JPS6398826A - Magnetic medium - Google Patents

Abstract

PURPOSE:To orient the axis of easy magnetization of a magnetic metal by electroless plating in a line recording direction by providing an Ni-Zn-P layer contg. a specific ratio of Zn on a substrate and forming ruggedness having specific max. roughness on the surface thereof. CONSTITUTION:The Ni-Zn-P layer contg. >=3wt% Zn is provided on the circular nonmagnetic substrate subjected to mirror finishing and the fine ruggedness having 0.08-0.20mum max. roughness (Rmax) is formed on the surface thereof. A magnetic layer is formed by an electroless plating method on the rugged surface. The orientation of the axis of easy magnetization of the magnetic metal is no longer admitted if the above-mentioned Rmax is below 0.08mum and the head no longer floats if the Rmax exceeds 0.20mum. The axis of easy magnetization of the magnetic metal by the electroless plating is oriented in the line recording direction according to the above-mentioned constitution and, therefore, the medium having high reproduction output is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic medium used in a poisonous disk device W.

[Conventional technology]

2. Description of the Related Art With the recent increase in the performance of computer equipment and the trend toward 1" type, there is a demand for higher linear recording density of magnetic recording media. Therefore, as a characteristic of the medium.

(1) The coercive force must be 800 degrees or more.

(2) The ratio of coercive force/residual magnetic flux density is small.

(3) Thin magnetic layer thickness.

It is said that these are necessary. Furthermore, thin film media that easily satisfy a % property of 1 or more, such as media coated with dispersed magnetic particles such as r-ferrite (γ-F6, 0.), are being used in small fixed-type magnetic disk drives. Became. Further, methods for producing thin film media include electroless plating and sputtering, but electroless plating is mainly used because media can be produced in large quantities with uniform properties.

[The problem that the discovery seeks to solve]

However, since the electroless plating method can form a uniform magnetic layer on the medium surface, the axis of easy magnetization of the magnetic metal becomes disordered, resulting in a lower output compared to a magnetic recording medium that is clearly oriented in the tough recording direction. There is a problem that it is inferior. In order to orient the axis of easy magnetization using the electroless plating method, it is necessary to form fine irregularities ft on the substrate, but N1-P
Even metals with autocatalytic properties such as 6&i
A metal oxide layer is formed on the surface through the step of forming all i'411 irregularities.

This layer has very weak catalytic properties, and in order to deposit a weakly autocatalytic alloy such as a magnetic plating film, the metal oxide layer must be etched or there is a core wall north of it on which the active metal is formed. However, since this oxide layer has strong corrosion resistance,
There is no method for uniformly etching, and even if it can be etched, the surface roughness will be poor, and when it is actually installed in a small fixed EB disk device, there is a problem that the head will not fly.

- When forming a magnetic layer by adsorbing and precipitating an active metal such as palladium (Pd) on top of the Banzai layer without removing it, as the thickness of the active metal layer becomes thicker, the orientation in the uneven direction is observed. In addition, if the thickness of the active gold (gold) J4 layer is made thinner, the magnetic plating is not formed uniformly, causing defects and increasing the number of missing bits.

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and its purpose is to increase the reproducing power by orienting the axis of easy magnetization of fully compressed magnetic material in the linear recording direction by electroless plating.

〔problem? Means to solve]

In the magnetic medium of the present invention, a u6-Z71-P layer containing 3 wt% or more of Zn is formed on a nonmagnetic substrate.

On top of that, RWZ has formed minute irregularities of 0.08 to 0.20 degrees on the surface? Features.

The content of zn contained in the u6-Zn-P film is preferably 3 wt or more, but if it is less than this. Since the magnetic layer is directly deposited, Rd activation treatment is safe.

As a result, no orientation can be seen9. The m-type layer no longer precipitates uniformly. In addition, the substrate OR'm1L with fine irregularities
Desirably, Z is 0.08 to 0.20 μm, but if it is less than this, the substrate approaches a mirror surface and the orientation of the axis of easy magnetization of the magnetic metal is no longer observed.

Also, when %ktnuxz becomes 0.20 or more, small IM
The above range is desirable for one or more reasons that the head will not fly when mounted on a formal magnetic disk drive.

[Implementation row]

Mirror finish? After plating yz-Zn-P shown in Table 1 on a circular non-magnetic substrate with an electroless plating solution of 100 OA, ≠2000*su3000, +60
00 abrasive tape, and immediately after that, the second
A magnetic medium was produced using the electroless C(-Nz-P) plating solution shown in Table 1. Plating conditions: pH 9.0, bath temperature 85°C.
Surface plating conditions: pH 9.0, bath temperature 70°C [Comparison row] On a non-magnetic substrate with a mirror finish, an N4p film was formed using the plating solution listed in Table 1 of Example 11 except for the zinc nucleic acid. 100
01 was deposited, and irregularities were made in the circumferential direction using a polishing tape of Na2000. Then, add Pd to 100A with palladium chloride solution, or MieP, c(, -Nz-
A m-type layer was formed using a p-electroless plating solution, and then a magnetic medium was mounted.

The Zn content in the N5-Zn-P film of the Ha medium produced by the above method was determined by analyzing the film dissolved in acid by plasma emission spectrometry (L/%), and the surface roughness was determined using a stylus diameter of 2.5βr.
Measurements were made in the direction of the center of the circle using Merisurf. The orientation is determined by measuring the monochronicity in the circumferential direction and the center direction using a vibrating sample force meter, which is the product of the residual magnetic flux density (Bτ) and the film thickness (δ).
δ and coercive force (HC)? 1] was established. In addition, for the floating customization and output of the placed medium, a certifier is used, with a gap width of 19 μm, a gap length I A m, and a turn width of 22 μm.
At the head of the turn #)% radius 2.5 - 2,5
The signal at the frequency of MI (z) was read and the output was read, and the number of missing bits was also measured.

The results measured using the above method are shown in Tables 3 and 4.

As mentioned above, if Ni-23-P containing % Z If the roughness R x is within the range of 0.01 to 0.05 μm, there is a medium with stable characteristics and orientation a that has high reproduction output! 8! I was able to build it.

〔Effect of the invention〕

In the present invention, since the N1-Z%-P film and fine irregularities are formed on a nonmagnetic substrate, it is possible to manufacture a medium with high reproduction output.

that's all Applicant: Seiko Epson Corporation Agent: Patent attorney Mogami and 1 other person (・

Claims (1)

[Claims] 3 weight percent (Wt) of zinc (Zn) on a non-magnetic substrate
%) or more of nickel-zinc-phosphorous (Ni-Zn-
P) form a layer on which the maximum roughness, (R_m_a_
x) A magnetic medium characterized by having fine irregularities of 0.08 to 0.20 μm formed on its surface.