JPS63234410A - Magnetic recording medium having protective film - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium having excellent resistance to friction and wear by forming a protective film of a fluorine compd. contg. at least one kind of metal element selected from a group of Fe, Ni, Cr, Co and Mn on the surface of the magnetic recording medium. CONSTITUTION:The protective film 30 of the fluorine compd. contg. at least one kind of the metal element selected from the group of Fe, Ni, Cr, Co and Mn is formed on the surface of the magnetic recording medium 10. Adhesion and shearing easily arise between the magnetic recording medium 10 and a head 20 when the protective film 20 is not provided on the medium surface, but there are less friction and a lower tendency to the adhesion and shearing if the protective film 30 consisting of the fluoride is formed on the surface, since the surface of the fluoride 30 is always stuck with a -OH group. The magnetic recording medium is thus hardly exfoliated and flawed. The magnetic recording medium which has the protective film and highly resists the friction and wear is thereby obtd.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to magnetic recording media, and more particularly.

Film strength, slipperiness, chemical stability of perpendicular magnetic recording media,
This invention relates to improving recording and reading characteristics.

[Conventional technology]

Perpendicular magnetic recording has been proposed as a new magnetic recording method that goes beyond the limitations of conventional longitudinal recording.

CoCr alloy perpendicular magnetization film, Co-0Fe-(Si,)
A combination of a -0 perpendicular magnetization film and a perpendicular head is being considered for practical use. These films are formed by various methods such as snobbing, tuttering, vacuum evaporation, ion blating, etc., and are simply formed as perpendicularly magnetized films on non-magnetic substrates. Compared to the RFC type, it has the disadvantage that the magnetic material is peeled off and damaged due to contact with the head during running. Therefore, when put into practical use, friction and wear between the magnetic recording medium such as CoCr and the magnetic head slider become important problems. That is, in the 7-lexiple disk device, the magnetic disk and the magnetic herad slider are in a state of so-called boundary friction, in which the magnetic disk and the magnetic herad slider are in contact with each other through a very thin lubricant layer.

big.

[Problem that the invention seeks to solve]

As a solution to these problems, changing the deposition conditions9
For example, attempts have been made to improve the wear resistance by changing the mechanical strength of the perpendicularly magnetized film by changing the Ar partial pressure. However, this method has the disadvantage that the magnetic properties also change at the same time. Next, adding several 100X oxide and other non-magnetic lubricant layers to the surface of the medium is also being considered. This method results in a gap gap and a spacing loss between the magnetic head and the magnetic recording medium, that is, the recording and reading characteristics deteriorate. For this reason, until now effective friction resistance,
No measures were taken to prevent wear, which was a major hindrance to the practical application of perpendicular magnetic recording.

The purpose of the present invention is to eliminate the above drawbacks and improve abrasion resistance.

An object of the present invention is to provide a magnetic recording medium with excellent wear resistance.

[Means for solving problems]

According to the invention, on the surface of a magnetic recording medium.

A magnetic recording medium having a protective film characterized by forming a protective film of a fluorine compound containing at least one metal element selected from the group of Fe, Ni, Cr, Co, and Mn is obtained.

〔Example〕

Next, regarding an embodiment of the present invention, at least one metal element selected from the above group will be described with reference to the drawings.

FxTloo-! (However, X is a value in the range of 3 to 80)
Hail to you.

The protective film includes: B, C, At, Si, P, As, Sb
, Bi, Se, Te.

V s Ga * Ge * Z r g Nb e
At least one element selected from the group Mo (hereinafter referred to as M).

It may further contain.

In this embodiment, the magnetic recording medium refers to a film formed by not only ordinary resistance heating vacuum evaporation, but also electron beam heating vacuum evaporation, sputtering, and ion blasting.

Further, the magnetic recording medium refers to a medium recorded by a single-plane recording method or a perpendicular recording method. The magnetic recording medium used in this example is Co-CLF'e-(Si
)-Os r-Fe203, oxide magnetic materials such as Fe3O41CrO2, nitride magnetic materials such as Fe-NICo-N+N1-N, fluoride magnetic materials such as Fe-F*Co-F, N1-F, and metals. @ Fe as a magnetic material
mCo5Nt*Other ferromagnetic metals.

Or Fe-Co, Fe-Cr, Fs-Co-Ni
, Co-Cr1Co-Cu, Co-AueCo-Pt
A magnetic alloy such as +Co-GcLCo-GaeCo-rare earth metal and its perpendicular magnetization film are used.

Further, even if the above-mentioned magnetic recording medium is a multilayer film in which a non-magnetic thin film is provided on a ferromagnetic thin film which is a mixed layer with a non-magnetic material, the magnetic recording medium of this embodiment can still be used. It can be used as

The substrate on which the magnetic recording medium of this embodiment is formed may be polyethylene terephthalate, polyimide, polyvinyl chloride, polycarbonate, glass, ceramics, or aluminum.

It is also possible to use metal substrates such as stainless steel and brass. The shape of the board is also tape or sheet.

Any shape such as a card, disc, r-ram, etc. can be used.

Next, the protective film, which is a feature of this embodiment, will be explained. F
Fluoride films containing a large amount of -
〇Has the characteristic of easily bonding with H group. Therefore, when a compound combines with 10H groups, that is, moisture, it undergoes alterations such as dissolution. However, when the composition and structure are changed to make it amorphous, the chemical bonding state between the F element and Ni and other elements changes, making it chemically stable. Furthermore, since the fluoride film is an ionic bonding crystalline material, there is little deterioration of materials such as metals due to oxidation. Therefore, as shown in Figure 2, when the protective film is not attached, the Rolide protective film 3 can be easily removed.
When 0 is added, 10H groups are always attached to the surface of fluoride 30.

Next, the structure of the protective film will be explained. Methods for forming a fluoride film include a vacuum evaporation method, an ion blating method, a sputtering method, and a reactive evaporation method, but the sputtering method will be explained here. The above-mentioned F-T system and F
-TM-based fluoride membrane.

It can be produced by +R sputtering from a fluoride powder target and a fluoride sintered target. For example, the structure of the N1-F series or Ni-F-M series 70ride film can be easily changed by changing the RF specific output as shown in FIG. Figure 3 shows the results of X-ray diffraction of a film fabricated by RF Snocktailing from a NiF2 powder target.
Measured in the range of ~150°.

On the low output side of RF output of 100 and 150W, Ni70.
The structure of phyto-e N1F2y is shown, but 200-300
In W, the strongest peak of NtF2 disappears and becomes amorphous, and another tetragonal structure appears. This structure does not match pure Ni:. The film produced at rf: 250W shows a small peak, but is slightly shear amorphous. At 300 W or more, a tetragonal structure grows.

A film exhibiting an amorphous structure of N i-F-M has no grain boundaries, so it is chemically stable and physically strengthened. The surface strength of the tab increases. Measure the film surface strength of the sample using a film surface strength meter (R = 0.1■)? : Measured using. The minimum load that caused scratches on the surface was used as an index of film surface strength. Sample without protective film (CoCr film) is 50.9
The total thickness of the protective film of the Nl fluoride film was 12.
Although it was damaged by 0I, the film surface strength was 92 times or more higher due to the protective film.゛Fluoride membranes of the above-mentioned FT series other than the N1-F series.

The above-mentioned F-T-M $70 magnetic recording medium with a protective film other than the Ni-F-M base has the same properties as the N1-F and Ni-F-M base magnetic recording media. , chemical stability.

Improves physical strength.

Next, in general, in the case of perpendicular magnetic recording, when a nonmagnetic protective film is provided between the magnetic head and the magnetic recording medium, a gap is created, and the output of the magnetic head is reduced in proportion to the square of the gap. however.

The protective film containing a large amount of F of the present invention exhibits perpendicular magnetic anisotropy, and has a structure that minimizes a decrease in the output of the magnetic head. FIG. 4 compares changes in the output of the magnetic head when the thicknesses of a nonmagnetic protective film and a fluoride protective film exhibiting perpendicular magnetic anisotropy are changed. As seen in FIG. 4, the fluoride protective film has a higher output than the non-magnetic protective film, and the output decreases less due to the protective film. FIG. 5 is an example of an MH curve of a protective film. The amount of magnetization M in the direction perpendicular to the film surface has a larger mechanical perpendicular magnetic anisotropy energy than N7 in the direction parallel to the film surface.

As explained above, by forming a protective film containing a large amount of F, which exhibits an amorphous structure and has positive perpendicular magnetic anisotropy to the film surface, on the surface of a magnetic recording medium made of a thin film. Furthermore, it was possible to improve the metaplastic and physical stability of the magnetic recording medium and prevent performance deterioration.

Two specific examples of the present invention will be described below.

Specific example 1 In the rf space A' tuttering device, 21 at4
Cr-C.

A CoCr thin film with a thickness of 0.4 μm was formed on a polyimide sheet with a thickness of 50 μm from the target. The film forming conditions were such that the Ar partial pressure and RF specific output were adjusted so as to provide the best perpendicular magnetic anisotropy film. After forming the CoCr film, NiF is deposited on top of it.
2 powder (99.99% purity) is press-molded to 9N
20 N1-F' perpendicular magnetization films from iF2 powder Tarda Soto
The film was formed for 0 hours. When the adhesion strength of the obtained magnetic recording medium and N1-F protective film to the substrate was examined by a peel test using Cellophane Teso, no peeling of both films was observed. In addition, the film surface strength of the sample was measured using a film surface strength meter using a 9R ball needle (R = 0.1 m).
14C1, and the protective film provided a film surface strength of 92 times or more. Furthermore, they created a disk, rotated the disk, and examined the coefficient of friction of the medium. As a result, compared to the CoCr film measured under the same conditions, the CoCr film with the N1-F film was lowered to A, confirming the effect of the protective film. The output performance was the same.

Specific example 2 CrF in NsF2 powder (purity 99.99%)
s powder (purity 99.9%), 5, 10.15, 20,
The mixture was mixed and stirred at 25° and 30%, and press molded. Each N1-Cr-F powder was RF sputtered.

A 200X film was formed on the CoCr film produced in Example 1.

Thereafter, the degree of adhesion to the substrate was measured by a peel test using cellophane tape, and the film surface strength of the sample was measured using a film surface strength meter, and the results shown in Table 1 below were obtained.

Table 1 0: Film surface strength meter without peeling: 8-ball needle (R = 0.1 dew) From the above results, the film surface strength was improved by adding Cri to Ni""F. Furthermore, other elements, B.

C, At, Si, P, As, Sb, Bi, Se, T
e, Ti, V, Cr.

Regarding Mn, Ga, Ge, Zr, Nb, and Mo, metal powders and fluoride powders are added to the N i F 2 powder to conduct s/? A film was formed by tsuttering and the film surface strength was measured.

The film surface strength was improved due to the alloying effect with Ni.

Specific example 3 N i F 2 powder (purity 99.99%) and metal powder,
and compound powder were mixed and stirred and press-molded. Each of the targut powders was RF sputtered to form a 200X film on a CoCr film in the same manner as in Example and Example 2.

Thereafter, the degree of adhesion to the substrate was measured by a peel test using cellophane tape, and the film surface strength of the sample was measured using a film surface strength meter, and the results shown in Table 2 below were obtained.

Below, as mentioned above, due to the alloy effect of rNlF2, Serono1
In tape test and measurement of film surface strength.

The effects of improvement are significant.

〔Effect of the invention〕

As explained above, according to the present invention, friction resistance is achieved.

Excellent wear resistance. It is possible to obtain an entire magnetic recording medium having the protective film 2.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining a magnetic recording medium having a protective film according to an embodiment of the present invention, Fig. 2 is a diagram for explaining a conventional magnetic recording medium, and Fig. 3 is a diagram for explaining a conventional magnetic recording medium. FIG. 4, which is a diagram for explaining the film structure as the rf output changes during film formation, shows changes in the film thickness of the non-magnetic protective film and the fluoride protective film. FIG. 5 is a diagram showing the output voltage of the magnetic head, and FIG. 5 is a diagram showing the magnetization curve of the N1-F protective film used in the present invention. 10... Magnetic recording medium, 20... Head, 30...
·Protective film.

Claims (1)

[Claims] 1. On the surface of the magnetic recording medium, Fe, Ni, Cr, Co,
1. A magnetic recording medium having a protective film, characterized in that a protective film is formed of a fluorine compound containing at least one metal element selected from the group of Mn.