JPS615423A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To reduce leakage flux and to improve S/N by laminating a nonmagnetic thin film and a soft magnetic thin film while winding a high molecular substrate in the normal direction, rewinding in the reverse direction, repeating said process, and then forming a vertical magnetic film. CONSTITUTION:A nonmagnetic thin film 11 and a soft magnetic thin film 10 are firstly laminated while winding a high molecular substrate 8 in the normal direction, and the substrate 8 is then rewound in the reverse direction to laminate again the nonmagnetic thin film 11 and the soft magnetic thin film 10 thereon. The process is repeated as desired, and then a vertical magnetic film 12 is formed. The magnetic recording medium thus obtained is a vertical recording medium consisting of a multilayered body with the soft magnetic layer 10 having a Neel wall, has a satisfactory S/N in the shortwave region, and is capable of contributing to the realization of high-density recording.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium suitable for high-density magnetic recording.

Conventional Structures and Problems The perpendicular magnetic recording system is attracting attention because the recording direction is perpendicular to the medium surface and is advantageous for high-density recording.

At present, from the standpoint of recording sensitivity alone, the combination of a two-layer medium and an auxiliary pole excitation type perpendicular head, as shown in FIG. 1, is considered to be the most excellent.

That is, the soft magnetic layer 2 and the perpendicularly magnetized film 3 on the polymer substrate 1
Layered medium, main magnetic pole 4, auxiliary magnetic pole 6, excitation coil 6
The head consists of a head that creates a steep magnetic field distribution in the thickness direction,
The residual magnetization is utilized to reproduce the residual magnetization by arranging elementary magnets facing each other perpendicularly to the thickness direction. 7 schematically shows the path of magnetic flux.

Although this method shows a significant improvement in recording sensitivity,
Because the noise that causes problems during recording and playback is not necessarily sufficient,
Since the required signal-to-noise (S/N) ratio cannot be obtained, improvements are desired.

OBJECTS OF THE INVENTION The present invention was made in view of the above circumstances, and an object of the present invention is to provide a magnetic recording medium with improved fs/H for recording and reproduction in a short wavelength region.

Structure of the Invention The magnetic recording medium of the present invention is characterized in that the soft magnetic layer has a multilayer structure having a Neel domain wall, and the S/N ratio at short wavelength is
is improved.

Description of examples The present invention will be described below with reference to the drawings.

FIG. 2 shows an example of the magnetic recording medium of the present invention.

In Fig. 2, 8 is a polymer substrate, 9 is a soft magnetic layer with a laminated structure of a soft magnetic thin film 1Q and a non-magnetic thin film 11, 12 is a perpendicular magnetization film, and a protective film, running auxiliary coating layer, etc. are added as necessary. will be arranged.

゛ The polymer substrate that can be used in the present invention is polyester such as polyethylene terephthalate.

Cellulose derivatives such as nitrocellulose, polyether sulfone, polyamideimide, polyimide, etc.
It also includes those with an undercoat layer.

Soft magnetic thin films that can be used in the present invention include Ni-Fe and Ni-Fe-Mo having a Neel domain wall.

N1-Fe-Go, Ni-Fe-Zn, Ni-
Mn-B1゜Ni-Ti-Zr, etc., and the non-magnetic thin film is a vacuum-deposited film of metal, semimetal, oxide, nitride, organic substance, etc.
These include sputtering films, glow polymerization films, etc. Perpendicular magnetization films include Go-Or, Go-Ti, Go-V, and G.
O-W.

These include Go-Mo, Qo-o, Go-Ni-Cr, and the like.

From the manufacturing point of view, the fewer the number of laminated layers, the better. It is preferable to laminate it with a non-magnetic thin film.

In the present invention, since the rotation of magnetic spins within the domain wall is performed in-plane, the magnetic flux leaking during reproduction after recording is substantially reduced, and it is thought that the S/N ratio is improved. - A more specific example will be described below.

〔Example〕

This was carried out using a winding vapor deposition machine. The winding evaporation machine used had two cylindrical cans with a diameter of 50 cnt, and a 27° deflection type electron beam evaporation source was placed directly below each can, and winding was performed in the forward and reverse directions. It can be wound in both directions.

While winding the polymer substrate in the forward direction, first layer a non-magnetic thin film and a soft magnetic thin film, then rewind it in the opposite direction and layer the non-magnetic thin film and soft magnetic thin film on top of it again in the same procedure. , 3. Laminated as many layers as needed in the same manner. ) A perpendicular magnetization film was formed.

Each magnetic tape was recorded and reproduced using an auxiliary pole excitation type head with a main pole thickness of 0.2 pm, and the S/Ni was compared.

Comparison was made at a recording wavelength of 0.4 μm.

The comparative tape used was one formed by the permalloy thinning spuntering method.

The main manufacturing conditions and measurement results are listed in the following table.

In the present invention, the type of domain wall is considered to be a Neel domain wall until a Bloch domain wall is clearly identified.

The substrate film used was polyimide with a thickness of 15 μm.

(The following is a blank space) From the above results, it can be seen that the magnetic recording medium of the present invention has an extremely good S/N ratio at short wavelengths.

Similar effects were confirmed with combinations of the other materials mentioned above, and excellent S/N ratios were also obtained in the form of disks and sheets other than tape.

Effects of the Invention The magnetic recording medium of the present invention is a perpendicular recording medium consisting of a multilayer structure in which the soft magnetic layer has a Neel domain wall, and has good S/Ni in a short wavelength region, making it suitable for practical use in high-density recording. It is something that contributes.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional perpendicular recording medium, and FIG. 2 is a cross-sectional view of the magnetic recording medium of the present invention. 8...Polymer substrate, 10...Soft magnetic thin film (Nel domain wall), 11...Nonmagnetic thin film, 12...
...Perpendicular magnetization film. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] 1. A magnetic recording medium comprising a laminated structure of a soft magnetic layer and a perpendicular magnetization film, wherein the soft magnetic layer has a multilayer structure having a Neel domain wall.