JPH0414614A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium having excellent C/N and storage reliability by forming a Co-Cr perpendicular magnetization film comprising columnar particles with 40 deg. - 10 deg. incident angle range. CONSTITUTION:A Co-Cr or Co-Ni-Cr perpendicular magnetization film is formed by electron beam vapor deposition method etc., on the polymer film 1 such as poyethyleneterephthalate, polyethylenenaphthalate, etc. the perpendicular magnetization film consists of columnar particles grown with 40 deg. - 10 deg. incident angle range so that the film gives directional variation in output when a ring head is used for recording/reproducing. The film is preferably made 0.05 - 0.35mum thick. A protective lubricating layer 3 provided thereon consists of a combination of a protective film such as SiOx, TiOx, etc., and a lubricant such as perfluoropolyether, aliphatic alcohol, etc. Thereby, the obtd. medium is excellent in C/N and storage reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium suitable for high-density magnetic recording.

Conventional Technology It has been more than 10 years since research on a new perpendicular magnetic recording method began as a next-generation magnetic recording technology, and its practical application is awaited. In particular, recently, since the C0-Ni-0 obliquely deposited film has excellent short wavelength characteristics, the level of practical application required for the C0-Cr perpendicular magnetization film has become higher.

On the other hand, a manufacturing method similar to that of Co-Ni-0 obliquely deposited film,
In other words, without heating the polyethylene terephthalate to a particularly high temperature and moving it along a rotating shaft, it is exposed to carbon dioxide in an oxygen atmosphere.
It is known that a C0-0 perpendicularly magnetized film can be obtained by depositing O or Co-Ni at an incident angle of 40 degrees or less (Japanese Patent Laid-Open No. 1-109531), and a ring-type magnetic head There are growing expectations for increasing the upper limit of the recording density that can be achieved.

Problems to be Solved by the Invention However, Co-0 perpendicular magnetization films currently cannot match the recording density achieved by single-pole vertical heads, and also from the viewpoint of corrosion resistance. Since it is inferior to a magnetized film, it is strongly desired to improve the high-density recording characteristics of a Co--Cr perpendicular magnetic recording medium improved by a system using a ring head. The present invention has been made in view of the above-mentioned circumstances, and provides a magnetic recording medium using a Co--Cr perpendicular magnetization film with improved high-density recording characteristics using a ring head.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention comprises:
A perpendicularly magnetized film made of Co--Cr is composed of columnar grains having an incident angle in the range of 40 degrees to 10 degrees.

The magnetic recording medium of the present invention, with the above-described configuration, is easily magnetized by the magnetic field of the ring head, and also has good magnetic separation between columnar particles, lowers noise, and improves C/N. Unlike oblique deposition, the filling rate of columnar particles is sufficiently dense from the viewpoint of improving corrosion resistance, and the good corrosion resistance of the Co-Cr material itself is rarely degraded by structural defects when thinned. C/
N, corrosion resistance can be improved at the same time.

EXAMPLES Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

[Example 1] FIG. 1 is an enlarged sectional view of a magnetic recording medium according to a first example of the present invention. In Figure 1, 1 is polyethylene terephthalate, polyethylene naphthalate polyether ketone, polyphenylene sulfide polyether sulfone,
With polymer films such as polyamideimide and polyimide,
It goes without saying that a layer provided with a fine particle coating layer may be used as required, and the formation of protrusions may be controlled by controlling the dispersion of an inherent filler. 2 is a Co-Cr perpendicular magnetization film.
-Ni-Cr may be used. This perpendicularly magnetized film may be formed by any method such as electron beam evaporation, ion-assisted evaporation, or sputtering.
This perpendicular magnetization film is characterized by being composed of columnar fine particles grown with components in the range of 10 degrees to 10 degrees, and the perpendicular magnetization film is characterized in that the output differs depending on the direction when recording and reproducing by the ring or throat. You can also give. Here, as for the incident angle, if it contains a component of 40 degrees or more, it is likely that the corrosion resistance will deteriorate, and if it contains a component of 10 degrees or less, it will increase the loss during recording by the ring head, which is a value that cannot be ignored in practice. It is necessary to select the incident angle range from Film thickness is 0
．． A range of 0.05 μm to 0.35 μm is preferred. 3 is a protective lubricant layer, S 1OxTiOx, Tic, BC, carbon,
A combination of a protective film such as a plasma polymerized film and a lubricant such as perfluoropolyether or aliphatic alcohol is suitable, and it is important to select the dimensions of the material to minimize spacing loss. You can decide. If it is in the form of a tape, a back coat layer may be provided, and if it is in the form of a disk, it can be devised as appropriate, such as making it impossible to access both sides.

Examples of the present invention will now be described in more detail in comparison with comparative examples.

2 protrusions with a height of 150 people using an internal filler with a thickness of 10 μm
Prepare a polyethylene terephthalate film with ~3 pieces/μ2 and a polyimide film, and place a cylindrical can with a diameter of 50 cm on the polyethylene terephthalate film (
High frequency sputtering method (13,56 MHz, 0.6 to 2.2
Co-Cr (Co:
80wt%) film was formed to a thickness of 0.2 μm. On the other hand, 230 cylindrical cans with a diameter of 50 cm were placed on the polyimide film.
C., and a Co--Cr (Co: 79 wt%) perpendicularly magnetized film having a thickness of 0.2 .mu.m was formed by changing the incident angle by electron beam evaporation.

Approximately 50 perfluoropolyether "Fonbrin AM2001" manufactured by Montegisson were placed in each case, and a bank coat layer containing 20 parts by weight of carbon black and 100 parts by weight of polyester resin as main components was formed by a solution coating method. The brightness C/N was compared in high band specifications by slitting 8 mm width and changing the direction using a metal-in-gap ring head with a gap length of 0.16 μm. Corrosion resistance was evaluated by comparing the C/N after 3W at 60° C. and 90% RH with the initial value. In the comparative example, since the incident angle was not changed from 40 degrees to 10 degrees on the polyimide film in addition to Co-Cr, oxygen gas was introduced at 0.25 (j'/m1n) [introduced from the 10 degree incident angle side, and argon gas was introduced from the 10 degree incident angle side. Gas was introduced at 0.06 (f/m1n) [introduced from the 40-degree incident angle side], Co was deposited by electron beam,
A Co-0 perpendicular magnetization film having a thickness of 0.22 μm was used. The conditions and evaluation results are summarized in Table 1.

(Margins below) [Example 2] Another means to solve the problem is to arrange a soft magnetic layer of 500λ or less on a polymer film, and then apply a columnar magnetic layer with an incident angle of 40 degrees to 10 degrees. A Co--Cr perpendicularly magnetized film made of particles is arranged. Due to the above-described structure, the magnetic recording medium of the present invention has less disordered orientation in the initial growth layer than those grown directly on a Co--Cr perpendicular magnetization film or a polymer film, and the soft magnetic layer allows the ring head to It is thought that the overall C/N will further improve as improvements in recording demagnetization progress, which is thought to be due to an increase in the perpendicular component of the recording magnetic field generated from the magnetic field.

FIG. 2 is an enlarged sectional view of a magnetic recording medium according to a second embodiment of the present invention, in which the same components as in FIG. 1 are designated by the same numbers. In Figure 2, 4 is the t-beam evaporation method;
A soft magnetic layer formed by ion-assisted vapor deposition, sputtering, etc., containing NlFe, Co-Ni, Co-Cr,
The film thickness is preferably 500 Å or less using Ni-Fe-Mn, etc.
More preferably 300 to 100 people.

Examples of the present invention will now be described in more detail in comparison with comparative examples.

A soft magnetic layer was placed under various conditions on an aramid film with a thickness of 11 μm (height of protrusions due to internal particles: 150, average density: 4 pieces/μ2), and a cylinder with a diameter of 50 μm was placed on top of the aramid film while keeping the can temperature at 220°C. Along the can, a 0.19 μm perpendicularly magnetized film of Co-Cr (Co79.5wt%) with an incident angle of 20 degrees is arranged (referred to as perpendicular magnetized film A), and a 0.19 μm perpendicularly magnetized film with an incident angle of 20 degrees from an incident angle of 35 degrees. degree of Co-Cr (Co8
A perpendicularly magnetized film of 0.2 wt %) with a thickness of 0.22 μm was prepared (referred to as perpendicularly magnetized film B), and “Fomblin Z-25” manufactured by Montageson was placed thereon at 35 μm/d. A 0.4 μm back coat layer was arranged and processed into an 8 mm wide magnetic tape. A comparative example without a soft magnetic layer was selected. The conditions and evaluation results are summarized in Table 2.

(Hereinafter in the margin) Effects of the Invention As described above, the present invention has excellent effects in that a magnetic recording medium with excellent C/N and storage reliability can be obtained.

[Brief explanation of drawings]

1 and 2 are enlarged sectional views of a magnetic recording medium according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Polymer film, 2... Perpendicular magnetization film, 3... Protective lubricating layer, 4... Soft magnetic layer.

Claims (2)

[Claims] (1) A magnetic recording medium characterized in that the perpendicularly magnetized film made of columnar grains with an incident angle in the range of 40 degrees to 10 degrees is made of Co-Cr. (2) Magnetic recording characterized by disposing a Co-Cr perpendicular magnetization film consisting of columnar grains with an incident angle of 40 degrees to 10 degrees on top of a soft magnetic layer of 500 Å or less on a polymer film. Medium.