JPS62256215A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To increase the surface roughness of the protective layer of a landing zone by providing a ruggedness forming layer between a base and magnetic layer of said zone and forming said layer so as to have the surface roughness larger than the surface roughness of the main surface of the base. CONSTITUTION:An underlying layer 13, a magnetic layer 14 and a surface layer 15 are laminated on the base 11 consisting of glass or ceramics and the ruggedness forming layer 12 is formed between the base 11 and layer 13 of the landing zone 10b. The layer 12 is formed to have the surface roughness larger than the surface roughness of the main surface of the base 11 and therefore, the layer 15 of the zone 10b has the desired surface roughness. Then, the suction of a magnetic head in the zone 10b is prevented and the starting is smoothed. In addition, the surface roughness of a read-wirte zone 10a remains small and therefore, high-density recording is maintained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic recording medium used in a magnetic recording device, and in particular, to a magnetic recording medium used in a magnetic recording device, the present invention relates to a magnetic recording medium used in a magnetic recording device, and in particular, to a magnetic recording medium that facilitates the start-up of the magnetic recording medium. Regarding recording media.

[Conventional technology]

As a magnetic recording medium, there is one shown in FIG. This disc-shaped magnetic recording medium 1 mainly stores information in a read/write zone 1a on the inside of the read/write zone 1a in the diametrical direction, where various information is written and read by a magnetic head. It is divided into a landing zone 1b where a magnetic head is placed after writing or reading is completed. A through hole 1C having a circular cross section is formed in the center of the magnetic recording medium 1, into which a rotation shaft for rotating the magnetic recording medium 1 is inserted. The structural difference ζ is disclosed in Japanese Patent Application Laid-Open No. 61-33
As described in Publication No. 22, there was one shown in FIG. Furthermore, a non-magnetic support 4 (hereinafter referred to as "support") consisting of a first substrate 2 and a nickel base plating layer 3, and a second Balt magnetic plating layer 5 (having a thickness of 0.2 .mu.m or less) are included. ). The entire surface of this nickel base plating layer 3 has the large surface roughness required for the landing zone 1b, and then only the read/write zone 1a has a surface roughness smaller than that of the landing zone 1 [). Polish it as shown to give it a finish.

The surface of the cobalt magnetic plating layer 5 on the nickel base plating layer 1 and layer 3 rotating clockwise around such a surface has a surface roughness that is higher in the landing zone 1b than in the read/write zone 1a, similar to the surface of the nickel base plating layer 3. It's big.

The reason why the surface roughness of the landing zone 1b described above is greater than that of the read/write zone 1a is due to the phenomenon that when the magnetic head is placed in the landing zone 1b, the magnetic head is absorbed into the sinking zone. This is to prevent the magnetic recording medium from becoming unrotatable, difficult to rotate, or covered.

[Problem that the invention seeks to solve]

However, in magnetic recording media with a conventional structure, the surface of the nickel base plating layer constituting the support has different surface roughness required for each of the read/write zone and the landing zone. It was extremely difficult to divide the read/write zone into a read/write zone and a landing zone and polish the read/write zone to an iα1 roughness suitable for high-density recording. In other words, conventional magnetic recording media have had problems when used for high-density recording.

[Means for solving problems]

The present invention has been made to solve the above-mentioned problems, and is characterized by a magnetic recording medium in which a magnetic layer is interposed between a support and a protective layer. between the support body and the magnetic layer of the landing zone, an unevenness forming side and an underlayer for forming unevenness on the surface of the protective layer of the landing zone toward the magnetic layer side. The magnetic recording medium is provided with a surface roughness of 11 degrees on the side where the unevenness is formed, which is larger than the surface roughness of the main surface of the support.

A desirable embodiment of the present invention is that the unevenness forming side is attached to the main surface of the support, and the underlayer, the magnetic layer, and the protective layer are sequentially laminated on the unevenness forming side, and the unevenness forming side is provided only in the landing zone. That is, the surface roughness of the main surface of the support is Rm
ax, is 150 Å or less, or the support is made of glass or ceramic.

〔Example〕

A first embodiment of the present invention will be described in detail below based on FIG. 1, and a second embodiment will be explained in detail below based on FIG. 2.

[Example 1] A magnetic recording medium 10 of this example will be explained based on FIG. 1. Note that this figure is a partially enlarged schematic cross-sectional view. Furthermore, the magnetic recording medium 10 of this example has a shape as shown in FIG. 4, and has a read/write zone 10a and a landing zone 10b.

The magnetic recording medium 10 shown in FIG. 1 has a support 11 made of soda lime glass (diameter: 13011+m, thickness=7.9+++m, diameter of the central through hole: 40mm).
and a concavo-convex forming side 12 (thickness: 300 layers) made of an aluminum (All) thin film adhered to the landing zone 10b on the main surface of the support 11, in order to improve magnetic properties.
Underlayer 13 (made of chromium (Cr)), which has the function of
Film thickness: 2000), cobalt (Co) and nickel (
The magnetic layer 14 consists of Ni) (the content of each is 7
5wt% and 25wt%, and the film thickness is 100 people. ) and a protective layer 15 made of a carbon (C) thin film (thickness: 5
00 people). The surface roughness of the main surface of the support 11 is Rmax, which is 40 people (hereinafter, the surface roughness is referred to as Rmax), and the surface roughness of the unevenness forming side 12 is 120 people, and the landing zone of the protective layer 15 is The surface roughness of the read/write zone 10b and the read/write zone 10a is 140, respectively.
and 50 people. In addition, in FIG. 1, the support body 11
The sawtooth shape of the surface roughness is shown only on the main surface on the side where the protective layer 15 etc. are provided, and the sawtooth shape on the opposing main surface is omitted (the same applies to FIG. 2, which will be described later).

Further, the sawtooth shapes of each layer 12, 13, 14, 15 and the support 11 are schematically shown in parentheses (the same applies to FIG. 2, which will be described later).

Next, a method for manufacturing the magnetic recording medium 10 of this example will be described. First, re-drying zones 1 to 10 are applied to the main surface of the support 11.
A film was formed on the unevenness forming side 12 by using a sputtering target and a no-sputtering method using a mask that covered only the portion a. In addition, in this film formation, since the temperature of the support 11 was set to 150°C, AjJt with developed grain boundaries
tlBI, the protective layer 1 of the landing zone 10b
5 can be formed with desired unevenness and roughness of the 5-sided surface. Next, a base layer 13 was formed on the above-described unevenness forming side 12 and the main surface of the support 11 with respect to the read/write zone 10a by sputtering using a target made of Cr.

Next, on this ground layer 13, a magnetic layer 14 is formed of Co and Ni.
A protective layer 15 was formed on the magnetic layer 14 by a sputtering method using a target made of carbon.

Note that in the protective layer 15, the read/write zone 10a
There is a difference in level between the landing zone 10b and the landing zone 10b of about 300 people, but since this is about 1710 degrees higher than the flight height of the magnetic head, the difference in level does not pose any problem for the movement of the magnetic head.

In the magnetic recording medium 10 of this example, the surface roughness of the main surface of the support 11 is smaller than that of the unevenness forming side 12, so the surface roughness of the protective layer j5 of the landing zone 10b is , the desired surface roughness is obtained by taking into account the influence of the surface roughness of the unevenness forming side 12. Further, the unevenness forming side 12 is formed by a film forming method (in this example, a sputtering method).

), the surface roughness of the read/write zone 10a on the main surface of the support 11 can be maintained well without increasing it, and as a result, high-density melon can be recorded.

Furthermore, in order to evaluate the performance of the magnetic recording medium 10 of this example, the coefficient of static friction between the magnetic head 2 or less and the magnetic recording medium 10 was measured and a durability test was conducted.

After applying a load of 15 grams to the magnetic head, a contact star l-/stop test of the landing zone 10b (starting and rotating the magnetic recording medium with the magnetic head in contact with the surface of the magnetic recording medium and stationary) (hereinafter referred to as "CSS test") was conducted.

The initial coefficient of static friction in this test was 0.15;
The static friction coefficient after 000 times C3S test is also 0.5,
The magnetic head did not cause the magnetic recording medium 10 to become unable to rotate or became difficult to rotate, and neither the magnetic head nor the magnetic recording medium 10 was damaged. On the other hand, for comparison, the surface roughness of the read/write zone 10a of the protective layer 15 is 50.

), when a similar C8S test was conducted, the initial coefficient of static friction was 0.2, but after 15,000 tests it became 2.5 or more, making it difficult for the magnetic recording medium 10- to rotate. In order to rotate the magnetic recording medium 10,
It was necessary to load the rotation source with more starting torque than necessary, making it impossible to maintain normal rotation.

[Example 2] A magnetic recording medium 20 of this example will be explained based on FIG. 2. The figure is a partially enlarged schematic cross-sectional view, and the magnetic recording medium 20 of this example has the same shape as that of the previous example, and has a read/write zone 20a and a landing zone 20b.

The magnetic recording medium 20 of this example includes a support 21 similar to that of the above example, and a landing zone 20 on the main surface of the support 21.
The unevenness forming side 22 (film thickness: 200 layers) consisting of ^L is adhered not only to the read/write zone 20a, but also to the read/write zone 20a.
It consists of an underlayer 23, a magnetic layer 24, and a protective layer 25, similar to the previous embodiment. The surface roughness of the main surface of the support body 21, the surface roughness of the unevenness forming side 22, and the surface roughness of the protective layer 25 are 40, 80, and 100, respectively. That is, the surface roughness of the read/write zone 20a and the landing zone 20b of the protective layer 25 is 100, respectively.

Next, a method for manufacturing this magnetic recording medium 20 will be described.

First, the unevenness forming side 22 was formed on the main surfaces of the read/write zone 20a and the landing zone 20b of the support 21 by sputtering using a heli target.

In this film formation, the temperature of the support 21 was set to 200° C. in order to achieve the surface roughness of 80 as described above. Next, a base layer 23, a magnetic layer 24, and a protective layer 25 are formed on the unevenness forming side 22 by the same method as in the above embodiment.

According to this example, since the surface roughness of the unevenness forming side 22 is greater than the surface roughness of the support body 21, the landing zone 20
The surface roughness of the protective layer 25 b is influenced by the surface roughness of the unevenness forming side 22, and has a desired surface roughness.

In addition, in this example as well, since the unevenness forming side 22 is formed by the film forming method as in the above example, the support body 2
The surface roughness of the main surface of No. 1 can be maintained. Further, in this example, the surface roughness of the read/write zone 20a of the magnetic layer 24 is influenced by the surface roughness of the unevenness forming side 22, but since the value is 100, the read/write zone 20a is 2
Since the surface roughness of the protective layer 25 is 100, it is possible to maintain the high density recording property of 0a, and the surface roughness of the protective layer 25 is 100.
′? 1' rope 15! No inconvenience occurs when the recording medium 20 is rotated.

Further, in the landing zone 20b, as a result of conducting a test similar to the above example, the static friction coefficient at the initial stage of the test was 0.15, and the static friction coefficient after 15000 times CSS test was 0.7, and the above example 15 compared to when
Although the coefficient of static friction increased after 000 tests, no phenomenon occurred in which the magnetic recording medium 20 became unable to rotate or became difficult to rotate. Furthermore, no damage was caused to the magnetic recording medium 20 or the magnetic head.

In this example, the surface roughness of the unevenness forming side 22 that is effective for both the landing zone 20b and the read/write zone 20a is from 60 to 150. In,
This prevents the magnetic head from being attracted, and at the same time, it can sufficiently accommodate the increase in density of the read/write zone 20a.

The present invention is not limited to the above-described embodiments, but may include the following embodiments. First, the material of the support is not limited to glass such as soda lime glass, aluminosilicate glass, quartz glass, etc.
It may be an AIL alloy or a ceramic. Preferably, glass or ceramic is used, which is easier to process to a desired surface roughness than A1 alloy, and whose main surface has very few pits or protrusions that adversely affect high-density recording performance.

Further, the surface roughness of the support is preferably 150 Å or less.

In other words, the surface roughness of the support affects the surface roughness of the underlayer and the magnetic layer, so if the surface roughness of the support exceeds 150, the surface roughness of the magnetic layer also exceeds 150. Therefore, when performing high-density recording by lowering the flying height of the magnetic head, recording defects such as missing (signals to be recorded are not reliably recorded) may occur. In other words, high density recording may sometimes be impaired. Further, in the above examples, the temperature of the support when forming the unevenness forming side made of Al was 150°C or 200°C, but the temperature is not limited to this, and other temperatures, that is, the temperature of the protective layer of the landing zone, may be used. The temperature may be such that the surface roughness is such that the surface roughness on the unevenness forming side is such that the magnetic head is prevented from being attracted to the magnetic head. Preferably, Al2. At 100°C, the grain boundaries develop significantly, that is, the surface roughness increases.
above, and practically 300°C or below. Note that the temperature of the support and the unevenness forming side (film thickness: 30
Figure 3 shows the relationship with the surface roughness of 0 persons). Although the unevenness forming side is made of a thin film of Hen, it may be made of other WJ layers, and preferably a crystalline thin film in which grain boundaries develop, such as Sn, In, Pb, Zn, Sb, etc. Gold scraps, alloys containing one of these or their oxides,
A film made of nitride or ZR 02, No F2
Alternatively, a dielectric film such as ZnS is preferable. Further, the film thickness on the side where the unevenness is formed is desirably 100 Å or more and Lr 1000 Å or less.

In other words, if the thickness is less than 100, it will be difficult to manufacture the surface roughness forming side with the desired surface roughness, that is, a surface roughness of 60 Å or more, which has a remarkable effect of preventing the magnetic head from attracting the landing zone. If it exceeds the range, depending on the material of the uneven surface, the moisture resistance may decrease, making it unsuitable for use in the hot and humid strip f1. Next, the underlayer may be made of a nonmagnetic material such as Ho, Ti, Ta, or the like. J, the magnetic layer is not limited to one made of CoNi alloy, but may be made of Co as a main component and Ni as a main component.

It may be made of an alloy containing at least one element selected from Fe, Pt, P, Cr, W, No, etc., or Fe2O3, as long as it can obtain predetermined magnetic properties.

The protective layer may be a composite layer, such as a laminate of a Cr layer and a 0 layer in contact with each other, a laminate of a Cr layer and a Si 021i layer in contact with each other, a Cr layer, a 0 layer, and a Si 02 layer, etc. The layer may be a layer formed by stacking these materials in proper contact with each other, or a mixed layer obtained by mixing the materials of the composite layer, or a layer made of a SiO2 layer or an organic polymer. The thicknesses of the magnetic layer and the protective layer may also be appropriately determined as necessary. Also, the sinding zone may be radially outward or in the middle step 1.

Furthermore, the method for forming the unevenness forming side, the magnetic layer, and the protective layer is not limited to the sputtering method, but may be a vacuum evaporation method or an ion blating method.

[Efficacy of invention]

According to the magnetic recording medium of the present invention, the magnetic recording medium can be started smoothly and high-density recording can be performed.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged schematic cross-sectional view showing one embodiment of the magnetic recording medium of the present invention, and FIG. 2 is a partially enlarged schematic cross-sectional view showing another embodiment of the present invention. The m3 diagram shows the temperature of the support and the An
FIG. 3 is a characteristic diagram showing the relationship between surface precision on the side where concavities and convexities are formed. FIG. 4 is a schematic plan view showing a general magnetic recording medium, and FIG. 5 is a partial cross-sectional view of the conventional magnetic recording medium. 10, 20...magnetic recording medium, 1(la, 20a...
・Read/write zone, 10b, 20b...Landing zone, 11.21...Support, 12.22...
・Irregularity forming side, 13.23... Base layer, 14.24・
...Magnetic layer, 15.25...Protective layer

Claims (5)

[Claims] (1) In a magnetic recording medium in which a magnetic layer is interposed between a non-magnetic support and a protective layer, a landing zone is provided in the magnetic recording medium, and the non-magnetic support and the magnetic layer in the landing zone an underlayer and an unevenness forming layer for forming unevenness on the surface of the protective layer of the landing zone are provided between the magnetic layers, and the surface roughness of the unevenness forming layer is equal to that of the non-magnetic layer. A magnetic recording medium characterized in that the surface roughness is greater than that of the main surface of a support. (2) Claim (1) characterized in that the unevenness forming side is adhered to the main surface of the non-magnetic support, and a base layer, a magnetic layer and a protective layer are sequentially laminated on the unevenness forming layer. Magnetic recording medium described in Section 1. (3) Claim (1) or (2) characterized in that the unevenness forming layer is provided only in the landing zone.
Magnetic recording medium described in Section 1. (4) The surface roughness of the main surface of the nonmagnetic support is Rmax. A magnetic recording medium according to claim (1), (2) or (3), wherein the magnetic recording medium has a thickness of 150 Å or less. (5) A magnetic recording medium according to claim (1), (2), (3), or (4), wherein the nonmagnetic support is made of glass or ceramic. .