JPH01144209A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To enhance both the coercive force and squareness ratio of the title medium and to decrease medium noises by providing a nonmagnetic alloy layer contg. specific 1st group elements and 2nd group elements on the surface of a nonmagnetic substrate and providing a magnetic Co alloy layer and protective layer successively on the surface thereof. CONSTITUTION:The nonmagnetic alloy layer contg. >=one kinds of the elements selected from Cr and W and >=one kinds of the elements selected from the group IVa elements and group Va elements and Mo of the periodic table is provided on the surface of the nonmagnetic substrate and the magnetic Co alloy layer and the protective layer are successively provided on the surface thereof. The compounding ratio of the 1st group elements and the 2nd group elements is preferably 99-85atom.%:1-15atom.%. The finer crystal grains of the nonmagnetic alloy are formed and the finer crystal grains of the magnetic Co alloy layer to be provided thereon are formed by providing the nonmagnetic alloy layer contg. the 1st group elements and the 2nd group elements on the surface of the nonmagnetic substrate. The magnetic film having the high coercive force and high squareness ratio is obtd. and the medium noises are greatly decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a magnetic recording medium used in an external storage device for a converter, an image storage device, and the like.

<Prior Art> In recent years, with the miniaturization of computers, magnetic recording media used in external storage devices are required to have even higher recording densities.

What about magnetic recording media? 'J film, high coercive force, and high flux density are required.

A CO alloy-based magnetic thin film that satisfies these conditions has been used as a recording medium and has been put into practical use by plating or sputtering. Compared to plating, sputtering allows the alloy composition to be controlled more freely. It has features such as good corrosion resistance and easy control of coercive force.

A sputtered CO alloy magnetic medium generally has a nonmagnetic metal layer provided on the surface of a nonmagnetic substrate, a CO magnetic alloy layer thereon, and a carbon layer as a protective film.

Cr is used as the material of the non-magnetic metal layer (%Kaida 61-120!130 and Japanese Patent Laid-Open No. 61-255).
428 Publication), one using Mo (Japanese Unexamined Patent Publication No. 61-24
6928 Publication) Work Cr.

Mo or wy&: what is used (JP-A-61-204
No. 830) is known.

In order to increase the coercive force, non-magnetic metal, 'F
j k Thickening or Ar pressure when sputtering in a vacuum chamber? Measures are being taken to raise the price.

<Problems to be Solved by the Invention I7> However, increasing the thickness of the nonmagnetic metal layer in order to increase the coercive force results in a significant decrease in productivity and cost.

Although the coercive force can be increased to some extent by increasing the Ar pressure during sputtering and sputtering, there are drawbacks such as a decrease in the squareness ratio when the Ar pressure is increased.

Further, although the coercive force can be increased to some extent by these means, the value is 100,008 or less. Furthermore, no magnetic recording medium with excellent high-density recording properties has been obtained.
Further, in the case of the material of the non-magnetic metal layer described in @, the crystal grains are large, and the crystal grains of the magnetic film provided thereon are also large, making it impossible to improve the magnetic properties. It is an object of the present invention to provide a magnetic recording medium which has both high coercive force and squareness ratio and low medium noise.

Means for Solving the Problems〉 The present inventors have conducted intensive studies to solve the above problems, and as a result, we have added the following WL1 group elements and the second
By providing a non-maternal alloy layer containing group elements, the crystal grains of the non-magnetic alloy are made finer, and the crystal grains of the COζG desert provided thereon are made finer. In other words, it is possible to obtain a magnetic film with a high coercive force and a high squareness ratio, and by making the crystal grains of the magnetic film finer, media noise can be greatly reduced, resulting in a high recording density. It has been found that this material can be used as a suitable magnetic recording medium.

That is, the present invention provides a magnetic recording medium in which a nonmagnetic alloy layer containing the following first group element and second group element is provided on the surface of a nonmagnetic substrate, and a Co magnetic alloy layer and a magnetic layer are sequentially provided on the surface of the nonmagnetic alloy layer. .

Group 1 elements: 91 or more elements selected from Cr-work W.

Group 2 elements: 19 or more elements selected from Group IVa elements of the periodic table and Group A elements and Mo.

In the present invention, the nonmagnetic substrate is a disk made of aluminum alloy, resin, ceramics, etc., and the surface thereof is polished. In the case of a substrate such as an aluminum alloy whose surface is relatively susceptible to serious injury, it is preferable to harden the surface by applying Ni--P electroless plating to the surface.

The first group element used in the present invention is one or more elements selected from Cr and W. In addition, the elements of Group 2 are I of the periodic table.
They are 91 or more elements selected from Va group elements, a group elements, and Mo. Group 1 Va elements of the periodic table are Ti, Zr
or Hf″t′. Also, the Va group elements of the periodic table are V, Nb, or Ta.

The blending ratio of the first group element and the second group element is preferably 99
~85 atoms: 1 to 15 atoms.

If necessary, metals other than the above may be added as components of the non-magnetic alloy, but the total amount of the first group element and the second group element in the non-magnetic alloy should be at least 94.
It is preferable that the number of atoms is 1 or more. If the amount is less than this, the crystal grains of the non-magnetic alloy will not be refined and the properties of the magnetic Co alloy will not be improved. Although the blending method uses these elements as an alloy, it is simpler to place a target piece made of the second group element on a target plate made of the first group element, and the blending ratio can be easily adjusted.

These non-magnetic alloy layers can be formed by sputtering or ion-blating, but among these methods, sputtering is the most preferred. A C01i magnetic layer is provided on the surface of the nonmagnetic alloy layer, and an intercalating layer is provided on the surface.

The material for the protective layer is preferably carbon. Recommended if necessary Depending on the situation, a liquid lubricant gold may be applied to the surface of the purulent membrane.

<Example> Hereinafter, specific examples 1 to 14 of the present invention and comparative example 1.
2 will be explained in detail. FIG. 1 is a sectional view of the magnetic recording medium of the example.

The nonmagnetic substrate was an aluminum alloy disk 1 with a diameter of 95 mm and a thickness of 1 to 25 mm, on which a Ni--P electroless plating layer 2 with a thickness of 20 μm was provided and then mirror-polished.

In the case of Examples 1 to 14, the nonmagnetic alloy layer was composed of a first group element and a second group element, as shown in Table 1.2. The mixing ratio of Group 1 elements and Group 2 elements is 9:1 in atomic ratio. The target was a disk made of group 1 elements on which chips made of group 2 elements were grown. In the case of Comparative Example 1.2, the second group element was not used as shown in Table 1.2.

I') A non-magnetic alloy layer 3 with a thickness of 1500'A was provided on the υ substrate using a sputtering device in C Magnetro, but the atmosphere during sputtering was at an Albin pressure of 10771 Torr.
, target applied power 5 W/cm” and then Co Ni Cr alloy (Co 62.5 atoms), N
160 atoms, processed Cr, 7.5 atoms) A Co injectable alloy layer 4 with a thickness of 50 OA was provided as a total target under the same sputtering conditions as above. Table 1 summarizes the magnetic properties of the thus obtained 90-degree recording medium. In the comparative example, the chip of the second group element exploded without being completely destroyed, and as is clear from Table 1, the magnetic recording media according to Examples 1 to 14 had a particularly high coercive force and a low squareness ratio. It can be seen that it is generally high.

Next, a carbon retainer layer 5 with a thickness of 600 Å was completely formed on these magnetic recording media using a swarming device, and then a fluorine-based liquid lubricant 6 was applied to a thickness of 30 Å by a spin cord method. The recording and reproducing characteristics of the nine magnetic recording media obtained were evaluated. These results are summarized in Table 2. The magnetic properties in each of the above Examples and Comparative Examples were measured using a VSM tester (vibration type % type) pressure gauge.

<Effects of the Invention> As is clear from the above embodiments, the present invention has a particularly high durability due to the use of a square layer containing a first group element and a second group element as a nonmagnetic alloy layer. In addition, a magnetic film with a generally high rod shape ratio can be obtained, and media noise can also be greatly reduced. Therefore, the magnetic recording medium of the present invention leads to high recording density.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the magnetic recording medium of the example. Code 1...Aluminum alloy disk, 2...N1-
P electroless plating layer, 3... nonmagnetic alloy layer, 4... C
Oi alloy layer...Carbon protective layer, 6...Liquid lubricant. Patent applicant Denki Kagaku Kogyo Co., Ltd.

Claims (1)

[Claims] A magnetic recording medium in which a nonmagnetic alloy layer containing the following first group element and second group element is provided on the surface of a nonmagnetic substrate, and a Co magnetic alloy layer and a protective layer are sequentially provided on the surface of the nonmagnetic alloy layer. . Group 1 element: one or more elements selected from Cr and W. Group 2 element: one or more elements selected from group IVa elements, group Va elements, and Mo of the periodic table.