JPS60251522A - Production of vertically magnetizable recording medium - Google Patents

Abstract

PURPOSE:To provide a titled medium which is improved in the uniformity of easy magnetizability of a high permeability thin magnetic film layer and has excellent uniformity of recording efficiency and reproducing efficiency by providing a magnetic shielding plate between a disk-shaped substrate and an evaporating source to prevent the influence of the magnetic field from an electron gun. CONSTITUTION:Vapor deposition is executed after the magnetic shielding plate 8 is disposed between the disk-shaped base body 4 and the evaporating source 1 in the stage of depositing the high permeability thin magnetic film layer 5 consisting of an Fe-Ni alloy on the base body 4 by electron beam heating using the magnetic field deflection type electron gun 2. A vertically magnetizable recording layer 10 consisting of a Co-Cr alloy is then formed by vapor deposition on the layer 5. The influence of the magnetic field from the magnetic field deflection type electron gun is prevented by providing the magnetic shielding plate between the body 4 and the source 1 and therefore the uniformity in the easy magnetizability of the resultant thin high permeability magnetic film layer is improved and the vertically magnetizable recording medium having the excellent uniformity of the recording efficiency and regenerating efficiency is produced.

Description

[Detailed Description of the Invention] [Before Industrial Use] The present invention relates to perpendicular magnetization used in the so-called perpendicular magnetization recording method in which information is recorded using residual magnetization perpendicular to the magnetic surface of a recording medium. This relates to a method for manufacturing a recording medium.

[Background technology and its problems]

For example, disk-shaped magnetic recording media that can be randomly accessed are widely used as storage media for computers, etc., but conventionally, this type of magnetic recording media has a magnetic Recording is performed by magnetizing the recording layer in the horizontal direction (in-plane direction magnetization).

However, in the case of recording using in-plane direction magnetization, as the recording signal becomes shorter in wavelength, that is, as the recording density increases, the demagnetizing field within the medium increases, the residual magnetic flux density Br attenuates, and the reproduction output decreases. This has become a major obstacle in promoting high-density recording in order to increase storage capacity.

Therefore, conventionally, a perpendicular magnetization recording layer that performs recording by magnetization in the thickness direction of the recording layer of a magnetic recording medium is more advantageous than recording by in-plane magnetization described above, especially in short wavelength recording and high-density recording. It is known that

The perpendicular magnetization recording medium used in this type of recording method is a C
A single-layer perpendicular magnetization recording medium with a perpendicular magnetization recording layer made of an o-Cr alloy, and a high magnetic permeability magnetic thin film layer made of a KF e -N L alloy between the nonmagnetic substrate and the perpendicular magnetization recording layer. Two-layer film perpendicular magnetization recording media are being considered, but two-layer film perpendicular magnetization recording media are attracting particular attention because of their superior recording efficiency and reproduction efficiency.

By the way, in this two-layer film perpendicular magnetization recording medium, the magnetic properties of the high permeability magnetic thin film layer are important, and especially in a disk-shaped recording medium, recording and reproduction are performed over the circumference. It is desirable that the high permeability magnetic thin film layer has as little directional anisotropy as possible.

However, the above-mentioned high permeability magnetic thin film layer is manufactured by a vacuum evaporation method using an electron beam heating method from the viewpoint of productivity, etc., and since this type of heating method uses a magnetic field deflection type electron gun, Anisotropy has occurred in the high permeability magnetic thin film layer obtained by the influence of the magnetic field for deflecting the beam. Therefore, the ease with which the high permeability magnetic thin film layer is magnetized differs depending on the location, and the recording/reproducing efficiency of the resulting perpendicular magnetization recording medium differs depending on the location.

[Purpose of the invention]

Therefore, the present invention provides a method for manufacturing a permeable magnetic thin film layer that exhibits excellent magnetic properties as an in-plane magnetization layer of a disk-shaped perpendicular magnetization recording medium, thereby providing a perpendicular magnetic thin film layer with excellent uniformity of recording and reproducing efficiency. An object of the present invention is to provide a method for manufacturing a perpendicular magnetization recording medium that can produce a magnetization recording medium.

[Summary of the invention]

In order to achieve the above-mentioned objects, the present invention provides the following steps when depositing a high permeability magnetic thin film layer made of Fe-N4 alloy on a disk-shaped substrate by electron beam heating using a magnetic field deflection type electron gun. A magnetic shield plate is arranged between the substrate and the evaporation source to perform the vapor deposition, and then a perpendicular magnetization recording layer made of a K Co -Cr alloy is formed on the high permeability magnetic thin film layer by vapor deposition. It is something.

〔Example〕

Hereinafter, a method for manufacturing a perpendicular magnetization recording medium to which the present invention is applied will be explained in accordance with the process order.

In the present invention, first, as shown in FIG.
N = A circular film made of non-magnetic material such as polyimide or polyethylene terephthalate is placed in a vacuum chamber 3 of an electron beam heating type vacuum evaporation apparatus equipped with an evaporation source 1 such as an alloy ingot and a magnetic field deflection type electron gun 2. The disk-shaped substrate 4 to be formed is placed, and the evaporation source 1 is heated with an electron beam (indicated by a broken line in the figure) of the magnetic field deflection type electron gun 2 to form evaporated atoms on the surface of the disk-shaped substrate 40. The film is deposited to form a high permeability magnetic thin film layer 5. Here, in the magnetic field deflection type electron gun 2, the electron beam emitted from the filament 6 is bent by the magnetic field of the magnet 7, and the evaporation source 1
However, in the present invention, the disk-shaped substrate 4 and the evaporation source 10 are arranged so that the magnetic field of the magnet 7 does not affect the high permeability magnetic thin film layer 5. A magnetic shielding plate 8 having six predetermined windows (aa) is disposed in between. As a result, the magnetic field of the magnet 7 is shielded, and anisotropy does not occur in the high permeability magnetic thin film layer 5.

By the way, the magnetic shield plate 8 has six windows 8a.
The size of the magnet 7L affects production efficiency, but in general, when the magnetic field is strong, the window 8a should be made small, and when the magnetic field is weak, the window 8a should be made large. Since the magnitude of the influence also differs depending on the distance between 1 and the substrate 4, χ may be set appropriately depending on the situation.

As mentioned above, by providing the magnetic shield plate 8, the Fe-N, L, alloy thin film can be formed as the high permeability magnetic thin film layer 5 with a film thickness of 0.2 without being affected by the magnetic field of the magnetic field deflection type electron gun 2. After depositing the film to a thickness of about 1.0 μm, a KTb thin film 9 and a perpendicular magnetization recording layer 10 are sequentially deposited on the high permeability magnetic thin film layer 5 by sputtering, vapor deposition, etc., as shown in FIG. Perpendicular magnetization recording medium 1 having a configuration as shown in
Complete 1.

The perpendicular magnetization recording layer 10 is fabricated by depositing a Co--Cr alloy containing 10 to 25 atoms of Cr and the remainder being CO by sputtering, vapor deposition, etc., and by kneading. Excellent vertical alignment is obtained.

The TL thin film 9 is provided to improve the film growth rate of the perpendicular magnetization recording layer 10 and form an excellent Co-Cr alloy film, and has a thickness of 100 to 50 mm.
Selected as OK. If the thickness of the TL thin film 9 is less than 100λ, it will be difficult to form a continuous TL film, and there is a risk that the effect as a TL base film will be insufficient. No further effects were observed on the magnetic properties or mechanical properties of the Cr alloy film. Note that this TL thin film 9 may be omitted depending on the case.

As described above, according to the above manufacturing method, since the magnetic shield plate 8 for shielding the magnetic field of the magnetic field deflection type electron gun 2 is provided between the disk-shaped substrate 4 and the evaporation source 1, A high permeability magnetic thin film 5 with little anisotropy and excellent uniformity is obtained, and as a result, it is possible to produce a perpendicular magnetization recording medium 11 with excellent uniformity in recording efficiency and reproduction efficiency.

That is, the perpendicular magnetization recording medium 11 or the third
As shown in the figure, a vertical magnetic head 14 comprising a main magnetic pole 12 and an auxiliary magnetic pole 13 is moved in sliding contact with the main magnetic pole 12.
The perpendicular magnetization recording layer 10 is magnetized in the thickness direction by the magnetic lines of force (indicated by broken lines in the figure) emitted from the magnetic field, and the lines of magnetic force are passed through the high permeability magnetic thin film layer 5 that is blocked by the in-plane magnetization layer to form the auxiliary magnetic pole. This may be because the Fe--Nb alloy thin film is easily magnetized regardless of the direction of the magnetic lines of force. Since these are the same, the recording efficiency and reproduction efficiency are approximately the same regardless of the orientation of the perpendicular magnetization recording medium 11.

Hereinafter, specific embodiments of the present invention will be explained.

Example 1 A disk-shaped substrate made of bolywood was prepared, and a film thickness of 0.394 was deposited on this substrate under the following evaporation conditions using an electron beam heating type vacuum evaporation apparatus using a magnetic field deflection type electron gun.
m of Fe-N=alloy thin film (Fe21.5%, N, 78
．． 5) was deposited.

Vapor deposition conditions vacuum degree 2. OX 10 Torr Substrate temperature 260°C Vapor deposition rate 39 people/sec At this time, a magnetic shield plate was provided between the substrate and the evaporation source for vapor deposition, but the strength of the magnetic field at the substrate position was 0.
5 I rarely met Oersted.

Next, a vacuum degree of 2.0 × 10
-'T..., a TL thin film with a film thickness of 300λ was formed under the conditions of a substrate temperature of 180°C and a deposition rate of 14 feet/g, and a vacuum degree of 2.0 × 10-' Torr on this TL thin film.
A sample disk was prepared by forming a Co--Cr alloy film with a thickness of 0.1 μIn at a substrate temperature of 180° C. and a deposition rate of 32 Eh/sec.

Magnetic fields were applied to the Fe-NL alloy thin film of the obtained sample disk in J% directions in the KA, B, and C directions as shown in Figure 4, and the coercive force HC and the magnitude of the magnetic field required for magnetization were determined. Examined. The results are shown in Table 1. In Table 1, H(0,8Is) is the magnitude of the magnetic field required to magnetize to 80% of the saturation magnetization, and H(0,9IS) is the magnitude of the magnetic field required to magnetize to the 90th factor of the saturation magnetization. It's something that shows.

Table 1 From Table 1, it can be seen that the uniformity of magnetization was improved compared to the comparative example described below.

Comparative Example In Example 1, except for the magnetic shield plate, Fe-
A sample disk was prepared in the same manner as in Example 1 by depositing a Ni alloy thin film.

The strength of the magnetic field at the substrate position when the Fe--Ni alloy thin film was deposited was Oersted.

Regarding the obtained Fe--Ni alloy thin film 4 of the sample disk, the coercive force He and the magnitude of the magnetic field required for magnetization were investigated in the same manner as in Example 1 above.

The results are shown in Table 2.

Table 2 [Effects of the Invention] As is clear from the description of the above embodiments, according to the present invention, a magnetic shield plate is provided between the disk-shaped substrate and the evaporation source to prevent the magnetic field of the magnetic field deflection type electron gun. Since the influence of the above is prevented, the uniformity of the ease of magnetization of the obtained high permeability magnetic thin film layer is improved, and therefore, it is possible to manufacture perpendicular magnetization recording media with excellent uniformity of recording efficiency and reproduction efficiency. It is possible.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an example of an electron beam heating type vacuum evaporation apparatus using a magnetic field deflection type electron gun used for forming a high permeability magnetic thin film layer, and Fig. 2 shows a perpendicular magnetization produced by the present invention. FIG. 3 is a sectional view of a main part showing the structure of a recording medium, and is a schematic diagram for explaining the perpendicular magnetization recording method. Figure 4 shows the coercive force H in the examples and comparative examples of the present invention.
FIG. 3 is a schematic plan view showing the direction of the magnetic field applied when measuring e and the magnitude of the magnetic field required for magnetization. 1... Evaporation source 2... Magnetic field deflection type electron gun 4... Disc-shaped substrate 5... High permeability magnetic thin film layer 8... Magnetic shield plate patent applicant N21 Co., Ltd. agent Patent attorney Kodo Shi Koike 1) Ei Mura - Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] When depositing a high permeability magnetic thin film layer of Fe-NL gold alloy on a disk-shaped substrate by electron beam heating using a magnetically deflected electron gun, a magnetic shield plate is placed between the substrate and the evaporation source. Then, a perpendicular magnetization recording layer made of KCo-Cr alloy is deposited on the high permeability magnetic thin film layer Kx! 1. A method for manufacturing a perpendicular magnetization recording medium, characterized by forming a perpendicular magnetization recording medium.