JPS6257122A - Thin metallic film type magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve durability by providing nonmagnetic particles which are embedded in the surface of a magnetic layer consisting of a thin metallic film formed on a substrate and have the average grain size smaller than the film thickness of the magnetic layer to a titled medium. CONSTITUTION:The thin magnetic metallic film 2 is formed on the substrate 1 and the nonmagnetic particles 3 having the average grain size smaller than the film thickness of the layer 2 is embedded in the surface thereof. SiO2, Al2O3, SiC, etc. having the hardness higher than the hardness of the layer 2 are used for the nonmagnetic particles 3 to improve the durability of the medium. The grain size of the particles 3 is made smaller than the film thickness of the magnetic layer 2 to permit the easy embedment.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a gold thin film type magnetic recording medium with excellent durability.

BACKGROUND ART Magnetic recording and reproducing devices are becoming denser every year, and there is a demand for magnetic recording media with excellent short wavelength recording and reproducing characteristics. The characteristics of coated magnetic recording media, which are currently mainly used and in which magnetic powder is coated on a substrate, have been improved to meet the above requirements, but they are approaching their limits. Metal thin film magnetic recording media are being developed to overcome this limit. The metal Igl type magnetic recording medium is manufactured by a vacuum evaporation method, a sputtering method, a plating method, etc., and has excellent short wavelength recording and reproducing characteristics. Metal IW:! The magnetic layer in the type magnetic recording medium includes co, Co-Ni, C
Thin film for in-plane recording such as o-N1-P, Aluminum G; tCo-
'n films for perpendicular recording such as Cr and Co-V are promising.

Problems to be Solved by the Invention Metal thin film magnetic recording media have excellent short-wavelength recording and reproducing characteristics, but they are easily scratched when recording and reproducing by bringing a magnetic head into contact with the recording medium. There was a problem with poor durability.

Means for Solving the Problems In order to solve the above problems, the gold [1 demolded magnetic recording medium of the present invention has a substrate, a magnetic layer made of a gold Re film formed on the substrate, and a magnetic layer formed on the substrate. This structure includes non-magnetic particles having an average particle size smaller than the thickness of the magnetic layer provided on the surface of the layer.

Effects According to the above configuration, since the nonmagnetic particles are embedded in the magnetic layer, durability can be greatly improved without deteriorating the short wavelength recording/reproducing characteristics.

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a cross-sectional view of a metal thin film type magnetic recording medium (hereinafter referred to as "medium") in one embodiment of the present invention, where 1 is a substrate, and gold l! An Iil film magnetic layer 2 is formed, and non-magnetic particles 3 having an average grain size smaller than the film thickness of the metal thin magnetic film 112 are embedded in the surface thereof. The material for the non-magnetic particles 3 is 5i, which has a higher hardness than the metal thin film magnetic layer 2, in order to improve the durability of the medium.
02, A1203.

SiC etc. are suitable. Furthermore, when the particle size of the non-magnetic particles 3 is made larger than the film thickness of the metal thin film magnetic layer 2, the non-magnetic particles 3
It becomes difficult to embed the metal thin film magnetic layer 2.
This is not desirable as it will cause more damage to the The amount of embedded non-magnetic particles 3 will be explained next. First, it will be described how far it is desirable for the non-magnetic particles 3 to extend from the surface of the magnetic thin metal film 1f2. If this value is expressed as g as shown in FIG. 1, it is desirable that ρ be in the range of 30 to 250 people. If it exceeds 250 A, the space loss during recording and reproduction becomes large, and the advantage of the metal thin film magnetic recording medium, which is the excellent short wavelength recording and reproduction characteristics, is lost. If it is less than 30A, the coefficient of friction will increase and scratches will occur easily, so A should be 3.
A thickness of 0 Å or more is required. Next, we will discuss how far the nonmagnetic particles 3 should be embedded from the surface of the metal thin film magnetic WJ2. Regarding this point, as a result of actually conducting a durability test of the medium by changing the amount of embedding, it was confirmed that if the embedding amount is about 275 or more of the particle size of the non-magnetic particles 3, sufficient durability can be obtained. If the non-magnetic particles 3 are simply coated on the surface of the thin metal WAin layer 2 without embedding it, it will cause problems when recording and reproducing with a magnetic head or when traveling along a post in the case of a tape-shaped medium. The non-magnetic particles 3 are scraped off and sufficient durability cannot be obtained.

Next, an example of a method for manufacturing the above-mentioned medium will be described. Second
The figure shows a method of embedding nonmagnetic particles 3 into a metal thin film magnetic layer 2 using pressure. During production, gold [9
A solvent 4 in which non-magnetic particles 3 are dispersed on the surface of the magnetic film layer 2.
(Figure 2 (A)). It is desirable that the solvent 4 contains an adhesive for bonding the nonmagnetic particles 3 and the metal thin film magnetic layer 2. After the volatile components in the solvent 4 have evaporated, pressure is applied to the medium by a pressure roller 5 to embed the nonmagnetic particles 3 into the surface of the metal i1 film magnetic layer 2, as shown in FIG. 2(B). The arrows in FIG. 2(B) indicate the moving direction of the medium and the rotating direction of the pressure roller 5.

By the above method, a medium as shown in FIG. 1 can be obtained.

FIG. 3 shows another method of manufacturing the medium, in which non-magnetic particles 3 are implanted into the thin metal magnetic layer 2 by well-known plasma spraying or detonation spraying. The amount of embedded non-magnetic particles 3 can be controlled by the kinetic energy given to the non-magnetic particles 3 during thermal spraying. Note that the arrow in FIG. 3 indicates the flying direction of the nonmagnetic particles 3.

Next, specific examples will be described.

[Specific Example 11] On a polyimide film having a thickness of 5 Gμl as a substrate 1, a metal wJWi type magnetic layer 2 was formed with a thickness of 0.5 Gμl by vacuum evaporation.
A 2 μm co-Cr perpendicular magnetic anisotropy film was formed, and a solvent 4 in which 5i02 particles as non-magnetic particles 3 were dispersed was applied thereon. The average particle size of 8102 particles is 200 people, C
The density of 5i02 particles on the o-Cr perpendicular magnetic anisotropy film was approximately 30 particles/μg. Further, the solvent 4 contained an adhesive. After evaporating the volatile components in the solvent 4, as shown in Fig. 2 (
As shown in B), 5i02 particles were embedded in the surface of the Co--Cr perpendicular magnetic anisotropic film using the pressure roller 5. In this state, the surface roughness of the medium was measured using a surface roughness meter and was found to be about 70 people. Therefore, approximately 130 people, which is more than half the particle size of 5i02 particles,
It is thought that it is embedded in the Cr perpendicular magnetic anisotropy film. As described above, Co-Cr embedded with 5i02 particles
On the perpendicular magnetic anisotropy film, a fluororesin having a thickness of about 80 mm was applied as a wet WI layer. When the thus obtained medium was recorded and played back using a floppy disk drive with an on-znn frame ring head, the result was 1ooo.
It showed durability of more than 10,000 passes. On the other hand, a medium in which fluorine-based resin is simply coated on a Co-Cr perpendicular magnetic anisotropic film without embedding 5i02 particles will exceed 10,000 passes using the same evaluation method as above. The surface was scratched, making it unusable. - [Specific Example 2] On a polyimide film with a thickness of 12 μI as the substrate 1, a film with a thickness of 0.03 μI is formed by vacuum evaporation, and on this, a film with a thickness of 0.15 μI as the metal thin film magnetic layer 2 is formed. A Co--Cr perpendicular magnetic anisotropic film was formed.

In the same manner as in Example 1, 5i02 particles having an average particle diameter of 150 were embedded thereon at a density of about 3011/μ. According to a surface roughness meter, the surface roughness was approximately 408. As described above, Co-
A carbon film having a thickness of 70 mm was formed on the Cr perpendicular magnetic anisotropy film by plasma polymerization.

When the medium thus obtained was used for still playback on an 8Il#I video deck, there was almost no change in the playback output even after 30 minutes or more had elapsed. On the other hand, 5i
A medium in which a carbon plasma polymerized film was simply formed on a Co-Cr perpendicular magnetic anisotropic film without embedding 02 particles was evaluated using the same evaluation method as above, and the surface was scratched in 20 to 30 seconds. , there is no playback output.

Effects of the Invention As described above, according to the present invention, durability can be significantly improved without deteriorating short wavelength recording/reproducing characteristics.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a metal thin film magnetic recording medium according to an embodiment of the present invention, and FIGS. 2 and 3 are the same metal thin film type magnetic recording medium. FIG. 3 is a cross-sectional view illustrating a method of manufacturing a thin model magnetic recording medium. DESCRIPTION OF SYMBOLS 1...Substrate, 2...Metal thin film magnetic layer, 3...Nonmagnetic particles

Claims (1)

[Claims] 1. A substrate, a magnetic layer made of a thin metal film formed on the substrate, and non-magnetic particles embedded in the surface of the magnetic layer and having an average particle size smaller than the thickness of the magnetic layer. A thin metal film magnetic recording medium. 2. The metal thin film type magnetic recording medium according to claim 1, wherein the nonmagnetic particles are a compound. 3. The metal thin film magnetic recording medium according to claim 1, wherein the nonmagnetic particles are carbide.