JPH04351701A - Magnetic recording method for magnetic recording medium - Google Patents

Abstract

PURPOSE:To furthermore improve the recording and reproducing characteristic of a magnetic recording medium having an oblique anisotropy superior in high- density recording and reproducing characteristic. CONSTITUTION:A ring type magnetic head is used to record information on a magnetic recording medium which has an axis 4 of easy magnetization in the direction inclined to a substrate normal 3 on a nonmagnetic substrate 1. In this case, the saturation magnetic flux density of magnetic materials forming a trailing edge 5 of the ring type magnetic head is made higher than that forming a leading edge 6, and the direction of an arrow 11 of relative movement of the ring type magnetic head to the magnetic recording medium is so set that the inclination direction of a head magnetic field 9 in the vicinity of the trailing edge 5 of the ring type magnetic head approximately coincides with the direction of the axis 4 of easy magnetization of the magnetic recording medium.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for magnetic recording on a magnetic recording medium having excellent high-density recording and reproducing characteristics.

0002

[Background Art] At present, magnetic recording and reproducing devices are becoming smaller and more densely packed. There are diagonally anisotropic media that have an axis of easy magnetization in a direction oblique to the line. This improves high-density characteristics by utilizing a recording magnetization component perpendicular to the substrate surface.

Currently, as such a magnetic recording medium, Co
-Metal thin film media mainly composed of -Ni-O have been put into practical use as magnetic tapes for VTRs, and coated metal tapes that previously had in-plane magnetic anisotropy have also been used.
A technique for orienting acicular magnetic fine particles obliquely to the substrate surface has been established, and efforts are being made to put it into practical use as an obliquely anisotropic medium. In addition, even in perpendicular magnetic recording media whose main components are Co-Cr, Co-O, etc., which are attracting attention as next-generation high-density magnetic recording media, recording and reproduction in combination with a ring-type magnetic head can be performed in the in-plane direction. It is known that the recording and reproducing characteristics are significantly improved by the contribution of the recording magnetization component, and development as an obliquely anisotropic medium using an oblique evaporation method is also progressing.

When recording on a diagonally anisotropic medium using a ring-shaped magnetic head, the recording and reproducing characteristics differ depending on the direction of relative movement between the magnetic recording medium and the magnetic head. In the Co-Ni-O oblique vapor deposition tape called ME tape that is currently in practical use, the direction of relative movement between the magnetic recording medium and the magnetic head is set at the leading edge 6 of the ring-shaped magnetic head, as shown in FIG. Recording is performed with the direction of inclination of the nearby head magnetic field 9 substantially coinciding with the direction of the easy axis of magnetization 4 of the magnetic recording medium. On the contrary, the direction 11 of the relative movement between the magnetic head and the magnetic recording medium is such that, as shown in FIG. If recording is performed in a direction that substantially coincides with the four directions, the high-density characteristics will be significantly degraded.

[0005] The reason for this is thought to be as follows. Figure 4
In the case of the arrangement shown in , since the direction of inclination of the axis of easy magnetization 4 almost coincides with the direction of inclination of the head magnetic field 9 near the trailing edge 5, magnetization reversal is mainly determined on the trailing side of the head magnetic field 9. considered to be a thing. For this reason, the recorded magnetization 10 at a certain point in time is subjected to a strong demagnetizing effect by the subsequent reversal magnetic field on the trailing side, and the reproduction output in the short wavelength recording region is reduced. On the other hand, in the case of the arrangement shown in FIG. 3, the direction of inclination of the axis of easy magnetization 4 almost coincides with the direction of inclination of the head magnetic field 9 near the leading edge 6, and the direction of inclination of the head magnetic field 9 near the trailing edge 5 corresponds to the direction of inclination of the magnetic field 9 near the trailing edge 5. Difficulty close to the axial direction. In other words, the recorded magnetization 10 caused by the head magnetic field 9 near the leading edge 6 is less susceptible to the demagnetizing effect caused by the head magnetic field 9 on the trailing side, and is therefore considered to have excellent high-density characteristics.

In FIGS. 3 and 4, 1 is a nonmagnetic substrate, 2 is a magnetic layer, 3 is a normal line to the substrate, and 8 is a metal magnetic film. Formed on both ring sides.

[0007]

However, in the long wavelength recording region, in recording and reproducing with the configuration shown in FIG. 4, a reproduction output equal to or higher than that with the configuration shown in FIG. 3 can be obtained. This is thought to be because the recording magnetization mode approaches longitudinal recording as the wavelength becomes longer. That is, even in the configuration shown in FIG. 3, magnetization reversal is determined at a portion of the head magnetic field 9 close to the gap center line 7, and the vertical component of the recording magnetization 10 due to the head magnetic field 9 on the leading side is determined by the head magnetic field 9 on the trailing side. It is easy to cancel out with 9. In cases similar to in-plane recording, recording with the configuration shown in Figure 4 has better recording efficiency, and in long wavelength recording, the influence of recording demagnetization is reduced, so high reproduction output can be obtained. considered to be a thing. From the above, it is highly likely that the current magnetic recording method with the configuration shown in FIG. 3 is unable to fully demonstrate the performance of the obliquely anisotropic medium, especially in the long wavelength region.

The present invention solves the above-mentioned problems, and aims to provide a method for magnetic recording on a magnetic recording medium that improves the recording and reproducing characteristics of an obliquely anisotropic medium.

[0009]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the magnetic recording method for a magnetic recording medium of the present invention includes a magnetic recording medium having an easy axis of magnetization on a non-magnetic substrate in a direction inclined with respect to the normal line of the substrate. When recording on a recording medium using a ring-shaped magnetic head, the saturation magnetic flux density of the magnetic material forming the trailing edge of the ring-shaped magnetic head is greater than the saturation magnetic flux density of the magnetic material forming the leading edge, and The direction of relative movement between the recording medium and the ring-shaped magnetic head is such that the direction of inclination of the head magnetic field near the trailing edge of the ring-shaped magnetic head substantially coincides with the direction of the easy axis of magnetization of the magnetic recording medium. be.

0010

[Operation] With the above configuration, the head magnetic field becomes asymmetrical with respect to the gap center line, and the head magnetic field near the trailing edge, which is considered to mainly determine magnetization reversal, has a relatively large vertical component. Therefore, in the long wavelength recording region, high reproduction output can be obtained due to the contribution of the recording magnetization component in the perpendicular direction. Furthermore, in the short wavelength recording region, the perpendicular component of the recorded magnetization further increases, thereby suppressing the demagnetizing effect, and it is possible to obtain a reproduction output equal to or higher than that of conventional magnetic recording methods.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. An embodiment of the present invention is shown in FIG. Note that the same members as those in the prior art are given the same reference numerals, and their explanations will be omitted.

As shown in FIG. 1, a ring-type magnetic head,
For example, in a metal-in-gap type magnetic head (hereinafter referred to as an MIG head) in which a metal magnetic film 8 having a high saturation magnetic flux density is formed in the gap portion of a ferrite head, the metal magnetic film 8 is formed only on the trailing side. ing. In other words, the metal magnetic film 8 is usually formed on both the leading side and the trailing side with the head gap as the boundary (
Hereinafter, both MIGs with metal magnetic films 8 formed on both sides will be described.
In both of these MIG heads, a head magnetic field that is axisymmetric with respect to the gap center line 7 can be obtained, but in this embodiment, the metal magnetic film 8 is formed only on the trailing side (hereinafter referred to as head). , this is referred to as a single MIG head), thereby obtaining a ring-shaped magnetic head in which the saturation magnetic flux density of the ferrite on the trailing side is greater than the saturation magnetic flux density of the ferrite on the leading side.

As magnetic recording media, in addition to ME tape, which has already been put into practical use, and coated metal tape in which acicular magnetic fine particles are oriented obliquely to the substrate surface, Co--Cr,
Substrate normal 3
The effects of the present invention can be obtained significantly if the magnetic recording medium has the axis of easy magnetization 4 in a direction inclined to the magnetic recording medium. Furthermore, the method of the present invention is effective even when an underlayer is provided between the non-magnetic substrate 1 and the magnetic layer 2, or an intermediate layer is provided between the magnetic layers 2 consisting of multiple layers, if necessary. be.

Below, as an embodiment of the present invention, the results of recording and reproducing on a Co--O obliquely deposited tape using an MIG head having a sendust film as the metal magnetic film 8 will be described in comparison with a conventional example.

(Example 1) The above configuration (configuration shown in FIG. 1)
The recording density characteristics of the Co--O obliquely evaporated tape were measured using a Sendust piece MIG head. Sendust piece M
The IG head had a gap length of 0.22 μm and a track width of 15 μm. Leading edge 6 of this head
The saturation magnetic flux density of the ferrite that forms is 5000 Gau
ss, the saturation magnetic flux density of the sendust film forming the trailing edge 5 is 11000 Gauss. Co-O
The oblique vapor deposition tape has a Co--O film (magnetic layer 2) formed on a polymer substrate 1 with a thickness of 10 μm by reactive vapor deposition. The Co-O film has a saturation magnetization of 620 emu/cc and a film thickness of 200 nm. As Comparative Example 1, measurements were also conducted using the configuration shown in FIG. 2 in which the direction of relative movement of the sendust piece MIG head with respect to the medium was reversed.

As a conventional example, the recording density characteristics of the same Co--O obliquely evaporated tape were measured using a Sendust dual MIG head with the configuration shown in FIG. 3, and compared with Example 1 and Comparative Example 1 described above. The gap length, track width, number of windings, and saturation magnetic flux densities of the ferrite and Sendust of this Sendust MIG head are all the same as the Sendust single MIG head described above. Furthermore, as Comparative Example 2, measurements were also performed on a configuration shown in FIG. 4 in which the relative movement directions of both Sendust MIG heads with respect to the medium were reversed in the conventional example.

The measurement results are shown in FIG. It can be seen that the reproduction output according to the first embodiment (indicated by the solid line) is significantly improved over the reproduction output according to the conventional example (indicated by the broken line), especially in the long wavelength recording region. Here, the reason why the reproduction output according to the configuration of Example 1 is higher than that of Comparative Example 1 in the long wavelength region is because
This is thought to be due to the same reason as the phenomenon in which the reproduction output in the long wavelength region of Comparative Example 2 is higher than that of the conventional example. However, in the short wavelength region, the output of Comparative Example 2 is significantly lower than that of the conventional example, whereas the reproduction output of the configuration of Example 1 is slightly lower than that of Comparative Example 1. It's nothing more than that. This is thought to be largely due to the fact that in the short wavelength recording region, the perpendicular component of recorded magnetization further increases, thereby suppressing the demagnetizing effect. Therefore, it is clear that Comparative Example 1 also has superiority over the conventional example, but when considering the S/N in the practical band, the configuration of Example 1 is the most superior.

(Example 2) From the measurement results shown in FIG. 5, by further reducing the gap length of the magnetic head in the configuration of Example 1, the low-frequency output was reduced to the same level as the conventional example, and the low-frequency output was further reduced. It is presumed that there is a high possibility that the reproduction output in the recording density area can be improved. Therefore, the same measurements as in Example 1 were carried out using a Sendust head with a gap length of 0.18 μm, and the recording density characteristics were compared with the conventional example of Example 1 (Sendust MIG head with a gap length of 0.22 μm). (measured data). The specifications and measurement conditions of the magnetic head and magnetic recording medium were the same as in Example 1, except that the gap length of the head was changed.

The measurement results are shown in FIG. By reducing the gap length, the superiority over the conventional example in the long wavelength recording region is smaller than in Example 1. On the other hand, in the short wavelength recording region, significant superiority over the conventional example, which was not observed in Example 1, was confirmed due to the reduction in gap loss. That is, in a magnetic recording system that already has sufficient low-frequency output, the high-density characteristics can be significantly improved by reducing the gap length in the magnetic recording method of the present invention.

The above are the measurement results obtained by self-recording and reproducing. However, even when another head was used as the reproducing head and the recording and reproducing separation was performed, the same effect as in the above experimental example was confirmed. In addition, ME tape, Co-Cr oblique vapor deposition tape, etc.
The same effects as in the above experimental example were sufficiently obtained for other diagonally anisotropic media.

[0021]

As described above, according to the present invention, when recording using a ring-shaped magnetic head on a magnetic recording medium having an axis of easy magnetization on a non-magnetic substrate in a direction inclined with respect to the normal line of the substrate, The saturation magnetic flux density of the magnetic material forming the trailing edge of the ring-shaped magnetic head is greater than the saturation magnetic flux density of the magnetic material forming the leading edge, and the direction of relative movement of the ring-shaped magnetic head with respect to the magnetic recording medium is , the direction of inclination of the head magnetic field in the vicinity of the trailing edge of the ring-shaped magnetic head is oriented almost in the same direction as the direction of the easy axis of magnetization of the magnetic recording medium, so that the axis of easy magnetization is set in a direction inclined with respect to the normal line of the substrate. It is possible to fully demonstrate the performance of the obliquely anisotropic medium having the following characteristics, and further improve its excellent high-density recording and reproducing characteristics.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of a magnetic recording method for a magnetic recording medium according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing the configuration of Comparative Example 1 of a magnetic recording method for a magnetic recording medium.

FIG. 3 is a schematic diagram showing an example of the configuration of a conventional magnetic recording method for a magnetic recording medium.

FIG. 4 is a schematic diagram showing the configuration of Comparative Example 2 of a magnetic recording method on a magnetic recording medium.

FIG. 5 is a diagram showing recording density characteristics of Example 1, Comparative Examples 1 and 2, and a conventional example.

FIG. 6 is a diagram showing recording density characteristics of Example 2 and a conventional example.

[Explanation of symbols]

1 Nonmagnetic substrate 2 Magnetic layer 3 Substrate normal 4 Axis of easy magnetization 5 Trailing edge 6 Leading edge 7 Center line of head gap 8
Metal magnetic film 9 Head magnetic field 11 Direction of relative movement

Claims (1)

[Claims] 1. When a ring-shaped magnetic head is used to record on a magnetic recording medium having an axis of easy magnetization in a direction inclined to the normal to the substrate on a non-magnetic substrate, the trailing edge of the ring-shaped magnetic head is The trailing edge of the ring-shaped magnetic head is set such that the saturation magnetic flux density of the magnetic material forming the leading edge is greater than the saturation magnetic flux density of the magnetic material forming the leading edge, and the direction of relative movement of the ring-shaped magnetic head with respect to the magnetic recording medium is set at the trailing edge of the ring-shaped magnetic head. A magnetic recording method for a magnetic recording medium in which the direction of inclination of a nearby head magnetic field substantially coincides with the direction of the easy axis of magnetization of the magnetic recording medium.