JPH0514967B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a magnetic recording medium for perpendicular magnetic recording.

[Conventional technology]

Conventionally, in order to improve the electromagnetic characteristics such as electromagnetic conversion characteristics of perpendicular magnetic recording media, a thin non-magnetic layer such as Ti is used as an underlayer of the perpendicular magnetic layer to improve the perpendicular orientation of the perpendicular magnetic layer. There were some that had a structure that included such things. An example is shown in FIG.
An alumite layer 2 is provided on an aluminum substrate 1 to improve mechanical properties such as surface flatness, and a soft magnetic layer such as a permalloy layer 3, an intermediate nonmagnetic layer such as a Ti layer 4, and a perpendicular magnetic layer such as a Co- Cr
Layer 5 is provided.

[Problem that the invention seeks to solve]

Conventional perpendicular magnetic recording media, so-called magnetic disks, have the above-described structure and require the intermediate nonmagnetic layer 4, resulting in problems such as complicated manufacturing steps. After conducting various studies, it was found that the perpendicular orientation of the perpendicular magnetic layer 5 mainly composed of Co--Cr depends on the surface roughness of the substrate when the soft magnetic layer 3 is provided. This will be explained with reference to FIG. The horizontal axis represents the thickness of the intermediate nonmagnetic layer, and the vertical axis represents the half width Δθ ₅₀ of the X-ray rocking curve representing the degree of perpendicular orientation of the perpendicular magnetic layer. In the figure, a is the relationship between the intermediate nonmagnetic layer 4 and Δθ ₅₀ when a substrate with a ten-point average roughness of 0.005 μm and a reference length of 0.025 μm is used, and b is a ten-point average roughness of 0.003 μm and a reference length of 0.025 μm.
Intermediate nonmagnetic layer 4 and Δθ ₅₀ when using a substrate of m
The relationship, c is the standard length of the ten-point average roughness of 0.002μm
It shows the relationship between the intermediate nonmagnetic layer 4 and Δθ ₅₀ when a 0.05 μm substrate is used.

The above surface roughness display method is JIS B0601-
The one shown in 1982 was used. As is clear from Fig. 2, when a substrate with large surface roughness is used, that is, in the case shown by a, by providing the intermediate nonmagnetic layer with an appropriate thickness, Δθ ₅₀ decreases and the vertical alignment improves. However, when a substrate with small surface roughness is used, that is, in the case shown in b, the value of Δθ ₅₀ hardly decreases even if an intermediate nonmagnetic layer is provided. Note that the surface roughness here is the ten-point average roughness.
For those larger than 0.003μm standard length 0.025μm, a
It becomes similar to the curve shown in . Furthermore, when a substrate with even smaller surface roughness is used, that is, in the case shown in c, the value of Δθ ₅₀ does not decrease even if an intermediate nonmagnetic layer is provided, that is, the vertical alignment does not improve, but rather worsens. In the cases shown in b and c, that is, when a substrate with a small surface roughness is used, even when an intermediate nonmagnetic layer is not provided, a substrate with a large surface roughness is used and an intermediate nonmagnetic layer is provided. The vertical alignment is better than in the case of

In addition, conventionally, providing an intermediate nonmagnetic layer between the perpendicular magnetic layer and the soft magnetic layer has the problem that it prevents magnetic coupling between the perpendicular magnetic layer and the soft magnetic layer, thereby impairing the advantage of providing the soft magnetic layer. The dot was hot.

The present invention has been made in view of the above points, and an object of the present invention is to provide a method for manufacturing a magnetic recording medium that has a good perpendicular orientation of a perpendicular magnetic layer and is simple to manufacture.

[Means for solving problems]

The method for manufacturing a magnetic recording medium of the present invention uses a substrate having a surface roughness of 0.003 μm or less in ten-point average roughness and 0.025 μm in reference length, and a soft magnetic layer and a perpendicular magnetization layer mainly composed of Co-Cr. Each layer is provided by a sputtering method.

[Effect]

In this invention, the substrate of the magnetic recording medium has a surface roughness of 0.003 μm and a reference length of 0.003 μm.
Since a layer smaller than 0.025 μm is used, the perpendicular orientation of the perpendicular magnetic layer is improved, and the manufacturing process is simplified because an intermediate nonmagnetic layer is not required.

〔Example〕

FIG. 1 is a sectional view showing a magnetic recording medium obtained by a method of manufacturing a magnetic recording medium according to an embodiment of the present invention. Hereinafter, a manufacturing method of one embodiment will be explained. The surface of an aluminum substrate 1 is pretreated and cleaned using a well-known method, and an alumite layer 2 is provided thereon to form a substrate. The surface of this alumite layer 2 is machined so that the surface roughness is 0.003 μm or less with a ten-point average roughness of 0.025 μm or less.
(Here, the ten-point average roughness is 0.003 μm, and the reference length is
0.025 μm or less means that the surface roughness is smaller than the ten-point average roughness of 0.003 μm and the reference length of 0.025 μm. ) After that, 5x with a sputtering device.
Exhaust to 10 ^-7 Torr or less, for example, 60 mm between substrate electrodes,
Permalloy is sputtered at an Ar gas pressure of 5 mTorr and an input power of 200 W to form a permalloy layer 3, that is, a soft magnetic layer of about 0.5 μm. Furthermore, for example, the distance between the substrate electrodes is 60 mm, the Ar gas pressure is 5 mTorr, and the input power is 200 W.
Co--Cr is sputtered to form a Co--Cr layer 5, that is, a perpendicular magnetization layer with a thickness of about 0.2 μm. As is clear from FIG. 2, the perpendicular orientation of the perpendicular magnetic layer of the magnetic recording medium thus obtained is good. Furthermore, there is no need to provide an intermediate nonmagnetic layer, and the manufacturing process is simple.

In the above embodiment, the substrate was formed by providing an alumite layer on an aluminum substrate, but it is also possible to use materials other than aluminum, such as polyimide. Further, it may be applied to both sides of the substrate.

Furthermore, a small amount of rhodium, tantalum, or the like may be added to the Co--Cr layer serving as the perpendicular magnetization layer.

〔Effect of the invention〕

As explained above, this invention uses a substrate with a surface roughness of 0.003 μm or less in ten-point average roughness and 0.025 μm in reference length, and a soft magnetic layer and a perpendicular magnetization layer mainly composed of Co-Cr on this substrate. Since the sputtering method is used to provide the perpendicular magnetic layer, the perpendicular orientation of the perpendicular magnetic layer is good, and the manufacturing process is simpler compared to the conventional method in which an intermediate nonmagnetic layer is provided. This has the effect of providing a method for manufacturing a magnetic recording medium with good bonding.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a magnetic recording medium obtained by a method for manufacturing a magnetic recording medium according to an embodiment of the present invention;
Figure 2 is a characteristic diagram showing the relationship between the perpendicular orientation of the perpendicular magnetic layer and the thickness of the intermediate nonmagnetic layer when the surface roughness of the substrate is different, and Figure 8 is a cross-sectional view of a magnetic recording medium obtained by a conventional manufacturing method. It is. 1... Aluminum substrate, 2... Alumite layer, 3...
... soft magnetic layer, 4 ... intermediate nonmagnetic layer, 5 ... perpendicular magnetic layer. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1 Manufacture of a magnetic recording medium using a substrate with a surface roughness of 0.003 μm or less, on which a soft magnetic layer and a perpendicular magnetic layer mainly composed of Co-Cr are provided by sputtering method. Method.