JPH0226774B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Technical Field of the Invention The present invention relates to a magnetic film formed on a substrate and a method for manufacturing the same. The present invention relates to a magnetic film that is obliquely formed on a nonmagnetic substrate using a vacuum film forming method to obtain a magnetic film having in-plane magnetic anisotropy, and a method for manufacturing the same.

(B) Technical Background and Problems Conventionally, for example, in coated magnetic film magnetic tape devices and magnetic disk devices, magnetic powder is used so that the recording direction is the axis of easy magnetization. is oriented. By performing such orientation, high signal output,
It is well known that this method is highly effective in increasing resolution and S/N.

However, when producing a continuous magnetic film, for example, a method of manufacturing a γ-Fe ₂ O ₃ thin film using sputtering as shown in Patent No. 1024363 is used, but the magnetic The properties are isotropic within the film plane, and using such a magnetic film to create magnetic anisotropy with the recording direction as the easy axis, as in the above-mentioned magnetic tape device using a coated magnetic film, is
It was extremely difficult.

(C) Object and Structure of the Invention The purpose of the present invention is to solve the above-mentioned problems. One major feature is that the ferromagnetic material is deposited obliquely on a substrate with different surface roughness along the Y and Y axes using a vacuum deposition method. A detailed explanation will be given below with reference to the drawings.

(D) Embodiment of the invention Magnetic metal such as Fe or permalloy is deposited obliquely on the substrate surface in vacuum by vapor deposition or sputtering (hereinafter referred to as oblique incidence).
It is already known that a metal magnetic film having in-plane anisotropy can be obtained by using this method. However, in the case of oxides, the effect of the above-mentioned oblique incidence is extremely small;
It has been practically impossible to provide anisotropy by oblique incidence.

Although it was conventionally thought as described above, the inventors discovered that when a film is formed by the above-mentioned oblique incidence on a substrate whose surface roughness differs depending on the direction, even in the case of an oxide magnetic film, remarkable magnetism is observed. It was discovered that anisotropy can be obtained. Of course, it goes without saying that even in the case of metal magnetic films, there are effects by varying the surface roughness and by performing oblique incidence.

Example 1 As a substrate, an aluminum substrate subjected to alumite treatment with different surface roughness in the X-axis direction and the Y-axis direction was used. The thickness of the alumite is approximately 2 [μm]. As shown in Figure 1, surface roughness is measured in the X-axis direction.
Rmax approx. 0.01 [μm], protrusion pitch approx. 3 [μm],
Rmax approx. 0.01 [μm] protrusion pitch approx. in Y-axis direction
30 [μm], and the diameter in the X-axis direction was approximately 10 times finer than that in the Y-axis direction.

On this substrate 1, as shown in FIG. 2, a pair of cathodes 2 having an opposing cathode structure are arranged with a target 3, and an external coil 4 for generating a magnetic field perpendicular to the cathode 2 is provided. A sputtering device 5 was used. The substrate 1 is arranged so that the illustrated X-axis direction is perpendicular to the surface of the target 3,
α-Fe is deposited on the substrate 1 by performing reactive sputtering in an atmosphere containing O ₂ using a pair of metal targets 3 containing Fe as the main component and 2% Co, 2.5% Ti, and 1.5% Cu. _{A 2O3} film was created. Then, by heating this in a reducing atmosphere containing H ₂ and further heating in air, it is reduced and oxidized to γ-
A Fe ₂ O ₃ film was obtained.

The BH characteristics of the membrane prepared in this way are
In the Y-axis direction, Hc620Oe, Br/Bs=0.9, and S ^* =0.84. Moreover, in the X-axis direction, Hc480Oe, Br/Bs=0.6, and S ^* =0.62. The above S ^* is defined by the formula (dB/dH) _H=Hc =Br/Hc/1-S ^* , and represents the angularity of the BH curve, and the S ^* is the value " The closer it is to 1'', the more convenient it is for high-density magnetic recording. Regarding the value of S ^* mentioned above, the value of "0.84" is extremely high compared to conventional ones.

Further, when a magnetic torque curve was drawn using the sample obtained as described above, the curve was as shown in FIG. This indicates that the sample has typical uniaxial anisotropy, and the anisotropy constant Ku is 9.6×
10 ⁴ [erg/cc]. The easy axis at this time is the Y-axis direction.

Example 2 Using an alumite-treated aluminum substrate with substantially the same surface roughness in the X-axis direction and Y-axis direction as the substrate, γ-Fe ₂ was prepared in the same manner as in Example 1 above. An O ₃ membrane was fabricated. However, the BH characteristics of the film were Hc = 600 Oe, Br/Bs = 0.77, and S ^* = 0.76 in both the X-axis direction and the Y-axis direction, and no anisotropy was observed.

Example 3 Using the same substrate as in Example 1 above, the fourth
As shown in the figure, reaction sputtering was carried out using a target with the same composition as in Example 1, with the surface of the target 3 and the surface of the substrate 1 parallel to each other. Finally in the same manner γ-
A Fe ₂ O ₃ film was fabricated. However, the BH characteristics of the film were Hc = 650 Oe, Br/Bs = 0.76, and S ^* = 0.76 in both the X-axis direction and the Y-axis direction, and no anisotropy was observed.

Example 4 Using the same substrate as in Example 1 above, the fifth
As shown in the figure, under the arrangement relationship such that the surface of the target 3 and the surface of the substrate 1 are at an angle of 45 degrees, the γ-
A Fe ₂ O ₃ film was fabricated. In this case, the BH characteristics of the film in the Y-axis direction were Hc = 630 Oe, Br/Bs = 0.9, and S ^* = 0.83. Furthermore, in the X-axis direction, Hc = 490 Oe, Br/Bs = 0.6, and S ^* = 0.63, indicating that the film has significant magnetic anisotropy.

Judging from the above examples, when the pitch of the unevenness in the X-axis direction is finer than that in the Y-axis direction, the magnetic effect is most noticeable when the flying direction is perpendicular to the Y-axis direction and obliquely incident on the substrate surface. Anisotropy is obtained,
The axis of easy magnetization is the Y-axis direction.

(E) Effects of the Invention As explained above, according to the present invention, a film exhibiting remarkable magnetic anisotropy can be obtained. Further, by using the magnetic film formed on the substrate, memory devices such as magnetic tape devices and magnetic disk devices can be obtained. It goes without saying that the present invention is not limited to magnetic materials with high coercive force, but can also be applied to the formation of thin films with soft magnetism, such as those used in magnetic heads. Furthermore, it is clear that the present invention can also be applied to the formation of metal magnetic films.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram for explaining the surface roughness of the substrate used in the example of the present invention, FIG. 2 is an explanatory diagram for explaining the aspect used in Example 1 of the present invention, and FIG.
The figure is an explanatory diagram for explaining the anisotropy of the obtained sample, FIG. 4 is an explanatory diagram for explaining the aspect used in Example 3 according to the present invention, and FIG. An explanatory diagram illustrating the mode used is shown. In the figure, 1 is the substrate, 2 is the cathode, 3 is the target,
4 represents a coil, and 5 represents a sputtering device.

Claims (1)

[Claims] 1. A magnetic film in which a ferromagnetic material is deposited on a substrate using a vacuum deposition method, wherein the substrate has different surface roughness in two orthogonal directions within a plane, The ferromagnetic material is deposited by a vacuum deposition method on the planes having different surface roughness from oblique directions excluding substantially 0° angle and substantially 90° angle, resulting in in-plane magnetic anisotropy. 1. A magnetic film formed on a substrate, characterized in that it is formed by molding a magnetic film with a magnetic property. 2. In a method for manufacturing a magnetic film in which a ferromagnetic material is deposited on a substrate using a vacuum deposition method, a substrate having different surface roughness in two orthogonal directions within a plane is used as the substrate, and the substrate A ferromagnetic material is deposited on the above-mentioned plane by a vacuum deposition method from an oblique direction excluding a substantially 0° angle and a substantially 90° angle,
A method for manufacturing a magnetic film formed on a substrate, characterized in that a magnetic film having in-plane magnetic anisotropy is formed. 3. The vacuum film forming method is characterized in that a target is placed on the cathode arranged in the diagonal direction with respect to the plane, and the ferromagnetic material is deposited on the plane by sputtering. A method of manufacturing a magnetic film formed on a substrate according to claim 2. 4 The above magnetic film with in-plane magnetic anisotropy is produced by reaction sputtering a metal containing Fe as a main component in an atmosphere containing O ₂ and then heat-treating it to form γ-Fe ₂ O _{3 .}
Claim 2 or 3, characterized in that the magnetic oxide film is formed into a continuous magnetic oxide film containing
A method for manufacturing a magnetic film formed on a substrate as described in 1.