JPS5840251B2 - magnetic recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims to provide a magnetic recording medium with high sensitivity, long life, and excellent S/N ratio. It exhibits excellent features in recording and reproducing systems, and in addition to the above-mentioned essential advantages, it also has the effect of reducing the geometrically occupied volume occupied by the recording medium in response to the demand for high-density recording of information.

An embodiment of the present invention will be described below with reference to the drawing of FIG.

In the figure, 1 is a base material made of a polymer molded product such as a polyethylene terephthalate film or a non-magnetic metal material (when applied to the magnetic disk field), and 2 is a base material made of Co, Fe provided on the surface of the base material 1. A ferromagnetic metal layer as a recording layer to which pNi or an alloy thereof or other elements are added depending on the purpose, 3 is a ferromagnetic metal layer as described above in an organic substance provided on the surface of the metal layer 2. This is a layer in which fine alloy particles are dispersed.

This layer 3 is in contact with a transducer such as a magnetic recording/reproducing head.

In FIG. 2, the ferromagnetic metal layer 2 is formed into a multilayer structure with a nonmagnetic layer 4 interposed therebetween, with layer 3 being the top layer.

In FIGS. 1 and 2, a bank coat layer and an overcoat layer (not shown) can be provided as necessary, but it is preferable to use a material structure that can be used practically in the structure shown in the figure. .

The formation of the recording layers 2 and 3 to achieve the present invention is as follows:
Any of the thin film techniques such as vapor deposition, plating, sputtering, and ion blating, which are the basis of current recording media, may be used.

Next, Figure 3 shows the results of an actual running test between the recording medium of the present invention and a thin ferromagnetic metal film recording medium with the same initial sensitivity, and Figure 4 shows the results of an actual running test after the same environmental test. The sensitivity comparison results are shown.

The magnetic recording medium is a 0.12μ Co 75φyNi 25φ thin film on a 12μ thick polyethylene terephthalate film at an incident angle of 25° in a vacuum atmosphere of 5XIO' Torr.
Co
90%, NiO% alloy fine particles (average particle size 0.35
μ) was set at a filling rate of 30%, a mixed resin of styrene-butadiene copolymer resin and polyurethane resin was applied as the main binder at 0.8 to 1.0 μm, and the magnetic field orientation was fixed in the longitudinal direction to form the structure shown in Figure 1. This is what I did.

As for magnetic properties, coercive force is 42 after super calender treatment.
00 e, and the squareness ratio was 0.93.

In order to achieve almost the same B-H characteristics with all ferromagnetic metal layers using a DC magnetization characteristic measuring device, 5XIO-5TOrr
Polyethylene terephthalate film (
12μ) 300 Ti on top, 75% Co on top
, a 25% Ni film with a thickness of 0.19 μm, and a Ti layer with a thickness of 3 μm.
00 people, with a CoNi layer on top of it at an incident angle of 0.19μ 50'
Vapor deposition was performed by the above-mentioned oblique vapor deposition method.

This sample was examined as a comparison sample. Figure 3 shows the change in sensitivity when the initial sensitivity was the same and it was mounted on a commercially available cassette tape deck and actually run. Figure 4 shows the results of a similar evaluation performed after exposure in the incorporated state.

In addition, in both figures, the running speed is 4.75 cm/sec,
The recording frequency is f=l KHz, the input is 250 mV, and the ◯ mark is the characteristic of the present invention, and the × mark and ∆ mark are the characteristics of the conventional medium.

In Figure 3, the product of the present invention shows almost no change in sensitivity even after 500 hours of accumulated running, whereas the conventional thin film tape shows signs of deterioration after 140 to 150 hours of running, and after running for more than 200 hours. It was impossible to use.

The effect of the present invention is even more obvious in FIG. 4, where the conventional example marked with an x has dotted rust, and the conventional example marked with a Δ has o and iμ protective layers (NiCr layer) on the dots. ), but although there was some improvement, deterioration was rapid.

The results shown in Figures 3 and 4 above, and the S/N ratio of 2 to 3
dB, a reduction in the level of modulation noise due to improved running properties, and higher sensitivity with the same magnetic layer thickness (the product of the present invention has a composite thickness) compared to the coated tape, which is a practical product. It was possible to reduce the recording volume compared to tape.

Note that a decrease in sensitivity was observed when the fine particles dispersed in the organic material were iron oxide-based, but no decrease in sensitivity was observed when ferromagnetic alloy fine particles were dispersed as in the present invention. .

As described above, the present invention can provide a magnetic recording medium that is comprehensively superior, and makes a great contribution to the field of magnetic recording.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views of each embodiment of the magnetic recording medium according to the present invention, and FIGS. 3 and 4 are sensitivity characteristic diagrams of the conventional magnetic recording medium and the present invention. 1... Base material, 2... Ferromagnetic metal thin film layer, 3... Layer in which ferromagnetic alloy fine particles are dispersed in an organic substance.

Claims (1)

[Claims] 1 At least one ferromagnetic metal layer as a recording layer directly or indirectly on the surface of a polymer molded product or a base material made of a non-magnetic metal material, and an organic substance directly or indirectly on the surface of the metal layer. A magnetic recording medium comprising a layer in which fine ferromagnetic alloy particles are dispersed.