JPS62150516A - Magnetic recording body - Google Patents

Abstract

PURPOSE:To improve coercive force and squareness ratio by providing an intermediate layer consisting of body-centered tetragonal structure by diagonal sputtering between a nonmagnetic substrate and thin film magnetic medium. CONSTITUTION:The intermediate layer 102 consisting of the thin nonmagnetic metallic film having the face-centered cubic structure is provided on the nonmagnetic substrate 101 and further the thin film magnetic medium 103 is provided thereon. The layer 102 is formed by diagonal sputtering and the crystal grains of the thin metallic film grown on the substrate 101 has the columnar structure inclining in the sputtering direction. Cr, Mo, W, V, Nb, and Ta of which the columnar structure of the crystal grains has the face-centered cubic structure are used for the material of the thin metallic film. Intra-surface magnetic anisotropy is thereby generated in the thin film magnetic medium, by which the coercive force and squareness ratio are considerably increased and the recording density is remarkably improved with good S/N.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium suitable for use in magnetic disk devices and the like.

[Conventional technology]

It magnetic recording bodies currently used in magnetic disk devices,
A magnetic medium is formed by coating magnetic fine particles such as γ-FeiO* on a nonmagnetic substrate, and this magnetic medium is a discontinuous medium. On the other hand, in recent years, there has been an increasing demand for higher recording densities in order to increase recording capacity, etc., and it is necessary to further increase the coercive force and squareness ratio even in the case of energy recording materials. Therefore, research and development of thin film continuous media as magnetic media is progressing.

Conventionally, methods for increasing coercive force include: (1) Depending on the composition of the material of the magnetic medium (Electric Corporation Research and Practical Application Report Vol. 26 No. 2 (1977) P, 585-5
94).

(11) An intermediate layer is provided between the nonmagnetic substrate and the thin film magnetic medium (see Japanese Patent Laid-Open No. 60-35332).

(iii) Forming a thin film magnetic medium by diagonally depositing it on a non-magnetic substrate (Kishikaku Choshin, "Physics of Ferromagnetic Materials (Part 2)", Shokabo (1982), p.

(iv) Treating the thin film magnetic medium in an fn field during or after formation (page 56-6 of the document (iii) above)
9) etc. are known.

[Problem that the invention seeks to solve]

However, with any of the above methods, there are limits to the coercive force and squareness ratio, and in order to promote higher recording density of magnetic recording media, it is necessary to further increase these.

An object of the present invention is to provide a magnetic recording medium that satisfies such requirements and further improves coercive force and squareness ratio.

[Means for Solving the Problems] An intermediate layer made of nonmagnetic metal crystal grains with a body-centered cubic structure formed by diagonal sputtering is provided between a nonmagnetic substrate and a thin film magnetic medium.

[Effect]

Due to oblique sputtering, crystal grains with a body-centered cubic structure grow obliquely to form an intermediate layer. Due to this oblique growth, a magnetic field parallel to the surface of the thin film magnetic medium formed on the intermediate layer is generated. Anisotropy (hereinafter referred to as in-plane magnetic anisotropy) occurs, and this is the coercive force.

Increase squareness ratio.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial sectional view showing an embodiment of a magnetic recording medium according to the present invention, in which 101 is a nonmagnetic substrate, 102 is an intermediate layer, and 103 is an I-film magnetic medium.

In the figure, an intermediate layer 102 of a nonmagnetic metal thin film having a body-centered cubic structure is provided on a nonmagnetic substrate 101, and a thin film magnetic medium 103 is further provided thereon.

The intermediate layer 102 is formed by oblique sputtering, and the crystal grains of the metal thin film grown on the nonmagnetic substrate 101 have a columnar structure that is inclined in the sputtering direction (that is, the direction of incidence of magnetism). In this embodiment, the material of this metal thin film is Cr or Mo, in which the columnar structure of crystal grains has a body-centered cubic structure.

W, V, Nb, Ta, etc. are used.

FIG. 2 shows a method of forming the intermediate 71101, in which the target 104 is non-magnetic and the normal 105 of the W slope 101 is
(that is, the direction perpendicular to the surface of the nonmagnetic substrate 101)
It is provided in a direction inclined by an angle θ with respect to the direction shown in FIG. target 1
The sputtered particles from 04 strike the non-magnetic substrate 10 at an incident angle θ.
1, thereby obtaining an intermediate layer 102 on the nonmagnetic substrate 101 in which crystal grains have grown in the direction of the incident angle θ.

When forming the thin film magnetic medium 103 (FIG. 1), the incident angle θ is set to θ245°, and in FIG. 2, the incident angle θ is set so that θ≦5°. Make it.

When the intermediate layer 102 and the thin film magnetic medium 103 are formed in this manner, in-plane magnetic anisotropy is generated in the thin film magnetic medium 103 having an axis of easy magnetization 106 parallel to its surface. The direction of this in-plane magnetic anisotropy is between the target lO4 and the nonmagnetic substrate 1.
01 (i.e.,
The direction is parallel to the plane containing the growth direction of the crystal grains of the intermediate grain 02. So, for example, target j
By changing the position of 04 with the normal 105 of the non-magnetic substrate 101 as the white center, the thin film magnetic medium! It is possible to change the direction of the in-plane magnetic anisotropy generated in 03.

Therefore, in this embodiment, by controlling the means for forming the intermediate layer 102 and the thin film magnetic medium 103, the direction of the axis of easy magnetization 106 is made to coincide with the circumferential direction of the magnetic recording medium 107, as shown in FIG. ing.

In the prior art described in (iii) above, magnetic anisotropy occurs in the thin film magnetic medium in which the direction of the easy axis of hexagonalization coincides with the direction of incidence of sputtered particles. Since the coercive force and squareness ratio of a magnetic medium decrease as the direction differs from the axis of easy magnetization, in the above embodiment that produces in-plane magnetic anisotropy, the coercive force and squareness ratio are smaller than in the above conventional technology. It is possible to improve the S/N ratio and further increase the recording density.

Next, this example will be explained in more detail.

Specific Example 1: As the non-magnetic substrate 101, an AIL alloy disk is used. After Ni-P alloy is electrolessly plated on this disk, its surface is mirror-polished so that the maximum surface roughness is 0.04.
The surface was finished so that it was below μm.

Next, a non-G1 magnetic metal is obliquely sputtered onto the non-magnetic substrate 101 by controlling the incident angle θ to be 45° or more.
An intermediate layer [102] with a thickness of 0.05 to 0.5 μm was formed.

In this case, the nonmagnetic metal is Cr.

MO, W, V, Nb or ra was used. As a result, the crystal grains constituting the intermediate layer 102 have a body-centered cubic structure.

Next, a magnetic material is sputtered onto the intermediate layer 102 to a thickness of 0.05 by controlling the incident angle θ to be smaller than 45°.
A thin film magnetic medium 103 having a thickness of about 17 μm was formed. As this magnetic material, Co-doped r-Fe and Oz are used, and the formed thin film magnetic medium 103 is a continuous medium.

In addition, in the above-described process of forming the intermediate layer 102, the non-magnetic substrate 101 was covered with a partially open hole, and the non-magnetic substrate 101 was rotated. As a result, the nonmagnetic substrate 10
The direction of sputtering was almost uniform over the whole of the iRH magnetic medium 103, and as shown in FIG. 3, the direction of the axis of easy magnetization 106 in the iRH magnetic medium 103 coincided with the circumferential direction of the magnetic recording medium.

The following table shows that Go-doped r-Few O, (Cor-F+1203) is used as the thin film magnetic medium 103, the thickness of the intermediate layer 102 is set to 0.3 μrQ, and the intermediate layer 10
2 materials are Cr, Mo, W, V, and Nb.

The coercive force and squareness ratio of the thin film magnetic medium 1t13 when Ta is used are shown in comparison with the prior art.

<Table> In the above table, example (a) is a case where the thin film magnetic medium 103 is directly formed on the nonmagnetic substrate 101 without providing the intermediate layer 102. Further, in Examples (B) to (D), the upper row relates to the above specific example, and the lower row shows cases where the intermediate layer 102 is formed by sputtering with an incident angle θ smaller than 45° (i.e., normal sputtering). It is.

As is clear from the above table, in the above specific example in which the intermediate layer 11102 having a body-centered cubic structure is formed by diagonal sppacking, when the thin film magnetic medium 103 is made of the same material, its coercive force and squareness ratio are equal to those of the intermediate layer 102. If not provided (
The magnetic properties of the magnetic recording medium are significantly improved, with an increase of about 2000a and 0.15 more than in example (a)), and an increase of about 1000e and 0.1, respectively, compared with the case where the intermediate layer 102 is formed by normal sputtering. has improved.

Although the above table shows the case where the thickness of the intermediate layer 102 is 0.3 μm, similar effects can be obtained if the thickness is in the range of 0.1 to 0.5 μm.

Specific Example 2: The same treatment as in Specific Example 1 was performed using CO as the material of the thin film magnetic medium 103. As a result, the coercive force is approximately 1000 times higher than that when the intermediate layer 102 is formed by normal sputtering.
e increased, and the squareness ratio also increased from 0.9 to 0.95. Similar effects were obtained when the thickness of the film 17 of the intermediate layer 102 was in the range of 0.1 to 0.5 μm.

Specific Example 3: The material of the thin film magnetic medium 103 was Co-30%Ni, and the same treatment as in Specific Example 1 was performed. As a result, the middle layer 10
Compared to the case where No. 2 was formed by normal sputtering, the coercive force increased by about 1000 e, and the squareness ratio also increased from 0.9 to 0.95. Similar effects were obtained when the thickness of the intermediate layer 102 was in the range of O01 to 0.5 μm.

As described above, by providing an intermediate layer made of non-Lit metal crystal grains with a body-centered cubic structure between the nonmagnetic substrate and the thin film magnetic medium by diagonal sputtering, the magnetic properties of the thin film magnetic medium can be greatly improved. improve.

In the above embodiment, the material of the thin film magnetic medium is Cor-
-Fe, ol, Co, Co-30%Ni, but the present invention is not limited to these. Further, the material of the intermediate layer may be other than the above-mentioned Cr, Mo, etc., as long as crystal grains having a body-centered cubic structure are formed by diagonal sputtering.

〔Effect of the invention〕

As explained above, according to the present invention, since in-plane magnetic anisotropy can be produced in a thin film magnetic medium, its coercive force and squareness ratio can be significantly increased, and recording density can be improved with good S/N. will be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view showing an embodiment of the magnetic recording medium according to the present invention, FIG. 2 is an explanatory diagram showing a sputtering method for the intermediate layer in FIG. 1, and FIG. FIG. 4 is a schematic diagram showing the easy axis direction 4 of magnetization. 101...Nonmagnetic substrate, 102...Intermediate layer, 1
03... Thin film magnetic medium, 106... Easy magnetization axis direction. l″HH,””-t. ・□ 11 Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] In a magnetic recording body comprising a nonmagnetic metal intermediate layer between a nonmagnetic substrate and a metal or oxide thin film magnetic medium, the intermediate layer is formed by oblique sputtering and is made of metal crystal grains with a body-centered cubic structure. A magnetic recording medium characterized by: