JPS6139226A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium which adapts itself satisfactorily to practicable use in both magnetic characteristic and durability by coating a recording layer consisting essentially of high-coercive force ferrite having vertical magnetic anisotropy on the intermediate layer of a two-layered film medium. CONSTITUTION:Ba ferrite powder is hexagonal Ba ferrite having the axis of easy magnetization in a vertical direction and after a magnetic paint is preped. by incorporating a dispersant and binder into such powder, the paint is coated on the intermediate Mn-Zn ferrite layer 2 formed on the polyester film substrate 3, by which the magnetic recording layer 1 is formed. The Ba ferrite coating film used as the layer 1 has the higher durability than the durability of a thin metallic film consisting of C0-Cgamma, etc.

Description

[Detailed description of the invention] [Industrial use duke] This invention relates to magnetic recording media.

More specifically, the present invention relates to a magnetic recording medium used in a device that performs storage using a perpendicular magnetic recording method in an external storage device such as a magnetic disk device.

[Conventional technology]

In conventional magnetic recording, recording is mainly performed by magnetization in a direction parallel to the surface on which the magnetic recording layer is formed (longitudinal magnetization). However, in the case of recording using longitudinal magnetization, as the recording density increases, the demagnetizing field within the medium increases, causing attenuation and rotation of residual magnetization, resulting in a significant decrease in reproduction output. On the other hand, when performing magnetization in the thickness direction of the recording layer, so-called perpendicular magnetization, the demagnetizing field becomes smaller as the recording density increases. Also, recording using perpendicular magnetization (hereinafter referred to as perpendicular recording) is more advantageous. As a recording medium suitable for such perpendicular recording.

A two-layer film medium has been proposed in which a recording layer of a perpendicular magnetic anisotropic film is provided on the surface and a soft magnetic film is provided in the lower layer, that is, between the recording layer and the substrate (Japanese Patent Publication No. 5.8-91)0 This will be explained with reference to FIG. In the figure, (1) is the recording layer, 12)
is an intermediate layer, I3) is a medium substrate, (4J is a recording/reproducing head main magnetic pole, (5) is a reinforcing core, and (61 is a coil).

The head shown in Fig. 1 is called a single-pole head, and various modifications are possible in addition to the shape shown in Fig. 1.
As an example, the one shown in Figure 1 is shown. Although a detailed explanation of the principle of magnetic recording using such a head and medium combination will be omitted, the magnetic field created by the head main pole (5)
The recording layer (1) is magnetized in the direction perpendicular to the film surface, and the perpendicular d
A personal record is achieved. In this case, the function of the intermediate Jfi t2i is to strengthen the magnetic field generated from the head main pole (5) during the recording process, and to strengthen the magnetic field generated from the recording layer t2i.
It is thought that the magnetic circuit on the back side of l+ should be partially closed to reduce the demagnetization effect and strengthen the residual magnetization.

[Problem that the invention seeks to solve]

Conventionally, such two-layer film media have mainly used C0-Cr for the recording layer and N1-Fo for the intermediate layer.
In the m method, a thin film is formed by sputtering or plating. Although the above-mentioned two-layer film media has been able to sufficiently satisfy current demands for high-density recording in terms of magnetic properties, it is difficult to ensure durability and mechanical properties against sliding between the head and the boat. It has not yet been put into practical use.

The present invention has been made in view of this point, and provides a magnetic recording medium for perpendicular recording that satisfies the performance for high-density recording and has sufficient durability.

[Means for solving problems]

The present invention is characterized in that, in a two-layer film medium, a recording layer containing high coercive force ferrite having perpendicular magnetic anisotropy as a main component is formed by coating on the intermediate layer.

[Operation of means for solving the problem] In this invention. A coating film recording layer whose main component is high coercive force ferrite having perpendicular magnetic anisotropy exhibits superior durability compared to metal thin films.

〔Example〕

FIG. 1 shows one embodiment of the present invention. Pan 11+ is a recording layer formed by coating Ba ferrite powder, (21 is Mn-Zn
The intermediate layer made of ferrite (3) is a polyester film substrate. The Ba ferrite powder used in this example was hexagonal Ba ferrite having an axis of easy magnetization in the perpendicular direction. After mixing this with a dispersant and a binder to create a magnetic paint, A magnetic recording medium is created by coating on the Mn-Zn 7-layer light intermediate layer +21 formed in the above.The function of the intermediate layer used here has already been described, but the necessary conditions for making it function as such are as follows. It is necessary that magnetic saturation does not occur in the intermediate layer itself.Therefore, the material must have high magnetic permeability, such as the Mnzfl ferrite mentioned above.

Magnetic properties with low coercive force are required. Other magnetic materials having such properties include Ni--Zn ferrite films, Hermalloy films, Sendust films, and amorphous alloy films, all of which can achieve similar effects.

The Ba ferrite coating film used as the recording layer fil.

Superior durability compared to metal thin films such as co-Cr0
Regarding the embodiment of the invention shown in FIG.

In a sliding test on a head for a flexible disk device, the number of durable sliding times is several times to several tens of times that of a conventional Co--Cr metal film.

〔Effect of the invention〕

As described above, according to the present invention, the recording layer is formed of a coating film containing ferrite as a main component.

A magnetic recording medium with sufficient magnetic properties and durability for practical use can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a magnetic recording medium according to an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram for explaining the principle of perpendicular recording. In the figure, (1) is a recording layer, (21 is an intermediate layer, (3) is a substrate, (4) is a main magnetic pole of a perpendicular recording head, (51 is a reinforcing core, and (6) is a coil.

Claims (1)

[Claims] An intermediate layer mainly composed of a high magnetic permeability and low coercive force material is formed on a substrate made of a polymeric substance or a nonmagnetic metal, and a high coercive force ferrite having perpendicular magnetic anisotropy is further formed on the intermediate layer. A magnetic recording medium characterized in that a recording layer as a component is formed by coating.