JPH0991669A - Magnetic recording media - Google Patents

Abstract

(57) Abstract: To provide a magnetic recording medium having a large coercive force and capable of coping with high density recording. Kind Code: A1 A magnetic recording medium in which an Fe-based metal magnetic film containing N is provided on a support, wherein the Fe-based metal magnetic film has an oblique column structure, and the periphery of the magnetic column. Part is mainly Fe ₂ N and / or Fe ₃ N
A magnetic recording medium composed of.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a magnetic recording medium having an Fe-based metal magnetic film.

[0002]

A metal thin film type magnetic recording medium in which a magnetic film is formed by dry plating means such as vapor deposition or sputtering is widely known. There are various materials for forming the magnetic film. As such magnetic materials, Co-Ni and Co-Cr based magnetic alloys have been mainly used so far.

However, Co, Ni, Cr, etc. are expensive. There are also concerns about pollution problems. In view of the above problems, attention is paid to Fe. This Fe is low in price and rarely causes pollution problems. An Fe-N-based metal magnetic film has been proposed as the Fe-based metal magnetic film.

However, the Fe-based metal magnetic films proposed so far have not been sufficient in coercive force, which is essential for high-density recording. While working diligently on this point, I came across an unexpected result. That is, iron nitrides of Fe ₂ N and Fe ₃ N never showed excellent magnetic properties, but when they coexist, they showed excellent magnetic properties.

The present invention has been achieved based on this finding, and an object of the present invention is to provide a magnetic recording medium having a large coercive force and capable of coping with high density recording.

[0006]

The object of the present invention is a magnetic recording medium comprising a support and a Fe-based metal magnetic film containing N, wherein the Fe-based metal magnetic film is an oblique column. It has a structure and the periphery of this magnetic column is
It is achieved by a magnetic recording medium characterized by being mainly composed of Fe ₂ N and / or Fe ₃ N.

A magnetic recording medium comprising an Fe-based metal magnetic film containing N on a support, wherein
In the Auger electron spectroscopic analysis of the metal magnetic film (the sputtering direction is diagonal to the metal magnetic film), the Fe amount has a wavy pattern when the Fe amount is on the vertical axis and the sputtering time is on the horizontal axis. Is achieved by a magnetic recording medium.

In particular, a magnetic recording medium comprising an Fe-based metal magnetic film containing N on a support, wherein
In the Auger electron spectroscopic analysis of the e-based metal magnetic film (the sputtering direction is oblique to the metal magnetic film), the vertical axis represents Fe.
When the amount of sputtering is plotted on the horizontal axis, the amount of Fe has a wavy pattern, and the Fe-based metal magnetic film has an oblique column structure, and the peripheral portion of this magnetic column is mainly Fe. _This is achieved by a magnetic recording medium characterized by being composed of ₂ N and / or Fe ₃ N.

In the above Fe-based metal magnetic film of the present invention,
Fe: N is 60 to 90 at. %: 10 to 40 at. % Is preferred. More preferably, 70-85 at. %: 15
~ 30 at. %.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A magnetic recording medium according to the present invention is a magnetic recording medium in which a Fe-based metal magnetic film containing N is provided on a support, and the Fe-based metal magnetic film is an oblique column. It has a structure and the periphery of this magnetic column is
It is mainly composed of Fe ₂ N and / or Fe ₃ N. Alternatively, it is a magnetic recording medium in which a Fe-based metal magnetic film containing N is provided on a support, and the Auger electron spectroscopy analysis of the Fe-based metal magnetic film (sputtering direction is oblique to the metal magnetic film). ), When the Fe amount is plotted on the vertical axis and the sputtering time is plotted on the horizontal axis, the Fe amount has a wavy pattern. In particular, a magnetic recording medium having a Fe-based metal magnetic film containing N provided on a support, wherein the Fe-based metal magnetic film is subjected to Auger electron spectroscopy analysis (sputtering direction is oblique to the metal magnetic film). ), When the Fe amount is plotted on the vertical axis and the sputtering time is plotted on the horizontal axis, the Fe amount has a wavy pattern, and
The metallic metal magnetic film has an oblique column structure, and the peripheral portion of this magnetic column is mainly Fe ₂ N and / or Fe ₃
It is composed of N.

In the above Fe-based metal magnetic film, Fe:
N is 60 to 90 at. %: 10 to 40 at. %, Especially 7
0-85 at. %: 15 to 30 at. %. In this specification, the wavy pattern refers to a pattern in which an amplitude variation of about 10% or more is recognized from the central virtual line except for the initial peak. Therefore, in the case of a small vibration of about several percent, it is not regarded as a wavy pattern.

Such a magnetic recording medium can be manufactured by using a PVD (physical vapor deposition) method such as vapor deposition or sputtering. For example, a vapor deposition method with a high film formation rate will be described as follows. First, for example, Fe in the total metal components is 95 to 98.5 wt% (so-called,
Fe with a purity of 95-98.5 wt%), Au, Pt, A
The total amount of g is 0 to 0.05 wt% (It is good that it is 0, but it may be contained as an unavoidable impurity to some extent. Even if it is contained, the total amount of Au, Pt, and Ag is included. Of the other metal components (for example, Co and N)
An Fe-based metallic material (i, Mn, Cr, etc.) is put in the crucible of the oblique vapor deposition apparatus. Such purity (95-9
(8.5 wt%) Fe material was used, and the purity was 99.
This is because it is much cheaper than the case of using high-purity Fe such as 95 wt% or more. Of course, 98.5
You may use high purity Fe of wt% or more. Then, the inside of the oblique vapor deposition apparatus is evacuated to a predetermined degree of vacuum, and the Fe-based metal material is evaporated (scattered) by an electron gun or other means to attach the Fe-based metal particles to the running support.
Deposit. At the time of this attachment / deposition, nitrogen ions are irradiated toward the Fe-based metal particle deposition surface. One of the features is that the dose of this nitrogen ion is higher than before. That is, when the dose of nitrogen ions was small, the metal magnetic film having the features of the present invention could not be obtained. For example, as shown in a comparative example described later, even if the same method is adopted, if the amount of nitrogen introduced is changed, the structure of the metal magnetic film proposed by the present invention is not obtained, and only a low coercive force is obtained. I can't. By the way, the amount of nitrogen gas supplied to the ion gun for irradiating nitrogen ions is conventional (the conventional amount of nitrogen gas is ⁵ scc when the vacuum degree in the vacuum chamber is 7 × 10 ⁻⁵ Torr).
m) was required about 2 to 5 times.

When the Fe-based metal magnetic film having a thickness of 1000 to 4000 Å is provided as described above, if necessary,
A protective film made of diamond-like carbon, boron carbide, silicon nitride or the like and having a thickness of about 50 to 200Å is provided on the Fe-based metal magnetic film. Further, a fluorine-based lubricant such as perfluoropolyether is provided with a thickness of about 20 to 70Å.

The magnetic recording medium configured as described above has a high coercive force and a high saturation magnetic flux density, and can be used for high density recording. Moreover, it was also excellent in corrosion resistance. Moreover, the magnetic material Fe is inexpensive and is unlikely to cause pollution problems. In particular, since it is not necessary to use high-purity Fe, the cost is lower.

[0015]

Embodiment 1 FIG. 1 is a schematic view of a magnetic recording medium manufacturing apparatus according to the present invention, and FIG. 2 is a schematic view of an ion gun. FIG.
Medium 1 is a non-magnetic support such as PET film, 2a
Is a PET film 1 supply side roll, 2b is a PET film 1 winding side roll, 3 is a cooling can roll, 4 is a shielding plate, 5 is a crucible, 6 is a Fe-based magnetic metal, 7 is an output 10
A kW electron gun, a vacuum chamber 8 and an ion gun 9. This ion gun 9 has the structure shown in FIG.
A current of 8 A is applied to the tungsten cathode 10 of φ,
500 between the anode 11 and the screen grid 12
A potential difference of V can be formed, and when nitrogen gas is supplied from the nozzle 13, nitrogen ions are emitted. Incidentally, 14 is a magnet.

The magnetic recording medium (magnetic tape) of this embodiment is obtained by using the oblique vapor deposition apparatus shown in FIG. That is, the PET film 1 having a thickness of 6.3 μm is passed between the supply side roll 2a and the winding side roll 2b,
It runs along the cooling can roll 3. After evacuation of the vacuum chamber 8 to a vacuum degree of about 10 ⁻⁴ to 10 ⁻⁶ Torr, for example, about 5 × 10 ⁻⁶ Torr, heating of the electron beam from the electron gun 7 causes the magnetic metal (purity of 99. 9 wt%
Fe) was melted and evaporated, and an Fe-based metal magnetic film having a thickness of 1800Å was provided on the PET film 1.

At the time of forming the Fe-based metal magnetic film, nitrogen gas was supplied from the nitrogen gas supply nozzle 13 at 10 sccm to irradiate the Fe-based metal magnetic film from the ion gun 9 with nitrogen ions. On the back surface of the raw sheet having the Fe-N-based metal magnetic film thus obtained, carbon black having an average particle diameter of 40 nm and carbon black having an average particle diameter of 80 nm were mixed at a ratio of 2: 1 to prepare urethane. A back coat paint dispersed in a binder resin of a base resin and a vinyl chloride resin was applied by a die coating method to a dry film thickness of 0.5 μm and dried.

After this, perfluoropolyether (FO
MBLIN ZDOL Montecatini Co., Ltd.) was diluted with a fluorine-based inert liquid (Fluorinert FC-77 Sumitomo 3M Co., Ltd.) to a concentration of 0.05 wt%, and a dry film thickness of 20 Å was obtained by a die coating method. It was coated on a -N-based metal magnetic film and dried at 105 ° C.

After that, it was slit into a width of 8 mm and loaded into a cassette to obtain a magnetic tape for 8 mm VTR.

[0020]

Example 2 The procedure of Example 1 was repeated except that the amount of nitrogen gas supplied from the nozzle 13 was changed to 20 sccm. In addition, the obtained Fe-based metal magnetic film is 1810 Å
Met.

[0021]

Comparative Example 1 The procedure of Example 1 was repeated, except that the amount of nitrogen gas supplied from the nozzle 13 was changed to 5 sccm. The obtained Fe-based metallic magnetic film had a thickness of 1790Å.

[0022]

[Comparative Example 2] In Example 1, except that the ion gun 9 was not operated, and the nitrogen gas was irradiated at a rate of 6 sccm toward the Fe-based metal magnetic film when the Fe-based metal magnetic film was formed. It carried out according to it. The obtained Fe-based metallic magnetic film had a thickness of 1820Å.

[0023]

[Characteristics] Cross-sectional TEM images of the Fe-based metal magnetic films obtained in the above examples are shown in FIGS. 7 to 10 show the results of Auger electron spectroscopic analysis (the sputtering direction is oblique to the metal magnetic film (column)).

In the Auger electron spectroscopic analysis, the acceleration voltage of the electron gun is 10 kv, the emission current thereof is 10 nA, the etching gas is Ar gas, the gas is introduced into the ion gun, and the acceleration voltage is 3 kv. Current 4
Etching was performed at 00 nA for 50 seconds and measurement was repeated to analyze the depth direction of the film. 7 to 10
Indicates an etching time of 1000 to 3000 seconds. still,
The etching time required from the surface of the magnetic film to the support is 6000 seconds.

According to this, the Fe-based metal magnetic film according to the present invention has an oblique column structure, and the peripheral portion of this magnetic column is mainly composed of Fe ₂ N and Fe ₃ N. I understand. Also, according to Auger electron spectroscopy analysis (the sputtering direction is an oblique direction with respect to the metal magnetic film), it is found that the Fe amount has a wavy pattern.

With respect to the obtained magnetic tape, the magnetic properties (coercive force Hc, saturation magnetic flux density Bs) and corrosion resistance (decrease in saturation magnetic flux density after being immersed in 5 wt% saline at 20 ° C. for 1 week) Since I checked the rate ΔBs),
The results are shown in Table-1. Table-1 Coercive force Hc (Oe) Saturation magnetic flux density Bs (G) Corrosion resistance ΔBs (%) Example 1 1530 5900 4 Example 2 1670 5200 3 Comparative example 1 330 10300 7 Comparative example 2 120 15700 48 48 , The present invention has Hc of 1000 O
e or more and Bs is 4000 G or more, which means that high density recording can be supported.

It can also be seen that the corrosion resistance is excellent.

[0028]

Industrial Applicability A magnetic recording medium suitable for high density recording and having excellent corrosion resistance is obtained by using an inexpensive Fe-based material.

[Brief description of drawings]

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

FIG. 2 is a schematic diagram of an ion gun.

FIG. 3 is a cross-sectional TEM of the Fe—N-based metal magnetic film of Example 1.
image

FIG. 4 is a cross-sectional TEM of the Fe—N-based metal magnetic film of Example 2.
image

5 is a cross-sectional TEM image of the Fe—N-based metal magnetic film of Comparative Example 1. FIG.
image

6 is a cross-sectional TEM image of a Fe—N-based metal magnetic film of Comparative Example 2. FIG.
image

FIG. 7 is a graph of Auger electron spectroscopy analysis of the Fe—N-based metal magnetic film of Example 1.

FIG. 8 is a graph of Auger electron spectroscopy analysis of the Fe—N-based metal magnetic film of Example 2.

FIG. 9 is a graph of Auger electron spectroscopy analysis of the Fe—N-based metal magnetic film of Comparative Example 1.

FIG. 10 is a graph of Auger electron spectroscopy analysis of a Fe—N-based metal magnetic film of Comparative Example 2.

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[Submission date] September 29, 1995

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 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junko Ishikawa 2606 Akabane, Kai-cho, Haga-gun, Tochigi Prefecture Kao Corporation Company Information Science Laboratory

Claims (3)

[Claims] 1. A magnetic recording medium comprising an Fe-based metal magnetic film containing N provided on a support, wherein the Fe-based metal magnetic film has an oblique column structure. A magnetic recording medium characterized in that the peripheral portion is mainly composed of Fe ₂ N and / or Fe ₃ N. 2. A magnetic recording medium comprising a Fe-based metal magnetic film containing N on a support, said Auger electron spectroscopy analysis of said Fe-based metal magnetic film (sputtering direction relative to the metal magnetic film). (A diagonal direction), the vertical axis represents the amount of Fe and the horizontal axis represents the sputtering time, so that the magnetic recording medium has a wavy pattern. 3. A magnetic recording medium comprising an Fe-based metal magnetic film containing N provided on a support, the Auger electron spectroscopy analysis of the Fe-based metal magnetic film (sputtering direction relative to the metal magnetic film). (A diagonal direction), the Fe amount is plotted on the vertical axis and the sputtering time is plotted on the horizontal axis, and the Fe amount has a wavy pattern, and the Fe-based metal magnetic film has a diagonal column structure. A magnetic recording medium characterized in that the peripheral portion of this magnetic column is mainly composed of Fe ₂ N and / or Fe ₃ N.