JPH09274716A - Magnetic recording medium and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a medium having excellent head-touch property, good reproducing characteristics and excellent corrosion resistance by forming a metal thin film type magnetic film containing Co3 O4 in an upper layer part and containing Co2 O3 in other part, especially in a lower part on a supporting body. SOLUTION: A metal thin film type magnetic film is formed on a supporting body. The upper layer part of the magnetic layer contains Co3 O4 and other part, especially a lower layer part of the film contains Co2 O3 . The proportion of Co2 O3 in the whole magnetic film is 4 to 50%, preferably 5 to 20%. Moreover, >=50% of the whole Co2 O3 , preferably 70 to 100% is included in the part from 7/20 depth of the magnetic film to the lower surface. The proportion of Co3 O4 in the whole magnetic film is 10 to 50%, and especially 15 to 30% is preferable. The proportion of Co3 O4 in the part from the upper surface to 1/20 depth is 30 to 100%, preferably 60 to 100%. Thereby, the obtd. magnetic recording medium has good head-touch property, good reproducing characteristics and excellent corrosion resistance.

Description

Detailed Description of the Invention

[0001]

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

[0002]

In a magnetic recording medium such as a magnetic tape, a magnetic layer provided on a support is not a coating type using a binder resin, but a binder. A metal thin film type using no resin has been proposed. That is, a magnetic recording medium in which a magnetic film is formed by wet plating such as electroless plating or dry plating such as vacuum deposition, sputtering or ion plating has been proposed. And this kind of magnetic recording medium has a high packing density of a magnetic material,
This is suitable for high-density recording. Incidentally, examples of the material of the magnetic film include Co-based materials such as Co and Co—Ni alloys.

However, the metal thin film type magnetic film is inferior in corrosion resistance. For this reason, surface oxidation is performed. For example, a magnetic recording medium having a magnetic thin film containing Co as a main component and Co ₃ O ₄ being present on at least the surface portion of the magnetic thin film has been proposed (JP-A-60-160027). Further, a magnetic recording medium has been proposed (Japanese Patent Laid-Open No. 58-83327) in which the amount of oxygen atoms in the magnetic film gradually increases as the distance from the support is increased, except in the vicinity of the surface of the magnetic film. In addition, an oxide crystal of a magnetic metal is formed in the vicinity of the surface of the magnetic thin film, and a layer in which the metal and the metal oxide are mixed is formed continuously in the film thickness direction of the layer. In the layer, the magnetic recording medium in which the ratio α of the metal atoms forming the oxide to the total metal atoms forming the metal and the metal oxide is continuously decreased in the film thickness direction from the surface of the magnetic thin film at each film thickness depth Has been proposed (Japanese Patent Laid-Open No. 60-171622). Further, it has a magnetic thin film composed of a Co-based alloy and oxygen, and a portion having the largest amount of oxygen is provided on the magnetic thin film surface portion in the thickness direction of the thin film, and the surface portion of the thin film and the surface in contact with the support are A magnetic recording medium has been proposed (Japanese Patent Publication No. 5-3048) in which a portion having a high oxygen component ratio is provided.

The proposed magnetic recording medium is said to have improved corrosion resistance. However, not only the corrosion resistance but also the head touch, that is, the recording / reproducing characteristics are essential conditions required for the magnetic recording medium. The above-mentioned proposal does not have sufficient head touch. Therefore, the problem to be solved by the present invention is to provide a magnetic recording medium excellent in corrosion resistance and head touch (recording / reproducing characteristics).

[0005]

The object of the present invention is a magnetic recording medium comprising a metal thin film type magnetic film provided on a support, wherein Co ₂ O ₃ is present in the magnetic film. This is solved by a magnetic recording medium characterized by the above.

In particular, a metal thin film type magnetic film is provided on the support.
A magnetic recording medium obtained by removing C from the magnetic film.
o_TwoO_ThreeIs present and Co is present in the upper layer of the magnetic film.
_ThreeO _FourA magnetic recording medium characterized by the presence of
Is resolved. In the above magnetic recording medium, Co
_TwoO_ThreeIs preferably present in a portion other than the upper layer of the magnetic film.
New In particular, what is mainly present in the lower layer of the magnetic film
preferable. Then, Co in the magnetic film_TwoO_ThreeOf
Is preferably 4 to 50%. More specifically,
Co in the all-magnetic film_TwoO_ThreeIs 5 to 15%
And from the depth of 7/20 of the magnetic film thickness to the bottom surface
All Co in the part of_TwoO_ThreeMore than 50% of
Is preferred.

Also, from the top surface of the magnetic film,
Co in parts up to a depth of 20 _ThreeO_FourIs 30
What is -100% is preferable. Especially in the all-magnetic film
Co in_ThreeO_FourIs 10 to 50%, and
From the top surface of the magnetic film to a depth of 1/20 of the thickness of the magnetic film
Co in part_ThreeO_FourIs 30 to 100%
Are preferred.

The above Co ₂ O ₃ crystal particles preferably have a particle size of 50 to 150Å, particularly 70 to 100Å, and the Co ₃ O ₄ crystal particles have a particle size of 50 to 150Å.
It is preferably 150 Å, especially 70 to 100 Å.
That is, when configured as described above, Co ₂ O ₃
Since the crystal particles have a large porosity and exhibit a cushioning effect, the head touch is improved in the case of a metal thin film type magnetic film. Since the magnetic head hits well, the reproduced waveform is beautiful and the reproduction characteristics are good.

Also, the corrosion resistance is improved by the oxidation. In particular, in the type in which Co ₃ O ₄ crystal grains are present in the upper layer portion of the magnetic film (therefore, the Co ₂ O ₃ crystal grains are mainly present in the portion other than the upper layer portion of the magnetic film), the Co ₃ O ₄ is resistant to corrosion. Since it is rich in corrosion resistance, its corrosion resistance is also improved. Further, the object of the present invention is to deposit Co-based particles on a support,
A step of supplying a cooled oxidizing gas in the initial stage where Co-based particles start to deposit on the support, and
And a step of supplying a heated oxidizing gas in the final stage of the deposition of the system particles.

The cooled oxidizing gas is -150 to 5 ° C.
The heated oxidizing gas is 80-
Those heated to 200 ° C. are preferred. And, the supply amount of the cooled oxidizing gas is 10 to 500 sccm,
The supply amount of the heated oxidizing gas is preferably 10 to 500 sccm. By thus forming the metal thin film type Co-based magnetic film, the magnetic film having the above characteristics can be obtained.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The magnetic recording medium of the present invention comprises a support
Magnetic recording medium having a metal thin film type magnetic film provided thereon
In the magnetic film, Co_TwoO_ThreeExists. Special
A magnetic thin film type magnetic film provided on the support.
A magnetic recording medium, wherein Co is contained in the magnetic film._TwoO_Threeexist
In addition, Co_ThreeO_FourExists
You. In the above magnetic recording medium, Co_TwoO_ThreeIs a magnet
It exists in the part other than the upper layer part of the elastic film. Especially under the magnetic film
It is mainly present in the layer part. Co in the magnetic film_TwoO_Three
Is 4 to 50% (particularly 5 to 20%). Special
In addition, Co in the all-magnetic film _TwoO_ThreeOf 4 to 50%
(Especially 5 to 20%) and 7 times the thickness of the magnetic film.
All Co from the depth of / 20 to the bottom surface_TwoO_Three
Of 50% or more (particularly 70 to 100%) is present.
Also, from the top surface of the magnetic film to a depth of 1/20 of the thickness of the magnetic film
In the part of_ThreeO_FourIs 30 to 100%
is there. In particular, Co in the all-magnetic film_ThreeO_FourIs 1
0 to 50% (particularly 15 to 30%) and magnetic
The part from the upper surface of the film to the depth of 1/20 of the thickness of the magnetic film
At Co_ThreeO_FourOf 30 to 100% (especially 6
0-100%). In particular, a Co-based magnetic film on the support
A magnetic recording medium comprising:
From the upper surface of the magnetic film to a depth of 1/20 of the thickness of the Co-based magnetic film
In the part of_ThreeO _FourOf 65 to 100%
(Especially 75 to 100%) of the Co-based magnetic film
From the depth of 1/20 of the thickness to the depth of 2/20
There is Co_ThreeO_FourOf 50 to 90% (particularly 60%
˜80%), which is 2/20 of the thickness of the Co-based magnetic film.
From the depth of 4/20 to the depth of Co_Three
O_FourIs 30 to 80% (particularly 40 to 55%).
From the depth of 4/20 of the thickness of the Co-based magnetic film to 16
In the portion up to the depth of / 20, the proportion of metallic Co is 3
0 to 70% (particularly 40 to 60%), and the Co-based
Depth of 16/20 to 18/20 of magnetic film thickness
For parts up to Co_TwoO_ThreeIs 30-80%
(Especially 40 to 55%), and the thickness of the Co-based magnetic film
From the depth of 18/20 to the depth of 19/20
Then Co_TwoO_ThreeOf 50 to 90% (especially 6
0-80%), which is 19 / of the thickness of the Co-based magnetic film.
Co from the depth of 20 to the bottom surface_TwoO_Threeof
The ratio is 65 to 100% (particularly 75 to 100%).
And the proportion of metallic Co in the total magnetic film is 46 to 86%.
(Especially 50 to 70%), Co in the total magnetic film_TwoO_ThreePercent of
4 to 50% (especially 15 to 20%) in the total magnetic film
Co_ThreeO_FourOf 4 to 50% (especially 15 to 30%)
It is. Co_TwoO_ThreeThe crystal particles of are 50 to 1 in particle size.
It is 50Å, especially 70 to 100Å. Also, Co_ThreeO_Fourof
The crystal particles have a particle size of 50 to 150Å, especially 70 to 1
It is 00Å.

[0012] In this specification, Co ₂ The O ₃ ratio of the cross section is irradiated to an arbitrary number points to focus the probe diameter 30Å to TEM sections, Co from the resulting electron beam diffraction image ₂
It is the ratio of the points determined to be O ₃ crystals to all the points.
The proportion of Co ₃ O ₄ means the total of all the points determined to be Co ₃ O ₄ crystals from the electron beam diffraction image obtained by focusing a probe diameter of 30 Å on a cross-sectional TEM slice and irradiating it at arbitrary points. It is a ratio to points. The proportion of Co is the proportion of all the points determined to be Co crystals from the electron diffraction image obtained by focusing a probe diameter of 30 Å on a cross-sectional TEM slice and irradiating it at arbitrary points.

The magnetic recording medium, especially the magnetic recording medium having the above characteristics, is provided with a cooled oxidizing gas in the step of depositing Co-based particles on a support and in the initial stage of starting the deposition of Co-based particles on the support. And a step of supplying a heated oxidizing gas in the final stage of the deposition of Co-based particles on the support. The cooled oxidizing gas is
It was cooled to 150 to 5 ° C, and the heated oxidizing gas was heated to 80 to 200 ° C. Further, the supply amount of the cooled oxidizing gas is 10 to 500 sccm, and the supply amount of the heated oxidizing gas is 10 to 500 sccc.
m.

That is, it is obtained by the apparatus shown in FIG. In FIG. 1, 1 is a support, 2a is a supply side roll of the support 1, 2b is a winding side roll of the support 1, 3 is a cooling can roll, 4 is a crucible (container), 5 is a container 4 filled 6 is an electron gun, 7 is a shield plate, and 8 is a vacuum chamber. Since this vapor deposition apparatus, particularly the oblique vapor deposition apparatus, has been known in the past, its details are omitted. The characteristic of this device lies in the nozzles 9a and 9b. The nozzle 9a is installed toward the position where Co-based particles evaporated from the Co-based metallic material with which the container 4 is filled start vapor deposition on the support body 1 guided by the cooling can roll 3, and vapor deposition has started. Co-based particles (Co-based deposited film at the initial stage of deposition, lower layer of Co-based magnetic film)
Oxidizing gas such as oxygen gas that has been cooled toward is supplied. The nozzle 9b is installed toward the position where the Co-based particles evaporated from the Co-based metallic material filled in the container 4 are vapor-deposited on the support 1 guided by the cooling can roll 3, and the vapor deposition is completed. Oxidizing gas such as heated oxygen gas is supplied toward the system-based particles (the Co-based deposited film at the final stage of the deposition, the upper layer of the Co-based magnetic film). By using this apparatus, Co-based particles are deposited on the support, and C-based particles are deposited on the support.
The cooling oxygen gas is supplied in the initial stage where the o-based particles start to be deposited, and the heated oxygen gas is supplied in the final stage when the Co-based particles are deposited, whereby the magnetic recording medium having the above-mentioned characteristics can be obtained.

The magnetic recording medium support 1 of the present invention may be magnetic or non-magnetic. Representative examples are polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, polycyclohexylene dimethylene terephthalate, and polyethylene bisphenoxycarboxylate; polyolefins such as polyethylene and polypropylene; cellulose acetate butyrate; Examples include cellulose derivatives such as cellulose acetate propionate, vinyl resins such as polyvinyl chloride and polyvinylidene chloride, and non-magnetic plastic materials such as polyamide and polycarbonate. Of course, it is not limited to these. Also, various kinds of processing may be performed. For example, surface treatment is performed by corona discharge or other appropriate means. Further, polyester, polyurethane or oligomer for improving the adhesiveness may be applied.

A metal thin film type magnetic film is provided on the support 1 by an oblique deposition method. The magnetic film may have a single layer or two or more layers. However, at least one layer has the magnetic film having the above characteristics. When there are two or more magnetic films, it is preferable that the magnetic film having the characteristics of the present invention is provided on the upper layer side. Examples of the material forming the magnetic film of the present invention include Co, Co—Ni alloys, Co—Pt alloys, Co—Ni—
Pt alloy, Co-Ni-Fe-B alloy, Co-Cr alloy, etc. are used. The magnetic film has a thickness (average thickness) of 6
It is from 00 to 5000Å. Therefore, it is a so-called metal thin film type that does not use a binder resin.

A protective film is optionally provided on the uppermost magnetic film provided by oblique vapor deposition or the like. As a material for forming this protective film, for example, Al, Si, Ti, Cr,
Oxides, nitrides and carbides of metals such as Zr, Nb, Mo, Ta and W, or diamond-like carbon and boron nitride are used. CVD as a film forming method
(Chemical vapor deposition) and PVD (Physical vapor deposition) are used. The thickness of the protective film is 10 to 500Å, especially 30 to 200Å.

When the uppermost magnetic film and protective film are provided, a lubricant film is provided on the protective film. For example,
A film of a fluorinated lubricant is provided with a thickness of about 20 to 70Å by means such as dipping or ultrasonic spraying. As the lubricant, for example,-(C (R) F-CF ₂ -O) _p- (where R is F, C
Groups such as F ₃ and CH ₃ ), especially HOOC-CF ₂ (OC ₂ F ₄ ) _p (OCF
₂ ) _q- OCF ₂ -COOH, F- (CF ₂ CF ₂ CF ₂ O) _n -CF ₂ CF ₂ COOH, carboxyl group-modified perfluoropolyether, HOCH ₂ -CF ₂ (OC ₂ F ₄ ) _p (OCF ₂ ) _q -OCF ₂ -CH ₂ OH, HO-
(C ₂ H ₄ -O) _m -CH _2- (OC ₂ F ₄ ) _p (OCF ₂ ) _q -OCH _2- (OCH ₂ C
H ₂ ) _n -OH, F- (CF ₂ CF ₂ CF ₂ O) _n -CF ₂ CF ₂ CH ₂ OH, such as alcohol-modified perfluoropolyether, or one or part of the molecule Examples thereof include a saturated hydrocarbon group such as an alkyl group, an unsaturated hydrocarbon group, an aromatic hydrocarbon group, or another functional group.
Specifically, Montecatini's FOMBLIN Z
There are DIAC, FOMBLIN Z DOL, and Demnum SA manufactured by Daikin Industries, Ltd.

A back coat film is provided on the other surface side of the support. When the back coat film is formed by coating,
Carbon black having a particle size of 10 to 100 nm is dispersed in a binder resin such as a vinyl chloride-based or urethane-based resin and applied by a gravure method, a reverse method or a die coating method so that the thickness after drying is 0.4 to 1 μm. To do. When the back coat film is formed by PVD means such as vapor deposition, Al-C
A metal material such as u alloy is placed in the evaporation source, and evaporated metal particles are deposited to a thickness of 0.05 to 1 μm. Then, a top coat layer may be provided on such a back coat film in order to improve running properties and durability.

[0020]

Example 1 Using the apparatus shown in FIG. 1, Co metal particles were vapor-deposited on a 6 μm-thick PET film running at 5 m / min along a cooling can roll 3 at −20 ° C. 100 scc of oxygen gas cooled from the nozzle 9a to -50 ° C
oxygen gas heated to 150 ° C from the nozzle 9b is 15
0 sccm was introduced. The vacuum degree in the vacuum tank 8 is 2 × 10
Exhausted to ^-5 Torr. The magnetic film formed by this oblique vapor deposition had a thickness of 2000Å. According to the cross-sectional TEM image of the magnetic film, the particle size is 50 to 90Å
Were observed. Table 1 shows the results obtained by irradiating each crystal grain of the magnetic film with an electron beam focused at a probe diameter of 30Å and examining each by electron beam diffraction.

Table-1 Depth from the surface Surface (0Å) Co ₃ O ₄ Co ₃ O ₄ CoO Co ₃ O ₄ CoO 200 Å CoO Co Co CoO Co ₃ O ₄ 400 Å CoO Co Co Co Co CoO 600 Å CoO CoO Co Co Co 800 Å Co Co Co ₂ O ₃ Co CoO 1000 Å Co ₂ O ₃ Co CoO CoO Co 1200 1200 Å Co Co ₂ O ₃ Co CoO Co ₂ O ₃ 1400 Å CoO Co ₂ O ₃ Co Co ₂ O ₃ Co 1600 Å Co ₂ O ₃ O _{2 3} Co ₂ O ₃ Co CoO 1800Å Co ₂ O ₃ CoO Co ₂ O ₃ Co ₂ O ₃ Co 2000Å (interface with the support) 80 Å thick diamond-like carbon film on the magnetic film formed by the oblique deposition Was provided, and a lubricant film having a thickness of 20Å was provided thereon. Then, a 0.5 μm-thick back coat film is provided on the opposite surface of the PET film.
It was slit to a width of mm to obtain a magnetic tape for 8 mm VTR.

[0022]

Second Embodiment In the first embodiment, the nozzles 9a to −50 are used.
8 mm magnetic tape for VTR was obtained in the same manner as in Example 1 except that the oxygen gas cooled to ℃ was 150 sccm, the oxygen gas heated to 80 ° C. from the nozzle 9b was 100 sccm, and the thickness of the magnetic film was 1900 Å. It was

[0023]

Third Embodiment In the first embodiment, the nozzles 9a to -10 are used.
An 8 mm magnetic tape for VTR was obtained in the same manner as in Example 1 except that the oxygen gas cooled to 0 ° C. was 50 sccm and the oxygen gas heated to 150 ° C. from the nozzle 9b was 50 sccm.

[0024]

Comparative Example 1 In Example 1, no oxygen gas was introduced from the nozzle 9a, and oxygen gas at 20 ° C.
8 m was carried out according to Example 1 except that 0 sccm was introduced.
A magnetic tape for mVTR was obtained.

[0025]

Comparative Example 2 In Example 1, no oxygen gas was introduced from the nozzle 9a, and oxygen gas at 150 ° C.
The procedure was carried out in the same manner as in Example 1 except that the introduction of 00 sccm was performed.
A magnetic tape for mmVTR was obtained.

[0026]

[Characteristics] For the magnetic tape for 8 mm VTR obtained in each of the above examples, RBW (Resolution Band Width) = 1 using a TR4171 type spectrum analyzer manufactured by Advantest.
Envelope measurement is performed under the conditions of 0 kHz, VBW (Video Band Width) = 30 kHz, frequency span = 0 MHz, sweep time = 40 ms, and average number = 16 times, and the degree of front chipping (output fluctuation) is calculated. The results are shown in Table 2. Also, corrosion resistance (when left for 1 month in an environment of 60 ° C, 90% RH,
The Bs retention rate (%) was examined), and the results are also shown in Table 2.

The proportions of Co ₂ O ₃ crystal particles, Co ₃ O ₄ crystal particles and Co crystal particles by electron diffraction are shown in Tables _{3, 4} and 5. Table-2 Thickness of magnetic film (Å) Head touch (%) Corrosion resistance (%) Example 1 2000 10 95 Example 2 1900 15 93 Example 3 2000 15 93 Comparative Example 1 2000 40 81 Comparative Example 2 1800 45 75 Table-3 Proportion (%) of Co ₂ O ₃ crystal particles A region B region C region D region E region F region G region H region I region Example 1 0 0 0 0 20 20 40 60 60 60 60 Example 2 0 0 0 0 30 50 60 60 60 70 Example 3 0 0 0 0 0 0 0 30 30 50 80 Comparative Example 1 0 0 0 0 0 0 0 0 0 0 0 Comparative Example 2 0 0 0 0 0 0 0 0 0 0 0 Table-4 Co ₃ O ₄ Crystal Particle ratio (%) A region B region C region D region E region F region G region H region I region Example 1 60 60 20 20 0 0 0 0 0 0 Example 2 50 50 40 10 0 0 0 0 0 0 0 Example 3 60 20 0 0 0 0 0 0 0 0 0 Comparison Example 1 10 0 0 0 0 0 0 0 0 0 Comparative Example 2 60 50 20 20 0 0 0 0 0 0 Table-5 Ratio of Co crystal grains (%) A region B region C region D region E region F region G region H region I region Example 1 40 40 40 60 60 50 40 20 20 20 20 Example 2 50 60 50 50 50 40 40 20 20 20 20 Example 3 40 50 60 60 70 70 70 70 60 40 20 Comparative example 1 40 50 60 70 70 70 60 70 50 50 Comparative Example 2 30 40 70 80 80 80 80 80 70 70 In Tables 3 to 5, in the area A, the area from the surface (upper surface) of the magnetic film to the depth of 1/20 of the thickness of the magnetic film, and the area B is The portion from the depth of 1/20 of the thickness of the magnetic film to the depth of 2/20, the C region is from the depth of 2/20 of the thickness of the magnetic film to 4 /
The area up to the depth of 20 and the area D is 4/2 of the thickness of the magnetic film.
The area from 0 to 6/20, the E area from 6/20 to 14/20 of the magnetic film thickness, and the F area from 14/14 of the magnetic film thickness. 1 from 20 depths
The portion up to the depth of 6/20, the G region is 1 of the thickness of the magnetic film.
The portion from the depth of 6/20 to the depth of 18/20, the H region is the portion from the depth of 18/20 to the depth of 19/20 of the magnetic film, and the I region is the thickness of the magnetic film. It is a portion from a depth of 19/20 to a depth of 20/20 (interface (lower surface) between the magnetic film and the support).

The total value may not be 100 in some cases because CoO exists. From this result, it is understood that the one according to the present invention is excellent in head touch, has good reproduction characteristics, and has excellent corrosion resistance.

[0029]

The head touch is excellent, the reproduction characteristics are good,
Moreover, a magnetic recording medium having excellent corrosion resistance can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus for manufacturing a magnetic recording medium of the present invention.

[Explanation of symbols]

 1 Support 3 Cooling Can Roll 5 Co-Based Metal Material 6 Electron Gun 8 Vacuum Tank 9a, 9b Oxygen Gas Supply Nozzle

Claims (9)

[Claims] 1. A magnetic recording medium in which a metal thin film type magnetic film is provided on a support, wherein Co ₂ O ₃ is present in the magnetic film. 2. A metal thin film type magnetic film is provided on a support.
A magnetic recording medium comprising:_TwoO_ThreeWith the presence of the magnetic
Co on the upper layer of the film_ThreeO _FourMagnetism characterized by the presence of
Mind recording medium. 3. The magnetic recording medium according to claim 1, wherein Co ₂ O ₃ is present in a portion other than the upper layer portion of the magnetic film. 4. The magnetic recording medium according to claim 1, wherein Co ₂ O ₃ is mainly present in the lower layer portion of the magnetic film. 5. The ratio of Co ₂ O ₃ in the magnetic film is 4
It is -50%, The magnetic recording medium in any one of Claims 1-4. 6. A half of the thickness of the magnetic film from the upper surface of the magnetic film.
The proportion of Co ₃ O ₄ in the portion up to the depth of 0 is 30 to
The magnetic recording medium according to claim 2, wherein the magnetic recording medium is 100%. 7. A step of depositing Co-based particles on a support, a step of supplying an oxidizing gas cooled in an initial stage where Co-based particles start to be deposited on the support, and Co-based particles on the support. And a step of supplying a heated oxidizing gas in the final stage of the end of the deposition of the magnetic recording medium. 8. The cooled oxidizing gas is cooled to −150 to 5 ° C., and the heated oxidizing gas is 80 to 2
The method for manufacturing a magnetic recording medium according to claim 7, wherein the magnetic recording medium is heated to 00 ° C. 9. The supply amount of the cooled oxidizing gas is 10 to 5
00 sccm, and the amount of heated oxidizing gas supplied is 1
9. The method for manufacturing a magnetic recording medium according to claim 7, wherein the magnetic recording medium has a size of 0 to 500 sccm.