JPH01232532A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To narrow the spacings between magnetic layers and a head core and to prevent the corrosion of the magnetic layers by forming LB films consisting of amphiphilic monomolecular or multilayers on the ferromagnetic material layers formed on a nonmagnetic substrate. CONSTITUTION:Underlying layers 21, 22 consisting of a nonmagnetic metal or alloy are formed by a method such as sputtering or ion plating on both faces of the nonmagnetic substrate 1. The ferromagnetic material layers 3 consisting of a metal or alloy are formed thereon. The LB films 6 consisting of the amphiphilic bilayers are formed on the magnetic layers 3. Since the LB films 6 have an insulating characteristic, the films are capable of surely preventing the corrosion of the lower magnetic layers 3. In addition, the LB films 6 are formable extremely thinly and, therefore, the spacings between the magnetic layers and the head core are narrowed as far as possible.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a means for preventing deterioration of a magnetic layer of a thin film type magnetic recording medium formed by forming a magnetic metal film such as Co-Ni or Co-Pt on a non-magnetic disk. With the aim of making the gap between the magnetic layer and the head core as narrow as possible and solving problems such as corrosion of the magnetic layer, an amphiphilic The structure is formed by forming a monomolecular or multi-layer LB film.

[Industrial Application Field] Magnetic recording media, which are recording media in magnetic disk drives, include a coating type, which is a non-magnetic disk coated with magnetic paint, and a coated type, which is a non-magnetic disc coated with magnetic paint, and a magnetic recording medium, which is a recording medium in a magnetic disk drive. There is a thin film type formed by forming a film of 11. The present invention relates to a means for preventing deterioration of a magnetic layer of a thin film type magnetic recording medium.

[Conventional technology]

As shown in FIG. 6, a conventional thin film magnetic recording medium has a base layer 2 made of Cr or the like, a magnetic layer 3 made of CoNi or CoNiCr, a magnetic layer 3 made of carbon, etc. on both sides of a non-magnetic substrate 1 made of aluminum or the like. A protective film 4 consisting of the following is laminated in this order, and a liquid lubricant 5 is applied to the surface.

The carbon protective film 4 is formed on the magnetic layer 3 by sputtering,
Ion plating and CVD (Chemical
It is physically or chemically formed by a method such as vapor deposition.

[Problems to be Solved by the Invention] However, in these formation methods, the formed atoms, molecules, ions, etc. are stacked randomly, resulting in variations in the film thickness distribution. Further, depending on the formation environment, film defects without a protective layer are likely to occur, and a potential difference is generated at the film defect portion, which causes the problem that the magnetic layer 3 is corroded.

If the protective film 4 is made thicker, the occurrence of the film defects can be suppressed, but for this purpose it is necessary to oxidize the protective layer 4 several hundred times. Alternatively, a Cr layer may be formed on the magnetic layer 3 and oxidized to form an insulating film, and the carbon protective film 4 may be formed thereon. However, if the protective layer 4 is made thicker or a chromium oxide layer is provided in this way, the distance from the gap part of the magnetic head to the surface of the magnetic layer 3 increases, as shown in FIG. 7, and the reproduction output change rate increases. becomes worse.

However, as high-density recording has progressed in recent years, there has been a demand to further reduce the thickness of the protective layer present in the gap between the magnetic layer and the magnetic layer, thereby improving the medium output and resolution. Therefore, increasing the thickness of the protective layer 4 or adding an additional insulating layer as described above goes against the desire for high-density recording.

A technical object of the present invention is to solve such problems in conventional thin-film magnetic recording media, to make the gap between the Lil layer and the hend core as narrow as possible, and to solve problems such as corrosion of the magnetic layer. There is a particular thing.

[Means for Solving the Problems] FIG. 1 is a sectional view explaining the basic principle of a thin film recording medium according to the present invention. 2, magnetic layer 3, LB film 6
are stacked in this order. LB film (Langmuir B
Lodget Film) 6 may be either an amphiphilic monolayer or a multilayer. Note that usually L
A lubricant such as a liquid is applied onto the protective film consisting of the B film 6 for use.

[Function] The LB film 6 has a uniform film thickness at the molecular level and can be precisely controlled. That is, it is possible to accurately control the thickness to a monomolecular layer, a bimolecular layer, or even a three-molecular layer or more. Furthermore, since the LB film 6 is insulating, it can reliably prevent corrosion of the lower magnetic layer 3, and provide the same effect as a conventional insulating chromium oxide layer. However, since the LB film 6 can be formed extremely thin, the gap between the magnetic layer and the magnetic layer is reduced, improving the reproduction output performance and meeting the demand for high-density recording.

[Example] Next, how the thin film magnetic recording medium according to the present invention is actually implemented will be explained using an example. FIG. 2 is a sectional view showing an embodiment of the magnetic recording medium according to the present invention. Underlayers 21 and 22 made of nonmagnetic metal or alloy are formed on both sides of nonmagnetic substrate 1, and ferromagnetic layer 3 made of metal or alloy is formed thereon. On this magnetic layer 3, an LB film 6 consisting of an amphiphilic bilayer is formed. In this embodiment, on this LB film 6, as a liquid lubricant 7 having an orientation, von Prin-Z-KoA is applied.
L, Z-Dol, etc. are applied. As in this example, when an amphiphilic bilayer LB film is used, the LB
The thickness of the membrane will be approximately 50 people.

FIG. 3 is a diagram illustrating a method for forming an LB film consisting of an amphiphilic bilayer as in this example.

Amphipathic molecules 6a are floating on the surface of water 9 in a water tank 8. The upper edge 11 of the side wall 10 of the water tank 8 serves as a guide rail, on which a slider 12 is placed.

A pressure plate 13 is attached to the slider 12 and presses the amphiphilic molecules 6a in the in-plane direction of the water surface to form a dense monomolecular surface.

The amphipathic molecule 6d consists of a hydrophilic base 61 and a hydrophobic base 62, and as shown in the figure, it floats with the hydrophilic base 61 aligned on the water surface side.

In this state, when the substrate 1d on which the magnetic layer is formed is vertically inserted into water as shown in (a) and (b), the single molecules 6a on the water surface will have their hydrophobic bases 62 attached to the substrate surface. do. When the amphiphilic molecules 6a adhere to the substrate 1d, the number of amphiphilic molecules 6a on the water surface decreases, so the slider 1
2 to the substrate ld side so that the amphiphilic molecules 6a on the water surface are always dense.

After inserting the entire substrate 1d into water, when it is pulled up from the water surface as shown in (C), the hydrophilic base 61 side is now attached to the substrate side. As a result, the lifted substrate becomes a bimolecular layer with the hydrophilic base 61 sides facing each other, and the second
As shown in the figure, a bimolecular layer LB film 6 is obtained.

FIG. 5 is a diagram comparing the error occurrence characteristics of the magnetic recording medium manufactured in this manner and a conventional magnetic recording medium. This characteristic is the result of an environmental test at 80°C 180% for 300 hours, and conventional carbon sputtered products are
While the number of errors caused by corrosion increases rapidly with the passage of time, the increase in the number of errors caused by the product of the present invention is due to
It can be seen that the LB film of amphiphilic molecules is extremely stable.

Further, as shown in FIG. 7, the reproduction output improves as the gap between the magnetic head and the magnetic layer decreases; however, according to the present invention, by reducing the number of layers of the amphiphilic LB film, By making the protective layer extremely thin, an 8% improvement in reproduction output value was achieved.

The substrate lifted from the water surface as shown in Figure 3(C) is then put in and out of the water by repeating the operations (a) to (C) again to form two-molecular layers, four-molecular layers, etc. Thus, a multilayer layer with an even number of layers is obtained.

On the other hand, as shown in FIG. 4(a), the amphiphilic molecules 6a are floated on the water surface -F with the substrate 1d first inserted into the water. Next, as shown in (b), when the substrate 1d is lifted above the water surface, the hydrophilic base 61 side of the amphipathic molecule is exposed to the substrate ld.
Attach to the side. When the substrate 1d is lifted out of the water in this manner, the amphipathic molecules adhering to the substrate 1d form a monomolecular layer.

When this monomolecular layer substrate is taken out and put into water again using the method shown in FIG. 3, the amphiphilic molecule layers become an odd number of multi-molecular layers, such as 3 layers, 5 layers, and so on.

[Effects of the Invention] As described above, by floating the amphiphilic monomolecular layer 6a on the water surface, standing the magnetic recording medium substrate 1d vertically, and raising and lowering it to accumulate single molecules on the medium surface, arbitrary It becomes possible to uniformly and accurately laminate amphiphilic molecules in a number of layers. Therefore, by shielding contact with oxygen in the air by the LB film of amphiphilic molecules, the corrosion of magnetic metals, which has been a problem in the past, can be almost certainly prevented. In addition, since the film thickness of amphiphilic molecules becomes extremely thin, it becomes easier to increase the reproduction output and resolution during magnetic recording, making it possible to improve the credibility of magnetic recording media, which are becoming increasingly dense. becomes.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view explaining the basic principle of the magnetic recording medium according to the present invention, FIG. 2 is a cross-sectional view showing an embodiment of the magnetic recording medium according to the present invention, and FIGS. 3 and 4 are magnetic recording media according to the present invention. FIG. 5 is a diagram showing error occurrence characteristics of a conventional magnetic recording medium and a magnetic recording medium according to the present invention.
FIG. 6 is a cross-sectional view of a conventional magnetic recording medium, and FIG. 7 is a diagram showing the gap between the head and the magnetic layer and the reproduction output change rate characteristics of the magnetic head. In the figure, l is a nonmagnetic substrate, 1d is a substrate, 2 is a base layer, 3 is a magnetic layer, 4 is a protective layer, 6 is an LB film of amphipathic molecules, 6a is an amphipathic molecule, 61 is a hydrophilic base, 62 is a hydrophobic base, 5.7 is a liquid lubricant, 8 is a water tank, and 9 is water. Patent applicant: Tomidotsu Co., Ltd. sub-agent Patent attorney: Yasushi Fukushima Text: Fundamentals of the invention Sutra time (
Hour) Nilar special special / 1st life Figure 5 5 Wave body lubricant rice [East's thin film watching record Figure 6 Regeneration pressure / Note Figure 7

Claims (1)

[Claims] 1. Ferromagnetic layer (3) formed on a non-magnetic substrate (1)
On top of the amphiphilic monomolecular or multilayer LB film (6
) A magnetic recording medium characterized by forming a magnetic recording medium. 2. A base layer (2) and a ferromagnetic layer (3) made of metal or its alloy are formed on a non-magnetic substrate (1) by sputtering, ion plating, etc. 1. A magnetic recording medium comprising a monomolecular or multilayer LB film (6).