JPH04113513A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To improve durability of a magnetic recording medium by forming a first nonmagnetic layer on a metal magnetic thin film on a supporting body in a manner that this first nonmagnetic layer contains carbon and at least one structural component of the metal magnetic thin film and then forming a second nonmagnetic layer containing carbon as the main structural component on the first nonmagnetic layer. CONSTITUTION:On a supporting body 1, a metal magnetic layer 2 is formed by a method of forming a thin film, on which a first nonmagnetic layer 3 containing carbon and at least one structural component of the metal magnetic thin film 2 as the structural components by a method of forming a thin film. Then a second nonmagnetic layer 4 essentially comprising carbon is formed on the first nonmagnetic layer 3. Thereby, adhesion strength between the magnetic layer 2 and the carbon layer 4 is improved, which improves durability of the magnetic disk.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to, for example, a Co--Cr based metal thin film type magnetic recording medium and a method for manufacturing the same.

[Prior art]

From the viewpoint of high-density recording, attention has recently been shifting from so-called coating-type magnetic recording media to metal thin film-type magnetic recording media. By the way, when a metal magnetic thin film such as a Co-based magnetic thin film is used as the recording layer of a magnetic recording medium, in order to maintain good sliding contact with the magnetic head over a long period of time, for example, in a hard disk, the magnetic thin film shown in FIG. As shown in FIG.
A protective film 8 having a thickness of 0 to 30 people is provided, and a fluorine-based lubricant 9 or the like is applied thereon to provide higher lubricity. That is, conventionally, the protective film provided on the metal magnetic thin film 7 is made of a material such as carbon or SiO□ by sputtering or the like to improve the durability of the magnetic recording medium. However, recently, as high hardness materials such as AI, O, and TiC have come to be used as constituent materials for magnetic heads, it has become difficult to ensure sufficient durability with the above-mentioned protective film. It's coming. In addition, since floppy disks and tapes with thin films are exposed to the outside air along with the magnetic head, dust and dust can enter between the magnetic recording medium and the magnetic head, scraping the protective film, and in the worst case, causing scratches. reaches the magnetic layer, making it impossible to record and reproduce information. In addition, in order to increase the reproduction output, it is necessary to bring the magnetic layer and the magnetic head as close as possible, and the protection film 8 and lubricant 9
It is desirable to make the thickness of the layer as thin as possible.

[Disclosure of the invention]

In order to solve the above-mentioned problems, the present inventors have particularly focused on Co,
As a result of our investigation into the durability issue of Co-Cr-based gold-alpha thin film type magnetic recording media whose main component is Cr (Co and C, Co is richer), we found that Co,
Co-Cr-based magnetic layer containing Cr as the main component (hereinafter referred to as Co-Cr)
It was discovered that this could be improved by improving the adhesion of the -Cr magnetic layer) and the protective film layer provided thereon, and research in this direction was carried out. By the way, Fig. 3 shows the results of Auger electron spectroscopy in the depth direction from the film surface when only a carbon film was formed by sputtering on a Co-Cr magnetic layer. Approximately 2 at the interface between the layer and the carbon layer
It can be seen that a mixed layer of Co--Cr magnetic material and carbon was formed for 0 to 30 people. It has been found that the presence of this mixed layer greatly influences the adhesion between the Co--Cr magnetic layer and the carbon layer. Therefore, in order to strengthen the adhesion between the Co-Cr magnetic layer and the carbon layer, the inventors developed a PET film as shown in FIG.
Considering the continuity of the Co-Cr magnetic layer 2 on the non-magnetic substrate 1 made of a metal material such as a polymer such as a resin or a metal material such as an aluminum alloy, and the carbon layer 4 as a protective film,
On the Cr magnetic layer 2, a layer (C
It was devised to form an r-0 layer, Cr:C having a ratio of, for example, 15:1 to 1:l)3, and to form a carbon layer (0 layer) 4 on the Cr-0 layer 3. When we performed Auger electron spectroscopy on this material (results are shown in Figure 2), we found that in a magnetic recording medium like the one shown in Figure 1, Cr and C overlap in each layer. It was found that the adhesive force between the Co--Cr magnetic layer 2 and the carbon layer 4 was improved by this. The present invention has been achieved based on the above findings,
A first non-magnetic layer containing at least one component of the metal magnetic thin film and carbon as constituent components is formed on the metal magnetic thin film on the support; The present invention proposes a magnetic recording medium characterized by comprising a second non-magnetic layer having the following constituent components. Further, a metal magnetic thin film forming step of forming a metal magnetic layer on a support by a thin film forming means, and a first metal magnetic thin film forming step of forming a metal magnetic thin film layer on the metal magnetic thin film layer, the metal magnetic thin film layer having at least one constituent component of the metal magnetic thin film layer and carbon as constituent components. The first non-magnetic layer is formed by thin film forming means.
and a second nonmagnetic layer forming step of forming a second nonmagnetic layer containing carbon as a main component on the first nonmagnetic layer using a thin film forming means. The present invention proposes a method for manufacturing a magnetic recording medium characterized by the following. In the above method for manufacturing a magnetic recording medium, the first nonmagnetic layer forming step is dual simultaneous sputtering using a target consisting of a constituent of the metal magnetic thin film layer and a target containing carbon as a constituent. Preferably. The thickness of the first nonmagnetic layer formed on the metal magnetic thin film on the support is preferably about 50 to 100, and the thickness of the second nonmagnetic layer formed on the first nonmagnetic layer is preferably about 50 to 100. The thickness of the nonmagnetic layer is preferably about 50 to 300 mm. Examples of sputtering conditions in the present invention include those shown below. Electrode open circuit 11M80mm Power source RF300W Ar gas pressure 5mTorr

[Example 1] As shown in Fig. 1, C
An o-Cr magnetic layer 2 was formed to a thickness of 2,000 layers by sputtering, and a Cr-C layer (Cr and C) was formed on this Co-Cr magnetic layer 2 by sputtering using a Cr2Cz alloy target (99.0% purity). The atomic ratio of is 15:I)3
A 100-layer thick film was formed, and a 100-layer thick film was formed thereon by sputtering to form a hard disk.

[Example 2] The thickness of the Cr--C layer 3 in Example 1 was controlled to be 50 mm thick.

[Comparative Example 1] A hard disk was constructed by forming a 0 layer 4 with a thickness of 200 layers by sputtering on the Co-Cr magnetic layer 2 of 2000 layers on the non-magnetic substrate 1 made of aluminum alloy in Example 1. .

[Comparative Example 2] A hard disk was constructed by forming a 0 layer 4 to a thickness of 150 layers by sputtering on the Co-Cr layer 2 of 2000 layers on the non-magnetic substrate 1 made of aluminum alloy in Example 2. did.

[Example 3] On the Co--Cr magnetic layer 2 with a thickness of 2'000 on the aluminum alloy non-magnetic substrate l in Example 1, Cr- was deposited by dual simultaneous sputtering using a Cr target and a carbon target. C layer (Cr: C=approximately 1.5:
1) Layer 3 was formed to a thickness of 100 layers, and layer 0 was formed thereon to a thickness of 100 layers by sputtering, thereby constructing a hard disk.

Example 4 The thickness of the Cr--C layer 3 in Example 3 was controlled to be 50 mm thick.

[Characteristics] The durability (Contact 5 tartand 5
top) We conducted a test and the results are shown in the table. The C3S test conditions are as follows. Head material: AlO0.・TiC head position: Media radius 4 (1+- position) Medium rotation cycle: Orpm ~3600 rpm (5 sec) (CS
31 times) 3600rpm (1sec) 360
0 rpm ~D rpm (55ec) Orpm (15
ec) Media lubricant: It can be seen from Table 2 that the durability of the magnetic disk is significantly improved when a Cr--C layer is provided between the C layer and the Co--Cr layer without coating. Note that even when the Cr--C layer is made thinner by 50 people, there is almost no change in its durability. When a CrlCg alloy target is used to form a Cr-C layer, the sputtering rate of Cr is more than 10 times higher than that of C, and the resulting Cr-C film is also rich in Cr. Cr3C2 alloy targets tend to contain impurities due to their manufacturing process, and therefore high-purity Cr-C
It is difficult to obtain a layer, and there is a risk of deterioration of magnetic properties. On the other hand, in Examples 3 and 4, in which the Cr-C layer was formed by binary simultaneous sputtering, in which Cr and C can be formed separately and simultaneously, the above-mentioned fear does not exist, or the magnetic It can be seen that the durability of the disc has also been significantly improved. Incidentally, the ratio of Cr:C in the Cr-C layer may be 15:1 to 1:1, particularly preferably about t, S:t
The ratio was ~1:1.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the cross section of one embodiment of the magnetic recording medium according to the present invention, FIG. 2 is a graph showing the results of Auger electron spectroscopy of the magnetic recording medium of the type shown in FIG. 1, and FIG. A graph showing the results of Auger electron spectroscopy of a conventional magnetic recording medium. FIG. 4 is a schematic diagram showing a cross section of a conventional magnetic recording medium. 1...Nonmagnetic substrate, 2...Co-Cr magnetic layer, 3... Cr-C layer, 4... carbon layer.

Claims (4)

[Claims] (1) A first non-magnetic layer containing carbon and at least one component of the metal magnetic thin film is formed on the metal magnetic thin film on the support. A magnetic recording medium comprising a second nonmagnetic layer containing carbon as a main component. (2) a metal magnetic thin film forming step of forming a metal magnetic layer on a support using a thin film forming means; a first nonmagnetic layer forming step of forming a first nonmagnetic layer using a thin film forming means; and forming a second nonmagnetic layer containing carbon as a main component on the first nonmagnetic layer using a thin film forming means. A method for manufacturing a magnetic recording medium, comprising: a second nonmagnetic layer forming step. (3) In the method for manufacturing a magnetic recording medium according to claim 2, the first nonmagnetic layer forming step includes a target made of a constituent of the metal magnetic thin film layer and a target made of carbon as a constituent. Two-dimensional simultaneous sputtering was used. (4) In the method of manufacturing a magnetic recording medium according to claim 2, the metal magnetic layer is Co--Cr based, and the first non-magnetic layer is Cr--C based.