JPH0721560A - Method of manufacturing magnetic recording medium - Google Patents

Abstract

(57) [Summary] [Structure] The vapor deposition source 7 is arranged so as to face the continuously running non-magnetic support 2, and a metal vapor flow evaporated from the vapor deposition source is applied onto the non-magnetic support 2 from a substantially vertical direction. Upon deposition, a magnetic field oriented parallel to the longitudinal direction of the non-magnetic support is applied to the metal vapor stream evaporating from the vapor deposition source. [Effect] It is possible to efficiently manufacture a vapor deposition film having an oblique axis of easy magnetization and to manufacture a magnetic recording medium having excellent recording and reproducing characteristics with high productivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a magnetic recording medium in which a magnetic layer is formed on a non-magnetic support by vacuum deposition.

[0002]

2. Description of the Related Art In the field of video tape recorders, for example, there is a strong demand for higher density in order to achieve higher image quality.
A magnetic layer is formed by directly depositing a magnetic material such as metal or Co-Ni alloy on the non-magnetic support by plating or vacuum thin film forming technology (vacuum deposition method, sparring method, ion plating method, etc.). A so-called metal thin film type magnetic recording medium has been proposed.

This metal thin film type magnetic recording medium is excellent not only in coercive force, squareness ratio and electromagnetic conversion characteristics in a short wavelength region, but also because the magnetic layer can be thinned, the packing density of the magnetic material is high. It has many advantages such as being able to do it. Among them, the magnetic recording medium of the vapor deposition type in which the magnetic layer is formed by the vacuum vapor deposition method has already been used as a high band 8 mm tape or a digital microtape because it has excellent short wavelength recording / reproducing characteristics and stable physical characteristics. It has been commercialized.

By the way, in order to manufacture the above vapor deposition type magnetic tape, as shown in FIG. 2, the non-magnetic support member 22 hung over the cooling can 21 and the vapor deposition source 23 are arranged to face each other and continuously run. A vapor deposition film is formed by depositing metal vapor evaporated from the vapor deposition source 23 on the non-magnetic support 22 to grow a metal structure.

At this time, when the metal vapor flow evaporated from the vapor deposition source is made incident on the surface of the non-magnetic support 22 in a direction perpendicular to the surface, the metal structure grows in a direction perpendicular to the axis of easy magnetization in the film thickness direction. A vapor deposition film is formed. On the other hand, as shown in FIG. 2, when the metal vapor flow is obliquely incident on the surface of the non-magnetic support 22 while the incident angle θ is regulated by the shielding plate 24, the metal structure grows in an oblique direction and the magnetization is increased. A vapor deposition film in which the direction of the easy axis is inclined with respect to the thickness direction of the vapor deposition film is formed.
The vapor-deposited film thus formed exhibits excellent recording / reproducing characteristics as a magnetic layer for longitudinal recording, as compared with a vapor-deposited film whose easy axis is the same as the thickness direction of the vapor-deposited film. In particular, it has been confirmed by experiments that a vapor-deposited film formed so that the easy axis of magnetization forms an angle of about 20 ° with the surface of the non-magnetic support has excellent recording and reproducing characteristics.

[0006]

However, when the metal vapor flow is obliquely incident on the surface of the non-magnetic support, a magnetic layer exhibiting excellent recording / reproducing characteristics is formed, but it is incident perpendicularly. Compared with the case, the deposition efficiency of the metal vapor flow is low and the growth rate of the metal structure is slow. Therefore, in order to grow to a predetermined thickness, it is necessary to slow down the running speed of the non-magnetic support and take a certain amount of time. Therefore, there is a problem that there is a limit to improvement in production efficiency.

Therefore, the present invention has been proposed in view of such a conventional situation, and a vapor deposition film in which the axis of easy magnetization is obliquely inclined with respect to the thickness direction is efficiently formed, and recording / reproducing characteristics are improved. An object of the present invention is to provide a method of manufacturing a magnetic recording medium, which can manufacture an excellent magnetic recording medium with high productivity.

[0008]

In order to achieve the above-mentioned object, the inventors of the present invention have conducted extensive studies, and as a result, when performing vapor deposition, a metal vapor flow is vertically incident on the surface of a non-magnetic support. In addition, by allowing the metal vapor stream to pass through the magnetic field in a direction parallel to the longitudinal direction of the non-magnetic support prior to the deposition on the surface of the non-magnetic support, the easy axis of magnetization with respect to the thickness direction. Thus, we have come to the knowledge that a vapor-deposited film that is obliquely inclined can be efficiently formed.

The present invention has been completed on the basis of the above-mentioned findings, and a vapor deposition source is arranged so as to face a continuously running non-magnetic support, and a metal vapor flow vaporized from the vapor deposition source is directed in a substantially vertical direction. In depositing on the non-magnetic support, a magnetic field oriented parallel to the longitudinal direction of the non-magnetic support is applied to the metal vapor flow evaporated from the vapor deposition source.

The vapor deposition source is a CoNi alloy. Further, the strength of the magnetic field applied to the metal vapor flow is 500 Oe or more.

[0011]

In the present invention, when forming a vapor deposition film, the vapor deposition source is arranged so as to face a continuously running non-magnetic support, and the metal vapor flow vaporized from the vapor deposition source is applied in a substantially vertical direction to the non-magnetic support. A magnetic field oriented parallel to the longitudinal direction of the non-magnetic support is applied to the metal vapor stream that is deposited on and vaporizes from the vapor deposition source.

When the vaporized metal vapor flow heated and evaporated is made to enter the continuously running non-magnetic support from a substantially vertical direction, the metal vapor flow efficiently adheres to the surface of the non-magnetic support and the metal structure grows at a high speed. Prior to the deposition of the metal vapor flow on the non-magnetic support, when a magnetic field in a direction parallel to the longitudinal direction of the non-magnetic support is applied to the metal vapor flow, the metal vapor flow is solidified. It is magnetized and oriented in the direction of this magnetic field, and the metal structure grows with an inclination. Therefore, the direction of the easy axis of magnetization tilts obliquely with respect to the thickness direction, and a vapor deposition film having excellent recording / reproducing characteristics can be efficiently formed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described with reference to the drawings.

First, a vacuum vapor deposition apparatus used in this embodiment is shown in FIG. That is, in the vapor deposition apparatus, a traveling system including an unwinding roll 3, a winding roll 4, and a cooling can 5 and a metallic magnetic material 7 serving as an evaporation source are housed in a chamber whose inside is in a high vacuum state. It is configured by accommodating a crucible 6 and the like.

A long non-magnetic support 2 is successively wound around the unwind roll 3, the cooling can 5 and the take-up roll 4, and is delivered from the unwind roll 3 to the cooling can 5 side to finally finish. It is designed to be wound around the winding roll 4. Further, a cooling device (not shown) is provided inside the cooling can 5 so as to control the deformation and the like of the non-magnetic support 2 due to the temperature rise.

The crucible 6 is disposed below the cooling can 5 and is opposed to the cooling can 5 at a position substantially parallel to the tangential direction of the cooling can 5. Then, the metallic magnetic material 7 contained in the crucible 6 is heated and evaporated by an electron gun or the like, and is deposited and formed as a magnetic layer on the non-magnetic support 2 traveling around the outer periphery of the cooling can 5. Has been done.

Between the cooling can 5 and the crucible 6 is provided a shield plate 8 for shielding the metal vapor flow due to the heating and evaporation of the metal magnetic material 7. The shielding plate 8 is
It covers a predetermined range of the non-magnetic support 2 so that the metal vapor flow is deposited on the non-magnetic support 2 within a predetermined angle range.

Further, in the above vapor deposition apparatus,
A pair of coils 9 are arranged between the shielding plate 8 and the cooling can 5, and the non-magnetic support 2 is arranged between the shielding plate 8 and the cooling can 5.
The magnetic field is formed in a direction parallel to the longitudinal direction of the. The pair of coils 9 magnetize and orient the metal vapor flow passing through the opening of the shield plate 8 in a direction parallel to the longitudinal direction of the non-magnetic support 2 before reaching the non-magnetic support 2. It is for.

In order to form a vapor deposition film on the non-magnetic support 2 by using the vapor deposition apparatus constructed as above, first the inside of the chamber is evacuated and then the unwinding roll 3 side to the winding roll 4 side. The non-magnetic support 2 is caused to travel over the entire length.
Then, the metal magnetic material 7 in the crucible 6 is heated and evaporated by an electron gun or the like. Of the heated and evaporated metal vapor flow, the metal vapor flow that has passed through the opening of the shield plate 8 passes through the magnetic field formed by the pair of coils 9 arranged between the shield plate 8 and the cooling can 5. As a result, the metal vapor flow is magnetized, and then vertically incident on and deposited on the non-magnetic support 2 to form a vapor deposition film.

At this time, since the metal vapor flow is incident on the surface of the non-magnetic support 2 in a direction perpendicular thereto, the metal vapor is efficiently deposited on the surface of the non-magnetic support 2 and the metal structure grows at a high growth rate. Further, the deposited metal vapor flow is magnetized and oriented in a direction parallel to the longitudinal direction of the non-magnetic support, and the metal structure grows obliquely. Therefore, the axis of easy magnetization is obliquely inclined with respect to the film thickness direction, and the vapor deposition film having excellent recording and reproducing characteristics can be efficiently formed.

In order to improve the recording / reproducing characteristics, it is preferable to form the vapor deposition film so that the easy axis of magnetization of the vapor deposition film is inclined by about 20 ° with respect to the surface of the non-magnetic support.
The easy axis of magnetization of the deposited film can be adjusted by controlling the magnitude of the magnetic field generated by the coil,
By setting the magnitude of this magnetic field to be 500 Oe or more, a vapor deposition film can be formed in which the easy axis of magnetization makes an angle of about 20 ° with the surface of the non-magnetic support.

As the metal material obliquely vapor-deposited by the vapor deposition apparatus, any of those usually used in the main medium can be used. For example, in addition to Co—Ni alloys, Co—Pt alloys, Co—Ni—Pt alloys, Fe
-Co alloy, Fe-Ni alloy, Fe-Co-Ni alloy,
Fe-Co-B alloy, Co-Ni-Fe-B alloy, etc. can be used.

As the non-magnetic support on which the vapor-deposited film is formed, those normally used in this type of medium can be used, for example, polyethylene terephthalate (PET) film, polyester such as polyethylene-2,6-naphthalate. Examples thereof include films, aromatic polyamide films, polyimide resin films and the like.

Next, a magnetic tape was actually manufactured using the above vapor deposition apparatus, and its magnetic characteristics and recording / reproducing characteristics were examined.

Experimental Example 1 to Experimental Example 4 First, the non-magnetic support 2 is housed in the crucible 6 of the above-mentioned vapor deposition apparatus while the Co--Ni type alloy is accommodated and the unwinding roll 3, the cooling can 5 and the winding roll 4 are covered. A polyethylene terephthalate (PET) film was wound. Then, after exhausting the inside of the chamber to 10 ⁻⁹ atm, a current is supplied to the coil to generate a magnetic field of a predetermined magnitude, and the Co—Ni-based alloy placed in the crucible 6 is irradiated with an electron beam. A 200-nm-thick vapor deposition film was formed by heating, melting and evaporating, and depositing on a PET film.

At this time, the current supplied to the electron beam for heating and vaporizing the vapor deposition source was set to 1.0 A. In the above vapor deposition apparatus, when the beam current is set in this way, a vapor deposition film having a film thickness of 200 nm is formed by setting the feeding speed of the nonmagnetic support to 30 m / min. The magnitude of the magnetic field generated by the coil is shown in Table 1.

The non-magnetic support on which the vapor deposition film was formed as described above was cut into a predetermined tape width to prepare a magnetic tape.

Experimental Example 5 A Co-Ni alloy having a film thickness of 200 nm was formed on a non-magnetic support by using an orthorhombic vapor deposition apparatus in which a metal vapor flow generated from a vapor deposition source was obliquely incident on the surface of the non-magnetic support. Was formed into a vapor deposition film. Then, the non-magnetic support on which the vapor deposition film was formed was cut into a predetermined tape width to prepare a magnetic tape.

The current supplied to the electron beam for heating and vaporizing the vapor deposition source was set to 1.0A. In the above-mentioned orthorhombic vapor deposition apparatus, if the beam current is set in this way, the feed rate of the non-magnetic support is set to 7 m / min to form a 200 nm-thick vapor deposition film. It

The magnetic easy axis, the coercive force, and the reproduction output of each magnetic tape produced as described above were measured.
The results are shown in Table 1 together with the magnitude of the magnetic field generated between the cooling can and the shutter set during the deposition of the deposited film and the traveling speed of the non-magnetic support.

In Table 1, the direction of the easy axis of magnetization is the angle between the surface of the non-magnetic support and the easy axis of magnetization measured by a sample vibrating magnetometer. Also, the playback output is a high-band 8 mm video deck (manufactured by Sony Corporation, trade name EVS-90.
0 remodeling machine), the output of a signal reproduced as a 7 MHz signal during reproduction was measured as a reproduction output under the conditions of a relative speed of 3.8 m / sec and a recording frequency of 7 MHz.
When measuring the reproduction output, the recording current for recording on each magnetic tape was set to a value at which the reproduction output was the highest.

[0032]

[Table 1]

In Table 1, first, Experimental Examples 1 to 4 in which vapor deposition was performed in a direction substantially perpendicular to the surface of the non-magnetic support and Experimental Example 5 in which vapor deposition was performed in a direction oblique to the surface of the non-magnetic support. Comparing the magnetic tape and the running speed of the non-magnetic support during vapor deposition, in Experimental Example 5, the running speed of the non-magnetic support was set to 7 in order to form a vapor deposition film having a thickness of 200 nm.
Whereas I had to set it slower to m / min,
In Experimental Example 1 to Experimental Example 4, the traveling speed of the non-magnetic support can be set as high as 30 m / min, which is about four times that in Experimental Example 5. From this, it is understood that it is more advantageous to perform vapor deposition in the direction perpendicular to the surface of the non-magnetic support in order to efficiently form the vapor deposited film.

Next, comparing Experiment Example 1 to Experiment Example 4 in which vapor deposition was performed in a direction substantially perpendicular to the surface of the non-magnetic support with respect to the magnitude of the applied magnetic field, the easy axis of magnetization, the coercive force, and the reproduction output, It can be seen that the easy axis, the coercive force, and the reproduction output change depending on the magnitude of the magnetic field applied to the metal vapor flow during vapor deposition. That is, when no magnetic field is applied to the metal vapor flow (Experimental Example 1), the axis of easy magnetization of the deposited film is perpendicular to the surface of the non-magnetic support, and the coercive force and the reproduction output show small values. When the magnitude of the magnetic field applied to the metal vapor flow is larger, the axis of easy magnetization of the vapor deposition film is inclined from the vertical to obliquely, and the coercive force and the reproduction output become higher accordingly. In particular, when a magnetic field of 1000 Oe is applied to the metal vapor flow (Experimental Example 4), a coercive force and a reproduction output equivalent to those obtained when vapor deposition is performed obliquely are obtained.

From the above, even when vapor deposition is performed in the vertical direction, the easy axis of magnetization tilts obliquely with respect to the thickness direction when a magnetic field parallel to the longitudinal direction of the non-magnetic support is applied to the metal vapor flow. It has been found that a vapor-deposited film can be formed and a magnetic recording medium having excellent recording and reproducing characteristics can be manufactured with high productivity.

[0036]

As is apparent from the above description, in the method of manufacturing a magnetic recording medium of the present invention, a vapor deposition source is arranged so as to face a continuously running non-magnetic support, and a metal vaporized from the vapor source is disposed. When depositing a vapor stream on a non-magnetic support from a substantially vertical direction, a magnetic field in a direction parallel to the longitudinal direction of the non-magnetic support is applied to the metal vapor stream evaporated from the evaporation source, so that the easy axis of magnetization is oblique. It is possible to efficiently form a vapor-deposited film that is tilted toward and to manufacture a magnetic recording medium having excellent recording and reproducing characteristics with high productivity.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a conventional vapor deposition device.

FIG. 2 is a schematic diagram showing a configuration example of a vapor deposition device to which the present invention is applied.

[Explanation of symbols]

 2 ... Non-magnetic support 5 ... Cooling can 7 ... Evaporation source 8 ... Shielding plate 9 ... Coil

Claims (3)

[Claims] 1. A vapor deposition source is arranged so as to face a continuously running non-magnetic support, and a metal vapor flow vaporized from the vapor deposition source is applied from the vapor deposition source to the non-magnetic support in a substantially vertical direction. A method for manufacturing a magnetic recording medium, which comprises applying a magnetic field in a direction parallel to a longitudinal direction of a non-magnetic support to a vaporized metal vapor flow. 2. The method of manufacturing a magnetic recording medium according to claim 1, wherein the vapor deposition source is a CoNi alloy. 3. The strength of the magnetic field applied to the metal vapor flow is 50.
The method of manufacturing a magnetic recording medium according to claim 1, wherein the magnetic recording medium is 0 Oe or more.