JPH0262715A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve both a high density recording characteristic and durability by providing projections consisting of implanted layers selected from C, N, B, and O on a nonmagnetic layer positioned on the uppermost part of a smooth high-polymer film. CONSTITUTION:The nonmagnetic layer 8 positioned on the uppermost part laminated with the nonmagnetic layers 6, 8 and the ferromagnetic layer 7 is so constituted on the smooth high-polymer film 5 as to have the implanted layers selected from the C, N, B, and O. The ferromagnetic layer 7 is made into the fine particle layer according to this constitution, by which the noises are decreased and the improved durability is resulted from the decrease in the contact area by the formation of the projections. On the other hand, the adverse influence of the increased noises by the converse generation of magnetic unequalness is minimized. Since the uniform constitution of the hard projections by the implanted layer is possible, the durability is improved by lowering the projection height and the degradation in the output of the short wavelength region is minimized. The high reliability is assured in this way in high-density digital recording.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium whose magnetic recording layer is a ferromagnetic metal thin film suitable for high-density magnetic recording.

Conventional technology Recent advances in recording technology have significantly improved the recording density not only per unit area but also per unit volume. There is a strong desire for the practical application of vapor-deposited tapes and the like that have magnetic recording layers as magnetic recording layers. Therefore, recently, the importance of research on tribology to deepen our understanding of friction, wear, etc. that occurs at sliding interfaces has been recognized, and development is progressing in various fields [Journal of the Society of Television Engineers, Vow, 40, 56 (1986)] 4
72 pages].

FIG. 2 is an enlarged sectional view of a conventional magnetic recording medium. Second
In the figure, 1 is a polymer film made of polyethylene terephthalate, polyimide, etc., which is provided with a finely divided surface if necessary [JP-A-59-207422, JP-A-69-121631] Publication is used. 2
is Co-N1-0 obliquely deposited film, Co-0r, G
A magnetic recording layer such as a perpendicular magnetization film such as o-Or-Wb, 3 is a protective layer, and 4 is a back coat layer, which is a resin layer containing particles such as carbon powder and calcium carbide powder, which mainly improves running properties. Therefore, it is often provided when a protective layer alone is insufficient.

Conventionally, the protective layer has been improved in wear resistance by a vapor-deposited film of a fatty acid metal salt disclosed in JP-A-54-113303;
Known examples include the sputtered film of a polymer having imide groups disclosed in JP-A-57-116771, and an example using a diamond-like hard carbon film (Japan Society of Applied Magnetics, 46th Research Meeting Materials). . Also, as a layer for lubricating purposes, vapor deposition method.

Many attempts have been made to coat fatty acids, fatty acid amides, etc. by wet coating methods (for example, Japanese Patent Publication No. 30609/1983).

However, in the above example, it is not possible to fully cope with the expansion of usage environmental conditions and the sophistication of practical requirements for alloy-based magnetic heads, so improvements are being considered by combining fluorocarbons on the adsorption layer of fatty acid metal salts. (Japanese Unexamined Patent Publication No. 61-120331), a hard carbon layer with a fluorine-containing lubricating oil layer (Japanese Unexamined Patent Application No. 61-126627), 5i-N-0
A lubricating layer is formed on a thin film of the JP-A-61-131
Publication No. 231), etc.

Problems to be Solved by the Invention However, with the above configuration, when high-density digital recording is performed with an alloy head, if reliability is emphasized,
There was a problem that recording characteristics deteriorated, and improvements were desired. The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a magnetic recording medium that has improved both high-density recording characteristics and durability.

Means for Solving the Problems In order to solve the above problems, the magnetic recording medium of the present invention comprises:
A non-magnetic layer and a ferromagnetic layer are laminated on a smooth polymer film, and the top non-magnetic layer is C, N, B, 0.
The protrusion is formed by an injection layer selected from the following.

Effect The magnetic recording medium of the present invention has the above-described structure, which improves noise by making the ferromagnetic layer finer, and improves durability by reducing the contact area by forming protrusions, but conversely reduces magnetic unevenness. The negative effects of increased noise can be minimized. Furthermore, since the hard protrusions formed by the injection layer can be formed uniformly, durability can be improved even if the protrusion height is lowered, and the drop in output in the short wavelength range can also be minimized.

EXAMPLE Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 is an enlarged cross-sectional view of a magnetic recording medium according to an embodiment of the present invention. In FIG. It is preferable to have a smooth material with a good average roughness of 20 to 50 grains and a maximum roughness of 40 to 10 grains.

Reference numeral 6 denotes a nonmagnetic layer of AJ, Si, Ti, Or, etc., which is preferably formed by an electron beam evaporation method, an ion blating method, a high frequency sputtering method, etc. and has a thickness in the range of 160 to 500 layers.

7 is a ferromagnetic layer of Go, Go-Ti, Go-Cr
, G.

-O, Go-W, Go-Or-Nb, Co-
Either a perpendicular magnetization film or an in-plane magnetization film of Ni-0 etc. may be used.
The structure may be the same or different, and the number of layers is preferably in the range of 2 to 5 layers.

8 is the topmost nonmagnetic layer, and this layer contains C1B, N
, O, the height of the projections is preferably 60 to 200, and the density is preferably 10 6 to 3×10′/−. 107 pieces/, -
The C/N is good below 1, but the durability deteriorates depending on the material of the alloy head. Above 4, the noise increases.
There is a preferred range that causes a reduction of dB or more. 10 is a protective lubricating layer made of plasma polymerized film, diamond-like carbon film, fatty acid, perfluorocarboxylic acid, or the like.

When the present invention is carried out in the form of a tape, the arrangement of the back coat layer, and in the case of the form of a disk, the above-mentioned structure may be arranged on the other side as well, etc. may be selected as appropriate. More specific examples will be described below in comparison with comparative examples.

Example-1 Thickness 9B7z! 11. On a smooth polyethylene terephthalate film with an average roughness of 25 mm and a maximum roughness of 60 mm, 30 OA of mug was deposited using an electron beam, and then a 1 m diameter layer was deposited on top of it.
along the cylindrical can, minimum angle of incidence 48 degrees, oxygen partial pressure 5
X 105 (Torr), Go-Ni (Co:ao
wt%) was deposited by 50OA electron beam evaporation. Similarly, A
30OA of J5, 500 people of Go-Ni, AI
Arrived at 3ooAM, N ions were accelerated to 13 sxv, and 6
5μA/l'! Protrusions with a diameter of 0.7μ were formed at a density of 5×10 6 /, -4. The height of the protrusion is 70 people.

On top of this, Go-Ni was further deposited by SOO, and on top of that, a plasma polymerized film of lauryl amine was placed on 90 layers, and on the other side of the polyethylene terephthalate, a back coat layer of Q, 4 μm was placed, and the width was 8 mm. A prototype magnetic tape was produced.

Example 2 360 layers of Sl were deposited on a smooth napolyethylene naphthalate film with a thickness of 12 μm with an average roughness of 20 layers and a maximum roughness of 60 layers using a high frequency sputtering method, and Co − 500 layers of Cr perpendicular magnetization film (co7swt%) were formed, and 36 layers of Sl were further formed.
0 manned C ions accelerated to 15Kv, 60 pk/c
In A, protrusions with a diameter of 0.7 μm were formed at a density of 3 x 107/- (protrusion height 100), on which 500 Go-Or perpendicular magnetization films were placed, and methane was further discharge-accelerated on top of it. 86 diamond-like carbon films were placed on top of the diamond-like carbon film, and 6 layers of perfluoroarachidic acid were vacuum-deposited on top of the diamond-like carbon film, to produce a prototype magnetic tape with an inch diameter.

Comparative Example-1 On a polyethylene terephthalate film with a thickness of 98 μm, 2×10′/- of 102 particles with a diameter of 200 particles were placed, and on top of that, Al and Go − were placed under the same conditions as in Example-1.
An 8 mm wide magnetic tape was experimentally produced by alternately depositing Ni with electron beams and disposing a similar protective lubricant layer and back coat layer.

Comparative Example-2 Using the same film as Example-2, a film with a diameter of 16
0 Cr2O5 fine particles were placed at 3 x 107/-, and on top of that, Sl and Go-Or perpendicular magnetization films, diamond-like carbon films, and perfluoroarachidic acid were placed under the same conditions.
Prototype of inch magnetic tape was produced.

Digital recording was performed using the above-mentioned tape with different alloy heads, and the error rate was evaluated.

Using a modified 8mm video, track pitch 10μm
, digital recording was performed with a pit length of 0.23 μm, and the error rate was measured.
50 type, track pitch 14 μm, bit length 0.2
The results of digital recording in μm and measurement of error rates are summarized in a table.

(Hereinafter referred to as blank spaces) Effects of the Invention As described above, the present invention has the excellent effect of ensuring high reliability in high-density digital recording.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a magnetic recording medium according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a conventional magnetic recording medium. 5...Polymer film, 6...Nonmagnetic layer, 7...Ferromagnetic layer, 8...Nonmagnetic layer, 9... - Ion implantation protrusion, 10...protective lubricant layer. Name of agent: Patent attorney Shigetaka Awano and one other person
---3 films

Claims (1)

[Claims] A non-magnetic layer and a ferromagnetic layer are laminated on a smooth polymer film, and the top non-magnetic layer is C, N, B,
A magnetic recording medium characterized by having protrusions formed by an injection layer selected from O.