetic recording medium obtained as described above was cut into a predetermined width to obtain a magnetic tape.

[0049]

Example 2 In Example 1, the amount of activated carbon in the cryogenic vacuum pump was doubled to improve the efficiency of removing H ₂ , and the degree of vacuum in the vacuum chamber was set to 5 × 10 ⁻⁶ Torr, and the partial pressure of H ₂ was reduced. To 7 × 10 ^-8 Torr and the partial pressure of H ₂ O to 8 × 10 ^-8 To
A magnetic tape was obtained according to the method of Example 1 except that rr was used.

[0050]

[Characteristics] The amount of H in the magnetic layer of the magnetic tape obtained in each of the above examples was determined by the HFS method. Also, the amount of Co in the magnetic layer was determined by the HFS method. HFS for Example 1
FIG. 5 shows the results obtained by the method. In addition, since the quantification was performed in the same manner for Example 2, the results (H / Co) are shown in Table-2.

The coercive force Hc and the saturation magnetic flux density Bs were also examined, and the results are shown in Table 2. Further, the magnetic tape obtained in each of the above examples was loaded into a commercially available Hi8 video camera to which a jitter meter was connected, and the jitter was examined. The results are shown in Table 2. Further, the magnetic tape obtained in each of the above examples was allowed to stand for one week in an atmosphere of 60 ° C. and 90% RH for an increase ΔHc in coercive force Hc and saturation magnetic flux density B
The amount of decrease ΔBs in s was examined, and the results are shown in Table-2.

Table 2 H / Co Hc Bs ΔHc ΔBs Jitter (at%) (Oe) (G) (Oe) (%) (ns) Example 1 6 1600 6200 +30 −5 51 Example 2 3 1620 6300 +20 -48 48 Comparative Example 1 8 1530 5900 +50 -858 * Comparative Example 1 is a DVC tape manufactured by Matsushita Electric Co. As can be seen from this, when hydrogen H / cobalt Co is 8 atomic%, jitter continues for a long time and reproduction characteristics are poor. You can see that. That is, running performance is poor. Further, as can be seen from the data of ΔHc and ΔBs, it can be seen that corrosion easily occurs under high temperature and high humidity, and the corrosion resistance is poor.

On the other hand, hydrogen H / cobalt Co is 7
It is understood that when the content is less than atomic%, the jitter is short and the reproduction characteristics are good. That is, the traveling property is good. Also, ΔHc, Δ
As can be seen from the Bs data, it can be seen that corrosion hardly occurs even under high temperature and high humidity, and the corrosion resistance is excellent.

[0054]

According to the magnetic recording medium of the present invention, since the ratio (H / M) of hydrogen H to the magnetic metal M in the magnetic layer is set to 7 atomic% or less, the running performance is good and jitter is hardly generated. It has features such as high corrosion resistance.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a vacuum oblique deposition apparatus.

FIG. 2 is a principle diagram of HFS.

FIG. 3 is an explanatory diagram of a magnetic recording medium.

FIG. 4 is a schematic diagram of an ECR plasma CVD apparatus.

FIG. 5 is a graph showing the result of examining the magnetic layer of Example 1 by HFS.

[Explanation of symbols]

 Reference Signs List 1 PET film (support) 11 Magnetic layer 12 Protective layer 13 Back layer 14, 15 Lubricant layer

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Katsumi Endo 2606 Akabane, Kaigamachi, Haga-gun, Tochigi Pref.

Claims (6)

[Claims] 1. A magnetic recording medium in which a metal thin-film type magnetic layer is provided on a support, wherein the metal thin-film type magnetic layer has a column structure. Containing hydrogen H, and the ratio of the hydrogen H to the magnetic metal M in the magnetic layer (H /
M) satisfying 0 <H / M ≦ 7 atomic%. 2. The magnetic layer of the metal thin film type has a column structure, wherein the inclination angle of the column is 40 ° to 55 °, and the thickness of the magnetic layer is 0.1 μm to 0.2 μm. The magnetic recording medium according to claim 1, wherein: 3. The magnetic recording medium according to claim 1, wherein the ferromagnetic metal is Co or a Co alloy. 4. The magnetic recording medium according to claim 1, wherein a protective layer made of carbon having a diamond bond is provided on the metal thin film type magnetic layer. 5. A lubricant layer comprising an organic compound having a liquid terminal at 25 ° C. and having an aliphatic alkenyl group having 8 to 32 carbon atoms at a molecular terminal is provided on the metal thin film type magnetic layer. The magnetic recording medium according to claim 1, wherein: 6. The method according to claim 1, wherein a layer made of a material selected from the group consisting of a metal, a metalloid, and a ceramic is provided on a surface opposite to the magnetic layer. Magnetic recording medium.