JPH02312013A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To obtain a recording medium excellent in C/N and durability for high density recording by providing a perpendicular magnetization film essen tially comprising Co-Cr or Co-Ni-Cr and containing 1-5 at.% Br or F. CONSTITUTION:A perpendicular magnetization film 2 essentially comprising Co-Cr or Co-Ni-Cr and containing 1-5 at.% Br or F is formed as the magnetic recording layer on a polymer film such as polyethylene terephthalate. A protec tive lubricating layer 3 is formed thereon. By using crystals of hexagonal struc ture essentially comprising Co-Cr or Co-Ni-Cr for the magnetic layer, C-axis orientation can be improved and segregation of Br and F improves the surface lubricating property and durability. Thus, the obtd. medium has excellent C/N in high density recording.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium with improved C/N and durability during perpendicular magnetic recording, and a method for manufacturing the same.

Conventional technology In recent years, the development of magnetic recording technology has been remarkable, with improvements in recording density, especially in the miniaturization and performance of devices.

Advances in multi-functionality have been remarkable, and this trend is predicted to continue in the future. Magnetic media, which is an important element, is being improved toward the adoption of thin-film magnetic recording layers and perpendicularly magnetized thin films.

Perpendicular magnetization thin films are typified by Co-Cr sputtered films, and Ni
-A combination of a so-called laminated dual-layer medium of Fe and Co-Cr and a single magnetic pole head has been reported to record and reproduce 680 KFRP I [IEEE Transactions on Magnetics].
CTIONSON MAGNETICS) vol, M
AG-23゜Arashi 5.2072 (1987)], on the other hand, it was also confirmed that high density was achieved using the existing interface technology of the Co-Cr-Nb single layer film and the ring head [JP-A-61-77128]. ] Expectations for the publication are increasing.

An important theme today for practical application is the establishment of a technology for manufacturing magnetic recording media such as magnetic disks and magnetic tapes with excellent durability and good recording performance at high speed and with good reproducibility. In view of these circumstances, we developed an electron beam evaporation technology [IEETRANSACTIONS ON MAGNETICS].
ACNETIC3) vo 1. MAG-23, m5. p
, 2449 (1987)] maintains the substrate at a high temperature of 200° C. or higher, or uses a titanium base [MAG-20, 1 of the same magazine].

687 (1984)] and germanium base [MA
G-21, p1426 (1985)], the sputtering method [
Same magazine, vo 1, MAG-23.

Studies are continuing in an effort to bring the film properties closer to those obtained in [P., 2443 (1987)].

Problems to be Solved by the Invention However, those with a base layer of titanium, Ge, etc.
Due to insufficient durability, overcoat layers and lubricants [JP-A-61-126627, JP-A-61-13]
1224, JP-A-61-131231], the spacing loss becomes large, and durability can be improved by oxidizing the magnetic layer;
[Patent No. 228412] This method also poses a problem of spacing loss, and it is an important issue to obtain a perpendicular magnetic recording medium that is durable and has a good C/N ratio.

The present invention has been made in view of the above circumstances and provides a perpendicular magnetic recording medium with a good C/N ratio and a method for manufacturing the same.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention has a perpendicularly magnetized film based on Co-Cr or Co-Ni-Cr containing 1 to 5 at% of Br or F. This is used as a recording layer.

Effect The present invention has the above-mentioned structure, and the present invention provides Co-Cr or Co-N
The C-axis orientation of the hexagonal close-packed structure crystal based on i-Cr is improved, the surface lubricity is improved due to the segregation of Br and F, and the durability is improved, resulting in a magnetic recording medium with a good C/N ratio. You will get it.

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

[Example-1] The figure is an enlarged sectional view of a magnetic recording medium according to an example of the present invention. In the figure, 1 is a polymer film made of polyethylene terephthalate, polyether sulfone, polyether ether ketone, polyphenylene sulfide, polyamideimide, polyimide, etc., and the durability is improved by the fine protrusions caused by the internal particles and the fine particle coating layer. Of course, it can be adopted as needed. 2 is Co-Cr.

Based on Co-Ni-Cr, 1 to 5 Br or F
In a perpendicularly magnetized film containing N 5 at %, if it is less than 1%, the durability will be insufficient, as will be clear from the example described later, and if it is more than N 5 at %, the crystal orientation will worsen.
The range is preferably 5 at%. The addition of Br and F improves the magnetic recording layer by adding Br to the columnar surface.
Alternatively, the high-concentration segregation layer of F may compensate for the insufficient or partially visible Cr high-concentration segregation layer and serve to reduce noise. 3 is a protective lubricant layer. , Mo S 2. S i 02. T i N
, W.C.

It is appropriately selected from carbon, plasma polymerized membrane, fatty acid, fatty acid amide, perfluoropolyether, perfluorocarboxylic acid, etc., and configured to minimize spacing loss. The present invention may be configured optimally by adding other elements depending on the magnetic disk or magnetic tape. EXAMPLES Examples of the present invention will be explained in detail below in comparison with comparative examples.

15 S i 02 microparticles with a diameter of 150 mm were placed on a polyethylene terephthalate film with a thickness of 10 μm (ttm
) 2 arranged, and on top of that, Go-Cr-Br, Co-C
r-F, Co-Ni-Cr-Br.

Targeting Co-N1-Cr-F (further targeting Co-Cr and Co-Ni-Cr as comparative examples), Ar partial pressure 0.007 to 0.04 (Torr), preliminary exhaust lXl0-6 (To r r), high frequency condition, 13.
56 (MHz) 0.45 (kw) ~ 2.2 (k
w) to form various perpendicularly magnetized films, and Fomblin Z-25 manufactured by Montegisson at 0 and 66 [■/nfl
Apply a urethane back coat layer containing carbon and CaCo3 to a thickness of 0.4 μm! ! ! We made a prototype magnetic tape with a width of 8 mm.

Using a modified 8 mm video tape, a bit length of 0.2 μm and a track width of 8 μm was recorded using a laminated alloy type ring head with a gap length of 0.14 μm, and the C/N was compared. Also, regarding durability, playback output is 3 in still state.
(dB) Comparison was made based on the time required for the drop to occur.

The tape conditions and evaluation results are summarized in Table 1. As can be seen from Table 1, according to the present invention, a magnetic recording medium with excellent durability and a good C/N ratio can be obtained.

(Margins below) [Example 2] A manufacturing method for manufacturing the above-described magnetic recording medium that makes it possible to provide a magnetic recording medium that can further improve high-density recording characteristics is provided below.

The method for manufacturing a magnetic recording medium of the present invention includes at least H
Using a discharge containing Br or HF gas, Co
-Cr or Co-Ni-Cr is deposited thereon. In the present invention, with the above-described structure, not only Br or F is incorporated into the film and improves the characteristics, but also hydrogen radicals formed by discharge decomposition further improve the crystal orientation and make the columnar grain size more uniform. This means that it is possible to form a magnetic recording layer that contributes to the development of high-density magnetic fields and improves noise caused by leakage from domain walls, which becomes a time issue with high density.

The implementation of the present invention is carried out in a sputtering method, in which case HB r, or HF alone is Ar,
It is used in combination with an inert gas such as Xe. The other method is carried out in the ion blating method, and if an evaporation source is used for the electron beam, it is relatively easy to maintain the discharge, so it is better to use HBr or HF alone or in a mixture. It is preferable to optimize the conditions by introducing H2 gas. Further, in the magnetic recording medium described above, C0-C
r-B (78:19:3), Co-Cr-
F(78:19:3)0.15μm, Co-Ni
-Cr-B (63:15:20:2)Co-Ni-
Cr-F (632 15: 20:
2) An example in which a magnetic recording layer having a thickness of 0.2 μm was manufactured by the above manufacturing method will be described. The film was coated with S i 02 fine particles in the same manner as in Example-1, and coated with Co-coal along a cylindrical can with a diameter of 50 ai at a cylindrical can temperature of 80°C (same as in Example-1).
Cr.

Targeting Co-Ni-Cr, HBr or HF
0.009 (Tor r), 13.56 (
Go-Cr-B (78:19:3), C
o-Cr-F (78:19:3) at 0.15am
Co-N1-Cr-B (63:15:
20:2), Co-N1-Cr-F (63:
15:20:2) with a thickness of 0.2 μm, Fonprin Z-25, and a back coat layer of 8 mm tapes were prepared under the same conditions and named A, B, C, and D, respectively.

Also Co-Cr-B (78:19:3), Co
-' Cr-F (78:19:3)0.15μ
Ar and HB or Ar and HF are mixed to form Ar:HB=1:3. Ar:HF=1:
3. 13.56 (at vacuum level 0.006 (Torr))
Samples E and F were manufactured under the same conditions except that the conditions were 1.4 (KW) (MHz) and 1.4 (KW).

Also Co-N1-Cr-B (63:15:20:2),
Co-N1-Cr-F (63:15:20:2) film 0
．． To form 2 μm, cylindrical can (can temperature 25
℃) and the electron beam evaporation source (distance: 30 al), a 6-turn high-frequency coil was placed at a distance of 3.5 am from the can, and 13.56 (MHz), 0.9 (KW), HB
r 4X10-' (Torr), HF 4x 10-
'(Torr), preliminary exhaust 8X10-'(Torr
) Sample tapes were made under the same conditions except that electron beam heating was performed at 30 KV and 55 KW, and named G and H, respectively. Relative C of each tape based on Example-1
/N comparison results are shown in Table 2.

Note that the durability was the same.

Also, in terms of productivity, which is one of the evaluation criteria for manufacturing methods,
Assuming that Example-1 is 1, the sputtering method is as follows:
The sputtering method of No. 2 was 1.4, and the ion blating method was 16. The sputtering method can be sped up using HF,
HBr decomposition radical.

By improving sputtering efficiency due to the reactivity of the
The ion blating method relies on the high speed of the electron beam evaporation method.

(The following is a blank space) Effects of the Invention As described above, the present invention has the excellent effect of providing a magnetic recording medium with good C/N characteristics and durability in high-density recording.

[Brief explanation of drawings]

The figure is an enlarged sectional view of a magnetic recording medium according to an embodiment of the present invention. 1... Polymer film, 2... For example, Co-Cr-Br perpendicular magnetization film, 3... Protective lubricant layer. Name of agent: Patent attorney Shigetaka Awano and 1 other person 1---g
, skeleton film 2 --- fIB1L'gco: Cr-8** straight 1
Igo order 3-・-1♀n5 closed slip layer

Claims (2)

[Claims] (1) A magnetic recording medium based on Co-Cr or Co-Ni-Cr and containing 1 to 5 at% of Br or F. (2) A method for manufacturing a magnetic recording medium, which comprises depositing Co-Cr or Co-Ni-Cr in a discharge gas atmosphere containing at least HBr or HF gas.