JPS6025802B2 - Metal thin film magnetic tape - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the improvement of a metal thin film magnetic tape for high-density magnetic recording, and has excellent properties as a long magnetic tape based on a polymer molded product used for magnetic recording. The purpose is to obtain.

/ - Conventionally, So "1 Fe2
03, Cr02 and other ferromagnetic powders are mixed with a binder,
In so-called coated magnetic tapes that are coated and cured, it is said that there is a limit to the improvement of recording density because ferromagnetic powder is dispersed in a binder, and the binder cannot be removed in principle11111'. There is.

Fill This also applies to recent improved products that use iron-based metal or alloy particles that have a higher saturation magnetic flux density than the oxide magnetic powders, and essentially do not require a binder. The superiority of ferromagnetic metal thin film magnetic tape is attracting attention.

This metal thin film magnetic tape is manufactured using known thin film techniques such as vacuum coating and plating, and in order to take advantage of its characteristics, a magnetic metal layer of up to about 0.5r is formed by polymer molding. It is constructed by forming it on a base material such as an object. Several proposals have already been made regarding the method and configuration. In addition, there is a strong trend toward higher density recording, and taking recording as an example, in order to increase the output in the high frequency range, surface roughness must not be overlooked, and this has also been raised, and surface flattening technology There are also many disclosures.

Regarding metal thin films, it has been reported that the surface roughness of the base material is important for plating films such as Co-P.

In view of this invention, as a result of careful consideration, the present invention has found that there is a limit to the improvement of mere surface roughness, especially centerline average roughness and maximum roughness, which has been conventionally referred to in this field. It is something.

As shown in FIG.

The configuration of a known metal thin film tape, that is, on the polymer molded base material 3, to C. Sn. A magnetic metal layer 1 mainly composed of iron group elements is formed through a non-magnetic layer 2 made of W, Mo, Ti, A, etc.
It was discovered that if only the regulation of the surface roughness of the base material 3, which was considered important for increasing the output and reducing noise of the conventional Takagi, caused a decrease in the output due to repeated running. The present invention is based on this fact. That is,
As shown in FIG. 2, when looking at the change in the reproduction output during repeated running for a recording wavelength of 31, 0.6 peaks in a commercially available tape recorder, a decrease in output is observed with the conventional consideration of surface writing.

This is due to the shape effect of inorganic additives such as A203, Si02, etc. to give the polymer molded material a surface roughness, especially the roughness that forms the maximum roughness. Caused by changes in magnetism due to large stress generated in minute parts of the thin film,
Stress relaxation was observed in the magnetic tape formed under the same conditions on a base material obtained by mixing the above-mentioned inorganic additives by pulverizing them into granules, and good results were obtained as shown in Figure 2. . This difference becomes more significant as the recording wavelength becomes shorter. Furthermore, as a result of detailed study, it was found that the average particle size as well as the shape of the additive substance become more important as the recording wavelength becomes shorter, and that it is preferable that the particle size is at least equal to or less than the recording wavelength.

FIG. 3 is a graph showing the output characteristics versus the average particle diameter of the inorganic material when the recording wavelength input is used as a parameter.

It can be seen from the figure that no decrease in output is observed when the average particle diameter is less than the recording wavelength. Note that the shape of this inorganic material does not have to be spherical, and may be an elliptical sphere as long as the ratio of the innermost axis to the shortest axis is 2:1 or less, and the effect can be maintained.

In any of the examples, the effects of the present invention are more noticeable when forming a magnetic thin film at high speed, and the industrial value thereof is high.

Next, specific examples will be described. [Example 1] Base material Polyethylene terephthalate added inorganic substance average particle size 0.5 - Carbon 0.3% Wt.
Non-magnetic layer Cro. 05×(5×10-5Ton formed by vapor deposition method) Ferromagnetic metal layer Co98% Si2% layer 0
．． 1 μm (average 2 in an oxygen atmosphere of 5×10M5 Torr)
Formed by electron beam evaporation at a high speed of f/min) [Example 2] Base material Polyimide-added inorganic substance average particle size 0.3 mm Aso203 type powder 0.7
%Nonmagnetic layer Mo (formed by sputtering method in ~1×10-3Ton) Ferromagnetic layer Feloo% 0.
13 Buddha (formed by oblique evaporation method in 4×10-5 tons of oxygen at an incident angle of 45 degrees or more) [Example 3] Base material Polycarbonate Added inorganic substance Average particle size 0.7 mm Silica 0.5%wt Non-magnetic layer Sn (ion plating in 1×10-4Ton) Ferromagnetic layer Coo. 1 Buddha (1×10-4To
Ion plating in rr02) Repeat again, S
n, Co layers are stacked to form a multilayer structure.

The following is a summary of comparative studies of metal thin film magnetic tapes having the same configuration as Examples 1 to 3, obtained by connecting commercially available base materials with the same roughness and the same thickness, and metal thin film magnetic tapes according to the present invention. is shown in Figure 2.

Note that the inorganic substance added may be a non-magnetic material or a magnetic material, but a non-magnetic material is preferable from the viewpoint of noise.

Examples include silicon and its compounds, carbon, or nonmagnetic metal oxides. As described above, the metal thin film type magnetic tape of the present invention hardly exhibits any decrease in output even after repeated running, is suitable for high-speed production, and has great industrial value.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing the present invention and a general metal thin film type magnetic tape, Figure 2 is a characteristic comparison diagram showing the relative output for the same number of runs, and Figure 3 is a diagram showing the inorganic material in the polymer molded material. It is a relative output level characteristic diagram with respect to an average grain level. 1...Magnetic metal, 2...Nonmagnetic layer, 3
・・・・・・Polymer molded material Motomura. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A metal thin film magnetic tape in which at least one non-magnetic layer and a magnetic metal layer are disposed on a polymer molded base material, wherein the shape of the inorganic material added to the base material is spherical or spherical. Metal thin film magnetic tape characterized by a similar shape. 2. The metal thin film magnetic tape according to claim 1, wherein the average particle diameter of the inorganic substance is less than the recording wavelength.