JPH0319124A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain the magnetic recording medium having reliability and excellent high-density digital recording and reproducing performance in combination by disposing a thin film of a ferromagnetic metal in which diagonally vapor deposited columnar fine particles and perpendicularly vapor deposited columnar fine particles are integrated on a substrate. CONSTITUTION:This recording medium is constituted by disposing the thin film of the ferromagnetic metal in which the columnar fine particles 2 consisting of the diagonally vapor deposited columnar fine particles and perpendicularly vapor deposited columnar fine particles are integrated on the substrate consisting of a high-polymer film 1. The ferromagnetical coupling among the columnar fine particles 2 is, therefore, weakened, unlike with an ordinary perpendicularly magnetized film. Noises are lowered and the higher C/N is obtd. A good error rate is obtd. in the high-density digital recording and reproducing; in addition, a lubricant intrudes in the spacings between the columnar particles 2 and the durability is improved. The magnetic recording medium for perpendicular magnetic recording having the high-density recording performance and the durability balanced at the high level is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording medium that is effective for use in magnetic tapes and the like.

Over the past few years, magnetic recording technology has made remarkable progress, with improvements in recording density, miniaturization, high performance, and multi-functionality of dividing devices, and this trend is expected to continue in the future. It is predicted that the magnetic media, which is an important element, will have a thin film magnetic recording layer. Improvements are being made toward the adoption of perpendicularly magnetized thin films.

Perpendicular magnetization thin films are typified by Co-Cr sputtered films,
Ni-Fe,! : In the combination of Cjo-Cr so-called laminated two-layer media and a single magnetic pole head, aso
Recording and playback of KFRPI has been reported.
Transactions on Magnetics (IK [T
RANSACTIONS ON MAGNETICS)
Vol. West ▲G 23 ,45 2072( 1
987) ], while Co-Cr-Wb
It has also been confirmed that high density can be achieved using the existing interface technology between a single layer film and a ring head [JP-A-61-771]
Publication No. 28] Expectations for practical application are high. An important theme today for practical use is magnetic disks with excellent durability and good recording performance. Magnetic tape? This can be said to be the establishment of a technology for manufacturing magnetic recording media such as those with good reproducibility and at high speed. In view of these circumstances, we developed electron beam evaporation technology [IEE Transactions on Magnetics].
IKKKTRANSACTI■N8 0N MAGNK
TICS) Vo7j. M A-23. 5 24
49 (1987) B-sho] Sputtering method [same magazine 24
43 (1987)] is mainly discussed.

Problems to be Solved by the Invention However, in order to obtain high-density digital recording with sufficient reliability using a Co-Cr perpendicular magnetization film, more than 200 protective films are currently required, and the pit length is short. In this case, the output was insufficient and the error rate could not be maintained, so improvements were desired. The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a magnetic recording medium that has both reliability and excellent high-density digital recording and reproducing performance.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention has a ferromagnetic metal thin film integrally composed of columnar fine particles of obliquely deposited fine particles and vertically deposited fine particles arranged on a substrate. be.

Operation Due to the above-mentioned feature, the magnetic recording medium of the present invention has weak ferromagnetic coupling between columnar fine particles, unlike conventional perpendicular magnetization films, and has low noise (F) and high C/N, allowing for high-density digital recording. Not only can a good error rate be obtained during regeneration, but also lubricant enters the gaps between columnar particles, improving durability.

EXAMPLES Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

[Example 1] Fig. 1 is an enlarged cross-sectional view of a magnetic recording medium according to an embodiment of the present invention, and Fig. 2 shows the main components of an electron beam evaporation apparatus used to manufacture the magnetic recording medium according to an embodiment of the present invention. FIG. 1st
In the figure, 1 is a substrate made of a polymer film such as polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, phoriate-sulfone, polyetheretherketone, polyamideimide, polyimide, etc., and has granular protrusions. It is also possible to use a material on which a worm-like raised layer is arranged in advance. 2 is a columnar fine particle constituting a strong metal thin film, which is a combination of obliquely deposited fine particles and vertically deposited fine particles, and the vertically deposited fine particles are Co-Cr, Co.
-Ti, Co-W, Co-Mo, Co-
0 etc., obliquely vaporized 41 fine particles are Cjo-Cr, Coo-
Ti, Co-W, Co-Mo,
Co-OCo-Ta, Cr, W, M
It can be selected from materials such as O, Ti, Ta, Si, Co, etc. Although not shown in the drawings, the magnetic recording medium of the present invention can be constructed by disposing a protective lubricant layer on a ferromagnetic metal thin film and disposing a pack coat layer on the opposite side of the substrate, etc., as necessary, and is put into practical use. It is provided.

FIG. 2 is a block diagram of the main parts of the vapor deposition apparatus used to manufacture the magnetic recording medium of the present invention. In Figure 2, 3 is the substrate, 4 is the rotating support, 6 is the unwinding shaft, 6 is the winding shaft 9, T is the electron beam evaporation source ▲, 8 is the electron beam evaporation source B, and 7 is the vapor pressure control. When using an alloy system that is difficult to evaporate, a dual evaporation source may be used, and in that case, it is preferable to arrange them in close contact with each other. γ
8 is the shape of the vertically evaporated fine particle part, and 8 is the evaporation source and the mask 1 so that it is in the shape of the obliquely evaporated particulate part.
1. Optimize the relationship in 12. 9 and 1o are steam flows ▲
, which schematically shows steam flow B.

Examples of the present invention will be specifically described below in comparison with comparative examples.

Using a polyimide film with a thickness of 9μ, one diameter is 50 (1
30℃ in advance along the cylindrical can of 'll1.
After degassing, diagonal vapor deposition and vertical vapor deposition were performed in combination at a temperature of 220°C to form various thin films. 26 to 0.93119
/m" Coating L. 0.5 μml +7) A coat layer was applied and processed into an 8 mm wide tape.

On the other hand, the tape used in the comparative example was obtained by performing diagonal deposition and then vertical deposition.

Using each magnetic tape, recording was performed using a modified 8mm video tape with a gap length of 0.12μ, a track pitch of y-6μ, and a bit length of 0.2μ, and the playback OA was compared.
The time required for the still playback output to decrease by 3 (IB) was compared.The tape conditions and evaluation results are summarized in Table 1.

(Margins below) As shown in Table 1, the products of the present invention have excellent durability and good O/N in high density regions, and are suitable for high density magnetic recording.

[Example 2] Another means for solving the problem is to oxidize the surface of Co-based vertically aligned columnar fine particles having a chrysanthemum flower-like polarization layer to form a magnetic recording layer. With the above-described configuration, the magnetic recording medium of the present invention improves the magnetic separation between columnar fine particles, and the magnetization mode becomes dominated by the rotational magnetization mode, resulting in finer magnetization units, which improves both output and noise. become. Examples will be described below with reference to the drawings. FIG. 3 is an enlarged sectional view of the magnetic recording medium of the present invention;
The figure is a top sectional view of columnar fine particles.

In Fig. 3, 13 is a perpendicular magnetization film represented by a co-cr perpendicular magnetization film, such as Co-1r-Wb, Co-ICr-
Ru, Co-Ti, Co-Mo, Co-W
etc., but the point is that the chrysanthemum flower-like polarized eyebrows are present in the columnar fine particles, as shown in Figure 4, and a perpendicularly magnetized film is formed. Such a structure is similar to that of II [KTra
nsaotions on Magnetios)
Vol, MAG-23. 2061 (1 98
7), this phenomenon mainly occurs in relation to the substrate temperature of polymer films, etc., and is mainly caused by electron beam evaporation. Ion grating method. The conditions for the ion beam deposition method may also be examined, and the film may be formed under the optimum conditions. 14 is a protective film such as a plasma polymerized film, Si02 film, carbon film, etc., and 16 is a lubricant such as fatty acid, fatty acid amide, half-fluoropolyether, perfluorocarboxylic acid, etc.

Note that before placing the perpendicular magnetization film, Ti, Co, S1, Cr
It is also possible to form an underlayer such as or a soft monomagnetic layer such as vermalloy, and it is possible to form a disc-shaped. It can be said that the configuration should be optimized depending on the tape-like embodiment.

In FIG. 4, 16 is a ColJ layer, 17d is a CrjJ layer (in the case of Co-Cr), and 18 is a Cor\1 layer.

This structure is compared to another type of polarization, in which the interior of the column is thought to be a Co-rich layer and the wall of the column is thought to be a CrU-rich layer. 19. Magnetically speaking, the presence of a plurality of magnetic particles 16 inside one is an element of noise improvement.

The formation of the COJ layer 1B is preferably carried out under dry conditions at a high temperature, and in the case of a tape, this step can also serve as a step of thermally shrinking the polymer film to flatten it. Of course, treatment may be performed in an ozone atmosphere to increase the speed. The purpose of the Co oxide layer is to weaken ferromagnetic coupling, and it is sufficient to have at most 20 to 40 layers.

Hereinafter, more specific examples will be explained in comparison with comparative examples.

Using polyimide film gold with a thickness of 12 μm, targeting GO alloy, ▲r +H2=I X10'~1
X10'(Torr)▲r: H2za: 1
, 13.56 (Mtlz), 0.9~3 (KW),
After forming a perpendicularly magnetized film of 0.2 μ hazy using high-frequency sputtering using the can temperature as a parameter, it was oxidized, and 90 plasma-polymerized films of hexamethyldisilazane were placed on top of it. !-143
A tape with a width of 8 mm was prepared by placing a back coat layer of 0.4 μm in thickness. On the other hand, as a comparative example, one that was not subjected to oxidation treatment was used. A modified 8mm video tape was recorded with a track pitch of 6μl and a bit length of 0.2μl using a laminated alloy head with a gap length of 0.13μ, and 07N was compared. The conditions and measurement results for each tape are summarized in Table 2 (composition ratios are average values, MS
is the saturation magnetization).

(Hereinafter, blank) As mentioned above, the product of the present invention has superior C/N compared to the conventional product,
Moreover, even when compared with the same protective lubricant, it can be seen that it has excellent durability and is suitable for high-density magnetic recording.

[Example 3] Another means to solve the problem is to use C having a chrysanthemum flower-shaped layer.
The surface nonmagnetic layer of o-Cr-P columnar fine particles is Co
A magnetic recording layer made of -P is used. With the above-described configuration of the magnetic recording medium of the present invention, the magnetic separation between columnar particles is improved, magnetization reversal becomes dominated by the rotational magnetization mode, and fine magnetic domains are divided within the columnar particles, resulting in improved output. This leads to noise reduction and improves high-density recording characteristics.

The magnetic recording medium of the present invention can be sputtered using Co-Cr-P as a target by optimizing the conditions by controlling the can temperature and increasing the sputtering speed, or by sputtering with Co-Cr as a target. It can be obtained by optimizing the conditions by mixing the gas with ▲r:PH5 and introducing P from the gas phase.

Of course, the manufacturing method is not limited, and the structure is the same as that shown in Fig. 4, with a chrysanthemum flower-shaped polarized layer and a columnar fine particle surface polarized layer (which corresponds to the oxidized layer). at
If the structure consists of a rich layer (corresponding to 17 in FIG. 4) and a P-rich layer (corresponding to 18 in FIG. 4), electron beam evaporation can be used. An ion plating method, an ion beam deposition method, etc. may also be used.

The Co-P surface polarization layer is nonmagnetic and its thickness is 20
~40 pieces is enough.

Examples of the present invention will be described in more detail below in comparison with comparative examples.

Using a polyamide film N having a thickness of 85 ml, it was degassed by making three reciprocations at 2 m/Ilin along a rotating can (IN! diameter: 50 cIn) at 300°C. During degassing treatment, Ar O,04 (Tor
r) 13 56(Mllz) 1ees(KW
) glow discharge treatment was also performed. Can temperature 1
The temperature was 86°C, 16KY electrons were irradiated with eo (μ▲/, J), and Co-Cr (75at%Co
) to Ar 4- PH 5 = 0.003 ( Tor
r) Ar: PH3 = 0.2 to 0.8; at nautical range, 1366 (Mllz), 1.9 to 37
(KW) soo (person/sec) ~ 920 (λ/8●
C) sputtering was performed at high speed to form a Co--Cr--P perpendicular magnetization film. The separation into a Co lithoti layer and a Cr rich layer is chrysanthemum-shaped, and the side surfaces of columnar fine particles are (3o5P).
2z (x = 0.7 to 0.94), and the film thickness was kept constant at 0.2 μm. The comparative example is co-Cr (Co:76!L
t type) t-target ▲ro, 009~0.04
(Torr) 1s. 6e(Mllz), o.
75 ~1. Perpendicular magnetization film obtained by sputtering with e(KW) 0.2/l! I1 is a magnetic recording layer. Both are Fontprin Z-2 manufactured by Montegisson.
5i1 (η/rn") and processed into an 8mm wide tape by placing a 0.4μ1 pack coat layer.Each tape was modified into an 8mm video tape with a laminated alloy type with a gap length of 0.13μ. Bit 4% with a track pitch of 6 μm in the head
Record 0.2 μm and evaluate the initial and saved values for playback 0/N, and check #! The results are summarized in Table 3. As described above, it can be seen that the product of the present invention significantly improves O/N and durability reliability due to the effect of Co5P2x compared to the comparative example.

[Example 4] Another means for solving the problem is to use a CO-based alloy perpendicularly magnetized film having microprotrusions along cracks arranged in a thin film on a polymer film as a magnetic recording layer. Due to the above structure of the magnetic recording medium of the present invention, the crystal orientation of the Co-based alloy is improved, and the microprotrusions along the cracks cause friction on the contact surface. Wear characteristics are improved, and O/N and durability are balanced at a high level. The magnetic recording medium of the present invention will be described below with reference to the drawings. FIG. 6 is an enlarged sectional view of the magnetic recording medium of the present invention, and 2o is Ti.
, Cr, Si, Ge, Mo, etc., and 21 is a crack. Thin film is 0.2 from 0.03μ theory
Sputtering method within the range of I. The cracks are formed by a t-beam evaporation method or the like, and the cracks are formed at a pitch of about 1/jll to 60 μm. 22 is Co-Cr, Co-Ti,
Co-Mo, Co-Ta, Co-Cr-N
It is a thin film of 0.05 μm to 0.3 μm formed by sputtering using a perpendicular magnetization film of a Co-based alloy such as B, and includes minute protrusions 23 called so-called nodules. Although the microprotrusions 23 are not unique to only the sputtering method, in the sputtering method, the microprotrusions 23 are concentrated in defects such as cracks and have a wide range of length. The protrusion height of the microprotrusions (height indicated as h in the figure) is preferably in the range of 100 to 200.

24 is a protective lubricating layer. If it is a tape, it may be provided with a pasoku coat layer, and if it is a disk, it may be of a double-sided access type with the same structure as described above on both sides, etc., as appropriate.

Examples of the present invention will be described in more detail below in comparison with comparative examples.

A thin film was formed by sputtering on a polyethylene naphthalate film with a thickness of 10.6μ1 (average roughness of 20 mm) to form cracks, and then a perpendicularly magnetized film of CO-based alloy was formed on top of it by high-frequency sputtering. 100 plasma-polymerized films of hexamethylene diamine were placed on top of the film, and DuPont's KRYTOX1 was added as a lubricant on top of the plasma-polymerized film of hexamethylene diamine.
43▲C to O. (η/m”), 0.66μl
A pack coat layer was applied to create an 8mm wide magnetic tape.
On the other hand, in a comparative example, 6 pieces/(μm)2 of Cr203 particles with a diameter of 150 were placed on a polyimide film with a thickness of 10 μm.
Co - Cr (
Co: 78at%) was electron beam evaporated, and 0.2p
An 8 mm tape was used, on which a Co--Cr perpendicular magnetization film of 100 m was disposed, a protective lubricant layer having the same structure as in the example was disposed, and a bathok coat layer was disposed thereon.

Each tape was recorded and reproduced using a metal-in-gap head using a sendust sputtered film with a gap length of 0.12 μm and a track pitch of 6 μm with a bit length of 0.2 μm.
O/N was compared. Table 4 shows the structural conditions of each TEG and the obtained C/H.

As described above, according to the present invention, it can be seen that the microprotrusions grown from cracks in the thin film are more durable and useful for maintaining O/H than the conventional improvement using microprotrusions.

Effects of the Invention As described above, the present invention has the excellent effect of providing a magnetic recording medium for perpendicular magnetic recording that has a high level of balance between high-density recording performance and durability.

[Brief explanation of drawings]

FIG. 1 is an enlarged cross-sectional view of a magnetic recording medium according to an embodiment of the present invention.
FIG. 2 is a cross-sectional side view of main parts of an electron beam evaporation apparatus used to manufacture a magnetic recording medium according to an example of the present invention, FIG. 3 is an enlarged cross-sectional view of a magnetic recording medium according to an example, and FIG. FIG. 6 is a top cross-sectional view of columnar fine particles and an enlarged cross-sectional view of the magnetic recording medium of the example. DESCRIPTION OF SYMBOLS 1...Polymer film, 2...Columnar fine particles, 3...Substrate, 4...Rotating support,
7... Electron beam evaporation source ▲, 8... Electron beam evaporation source B, 13... Perpendicular magnetization film, 16
...GO rich layer, 17...Cr rich layer, 18.1...coI2 layer, 2o...
Thin film, 21...Crack, 23...Minute protrusion (nodule).

Claims (4)

[Claims] (1) A magnetic recording medium characterized in that a ferromagnetic metal thin film in which obliquely deposited columnar fine particles and vertically deposited columnar fine particles are integrated is disposed on a substrate. (2) A magnetic recording medium characterized in that the surface of Co-based vertically aligned columnar fine particles having a chrysanthemum flower-like polarization layer is oxidized. (3) A magnetic recording medium characterized in that the surface nonmagnetic layer of Co-Cr-P columnar fine particles having a chrysanthemum flower-shaped polarization layer is made of Co-P. (4) A magnetic recording medium characterized in that the magnetic recording layer is a Co-based alloy perpendicularly magnetized film having minute protrusions along the cracks arranged in a thin film on a polymer film.