JPH0973622A - Magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording medium having excellent electromagnetic conversion characteristics without pollution problems by providing the surface of a base with an Fe-N-O-based metallic magnetic film and increasing the content of O in the intermediate part in the thickness direction of this metallic magnetic film. SOLUTION: Olefin resins, such as polyester, including PET, etc., which are nonmanagement materials, are generally used for the base 1. The surface of the base 1 is suitably provided with an under coating layer in order to improve the adhesion property to the magnetic films. The base 1 is guided from a supply side roller 2a via guide rollers 3 to a cooling can roll 4a and is guided to a cooling can roll 4b via guide rollers 31 and is guided to a take-up side roll 2b. Fe material particles fly from crucibles 5a, 5b and adhere and deposit on the base at the time the base travels along the cooling can rolls 4a, 4b. The base is irradiated with nitrogen ions from an ion gun 6a and gaseous oxygen from a nozzle 7 is supplied from the downstream side at the time of the base travels along the can roll 4a, by which the surface of the base is provided with the metallic magnetic film contg. ample O.

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. In view of this problem, Fe is drawing attention. This Fe is low in price and rarely causes pollution problems. Then, as a Fe-based metal magnetic film, Fe-N-
O-based metal magnetic films have been proposed. However, the Fe-based metal magnetic films proposed so far have not been sufficient in coercive force, which is essential for high-density recording.

As a result of earnestly conducting research on this point, it was possible to obtain a great improvement in coercive force due to the structure of the Fe—N—O-based metal magnetic film. That is, Fe
It has been found that the magnetic properties such as the coercive force Hc and the residual magnetic flux density Br can be improved by controlling the O content ratio in the depth direction of the -N-O based metal magnetic film.

The present invention has been achieved on the basis of such knowledge, and causes less pollution problems.
An object of the present invention is to provide a magnetic recording medium excellent in electromagnetic conversion characteristics by using the e material.

[0006]

The object of the present invention is a magnetic recording medium comprising a support and a Fe--N--O type metal magnetic film provided on the support, wherein the metal magnetic film has a thickness direction. Is achieved by a magnetic recording medium characterized by having a high O content in the intermediate portion of.

In particular, in a magnetic recording medium in which a Fe--N--O type metallic magnetic film is provided on a support, the metallic magnetic film has a maximum O content in the middle portion in the thickness direction. It is achieved by a magnetic recording medium characterized in that In the above magnetic recording medium, the metal magnetic film preferably has a low Fe content in the middle portion having a high O content. In particular, although the Fe content is low in the middle portion where the O content is high,
It is preferable that the N content does not change significantly.

If the region showing the maximum value (maximum value) of the O content ratio is located too shallow, the electromagnetic conversion characteristics tend to be unpleasant, and conversely, even if it is located too deep, the electromagnetic conversion characteristics will be reduced. The characteristics tend to be unpleasant, and from this point of view, the region where the O content ratio shows a maximum value (maximum value) is
From the surface of the metal magnetic film to 1/4 to 1 / thickness of the metal magnetic film
Those at a depth of 2 are preferred. Further, in consideration of the thickness of the metal magnetic film, specifically, the distance from the surface of the metal magnetic film is 5
Those having a depth of about 00 to 1500Å are preferable.

The maximum value means that there is a peak (mountain) in a certain area, and the maximum value means that there is a maximum point in a certain area.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to Fe-N- on a support.
A magnetic recording medium provided with an O-based metal magnetic film, wherein the metal magnetic film has a high O content in an intermediate portion in the thickness direction. In particular, in a magnetic recording medium in which an Fe—N—O-based metal magnetic film is provided on a support, the metal magnetic film has a maximum O content in the middle portion in the thickness direction. is there.

The metallic magnetic film in the above magnetic recording medium has a low Fe content in the middle portion where the O content is high. In particular, although the Fe content is low in the middle portion where the O content is high, the N content does not change significantly. The region where the O content ratio shows a maximum value (maximum value) is at a depth of 1/4 to 1/2 of the thickness of the metal magnetic film from the surface of the metal magnetic film. Particularly, from the surface of the metal magnetic film to 500 to 15
It is at a depth of 00Å.

In the present invention, it is determined whether or not the intermediate portion having a high O content ratio has an intermediate portion, and whether or not the Fe content proportion is low in the intermediate portion having a high O content ratio.
Further, whether or not the N content in the region is not largely changed can be easily known by examining the Fe—N—O-based metal magnetic film by Auger electron spectroscopy. A typical example of the spectrum obtained by the Auger electron spectroscopy analysis is shown in FIG. Further, FIG. 5 shows an example of a spectrum which does not show the features of the present invention. According to this, whether or not it has an intermediate portion with a high O content ratio, whether or not the Fe content ratio is low in the intermediate portion with a high O content ratio, and N content in that region It is easy to see whether or not there is a large fluctuation in the ratio. It should be noted that slight variations are recognized in the distribution curves of the amounts of Fe, O, and N due to the difference in sensitivity. However, in the present invention, such minute fluctuations are not regarded as fluctuations and are considered to be smooth.

From the spectrum obtained by Auger electron spectroscopic analysis shown in FIG. 2 and the like, it can be seen that a carbon film as a protective film is provided on the outermost surface, and an Fe—N—O type metallic magnetic film is present under the carbon film. The starting point of this Fe—N—O based metal magnetic film is the distribution curve of C due to the carbon film and Fe.
It is considered as a position where the distribution curve of Fe resulting from the —N—O based metal magnetic film intersects. Further, the end point of the Fe—N—O based metal magnetic film is regarded as the position where the C distribution curve due to the support and the Fe distribution curve due to the Fe—N—O based metal magnetic film intersect.

The magnetic recording medium of the present invention having the above characteristics can be obtained as follows. First, the oblique vapor deposition apparatus of FIG. 1 is prepared. In FIG. 1, reference numeral 1 denotes a support, which may be magnetic or non-magnetic, but is generally non-magnetic. For such a support, an organic material such as polyester such as PET, polyamide, polyimide, polysulfone, polycarbonate, olefin resin such as polypropylene, cellulose resin, or vinyl chloride resin is mainly used. An undercoat layer for improving the adhesion with the magnetic film is appropriately provided on the surface of the support. 2a is a supply side roll of the support 1, 2b is a winding side roll of the support 1, and the support 1 is a supply side roll 2a
Is guided to the cooling can roll 4a through the guide roller 3 and then passes through the guide roller 3 and the cooling can roll 4b.
And finally to the winding-side roll 2b. In this traveling route, that is, the cooling can rolls 4a, 4
When traveling along b, particles of the Fe-based material come from the crucibles 5a and 5b, and adhere and deposit. When traveling along the cooling can roll 4a, nitrogen ions are emitted from the ion gun 6a. Also, oxygen gas is supplied from the nozzle 7 from the downstream side. In this manner, a Fe—N—O-based metal magnetic film (lower layer Fe—N—O-based metal magnetic film) rich in O is provided on the surface side in a thickness of 500 to 4500Å. Then, after that, when traveling along the cooling can roll 4b, the ion gun 6b irradiates the deposited metal film with nitrogen ions. As a result, the Fe—N-based metal magnetic film or the Fe—N—O-based metal magnetic film is provided on the lower Fe—N—O-based metal magnetic film to a thickness of 500 to 1500Å. That is, the Fe-N-O-based metal magnetic film having a high O content in the middle portion in the thickness direction is 1000 to 1000 on the support.
It is provided with a thickness of 6000Å.

When the Fe--N--O type metal magnetic film is provided, if necessary, 50 to 2 made of diamond-like carbon, boron carbide, silicon dioxide, silicon nitride or the like.
A protective film having a thickness of about 00Å is provided on the Fe—N—O based metal magnetic film. Further, a fluorine-based lubricant such as perfluoropolyether, a hydrocarbon-based lubricant, or a composite lubricant thereof is provided in a thickness of about 10 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.

[0017]

Example 1 The magnetic recording medium of this example is obtained by the oblique vapor deposition apparatus shown in FIG. That is, a non-magnetic support (PET film having a thickness of 6 μm) 1 is provided on the supply side roll 2
A is passed from a through the cooling can roll 4a and the cooling can roll 4b so as to be guided to the winding side roll 2b, and the inside of the vacuum chamber is evacuated to a vacuum degree of about 10 ⁻⁴ to 10 ⁻⁶ Torr. And PET running at a speed of 2.5 m / min
The Fe-based metal particles are attached and deposited on the PET film 1 by irradiating the film 1 with an electron beam from an electron gun. At this time, the deposited film is irradiated with nitrogen ions from the ion gun 6a, and oxygen gas is supplied from the nozzle 7 from the downstream side. As a result, F with rich O on the surface side
An e—N—O-based metal magnetic film (lower layer Fe—N—O-based metal magnetic film) is provided with a thickness of 1000 Å. Particles of the Fe-based material from the crucible 5b fly at the position of the cooling can roll 4b with respect to the PET film 1 provided with the lower Fe-NO-based metal magnetic film, and the lower Fe-N-O-based metal F deposited and deposited on the magnetic film with a total thickness of 2000Å
An eN0-based metal magnetic film is provided on the support. still,
Even at the position of the cooling can roll 4b, nitrogen ions are irradiated from the ion gun 6b toward the deposited film. However, oxygen gas is not supplied.

After that, E was formed on the Fe--N--O system metal magnetic film.
A diamond-like carbon film is formed to a thickness of 50Å by the CR plasma CVD method, and then a fluorine-based lubricant such as perfluoropolyether (trade name FOMBLIN A
M2001) was formed to a thickness of 20Å. Further, an Al vapor deposition film (back coat film) having a thickness of 0.2 μm is provided on the surface of the PET film 1 opposite to the surface on which the magnetic film is formed. A tape was made.

The spectrum obtained by Auger electron spectroscopy analysis of the thus obtained product is shown in FIG.
As can be seen from FIG. 2, at a depth of 1/4 to 1/2 of the thickness of the Fe—N—O-based metal magnetic film, 5 from the surface of the metal magnetic film.
The O content rate shows the maximum value in the depth range of 00 to 1500Å, and at this point Fe
Although the N content is low, the N content does not change significantly.

[0020]

Second Embodiment In the first embodiment, the ion guns 6a and 6b are used.
The amount of nitrogen ion irradiation from the nozzle and the amount of oxygen gas supplied from the nozzle 7 are changed, and the lower Fe—N—O-based metal magnetic film is changed to 1
000 Å thickness, total thickness of 1500 Å thickness, Fe-N- of the spectrum by Auger electron spectroscopy analysis of FIG.
A magnetic tape for 8 mm VTR was manufactured in the same manner as in Example 1 except that the O-based metal magnetic film was manufactured.

As can be seen from FIG. 3, at a depth of 1/4 to 1/2 of the thickness of the Fe--N--O type metal magnetic film, and within a region of 500 to 1500 Å from the surface of the metal magnetic film. Shows the maximum O content and the Fe content is low at this point, but the N content does not change significantly.

[0022]

Third Embodiment In the first embodiment, the ion guns 6a and 6b are used.
The amount of nitrogen ion irradiation from the nozzle and the amount of oxygen gas supplied from the nozzle 7 are changed, and the lower Fe—N—O based metal magnetic film is changed to 4
Fe-N- of the spectrum by Auger electron spectroscopic analysis of FIG. 4 is set to 500 Å thickness and the total thickness is 6000 Å thickness.
A magnetic tape for 8 mm VTR was manufactured in the same manner as in Example 1 except that the O-based metal magnetic film was manufactured.

As can be seen from FIG. 4, at a depth of 1/4 to 1/2 of the thickness of the Fe—N—O type metal magnetic film, and within a region of 500 to 1500 Å from the surface of the metal magnetic film. Shows the maximum O content and the Fe content is low at this point, but the N content does not change significantly.

[0024]

Fourth Embodiment In the first embodiment, the ion guns 6a and 6b are used.
The amount of nitrogen ion irradiation from the nozzle and the amount of oxygen gas supplied from the nozzle 7 are changed, and the lower Fe—N—O-based metal magnetic film is changed to 5
Fe-N-O of the spectrum by Auger electron spectroscopy analysis of FIG. 5 with the total thickness of 00Å and the total thickness of 2500Å
The same procedure as in Example 1 was carried out except that a metallic magnetic film was prepared.
A magnetic tape for 8 mm VTR was produced.

[0025]

Comparative Example 1 In Example 1, the cooling can roll 4a is used.
Was carried out in accordance with Example 1 except that the film thickness was 1500 Å at the position, but not at the position of the cooling can roll 4b.
A magnetic tape for mVTR was produced.

A spectrum obtained by Auger electron spectroscopy analysis of this Fe--N--O type metal magnetic film is shown in FIG. As can be seen from FIG. 6, the O content ratio is not high in the middle portion in the thickness direction of the Fe—N—O based metal magnetic film, and the O content ratio is high in the uppermost layer and the lowermost layer of the metal magnetic film. For example, the thickness of the Fe-N-O-based metal magnetic film is 1
In the depth of / 4 to 1/2, the O content ratio shows the minimum value.

[0027]

[Characteristics] The magnetic characteristics and electromagnetic conversion characteristics of the magnetic tapes obtained in the above examples were examined, and the results are shown in Table-1. Table-1 Hc (Oe) Br (G) Luminance S / N (dB) Color S / N (dB) Corrosion resistance AM PM ΔBs (%) Example 1 1680 5400 +1.2 +1.0 +1.1 −6 Example 2 1710 5000 +2.1 +0.6 +0.4 -8 Example 3 1540 5700 +0.5 +1.4 +1.7 -6 Example 4 1700 4800 +0.8 +0.2 +0.3 -9 Comparative Example 1 1580 5100 0 0 0 -6 * Magnetic characteristics are measured by VSM * S / N is measured by modifying a commercially available Hi8mm VTR and using a spectrum analyzer and signal oscillator * Corrosion resistance is displayed as a deterioration rate of Bs after being left at 60 ° C and 90% RH for 1 week According to this, Fe—N—O having the characteristics defined in the present invention
It can be seen that the metal-based magnetic film has excellent magnetic characteristics, high electromagnetic conversion characteristics, and further excellent corrosion resistance.

On the other hand, even Fe—N—O type metal magnetic films do not have the characteristics specified in the present invention.
It can be seen that the NO magnetic metal film is inferior in magnetic properties, inferior in electromagnetic conversion properties, and inferior in corrosion resistance.

[0029]

[Effect] A magnetic recording medium suitable for high density recording can be obtained by using an inexpensive 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 an Auger electron spectroscopic analysis spectrum of the Fe—N—O based metal magnetic film of the present invention.

FIG. 3 is an Auger electron spectroscopy analysis spectrum of the Fe—N—O-based metal magnetic film of the present invention.

FIG. 4 is an Auger electron spectroscopic analysis spectrum of the Fe—N—O based metal magnetic film of the present invention.

FIG. 5 is an Auger electron spectroscopic analysis spectrum of the Fe—N—O based metal magnetic film of the present invention.

FIG. 6 is an Auger electron spectroscopic analysis spectrum of a Fe—N—O based metal magnetic film outside the present invention.

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

Claims (6)

[Claims] 1. A magnetic recording medium comprising an Fe—N—O-based metal magnetic film provided on a support, wherein the metal magnetic film has a high O content in an intermediate portion in the thickness direction. A magnetic recording medium characterized by the following. 2. A magnetic recording medium comprising an Fe—N—O-based metal magnetic film provided on a support, wherein the metal magnetic film has a maximum O content in the middle portion in the thickness direction. What is shown is a magnetic recording medium. 3. The magnetic recording medium according to claim 1, wherein the metal magnetic film has a low Fe content in an intermediate portion having a high O content. 4. The metal magnetic film has a low Fe content in the middle portion having a high O content, but has a small fluctuation in the N content.
Or the magnetic recording medium according to claim 2. 5. The region in which the O content ratio has a maximum value is at a depth of 1/4 to 1/2 of the thickness of the metal magnetic film from the surface of the metal magnetic film. The magnetic recording medium according to claim 4. 6. The magnetic recording medium according to claim 1, wherein the region where the O content ratio has a maximum value is at a depth of 500 to 1500Å from the surface of the metal magnetic film.