JP2736960B2 - Magnetic recording medium and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium used for a magnetic recording device such as a magnetic disk device and a method of manufacturing the same.

[0002]

2. Description of the Related Art The density of magnetic recording is increasing at a remarkable rate, and a hard disk (hereinafter abbreviated as HD), which started out as an external storage medium for a large-sized computer, has been reduced in size and cost. Incorporation into personal models has progressed, and in recent years, HD built-in type laptop computers have become uncommon. Behind that, the recording medium HD
Of course, the performance of both the magnetic head and the magnetic head has been improved, but especially on the HD side, the electromagnetic characteristics of the magnetic layer have been improved, the film thickness has been reduced, and the surface of the disk has been reduced in order to respond to the improvement in recording density. Further smoothing has been attempted. In other words, the former has been devised in terms of the composition of the magnetic layer and thin film preparation technology such as sputtering, and the latter has been devised in terms of substrate material and surface processing to improve flatness and smoothness, and surface treatment technology. is there.

However, the decrease in the flying height (glide height) of the magnetic head accompanying the increase in the recording density results in the importance of the interaction between the magnetic head and the HD at an accelerating rate. It is a situation that is increasing more than before. For example, on the HD side, demands for improving the flatness and smoothness of the surface and the contact sliding characteristics with the magnetic head, particularly the durability and stability thereof, are rapidly increasing.

[0004]

To meet the above-mentioned demands for HD, new substrate materials such as glass, carbon, silicon and the like have been proposed. However, no matter which substrate material is used, the key to improving the magnetic recording density is the magnetic property of the magnetic layer, and how to improve it is the key to high performance in HD. In order to improve the characteristics of the magnetic layer, conventionally, techniques such as increasing the film forming temperature or applying a bias voltage have been used. However, although the correlation between the film forming temperature and the magnetic properties, for example, the coercive force, is recognized in the case of a cobalt alloy or the like, the control and application are not always easy due to restrictions on the thermal properties of the substrate. On the other hand, the application of the bias voltage is effective in improving the magnetic properties in general, but in this case, it is still inevitable from the restriction on the electrical properties of the substrate. Therefore, there has been a demand for a means for improving the magnetic properties of the magnetic layer without being restricted by the properties of the substrate.

[0005]

Means for Solving the Problems The present inventors have studied in detail the formation of a magnetic layer by sputtering deposition, and found that a metal layer such as Pd or Pt was interposed between a silicon substrate and a Cr underlayer. It has been found that the magnetic properties are dramatically improved by doing so, and the present invention has been accomplished.

That is, first, a metal layer (intervening layer) such as Pd or Pt is formed on a silicon substrate, and an underlayer such as Cr and then a magnetic layer such as a cobalt alloy are formed thereon. Compared to the case without the intervening layer, not only the magnetostatic characteristics such as the coercive force and the coercive force squareness ratio are greatly improved, but also the electromagnetic conversion characteristics such as the bit shift are greatly improved. Is recognized. This phenomenon is presumed to be due to the spin correlation of d electrons, and is found in all platinum group elements. The thickness of the intervening layer of the platinum group element or its alloy is in the range of 30 to 1000 °, more preferably 50 to 1000 °.
Å600Å, more preferably 50〜300Å.
When the thickness of the intervening layer is less than 30 °, the effect of improving the coercive force squareness ratio and the effect of improving the electromagnetic conversion characteristics are not sufficiently exhibited. On the other hand, when the thickness is more than 1000 °, no further effect is recognized and the material is wasted.

[0007] The above-mentioned effects are exhibited irrespective of the type of the substrate. However, there is a trend toward higher performance of HD, specifically, higher flatness, smoothness, light weight, stability, and higher performance. In consideration of the usage demand trend such as strength, a silicon substrate is determined to be most preferable.

[0008]

Embodiments of the present invention will be described below.

Example 1 and Comparative Examples 1 and 2 A Pd layer was formed on a silicon substrate by a normal sputtering method.
A Cr underlayer, a magnetic layer, and a protective film are sequentially formed, and P
A magnetic recording medium of Example 1 was manufactured by applying an FPE (perfluoropolyether) -based lubricant. Table 1 shows the configuration contents, film thickness values, and the like. In addition, the magnetic characteristics of the magnetic recording medium and the bit shift were measured as an index for increasing the recording density, and the respective values are shown in Table 2. Magnetic properties were determined by cutting a 7 mm test piece from the manufactured recording medium, and using a vibrating sample magnetometer (VSM) to measure Hc (coercive force) and Brδ (residual magnetization ×
The magnetic film thickness) and S ^* (coercive force squareness ratio) were measured. The measurement conditions of the bit shift were as follows: a thin film head having a gap length of 0.35 μm and a track width of 6.9 μm was used, and the flying height was 64 n.
m and a radius of 20 mm. The modulation code is M. F.
M. The recording pattern was evaluated by B6D9h. For comparison, a magnetic recording medium (Comparative Example 1) having exactly the same configuration as in Example 1 except that the Pd layer was not provided, and a magnetic recording medium having exactly the same configuration as in Example 1 except that the silicon substrate was replaced with a glass substrate. A magnetic recording medium (Comparative Example 2) was manufactured, and the same measurement and evaluation were performed. The results are also shown in Table 2.

[0010]

[Table 1]

[0011]

[Table 2]

<Examples 2 and 3 and Comparative Example 3> A magnetic recording medium having exactly the same configuration as in Example 1 except that the thickness of the Pd layer was changed in the range of 1000 to 20 ° (thickness 1000 °)
... Example 2, film thickness 500 Å Example 3, film thickness 20 Å Comparative Example 3) was prepared, and the results of similar measurements and evaluations are shown in Table 3.

[0013]

[Table 3]

Example 4 A magnetic recording medium (Example 4) having exactly the same structure as in Example 1 except that a Pt layer was interposed in place of the Pd layer was prepared, and similar measurements and evaluations were performed. Table 4 shows the results.

[0015]

[Table 4]

<Embodiments 5 to 8> A magnetic recording medium having exactly the same configuration as that of Embodiment 1 except that another platinum group element (Rh, Ir, Ru, Os) layer is interposed in place of the Pd layer. Examples 5 to 8) were prepared, and the results of similar measurements and evaluations are shown in Table 5.

<Embodiment 9> Instead of the Pd layer, Pt-Pd
A magnetic recording medium (Example 9) having exactly the same configuration as in Example 1 except that an alloy layer (Pt10% -Pd90%) was interposed was produced, and the same measurement and evaluation were performed.
It was shown to.

<Embodiment 10> Instead of the Pd layer, Pd-R
A magnetic recording medium (Example 10) having exactly the same configuration as in Example 1 except that a u alloy layer (Pd95% -Ru5%) was interposed was produced, and the same measurement and evaluation were performed. It was shown to.

[0019]

[Table 5]

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be implemented in any manner without changing the configuration described in the claims.

[0021]

As described above, the present invention relates to a magnetic recording medium having improved magnetic properties by forming a platinum group element or its alloy layer directly on a silicon substrate.
A magnetic recording medium suitable for high-density recording is provided.

Claims (2)

(57) [Claims] 1. A semiconductor device comprising a platinum group element or an alloy thereof between a silicon substrate and an underlayer containing Cr as a main component.
A magnetic recording medium comprising a layer of 1000 mm interposed. 2. A layer of 30 to 1000 ° made of a platinum group element or an alloy thereof is formed on a silicon substrate, and an underlayer, a magnetic layer, a protective film, and a lubricant film containing Cr as a main component are formed thereon. Are formed in this order.