JPH0589403A - Magnetic recording method - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording system having high recording density because electromagnetic transducing characteristics are not deteriorated even by increasing recording density. CONSTITUTION:In a magnetic recording system by which recording and reproduction are carried out on a magnetic recording disk with a magnetic head, the direction of magnetization for recording is allowed to coincide with a radial direction (direction perpendicular to a track).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording method for a magnetic recording medium for high density recording mounted on a magnetic disk used as a magnetic memory in an external storage device (magnetic disk device) such as a computer. Is.

[0002]

2. Description of the Related Art Conventionally, tapes coated with magnetic powder have been widely used as storage media for computers and the like.
However, this storage tape method has drawbacks such as low storage density and long access time. For this reason, recently, a disk-shaped magnetic disk capable of random access has been widely used, and among them, a magnetic disk using an aluminum alloy or the like as a substrate, a so-called hard disk is used.

This magnetic disk generally has a thickness of 2 mm.
The magnetic layer is generally formed by forming a magnetic layer having a thickness of about 1 μm on a substrate having a hardness of about 1 μm.
A magnetic powder such as —Fe ₂ O ₃ mixed with a binder and applied on a disk substrate by a method such as a spin coat has been used. However, in this method, there is a limit to the magnitude of saturation magnetization, and it has almost reached the limit as a high density recording magnetic medium. Therefore, recently, cobalt (Co), cobalt-nickel (Co-Ni), cobalt-platinum (Co-Pt), which have higher saturation magnetization,
Vacuum deposition of metal or alloy such as cobalt-rhenium (Co-Re), samarium-cobalt (Sm-Co),
Those formed on a disk substrate or an underlayer formed on the substrate by a vacuum film forming technique such as sputtering, and in addition to these, cobalt-phosphorus (Co-P), cobalt-nickel-phosphorus (Co- Ni-P) and other alloy thin films formed by a wet method such as electroless plating have begun to be used.

On the other hand, the magnetic recording method generally used at present is called an in-plane magnetic recording method, and the direction of the recorded magnetization is the circumferential direction (parallel to the track).

[0005]

As described above, when a metal or an alloy having a larger saturation magnetization is used as the recording layer of the magnetic recording medium, in the current longitudinal magnetic recording method, the direction of the magnetization recorded. Since the magnetic field is in the circumferential direction (parallel to the track), the demagnetizing field in the bit increases as the recording density is increased, and the electromagnetic conversion characteristics in the high recording density region deteriorate rapidly, resulting in high recording density. It becomes difficult to obtain high electromagnetic conversion characteristics in the part.

[0006]

In view of the above situation, the inventors of the present invention have made earnest studies, and as a result, if the direction of magnetization to be recorded is the radial direction (direction perpendicular to the track), the recording density is The inventors have found that the electromagnetic conversion characteristics do not deteriorate even if the value is increased, and completed the present invention.

That is, the present invention relates to a magnetic recording method for recording / reproducing on / from a magnetic recording disk using a magnetic head, wherein the direction of the recorded magnetization is in the radial direction. ..

The present invention will be described in detail below.

The magnetization pattern obtained by the method of the present invention is shown in FIG. The present invention is characterized in that the direction of the recording magnetization 3 is the radial direction (direction perpendicular to the track 2).
It is considered that the reason why the electromagnetic conversion characteristics are improved by the present invention is that the demagnetizing field in the bit becomes smaller and the bit exists more stably when the recording pattern has a higher recording density by making the magnetization pattern in the radial direction. But the details are still unclear.

In the conventional magnetic recording method, the thinner the magnetic recording layer, the better the characteristics. However, in the magnetic recording method of the present invention, if the magnetic recording layer is extremely thin, the recording / reproducing characteristics may deteriorate. The reason for this is considered as follows.
That is, in the present invention, since the direction of recording magnetization is perpendicular to the track, it is considered that the leakage magnetic field is generated from the magnetic charge on the surface due to the Bloch domain wall. Therefore, when the magnetic recording layer is thinned, the domain wall becomes a Bloch type,
This is because it becomes a nail type in which the magnetization is inverted in the plane and the magnetization does not appear on the surface. However, such an assumption does not limit the present invention in any way.

The thickness of the magnetic recording layer of the magnetic recording disk applicable to the magnetic recording method of the present invention is preferably 500-.
5000 angstrom, more preferably 800-2
000 angstroms.

FIG. 2 shows the relationship between the magnetic head 4, the stray magnetic field 5 of the head, and the magnetic recording disk during signal writing.

At the time of writing data, the inductive head used in the conventional in-plane magnetic recording method is changed to 90.
The write magnetic field may be applied in the direction perpendicular to the track by rotating the disk once.

When reading data, a conventional inductive head can be used, but a more efficient magnetoresistive head (MR head) is more preferable.

As the magnetic recording disk to be used, a conventional coating type or metal thin film type magnetic recording disk can be used as it is.

[0016]

According to the present invention, since the direction of the recorded magnetization is the radial direction (the direction perpendicular to the track), the electromagnetic conversion characteristics are not deteriorated even if the recording density is increased. Magnetic recording system of
Its industrial value is high.

[0017]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 As a magnetic recording disk, nickel-phosphorus (Ni-P) was used.
A 2000 Å thick chromium layer is formed on a plated aluminum substrate by a sputtering method, and a 1000 Å thick nickel layer containing 20 atomic percent nickel and 10 atomic percent chromium is deposited on the nickel layer. A chromium-cobalt (Ni-Cr-Co) alloy is formed as a magnetic recording layer by sputtering, and a thickness of 400 is further formed thereon.
An angstrom carbon film was used as a protective layer by sputtering.

The magnetic head is installed so that the recording magnetization is in the radial direction as shown in FIG. 2, g is 3 μm, and W is 10 μm.
m, and the number of turns of the coil was 30 times. As for other measurement conditions, the test radius is 3 (from the center of rotation).
0.0mm, rotation speed of magnetic recording disk is 3600RP
M, the flying height of the head was 0.15 μm.

FIG. 3 shows the recording density dependence of the reproduction output when a signal is recorded under the above conditions. For output reproduction, the gap length is 0.50 μm and the track width is 10.0.
.mu.m, the head flying height was 0.15 .mu.m, and the number of turns was 30 revolutions. The recording density D50 when the output becomes 1/2 was 85 kFCPI.

Comparative Example 1 The same magnetic recording disk as in Example 1 was used to perform recording and reproduction by a conventional in-plane magnetic recording method (the direction of recording magnetization is the circumferential direction). As a recording / reproducing condition, the test radius is 3
0.0mm, rotation speed of magnetic recording disk is 3600RP
M, the gap length of the test head was 0.50 μm, the track width was 10.0 μm, the flying height of the head was 0.15 μm, and the number of turns was 30 rotations.

FIG. 4 shows the recording density dependence of the reproduction output when a signal is recorded under the above conditions. D5 at this time
0 was 44 kFCPI.

As is apparent from FIGS. 3 and 4, by adopting the magnetic recording method in which the direction of the recorded magnetization is the radial direction (direction perpendicular to the track), the electromagnetic conversion characteristics can be obtained even if the recording density is increased. It can be seen that does not decrease.

[Brief description of drawings]

FIG. 1 is a diagram showing a magnetization pattern on a magnetic recording disk obtained by the method of the present invention.

FIG. 2 is a diagram showing a relationship between a magnetic head, a leakage magnetic field of the head, and a magnetic recording disk at the time of writing a signal.

FIG. 3 is a diagram showing recording density dependence in the magnetic recording method of the present invention.

FIG. 4 is a recording density dependence diagram in a conventional magnetic recording method.

[Explanation of symbols]

 1 ... Magnetic recording disk 2 ... Track 3 ... Recording magnetization 4 ... Magnetic head 5 ... Head leakage magnetic field 6 ... Input signal

Claims (1)

[Claims] 1. A magnetic recording method for performing recording and reproduction on a magnetic recording disk using a magnetic head, wherein the direction of magnetization to be recorded is in the radial direction of the magnetic recording disk.