JPH0482011A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain good output characteristics under a wide range of service conditions by forming a magnetic recording layer of a perpendicularly magnetized film consisting of Co-Pt-M-O, adopting any of Zn, Cd and Mg for M and specifying the atomic % of M and O. CONSTITUTION:The perpendicularly magnetized film 2 which consists of the Co-Pt-M-O and is provided atop a high-polymer film 1 is constituted of the thin film formed by a sputtering method using a Co-Pt-M alloy as a target and using a discharge gas, such as Ar+O2 or Ar+H2+O2, while moving the high-polymer film 1 along a cylindrical can. The M in the atomic % compsn. of the Co-Pt-M-O is 0.5 to 5atomic% and the O is 5 to 15atomic%. The Zn, Cd or Mg is used as the M. The adhesion of a composite head material of an alloy system and the magnetic recording medium in low-temp. environment is substantially prevented in this way and the higher output is obtd.

Description

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

Conventional technology In conventional thin film magnetic recording media, the Co-Ni-0 diagonally deposited film has achieved the highest recording density at a practical level, and in the future -
Further progress is expected. Until now, a number of materials have been proposed for ferromagnetic metal thin films, mainly from the viewpoints of corrosion resistance and magnetic properties. Among them, so-called perpendicular magnetization films are advantageous for high density, and include Co-Cr, Co-0, etc. [Journal of
the Magnetics Society of J.
apan vol, 13611-630 (1989) 1゜In particular, the recently announced Co-Pt-B-○ thin film [
34th Annual Conference on
Magnetism and Magnetic Ma
terials DC-12 (1989)] is Co-
It is attracting attention because of its output characteristics that surpass that of Cr and because it allows the use of polyester as a polymer film.

Problems to be Solved by the Invention However, when recording and reproducing conventionally known materials using ring magnetic heads using recent composite materials, they are not compatible with magnetic heads in low temperature and low humidity environments, and short-term problems occur. There was a problem in that the output decreased in a short time as the wavelength increased, and improvements were desired.

The present invention solves the above-mentioned problems, and aims to provide a magnetic recording medium having a perpendicular magnetization film that exhibits excellent characteristics even in a low-temperature, low-humidity environment as in a normal temperature and humidity environment. It is.

Means for Solving the Problems In order to achieve the above object, the magnetic recording medium of the present invention has the following features:
The magnetic recording layer is a Co-Pt-M-0 film made of Zn, Cd, or Mg with M of 0.5 to 5 at%, and ○ is 5 to 1.
It is composed of a perpendicularly magnetized film having a composition of 5 atomic %.

Function Therefore, according to the magnetic recording medium of the present invention, the above-described configuration makes it difficult for the alloy composite head material to adhere to the magnetic recording medium in a low-humidity environment, thereby improving spacing loss due to adhesion. Also, Cd, Zn, or Mg itself has the same crystal structure as Co, and by improving crystallinity, higher output can be achieved.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Example 1) FIG. 1 is a partially enlarged sectional view of a magnetic recording medium according to an example of the present invention, and in the figure, numeral 1 represents polyethylene terephthalate and polyethylene naphthalate.

Polymer film such as polyphenylene sulfide, polyether ether ketone, polyether sulfone, polyimide, aramid, etc., and if necessary, a fine particle coating layer, a base layer, and a soft magnetic layer can be provided on the top surface. . 2 is a perpendicular magnetization film of Co-Pt-M-〇; 4, while moving the polymer film 1 along the cylindrical can, targeting the Co-Pt-M alloy;
Ar+02. It is composed of a thin film of 0.05 to 0.3 μm formed by a sputtering method using a discharge gas such as Ar+82+02. The atomic % composition of Co-Pt-M-0 is 0.5 to 5 atomic % of M, 5 to 15 atomic % of O, Pt
is 5 to 20 atom%, with the remainder being C.

Consists of. In the above examples, if M is less than 0.5 at %, adhesion cannot be prevented. On the other hand, if the content exceeds 5 at %, the frictional properties in a high humidity environment will deteriorate. Also, M as Z
n, Cd or Mg can be used. In addition, C
C containing 15 to 25 atom % of Ni in place of O to its CO
It can also be o-Ni. 3 is a protective lubricating layer;
Plasma polymerized membranes, carbon membranes, fatty acids, fatty acid amides, perfluorocarboxylic acids, perfluoropolyethers, etc. are used, and the thickness must be set to an appropriate thickness in consideration of spacing loss. This consideration is essential to achieve high-density recording, and therefore, despite the presence of a protective lubricant layer, the properties of the underlying magnetic recording layer will affect the sliding properties, and the present invention This gives rise to value.

The details of the examples will be further explained below while comparing them with comparative examples.

Cr2O with a diameter of 150A is placed on a polymer film 1 made of a polyethylene terephthalate film with a thickness of 11 μm.
3 fine particles using polyester resin at an average of 20 particles/μd
The CO-Pt was dispersed and fixed so that the CO-Pt
- Using an M target (flat plate cathode spaced 5 times from the can surface at the shortest point), Ar+02 or Ar+82+C
h gas pressure in a gas atmosphere of 0.02 to 0.1T.
orr.

Various types of Co-Pt-M-0 perpendicular magnetization films were formed to a thickness of 0.18 μm at 13.56 MI (z, 1.1 to 2.4 kW), and A
The gas pressure is 0.1 Torr in the r+82 gas atmosphere.
, Ar and H2 mixing ratio is 1:3.13.56M soil, 0.
A 70A diamond-like hard carbon film was formed under the condition of 8kW. Next, 15 mg/- of Fomblin AM2001 manufactured by Montegisson was applied on top of the coating, and a back coat layer (not shown) containing a 0.4 μm carbon filler (diameter 0.08 μm) and a polyester resin was formed using a polymer. It was formed on the back side of Film 1 to obtain a magnetic tape with a width of 8 cabinets. C with a thickness of 0.18 μm as a comparative example.

8 with Cr or Co-Pt-B-○ perpendicular magnetization film formed
A magnetic tape with a width of m was used. The luminance signal output of each of the magnetic tapes produced as described above was measured and compared using an 8 mm video camera and three types of magnetic heads. The magnetic head is a metal-in-gap type. The metal part is Co-
Type A is a head made of a Zr-based amorphous sputtered film, Type B is made of a sendust sputtered film for the metal part, and Type C is a laminated head made of a Co-Zr sputtered film and a SiO2 sputtered film. It was used as Table 1 shows the results of comparing the working example and the conventional example with respect to the usage environment conditions and output characteristics of the magnetic tape.

(Left below) (Example 2) Another means for achieving the object of the present invention is that a perpendicularly magnetized film formed on a polymer film is
The magnetization efficiency is directional due to the magnetic field generated by the magnetic head, and the direction of high output tends to cause digging and wear during high-speed sliding with the magnetic head. It is possible to maintain a high output because there is no step difference in the magnetic recording layer.Also, since the magnetization film can have a high filling rate, it is possible to maintain a high output even if the vertical component of the magnetic recording layer is not included. If this is the case, corrosion resistance and high output properties can be achieved that are comparable to those of a magnetic recording layer formed of vertical components.

The present embodiment will be described below with reference to the drawings.

FIG. 2 is a partially enlarged sectional view of the magnetic recording medium of this embodiment, and the same parts as in FIG. 1 are given the same numbers. In the figure, 4 is a perpendicularly magnetized film, which is made of a film sputtered at an incident angle in the range of 40 degrees to 10 degrees, and is a model showing the case where the interfaces of columnar particles are visible. The columnar particles 5 are inclined with respect to a perpendicular line drawn on one surface of the polymer film, and are used so that the direction of relative movement with the magnetic head during recording and reproduction is in the direction of arrow A shown in the drawing. be.

The perpendicular magnetization film 4 in the present invention is Co-Cr.

Co-Ti, Co-Ta, Co-W, Co-Mo.

Co-0, Co-B-Pt-0 and Co-TiPt-
By using a mask that limits the incident angle and changing the positional relationship between the target and the polymer film 1, the degree of vacuum can be adjusted to 1O-2T during sputtering.
It can be carried out under appropriate conditions while ensuring that the temperature does not exceed orr.

The present example will be described below while being compared with a comparative example.

On a polymer film 1 made of an aramid film with a thickness of 8 μm, TiO2 fine particles with a diameter of 150 A were dispersed and fixed using a polyester resin at an average density of 15 particles/μd.
The straight part is 501 when the titanium foil with a thickness of 30 μm is used as a rotating support.
The target was tilted, the mask was adjusted, and the angle of incidence was limited to a range of 10 to 40 degrees. Form a perpendicular magnetization film. Next, on top of that, protective lubricant layer 3 (Fomblin Z-25 manufactured by Montegisson) is applied at 20w/j! A 0.4 μm back coat layer (not shown) was further provided on the back surface of the polymer film 1 to obtain a magnetic tape with a width of 8 m.

Table 2 shows the results of a comparison between Examples and Comparative Examples in terms of the environmental conditions in which the magnetic tapes were used and the magnetic tape characteristics using the magnetic tapes prepared as described above. Note that the measurement was carried out using head C.

(See the margin below.) As described above, it can be seen that according to the above-mentioned examples, magnetic properties superior to those of the prior art can be obtained in terms of reproduction output and still properties at low temperatures and low humidity or at high temperatures and high humidity.

Effects of the Invention As is clear from the above embodiments, the present invention provides a magnetic recording layer made of Co-P in which M is any one of Zn, Cd and Mg.
Since it is composed of a perpendicularly magnetized film of t-M-0, it has an excellent effect in that good output characteristics can be obtained regardless of the type of magnetic head even under an extremely wide range of usage conditions. Furthermore, the perpendicularly magnetized film is attached at an incident angle of 10
Extremely excellent still characteristics can be obtained by sputtering at an angle of 40° to 40°.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a magnetic recording medium in one embodiment of the present invention, and FIG. 2 is a sectional view of a main part of a magnetic recording medium in another embodiment. 1... Polymer film, 2.4... Perpendicular magnetization film. Son'δ child Philemt direct a 1m l fee student -16 grade te 4 luxury

Claims (2)

[Claims] (1) The magnetic recording layer is a perpendicularly magnetized film made of Co-Pt-M-O, where M is either Zn, Cd or Mg,
A magnetic recording medium in which M is 0.5 to 5 atomic % and O is 5 to 15 atomic %. (2) A magnetic recording medium in which the perpendicularly magnetized film formed on the polymer film is a sputtered film with an incident angle of 10 degrees to 40 degrees.