JPS59112431A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic disc, magnetic tape or the like having excellent wear resistance and still resistance and having no problem in running property by forming the surface on the magnetic recording surface side of a magnetic recording medium into island-shaped or network structure. CONSTITUTION:A magnetic layer 2 of a ferromagnetic metal or the alloy thereof is formed on a nonmagnetic base 1 by a chemical deposition method or vacuum deposition method. An island-shaped structure having several tens - several hundreds Angstrom height or a network structure having linked island 3 parts is formed on the layer 2 by using a material different from the layer 2, for example, metal such as Cr, Ti or the like, Al2O3, TiO2, 2MgO.SiO2 or the like and depositing lightly these materials by evaporation. A thin metallic film type magnetic disc or tape having excellent still resistance and wear resistance is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium, which has excellent abrasion resistance and still resistance by configuring the magnetic recording side surface of the magnetic recording medium to have an island-like structure or a mesh structure. The purpose is to provide a magnetic recording medium that can be used as a magnetic recording medium.

Conventionally, magnetic recording media having a structure in which γ-Fe203 powder or Cro2 powder is coated on a non-magnetic base material surface with a binder, so-called coated magnetic recording media, have been mainly used.

However, in recent years, with the demand for higher density recording, vacuum deposition,
PV such as sputtering or ion blasting
Forming a magnetic recording layer by paper deposition method using D method or CVD method (i.e., without using a binder)
A so-called metal thin film magnetic recording medium has been proposed, and efforts are being made to put it into practical use.

A major problem in putting this metal thin film type magnetic recording medium into practical use is that its still resistance and abrasion resistance are extremely poor. In other words, the magnetic layer of a coated magnetic recording medium contains a lubricant in addition to magnetic powder, binder, etc., and the action of this lubricant makes the running properties of the magnetic recording medium good. However, in metal thin film magnetic recording media, the magnetic layer is made of 100% magnetic metal, so such metal thin film magnetic recording media have poor running properties, poor wear resistance, and poor still resistance. .

Therefore, as a means to eliminate such defects, it is possible to apply, for example, an oil-based lubricant to the surface of the magnetic recording layer formed by the paper deposition method.
If a large amount of lubricant is applied, the characteristics of the metal thin film magnetic recording medium will be lost, that is, the reproduction output will decrease due to the space 77 gloss between the head and the medium in the high-density short wavelength region, and If too little lubricant is applied, the running properties will become poor in a short time due to desorption of the lubricant during running, which has the disadvantage of requiring frequent lubricant application. Conventional metal thin film magnetic recording media in which a recording layer is formed cannot improve methyl resistance and abrasion resistance.

The present inventor was studying the abrasion resistance and methylation resistance of a metal thin film magnetic recording medium in which a magnetic recording layer was formed by a paper deposition method such as an OVD method or a PVD method. When a substance to be deposited is vaporized or ionized and deposited on a substrate, in the initial stage of deposition, the deposited film is thin and cannot be used as a magnetic recording layer of a magnetic recording medium. At the stage, this membrane is not continuous;
The structure looks like islands floating on the sea.

In other words, it has an island-like structure, and as the precipitation continues, the islands grow and coalesce, and as this coalescence continues, the islands connect to form a network structure, and as the precipitation continues, the islands coalesce. As the film thickness increases, the spaces between the meshes gradually fill up and become flat, making it possible to improve methyl resistance and abrasion resistance by using magnetic recording in magnetic recording media. They thought that it would be possible to achieve this goal, and based on this technical idea, they accomplished the present invention.

That is, iron, cobalt, nickel, or other strong materials are placed on a flat, nonmagnetic substrate (which may be flexible such as polyester or polyimide, or hard materials such as glass, ceramic, metal, or metal oxide). Magnetic metals or alloys thereof, such as Fe-Co, Fe-Ni
, Co-old, and even these, e.g. M n s
Z n s S t s O+1, Or, Ru, F
Le, P.

When a magnetic recording layer is formed by a paper deposition method using Y, V, B, W, Sm, etc. alone or in combination to a thickness required for a magnetic recording medium, the magnetic recording j of this magnetic recording medium is - Although the coating surface does not have an island-like structure or a network structure, after forming such a magnetic recording layer, using a material different from that of the magnetic recording layer, for example, Or, Zr, 5n1Ta,
W, Ti1 alumina (At2o3), forsterite (2Mgo-8i02), steatite (MgO-8
I02), Mullite (3At203・2S+02
), Nisilite (2Mg0.2 A 40g.5
S + Ox), Lithia (Li, O・At203・5
in2), titania (Tie, ), silicon carbide (Sin)
, silicon oxide (Sin, ), norcon (Zr0a ・Sr
Lightly perform paper deposition on the surface of the magnetic recording layer using an appropriate amount of oxidized oxide (Orb2.0r203) to form an island-like structure or a network structure on the surface of the magnetic recording layer. They constructed a metal thin film magnetic recording medium with the structure shown in the drawing. In addition, in the drawing, 1
is a non-magnetic substrate, and 2 is, for example, about 0.08 to 1
μm thick magnetic recording layer by paper deposition method, 3
1 is an island formed by a paper deposition method using a material different from that of the magnetic recording layer 2, and the structure shown in the drawing is one in which the surface has an island-like structure.

If such an island is formed on the side of the magnetic recording medium where the magnetic head slides, it is possible to improve wear resistance and methyl resistance, and it is desirable that the height of the island be reduced. Several tens to hundreds of A1, especially preferably the height of the island is about 30 to 5
Abrasion resistance The methylity was improved.

Hereinafter, specific examples of the magnetic recording medium according to the present invention will be described.

Example 1 A cobalt-chromium alloy is deposited on a 50 μm thick polyethylene terephthalate film by high frequency sputtering to form a 05 μm thick magnetic recording layer. still,
The chromium content was 20W, the gas pressure during sputtering was I x 10-2 torr, and the resulting magnetic recording layer was a perpendicularly magnetized film.

In this way, without taking out the resulting material from the vacuum chamber, using titania provided on a separate electrode, the height of the titania islands is transferred onto a magnetic recording layer made of a perpendicularly magnetized film of a cobalt-chromium alloy. Sputtering is performed so that the magnetic field is about 80 to 120 A to obtain a magnetic recording medium having a structure as shown in the drawing. This magnetic recording medium is then processed into a 5-inch flexible disk.

Example 2 On a polyethylene terephthalate film tape having a width of 1 inch, a length of 50 m, and a thickness of 12 μm, cobalt was deposited by oblique electron beam evaporation to form a magnetic recording layer having a thickness of 0.2 μm.

The degree of vacuum during vapor deposition was 5×1O-5 torr.

The deposition beam angle is 70° to the film surface normal.

The product thus produced was taken out of the vacuum chamber, and Sn was electron beam evaporated onto the cobalt surface so that the Sn islands had a height of 50 to 100 A, and the surface became as shown in the drawing. A magnetic tape with an island-like structure is obtained. Same, S
The angle between the deposition beam of n and the normal to the film surface is Oo.

Comparative Examples 1 and 2 In Examples 1 and 2, after forming the magnetic recording layer, the steps of sputtering and electron beam evaporation of a material different from the material constituting the magnetic recording layer were omitted, and flexible disks and magnetic tapes were obtained.

As described above, running tests were conducted on the flexible disks obtained in Example 1 and Comparative Example 1, and the decrease in reproduction output was investigated as shown in Table 1.

Table 1: In the above test, the relative speed between the head and the medium was set to 2.
m/S, the same track was run many times, the recorded frequency was 62.5 KHz, and the track pitch of the ring head was 96 TPI.

In addition, running tests were conducted on the magnetic tapes obtained in Example 2 and Comparative Example 2, and changes in playback behavior were examined as shown in Table 2.

Table 2 Same as above, in the above test, home VTR, (VH8-6
500, manufactured by Victor Japan), and the recording frequency was 4. OM Hz, and the track width of the head is 56
It is μm.

Furthermore, after these tests were completed, when the surfaces of the flexible disk and magnetic tape were observed using an optical microscope, almost no scratches were observed on the samples of this example, but deep scratches were observed on the samples of the comparative example. .

In the above embodiment, after the magnetic recording layer of the magnetic recording medium is formed, a material different from that of the magnetic recording layer is used to make the surface have an island-like structure and an insulated mesh structure. However, an island-like structure or a network structure is first formed on the base film using a material different from that of the magnetic recording layer, and then the magnetic recording layer is deposited to the required thickness as a magnetic recording medium by paper deposition. Even if it is formed, the surface will have an island-like structure or a network structure. Whether the surface has an island-like structure or a network structure can be determined by a cross-sectional observation method using a transmission electron microscope, a cross-sectional observation method using a scanning electron microscope, and a combination of X-ray microanalysis, or by the surface electrical resistance. This can be determined by measurement.

As mentioned above, the magnetic recording medium according to the present invention has an island-like structure or a mesh structure on the magnetic recording side surface of the magnetic recording medium, and therefore has extremely excellent still resistance and abrasion resistance. , the problem of runnability, which had been a major obstacle to the practical application of metal thin film magnetic recording media, has been almost completely resolved, and its practical application has been promoted.

[Brief explanation of the drawing]

The drawing is a schematic explanatory diagram showing the structure of a magnetic recording medium according to the present invention. 2...Magnetic recording layer, 3...Island. Patent Applicant: Victor Japan Co., Ltd. Agent Katsu Utaka 1, Self 51 22 (11)

Claims (1)

[Claims] 1. A magnetic recording medium characterized in that a magnetic recording surface side surface of the magnetic recording medium has an island-like structure or a mesh structure.