JP2513597B2 - Perpendicular magnetic recording - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a perpendicular magnetic recording system for recording magnetic information on a perpendicular magnetic recording medium, and more specifically, it provides high-quality perpendicular magnetic recording that is stable for a long period of time. It concerns a new recording method that has become possible.

Also in a magnetic recording apparatus using a flexible magnetic recording medium, a perpendicular magnetic recording method has been tried for high density recording, and the basic structure is disclosed in Japanese Patent Publication No. 58-91.

[Conventional technology]

The flexible perpendicular magnetic recording medium disclosed in Japanese Patent Publication No. 58-91 is, for example, a sheet of polyethylene terephthalate having a thickness of about 50 .mu.m and Ni of about 0.5 .mu.m on one or both sides.
-Soft magnetic thin film made of Fe alloy (permalloy), 0.3
It has a structure in which perpendicular magnetic anisotropic thin films of Co—Cr alloy having a thickness of about μm are sequentially laminated. However, in a recording medium using such a continuous thin film of a magnetic material as a magnetic recording layer, friction and wear with a magnetic head are reduced by a binder resin and a lubricant impregnated into the binder resin like a general-purpose coating type medium. However, there is a drawback that the durability is not good because the method of making it possible cannot be adopted.

As a means for improving the durability, a lubricant or a rust preventive agent is applied on the magnetic recording layer, or an organic thin film, an oxide thin film such as SiO ₂ or a hard metal thin film such as Rh (rhodium) is formed. The method has already been proposed and has been tentatively applied to the application to the magnetic tape for video.

[Problems to be solved by the invention]

However, application to flexible magnetic disks such as floppy disks is still insufficient because it requires long-term durability under severe conditions compared to magnetic tapes for video. That is, in the video magnetic tape device, the relative movement speed between the magnetic tape and the magnetic head is as high as 3 to 6 m / sec, but the air is drawn into the space between the two members to alleviate their contact. In addition, the required long-term durability is at most about 60 minutes of still reproduction operation. On the other hand, in a flexible magnetic disk, the disk medium and the magnetic head are always in contact with each other under a load of several grams to several tens of grams, and 3 million passes (16 rpm at 300 rpm) according to the JIS C6290 standard.
Durability of 7 hours) is required, but at present it has not been possible to satisfy this condition.

On the other hand, as a perpendicular magnetic head, one in which the medium sliding surface is made of barium titanate (TiBaO ₃ ) is known, and the medium sliding surface has a hardness higher than that of the material and a porosity smaller than that of the material. The flexible magnetic disk is apt to be damaged by sliding on the magnetic recording layer made of a Co--Cr alloy, and the damage causes deep scratches on the recording layer to make it unusable.

Therefore, with such a combination of a flexible magnetic disk and a magnetic head, it is impossible to perform high-quality perpendicular magnetic recording or reproduction for a long period of time.

[Means for solving problems]

This invention particularly provides a perpendicular magnetic recording system for a floppy disk device or the like in which a magnetic head is brought into contact with a recording medium to record information, and a perpendicular magnetic recording system of Co--Cr oxide having a film thickness of 50 to 500 Å is provided. Corresponding to input information by combining a perpendicular magnetic recording medium having a protective layer and a perpendicular magnetic head whose sliding surface with the recording medium is composed of titanium carbide containing alumina ceramics (Al ₂ O ₃ .TiC) It is characterized in that it is configured to perform perpendicular magnetic recording.

[Action]

In the perpendicular magnetic recording medium having the protective layer of Co-Cr oxide having a film thickness of 50 to 500 Å of the present invention, the oxidation of the magnetic recording layer is prevented without interfering with the spacing loss with the magnetic head. The advantage is that both members will not be damaged and will not be peeled off when sliding with the magnetic head.Also, in a perpendicular magnetic head with a medium sliding surface of Al ₂ O ₃ · TiC, Al ₂ O _Since 3TiC has higher hardness and smaller porosity than the Co-Cr alloy layer of the recording medium, it is not scratched by the medium, resulting in improved durability of both members and long-term It becomes possible to perform high quality perpendicular magnetic recording or reproduction.

〔Example〕

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

FIG. 1 is a sectional view showing an embodiment of the present invention, in which 1 is a flexible perpendicular magnetic disk and 2 is a perpendicular magnetic head. The flexible perpendicular magnetic disk 1 is, for example, perpendicular 5.
A 25-inch, 50 μm thick polyethylene terephthalate film is used as a substrate 11, and a 0.5 μm Ni-Fe alloy soft magnetic layer 12 and 0.4 μm Co-Cr (Cr: 20 at%) are used as the base 11.
A perpendicular magnetic recording layer 13 made of an alloy is sequentially laminated, and a protective layer 14 of 200Å Co-Cr oxide is further formed thereon. The Co-Cr oxide constituting the protective layer 14 is a Co-Cr alloy containing Co as a main component and containing 20 at% of Cr as a target, and the target material is sputtered in an oxidizing gas atmosphere to form an oxide. It was formed into a film. The oxidizing gas atmosphere will be described here as long as it is an atmosphere exhibiting an effect of oxidizing the metal sputtered from the alloy target material. Oxygen and ozone alone or a mixed gas thereof, or oxygen and ozone alone or these Mixed gas and neon, argon, krypton,
It is possible to use a gas atmosphere in which one kind or a mixture of two or more kinds of inert gases such as xenon is used. It is also possible to use a forming method other than the sputtering method, that is, a vacuum vapor deposition method or an ion plating method.
The sputtering method is more preferable in consideration of the vapor pressure relationship of o, Cr or these oxides.

According to the flexible perpendicular magnetic disk 1 having such a structure, the protective layer 14 can prevent the perpendicular magnetic recording layer 13 made of a Co--Cr alloy thin film from being oxidized, and the protective layer itself can also be Co--.
Since it is a Cr oxide, there is an advantage that it is not oxidized during practical use and is not peeled off.

On the other hand, in the perpendicular magnetic head 2, a permalloy (Ni-Fe) thin film having a width of 300 μm and a thickness of 1 μm is used as the main magnetic pole 21, and it is Mn−
It is supported by a Zn ferrite core 22 and wound by an exciting coil 23, and 38% to 36% of titanium carbide (TiC) is applied to the sliding surface with the disk medium corresponding to the tip of the main magnetic pole 21.
It has a structure in which a slider 24 made of the contained alumina ceramic (Al ₂ O ₃ .TiC) is formed. The slider section 24
The surface of is shaped to have a curvature of 60 mmR by mirror polishing. In addition, the titanium carbide-containing alumina ceramic that constitutes the slider has a porosity smaller than that of barium titanate used in the past, and the hardness of the material is not less than that of the Co-Cr alloy (Vickers hardness: 2000).
~ 2300). Therefore, according to such a perpendicular magnetic head, it is possible to exhibit a large abrasion resistance and exhibit smooth slidability with respect to the medium.

When perpendicular magnetic recording is performed by combining the flexible perpendicular magnetic disk 1 and the perpendicular magnetic head 2 as described above, the slider portion 24 of the head is brought into contact with the protective layer 14 of the disk and the disk is rotated at a predetermined speed. In this state, a magnetic field corresponding to the input information is generated in the head to form perpendicular magnetization in the magnetic recording layer 13 of the disk.

The attached table compares the durability of the above-described combination configuration example of the flexible perpendicular magnetic disk 1 (A) and the perpendicular magnetic head 2 (H1) according to the present invention with various combination configuration examples of the conventional disk and head of this type. It has been shown. That is, as a comparative flexible perpendicular magnetic disk (B), the protective layer 14 is omitted from the above-mentioned disk 1 of the present invention, that is, no coating layer is formed on the perpendicular magnetic recording layer 13 of Co--Cr alloy. A medium, and as the perpendicular magnetic head, the same main magnetic pole excitation type structure as that of the present invention using glassy carbon as the material of the magnetic pole supporting member (H2), the same as the photoceram [trade name of Corning Co.] Those used (H3), those using barium titanate (H4), and those using MnZn ferrite in the medium sliding part in the ring structure (H5). In the durability test, the disk medium was rotated at 300 rpm, and relative sliding between the medium and the head was performed for 11 hours (198,000 passes). The durability was evaluated by observing the medium and the surface of the head with an optical microscope and determining the degree of scratches.

As is clear from this table, the combination of the disk medium (A) and the head (H1) according to the present invention is extremely effective in improving the durability without causing scratches on the medium and the head. . This combination structure was further subjected to a durability test of 3 million passes, and no scratch was generated by this, and the above JIS C6290 standard was satisfied. On the other hand, in the combination of the disk (A) of the present invention and the conventional heads (H2 to H5), the combination of the head (H1) of the present invention and the conventional disk (B), and the combination of conventional members, the medium is ， The head has scratches, and the durability is not good.

Although one embodiment of the present invention has been described above, the following modifications and applications are possible in the present invention.

That is, as a modification, the perpendicular magnetic head can be applied to a ring type head as shown in the perspective view of FIG. 2, in which 31 is a ring core made of Mn-Zn ferrite,
Is an exciting coil, and 33 is a slider portion which is attached to both sides of the core 31 and is made of an alumina ceramic containing titanium carbide for forming a medium sliding surface together with the core.
Further, in the flexible perpendicular magnetic disk, the content of Cr with respect to Co in the Co-Cr oxide protective layer can be freely selected in the range of 5 to 40 at%, and Co in the protective layer can be selected as long as the durability is not impaired. It is also possible to include elements other than Cr. Furthermore, the thickness of the protective layer can be applied within the range of 50 to 500Å. If it exceeds 500Å, the spacing loss will increase significantly, and if it is less than 50Å, improvement in wear resistance cannot be expected.

Further, as an application example, application to a rigid perpendicular magnetic disk and a magnetic tape device for video can be cited.

〔The invention's effect〕

As is clear from the above description, according to the present invention, it is possible to improve the durability of the flexible perpendicular magnetic recording medium and the perpendicular magnetic head, and accordingly, it is possible to maintain high-quality perpendicular recording for a long period of time, and it is extremely practical. Great effect.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a perpendicular magnetic recording system according to the present invention, and FIG. 2 is a perspective view of a perpendicular magnetic head according to a modification of the present invention. 1: Flexible vertical magnetic disk, 2: Vertical magnetic head,
11: Flexible substrate, 12: Soft magnetic material layer, 13: Perpendicular magnetic recording layer made of Co-Cr alloy thin film, 14: Protective layer made of Co-Cr oxide, 21: Main pole, 22: Core, 23 and 32 : Excitation coil, 24 and 33: Slider part made of alumina ceramic containing titanium carbide, 31: Ring core.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junzo Toda 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Fujitsu Limited (72) Inventor Hitoshi Mikoshiba, 3-2, Asahigaoka, Hino City, Central Research Laboratory, Teijin Limited ( 72) Inventor Michio Yamaura 4-3-2 Asahigaoka, Hino City, Central Research Laboratory, Teijin Limited (56) References JP-A-56-143538 (JP, A) JP-A-55-163665 (JP, A)

Claims (2)

(57) [Claims] 1. 50 to 500 on a magnetic thin film to be a magnetic recording layer.
A perpendicular magnetic recording medium having a protective layer of Co--Cr oxide having a film thickness of Å, and a perpendicular magnetic head having a sliding surface with the recording medium made of a titanium carbide-containing alumina ceramic, Both members are relatively moved in a state where the perpendicular magnetic head is in contact with the protective layer of the perpendicular magnetic recording medium, and magnetic recording of input information is performed on the recording layer of the magnetic recording medium by the magnetic head. Perpendicular magnetic recording method. 2. The magnetic thin film of the perpendicular magnetic recording medium is Co
The perpendicular magnetic recording system according to claim 1, wherein the perpendicular magnetic recording system comprises an alloy thin film containing -Cr as a main component.