JPS6052931A - Method for manufacturing magnetic recording media - Google Patents

Abstract

PURPOSE:To form a magnetic layer having coercive force at a high speed by forming the magnetic layer consisting of a Co alloy on the surface of a base by an ion plating method by making the kinetic energy of the ion of the element to be added to Co larger than that of the Co ion. CONSTITUTION:Co 6 and an element M7 to be added are put into respectively separate tanks of, for example, a vapor source 5 in the stage of forming a magnetic layer 4 consisting of a two-element alloy such as C-Cr, Co-Mo or a three- element alloy such as Co-Cr-Mo by an ion plating method on a base consisting of polyethylene terephthalate, etc. Said elements are polarized respectively as Co vapor flow 8 and M vapor flow 9 by deflecting magnetic fields 12, 15 and are stuck thereto. The kinetic energy of the element M ion is made larger than the kinetic energy of the Co ion in this stage. Co<+> is made to 600eV and Mo<+> to 1,000eV in order to obtain, for example, an Mo 20.5wt% film of Co-Mo at a rate of about 4,000Angstrom /sec, by which the vertical magnetized film 4 having high coercive force of about >=1,000Oe is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a magnetic recording medium in which a thin film made of a CO-based alloy is used as a magnetic recording layer.

Conventional configuration and its problems High density in magnetic recording? It is well known that the media required for this purpose are a thin magnetic recording layer and a large coercive force.

Meeting this demand on a production scale is not necessarily easy.

In particular, it is not easy to obtain a magnetic recording layer of a medium used for so-called perpendicular magnetization recording, which utilizes magnetization in a direction perpendicular to the surface of the medium, at high speed and to control it to a large coercive force.

At present, the only way to reliably control a large coercive force is to inject cations f generated by glow discharge into a target such as a Co--Cr alloy.

This is a so-called sputtering method in which Cr atoms are ejected and attached to a predetermined support, but as expected from the mechanism described above, the film formation rate is extremely slow at most 10/sec.

On the other hand, in the vacuum evaporation method, the temperature of the support 'i2. , the perpendicular coercive force becomes 1KO only when the temperature is raised to 00°C or higher.
However, there are restrictions on the heat resistance of the support used, and it is difficult to accurately control the temperature of the support during vapor deposition to, for example, ±6°C, so it is difficult to continuously control the temperature of the support on a long support. It is difficult to obtain a perpendicularly magnetized film with constant characteristics.

However, this method has a film formation rate of 200 people/
sec ~ 2,000 people/sec, which is large +7)
As an improvement to this method, the ion-blading method is being intensively studied in order to lower the support temperature.

In the ion blating method, the adhesion between the film formed on the support and the support is increased. Support temperature i100
Although there are advantages such as a tendency to obtain a large coercive force even at temperatures below .degree. C., for example, when obtaining a coercive force of 1000 (0.theta.), the film formation rate depends on the power of the 5 glow discharge as shown in FIG.

It can be seen that by increasing the power of the glow discharge, the film formation rate can be increased to a certain extent, but even if the power is increased, the coercive force decreases.

The results shown in Figure 1 show that polyethylene terephthalate with a thickness of 20 μm was moved along a rotating drum with a diameter of 50 cm, and Co-'Cr was evaporated from an electron beam evaporation source placed 2 cm directly below the drum. This is a case in which a shielding plate having an opening of 2.5 (:@) was placed in the direction of movement of the polyethylene terephthalate and ion blating was performed.

Glow discharge is performed by placing a two-turn high-frequency coil between 6Cm and 16crnO from the shielding plate, and connecting the coil to 13.
It was generated by inputting 56hh of high frequency power. The discharge gas used was 8mm, and the degree of vacuum was 4.2 x 10.
In the case of TORR, the Cr content is 18% by weight,
The Co-Cr film thickness was kept constant at 0.2 μm.

Improvements made by the conventional ion blating method have limitations, as shown in FIG.

This phenomenon is the opposite effect of ion bombardment when the power of glow discharge is increased.

This is due to the fact that the effect of generating defects in the crystal becomes dominant, which actually worsens the crystal orientation, and in order to obtain a large coercive force, it is necessary to raise the temperature of the support, and the scope of improvement is beyond imagination. It was narrow.

OBJECTS OF THE INVENTION The present invention provides a complete method for manufacturing a magnetic recording medium that produces a magnetic recording layer made of a high coercive OCO alloy at high speed.

Structure of the Invention The present invention is directed to the use of CO
The kinetic energy of the ions of the element added to the carbon dioxide is larger than the kinetic energy of the ions of CO.

The ratio of ions to CO and the elements added to CO is about 10 factors at most.

Of course, it can be composed of 10% ions, but the film formation rate is of course comparable to that of the sputtering method, and the effective use of ions at the above-mentioned level, that is, about 10%, brings about the characteristic effects of the present invention. That's the point.

That is, unlike the conventional example in which both the ion f Co and the element added to CO have the same energy, increasing the kinetic energy of the element added to CO increases the
It can be inferred that the mobility of the additive element increases, making it easier to move along the surface of the crystal, and as a result, the magnetic interaction between particles is weakened, thereby increasing the coercive force.

In order to clearly obtain this effect, it is preferable to set the kinetic energy to a range from 1.2 times or more to at most 3 times the kinetic energy of CO ions, although it depends on the temperature of the support.

On the other hand, from an energy perspective, at most 2. It is preferable to suppress it to KeV.

This is because if it exceeds this range, the crystal orientation deteriorates, the dispersion of coercive force becomes narrower, and the recording sensitivity decreases when used as a magnetic recording medium.

Therefore, the energy selection is made within the range of the above conditions, both in terms of magnification based on Co ions and in absolute value.

Description of examples Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows the basic configuration of a vapor deposition apparatus used to explain the present invention in detail.

In the process of being wound up by a winding device (not shown), the support 1 is cooled by a cooling device (not shown), and then the shielding plate 2 is rolled up.
The vapor flow that has completely passed through the opening slit 3 acts to form a ferromagnetic metal thin film 4 that will become a magnetic recording layer.

The evaporation source 5 is arranged adjacent to both the element for Co and the element to be added to CO (all referred to as M) directly below the throat 3. Co 6 and M7 are each controlled to a predetermined evaporation temperature and are directed toward a part of the support 1 as a Co vapor flow 8°M vapor flow 9, as schematically shown by the arrows.

The CO vapor flow s and the M vapor flow 9 contain some ions, for example, when the heating source is an accelerated electron beam.

Here, both of these ions were made to have a coefficient of less than 1 and were actively accelerated.

The ion sources are arranged separately, and the ions emitted from the CO ion source 1o are given a predetermined kinetic energy and turned into a CO ion beam 11, which is deflected by a deflection magnetic field 12. 3 and accelerated in the same direction as the one heading towards it.

Similarly, the M ion beam 14 was also deflected by the deflection magnetic field 15 from the M ion source 13 and directed toward the support 1 .

(Example-1) A 10.5 μm polyethylene terephthalate film was used as a support and a 6°C medium was circulated near the surface.
The support was moved at f6.9 m/min along a cylindrical can having a heavy cylindrical structure and a diameter of 50 cm.

The width of the slit opening in the support movement direction is 4.6 cm,
A pair of deflected electron beam evaporation sources were used as the evaporation sources. A magnetron discharge type metal ion source was used as the ion source.

Ions are deflected by a magnetic field (pole piece diameter is 10cm)
k adjustment (-) to use only Co+ and M+ ions.

Figure 3 shows CO and Cr selected as M, and the ion ratio f
Assuming that the proportions of Co and Cr in the total are 8% each, C
The energy of o+ is 600 e V, 1000 e
Choose two levels of V, energy of M+ for CO+? On the other hand, the perpendicular coercive force of a 0.2 μm CoCr film is shown with the thin film formation rate constant at about 5,000 people/5 ec.

(However, Cr is 18 weight division.) As is clear from the comparison with Figure 1, 5,0008/se
There is an advantage that a perpendicularly magnetized film having a large coercive force of 100Q[083 or more] can be obtained at a high speed of c.

Another advantage is that a perpendicularly magnetized film can be obtained even when the support is cooled, and a polyethylene terephthalate film, which has the best magnetic properties for magnetic tapes, can be selected as the support.

(Example 2) A Co--Mo perpendicularly magnetized film was prototyped using the same equipment conditions as in Example 1'.

Co-Mo (Mo: 20.5% by weight) 0.1
The film formation rate was 6 pm f about 4,000 C to μ].

Select two levels of the proportion of each ion, 5% and 1o%.
``Energy of MO+ ion assuming 1 eooev constant''
! z 1000 eV, 1500 eV, 2o
The vertical coercive force obtained by setting the three conditions of ooev was as shown in the following table.

As a comparative example, a Co--Mo film obtained at a speed of about 40,000/sec using the apparatus that obtained the results shown in FIG. 1 had a maximum coercive force of 6o6[0e:l.

Note that the present invention is capable of obtaining a large coercive force not only in a perpendicularly magnetized film but also in an in-plane magnetized film.
Not limited to Cr and Co-Mo, but also Co-Ti and Co-3
i.

Co-Ni, Co-Ru, Co-W, etc.OC
O-based binary alloy, C〇-Cr-Mo, Co-Ni
-Cr, Co-Cr-Rh, and other ternary alloys have the same effect.

In the case of a ternary alloy, it is assumed that the magnetic total of co is made larger than the ion energy fco+ of the element to be diluted the most.

Effects of the Invention As described above, according to the present invention, the support temperature (i-2000
A perpendicularly magnetized film with a large coercive force can be obtained at an extremely high film formation rate without raising the temperature to a temperature higher than °C.

Therefore, metal thin film magnetic recording media with perpendicularly magnetized films can be easily produced with high productivity without using special films with high heat resistance, so their use is not limited to magnetic disks, but can also be used for short wavelength recording as magnetic tapes. can meet the demands of

[Brief explanation of the drawing]

Fig. 1 is a characteristic diagram of a perpendicularly magnetized film obtained by the conventional ion blating method, Fig. 2 is a diagram showing the basic configuration of the ion blating apparatus used to carry out the present invention, and Fig. 3 is a diagram of the present invention. FIG. 3 is a characteristic diagram of a perpendicularly magnetized film obtained by the invention. 1... Support body, 2... Shielding plate, 3.
...Slit, 4...Ferromagnetic metal thin film, 6
...Evaporation source, 10゜13...Ion source,
11.14...Ion beam. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Figure 2 Figure 3

Claims (1)

[Claims] CO is applied to the surface of the support by φ by the ion blating method.
When forming the magnetic recording layer made of the alloy, the kinetic energy of the ions of the element added to CO is c. A method for manufacturing a magnetic recording medium, characterized in that the kinetic energy of the magnetic recording medium is made larger than the kinetic energy of ions.