JPS59163810A - Vertical magnetic recording means and manufacture of the same - Google Patents

Abstract

PURPOSE:To realize efficient mass-production of a uniform vertically magnetized film by a method wherein O2 gas is introduced and Co and Ni are deposited by vertical incidence. CONSTITUTION:A vertically magnetized film of the composition of Co-Ni-O is formed on a non-magnetic substrate (a) such as a PET tape substrate directly or with a soft magnetic thin film layer (such as permalloy) formed on the substrate in between. For instance, by utilizing a container 1 in which a cooling can 2, rollers 4, 5, an electron beam evaporation source 3 and deposition shielding plates 7 are provided, Co and Ni atoms are deposited on the surface of the substrate (a) by practically vertical incidence and at the same time, O2 gas is introduced from a supplying pipe 6. Then a vertically magnetized film expressed by (Co1-xNix)1-yOy (where 0<x<0.40, 0.15<y<0.50) is formed.

Description

[Detailed Description of the Invention] Recently, as a new magnetic recording method capable of high-density recording,
Perpendicular magnetic recording and magneto-optical recording have been attracting attention and research, but the media used in these systems have magnetic anisotropy in the perpendicular direction and have 2πMI! 1! Or H
Q L > Hc tt @ B r 4) Brn
It is necessary to use a so-called perpendicular magnetization film that satisfies the following conditions.

As is conventionally known, OO has a large magnetocrystalline anisotropy in the a-axis direction of the HOP structure, and when attempting to obtain a perpendicularly magnetized film by utilizing this property, 6, whose crystals are oriented so that the a-axis is almost perpendicular to the image, ■The magnetocrystalline anisotropy Ku is the demagnetizing field 2 in the perpendicular direction of the thin film.
It is necessary to satisfy two conditions of being larger than πMg2. However, since the Oo thin film has a large value of saturation magnetization MIl, the above-mentioned condition (2) is not satisfied, and the film cannot be a perpendicularly magnetized film.

On the other hand, conventionally, O
There is an o-Or system film, which is created by sputtering and vapor deposition. However, since the sputtering method has a low folding speed, there is a problem in mass production of media that are used in large quantities, such as floppy disks and magnetic tapes. In addition, in the vapor deposition method, since the vapor pressures of Oo and Or differ greatly, it is difficult to control a stable Or composition over a long period of time. Perpendicular magnetic properties are obtained, but a perpendicularly magnetized film cannot be obtained when the substrate is unheated at room temperature, which brings about disadvantages such as the necessity of using a heat-resistant material as the substrate.

In view of the above points, the present invention provides a new type of 0o-
This provides a perpendicular magnetic recording body having a perpendicular magnetization film consisting of a composition of Ni-0, in which (Ool, N1X)1-yOy(t
A perpendicularly magnetized film having a composition of 0o-Ni-0 expressed as 0(x(0,40°0,15 (7<0.50)) is formed.

Furthermore, a second invention provides a method for manufacturing the above-mentioned novel perpendicular magnetic recording material, in which an incident beam is substantially perpendicular to the surface of a nonmagnetic base material or to the surface of a soft magnetic thin film layer formed in advance on that surface. At the same time, 00 and N1 atoms are deposited so that 0. By introducing the gas, (Ool-XNiX) 1-yOy(fiteo(x(0,40°0,15 (Oo-Ni- expressed as 7(0,50)).

It is characterized by forming a perpendicularly magnetized film with a composition.

Next, examples of the present invention will be described.

FIG. 1 shows a vacuum evaporation apparatus for carrying out the present invention, in which a rotary cooling can (2) and a VCit child beam evaporation source (3) are installed directly below it in a container (1) connected to a vacuum pump on one side.
, an unwinding roller (4) and a take-up roller (5) are arranged on both sides of the upper part, and a non-magnetic base material, such as a roll-shaped P-T tape, is wound around the roller (4). The base material a was rotated along with the rotation of the circumferential surface of the cooling can (2) so that it could be wound up on the roller (5). According to the invention, the supply pipe (
6).

In the illustrated example, this is a long one that opens near the a side of the running tape. (7) shows an adhesion prevention plate placed horizontally leaving the bottom surface of the cooling can (2) facing directly i to the evaporation source, which prevents the evaporation of 00 atoms and N1 from the evaporation source.
The atoms were incidentally deposited substantially perpendicular to the tape substrate color plane.

Using this device, the inside of the container (1) is evacuated to below 1 x 10) -1 evaporated material, i.e., Oo-Ni alloy or a metal mixed with Oo and N1 at a predetermined ratio, is heated by electron beam heating. , evaporate at a constant rate, and connect one side of the supply pipe (6
) from 0. A gas is introduced and vertical vapor deposition is performed on one surface of the tape substrate running at a constant speed to obtain a deposited film having a composition of 0o-NiO. By varying the amount of ot gas introduced so that the gas is introduced at various partial pressures, or by varying the ratio of Oo and N1 to be evaporated, 0o-Ni-00 with various composition ratios can be obtained. A magnetic recording medium with a deposited film was manufactured. The film thickness was set in the range of 1000A to 10000A by changing the running speed of the tape base material. In this way, various magnetic films having different composition ratios of the Qo-Ni-0 ternary components and their magnetic properties were investigated. The results are shown in FIGS. 2 and 3-4, respectively. As is clear from Fig. 2, as the 0 component increases, the ratio of the coercive force in the vertical direction ■0 to the coercive force Ha in the parallel direction Ha/゛HQ// increases, and the 0 component 15 at % or more in the area surrounded by diagonal lines in the figure, it becomes H6 above / 1 (.> 1. The residual magnetic flux density also increases as the 10 component increases, as shown in Figure 5, and the 0 component 15 at%>1.

However, when the O component is 50 at% or more, the saturation magnetization becomes zero in all cases. From the above results, (Ool, MIX)
1. oy, (fi in O(x (0,40°0,15 (
It can be seen that a perpendicular magnetization film is obtained in the region of 7 (0, 50). Figure 5 shows 5 (coo, 9N1°, 1). ,
This is a hysteresis curve of a typical perpendicular magnetization film of the present invention having a composition of , 0°, and it can be seen that the film is a perfect perpendicular magnetization film. In this way, the 0 composition is 15-50&t
%, and the composition ratio X of Oo and N1 is
A perpendicular magnetization film can be obtained in the range of 0 to 0.40. 0.40
In this case, the crystal structure of the precipitated metal particles becomes an FOO structure, and the magnetocrystalline anisotropy is extremely reduced, making it impossible to obtain a perpendicularly magnetized film. Further, the perpendicularly magnetized film of the present invention to which Ni is added has an additional feature of excellent corrosion resistance. or,
In the perpendicularly magnetized film of the present invention, the perpendicular coercive force Hc
The value is about 400 to 10001 O, which is the best value for a perpendicular magnetic recording medium.

Note that when the evaporation rate of OONi is changed, the amount of O2 gas introduced is also changed in order to obtain a film having the above composition range. Since this relationship is approximately proportional to the frequency of incidence of oO and N1 atoms and 0 atoms on the base material, when the amount of evaporation of ao-Ni increases, it is necessary to also increase the O2 partial pressure.

According to the present invention, there is no need to heat the base material, and a perpendicularly magnetized film can be obtained by actively cooling it with a water cooling can or unheated at room temperature, and it is possible to obtain a perpendicularly magnetized film without heating the substrate.

As in the manufacturing method of perpendicular magnetization film of Or, the base material is 200 to 30%
It is advantageous compared to those that require heating to 0°C,
As the base material, there is no need to use heat-resistant and expensive materials such as polyimide film 8, and an inexpensive plastic film such as PET tape can be used, and the material of the base material can be freely selected and used. The perpendicularly magnetized film of the present invention can also be obtained by heating the base material.

Further, according to the present invention, since the vapor pressures of Co and N1 are almost equal, even if a 0o-Ni alloy with a desired composition is made in advance and evaporated from one evaporation source, the composition of the deposited film will be the same. Since a predetermined ratio of 0o-Ni can be deposited with almost no change, if the amount of O gas introduced is kept at a predetermined constant amount, the perpendicularly magnetized film of the present invention can be produced with a predetermined uniformity over a very long period of time. This eliminates the disadvantage of producing films with non-uniform component compositions, as in the conventional production of perpendicularly magnetized films in which components with significantly different vapor pressures of 0O-or are evaporated.

In addition, the perpendicular magnetization film of the present invention does not cause curling even when formed on a PET substrate or a floppy disk substrate, so it is extremely curly compared to the 0o-Or perpendicular magnetic recording material, which causes very severe curling. Easy to manufacture and a good product can be obtained.

The reason why the Oo-Ni-0 thin film of the present invention exhibits perpendicular magnetization characteristics is not fully clear, but it is thought to be as follows.

That is, when 00 and N1 atoms are incident perpendicularly to the base material and deposited, the vertical direction 1/(HOP
A thin film with a columnar grain structure is created with the zero axis of the structure oriented. At this time, 0. When gas is introduced,
Some of the deposited Oo and N1 atoms are oxidized to form G o O,
HiO or an oxide similar to it is simultaneously precipitated and ao-
It is thought that it has a film structure in which the periphery of Ni particles is covered with the non-ferromagnetic oxide. Therefore, the Oo-Ni columnar particles have shape magnetic anisotropy in addition to crystal magnetic anisotropy, and improve perpendicular magnetic anisotropy. When the film structure is partially oxidized as described above, the average saturation magnetization value of the entire film decreases, so it is considered that the condition Ku≧2πMs2 is satisfied and perpendicular magnetization characteristics are obtained. Furthermore, the particle size of the 0o-Ni columnar particles is thought to be on the order of several hundred to several thousand X, and since they are in the form of fine metal particles, a high coercive force can be obtained.

A trace amount of other elements may be mixed into the predetermined 0o-Ni-0 perpendicular magnetization film of the present invention. Also, elements that dissolve in CO and do not harm the Hap structure, such as O
r, V, Mo, W, Rh, Ti.

There is no problem with the inclusion of a trace amount of Rs.

In the perpendicular magnetic recording method, permalloy, Fe, Oo is used between the perpendicular magnetization film and the non-magnetic base material surface.

If a thin film of a magnetic material exhibiting relatively soft magnetism and high saturation magnetization, such as a co-Zr amorphous film, is interposed, the recording current can be reduced and the reproduction output can be increased. After forming a soft magnetic thin film layer on the non-magnetic base material surface in advance,
By forming a perpendicular magnetization film with a predetermined 0o-N1-0 composition on the upper surface of the thin film layer, for example, according to the above embodiment, a perpendicular magnetic recording body of the present invention in which the soft magnetic thin film layer is interposed is manufactured. I can do it.

Further, when the present invention is applied to a floppy disk, a perpendicular magnetization film having the predetermined 0o-Ni-0 composition is formed on one or both sides of the base material, either directly or with the soft magnetic thin film layer interposed therebetween. A perpendicular magnetic recording body may be manufactured.

Thus, according to the present invention, (001-XNiX
) 1-yOyl: 0 (x (0,40,0,15
(A perpendicular magnetic recording medium having a good perpendicular magnetization film can be obtained by using a thin film with an O o -N i -0 composition consisting of y〈0.5. When Oo and N1 are deposited through the magnetic thin film layer, Ot gas is introduced to form a perpendicularly magnetized film with the above-described predetermined 0o-Ni-0 composition. Unlike the manufacturing method of This has effects such as obtaining a magnetized film.

[Brief explanation of drawings]

FIG. 1 is a cutaway side view of an example of an apparatus for carrying out the manufacturing method of the present invention, and FIGS. 2, 3, and 4 show various types of
Figure 5 is a diagram showing the relationship between Ni-0 composition and magnetic properties.
A hysteresis curve diagram of one example of the perpendicularly magnetized film of the present invention is shown. (1)...Container a...Tape base material (3)...Evaporation source b...Evaporation material Oo, N1 (4) (51...Roller (6)
)... Oxygen gas supply pipe (7)... Anti-adhesion plate patent applicant Japan Vacuum Technology Co., Ltd.

Claims (1)

[Claims] 1. Directly or through a soft magnetic thin film layer on the non-magnetic substrate surface (Oo 1-Xxi,
(a expressed as x (0, 40, 0, 1s<y<o, 50). A perpendicular magnetic recording body formed by forming a perpendicular magnetization film having a -Ni-0 composition. 2 On the nonmagnetic base material surface, or Oo and N are incident substantially perpendicularly to the surface of the soft magnetic thin film layer previously formed on that surface.
At the same time as one atom is evaporated, a gas is introduced (O
O1x N i X) 1 y Oy (O<1<0 on the drum
．． 40. O,j 5〈O expressed as y(0,50)
A method for manufacturing a perpendicular magnetic recording body, comprising forming a perpendicularly magnetized film 'f having an o-Ml-0 composition.