JPH0520603A - Magnetic recording / reproducing system - Google Patents

Abstract

(57) [Summary] [Structure] A ring having a high saturation magnetic flux density material only on one side of a gap portion when recording a magnetic recording medium having substantially one-way oblique magnetic anisotropy with respect to a film surface. Recording / reproduction is performed by moving the head in the forward direction with the gap edge on the high saturation magnetic flux density material side of the head as the head. [Effect] The magnetic characteristics can be significantly improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing system. More specifically, the present invention relates to a magnetic recording / reproducing system capable of realizing excellent magnetic characteristics in an oblique magnetic anisotropic recording medium.

[0002]

2. Description of the Related Art With the development of the information society, demands for large capacity and high density are remarkably increasing in the field of recording technology. Under such circumstances, rapid technical improvements are being made in various fields such as optical recording and semiconductor memory. This movement is similar in the field of magnetic recording,
Recently, by shifting from the conventional magnetic powder coating type recording medium to a thin film type medium such as a metal film, an attempt has been made to further increase the density, and some of them have already been put into practical use. Especially in the field of image recording,
It is expected that digitalization will progress rapidly, and there is a strong demand for the development of higher-density recording technology for magnetic tape and the like.

Against this background, recently, an oblique magnetic anisotropic thin film (Metal-Evaporated tape, abbreviated as ME tape) obtained by obliquely depositing a Co-Ni alloy on a base film surface is used for a high band 8 mm VTR. It was developed as a tape and has already been commercialized. This material is excellent in high-density recording performance and is one of the most excellent recording medium materials developed so far in terms of performance.

Generally, as a magnetic head for recording / reproducing an ME tape, a so-called Metal-In having a high saturation magnetic flux density sendust and a Co-based amorphous sputtered film provided at both ends of a gap portion.
-A Gap (MIG for short) type ring head is used. However, even if such a magnetic head and obliquely vapor-deposited tape (ME tape) are combined, it is difficult to realize recording characteristics that can sufficiently follow future high definition image quality and digitization.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the drawbacks of the prior art and to provide a magnetic recording / reproducing system capable of exhibiting excellent recording characteristics in an oblique magnetic anisotropic recording medium. To do.

[0006]

In order to achieve the above object, in the present invention, when recording a magnetic recording medium having substantially one-way oblique magnetic anisotropy with respect to a film surface, Recording / reproducing is performed by causing the gap edge on the high saturation magnetic flux density material side of the ring head equipped with the high saturation magnetic flux density material only on one side to be the leading end and traveling in the forward direction with respect to the oblique magnetic anisotropic recording medium. A characteristic magnetic recording / reproducing system is provided.

[0007]

As described above, in the magnetic recording / reproducing system of the present invention, the ring head having the high saturation magnetic flux density material only on one side of the gap portion (hereinafter referred to as "one side MIG head").
High saturation magnetic flux density starting from the gap edge on the material side,
Excellent forward S / N ratio and magnetic properties are achieved by running the magnetic recording medium in an oblique direction in the forward direction.

As described above, there is still no accurate mechanism that the magnetic characteristics are improved when the gap edge on the high saturation magnetic flux density material side of the one-sided MIG head is used as the leading edge and the magnetic characteristics are improved by running in the forward direction with respect to the oblique magnetic anisotropic recording medium. Since it has not been clarified, it does not come out of the speculation range. However, as shown in FIG. 1A, when recording and writing from the upper side of the magnetic anisotropy principal axis azimuth 4 at the high saturation magnetic flux density material side edge 2, Since the low-saturation magnetic flux density material side edge 1 passes only at the lower part of the magnetic anisotropy principal axis direction 4, the previously written information is not demagnetized much and remains as it is, and the recording magnetization remaining after passing through the head. Is expected to grow. On the other hand, as shown in FIG. 1B, when the gap edge on the high saturation magnetic flux density material side of the ring head is set as the head and the magnetic recording medium is run in the opposite direction to the oblique magnetic anisotropic recording medium, the head edge 2 Recording layer 3
Is strongly and deeply recorded in the direction close to the hard axis of magnetization, but no large residual magnetization remains because it is close to the hard axis. afterwards,
Even if the trailing edge made of a low saturation magnetic flux density material passes through, it is considered that only weak recording magnetization remains because the vector magnetic field generated here is weak.

In order to obtain the intended effect of the present invention, it is necessary that the saturation density difference between the low saturation magnetic flux density material side and the high saturation magnetic flux density material side of the ring head is at least 1.2 times or more. As a practical level, it is preferable that there is a difference of 1.4 times or more. The difference in saturation density is large, but the effect saturates at about 10,000 G, so
Any further difference will simply be uneconomical.

The constituent material of the one-sided MIG head used in the present invention is, for example, Mn-
Examples include Zn ferrite, Ni—Zn ferrite, and amorphous alloys rich in nonmagnetic elements. On the other hand, as materials for high saturation magnetic flux density side, permalloy, sendust,
Examples thereof include Fe-Si, Fe, Fe-Co, Fe-C, and Co-based amorphous alloys, or nitride multilayer films of such alloys. A method for manufacturing the one-sided MIG head of the present invention using such a material is well known to those skilled in the art, and thus it is not necessary to specifically describe it.

Further, by recording the oblique magnetic anisotropic recording film as described above in the forward direction by the one-sided MIG head,
In order to realize excellent recording characteristics, it is preferable that the substantial direction of the principal axis of the oblique magnetic anisotropy rises from the film surface by 10 to 80 degrees. If the rising angle is less than 10 degrees, the recording mode of perpendicular magnetization, which is excellent in high-density recording performance, cannot be utilized in principle, and sufficient high-density recording performance cannot be obtained. On the other hand, when the rising angle exceeds 80 degrees, the recording / reproducing characteristics almost the same as those of the so-called double-sided MIG head in which high saturation magnetic flux density materials are provided at both ends are obtained, and saturated recording is difficult in any case, and remarkable recording characteristics are obtained. No improvement is seen.

By combining the diagonal magnetic anisotropic recording film 3 and the one-sided MIG head 1, recording and reproduction can be performed by one head while maintaining the relative positional relationship shown in FIG. 1 (a). If only the arrangement shown in FIG. 1A is performed and the signal reproduction is performed by another magnetic head, for example, a magnetoresistive head (MR head), the recording / reproducing characteristics are further improved. However, this recording / reproducing method is expensive.

The recording medium may be a recording film having an oblique magnetic anisotropy substantially unidirectional with respect to the film surface, and such a film is made of Fe, Co, Ni or an alloy containing them as a main component. Can be formed by obliquely incident and depositing on the substrate surface. An example of the manufacturing apparatus is shown in FIG.
, (B).

FIG. 2 (a) is a schematic view of a batch vapor deposition apparatus for oblique vapor deposition, in which a vapor flow from an evaporation source 6 is obliquely incident on a substrate 5. Fig. 2 (b)
Is a roll-up type vapor deposition apparatus for producing a long tape and realizes oblique vapor deposition by adjusting the position of the mask 12. Although an example of a vapor deposition apparatus is shown here, even in the case of another thin film forming method such as ion plating or sputtering, if a metal atom is obliquely incident on the substrate, an oblique magnetic anisotropic film is obtained. I was able to. In order to improve the magnetic and mechanical properties of the film, oxygen,
The film formation may be performed while introducing nitrogen, an inert gas or a mixed gas thereof.

The oblique magnetic anisotropic recording film that can be used in the present invention is not limited to the above-mentioned metal-based thin film, but a medium in which magnetic fine particles are dispersed in a binder and coated on a substrate (so-called coating type medium). May be As the magnetic fine particles used, γ-Fe ₂ O ₃ , Fe ₃ O ₄ , Co deposited γ-
Needle-like particles such as Fe ₂ O ₃ , Fe, and Fe alloy can be used.

In the case of the former acicular particles, the main magnetic anisotropy is due to the shape anisotropy, and in order to have the oblique magnetic anisotropy with such a material, the structure shown in FIG. As shown in the schematic sectional view, the acicular particles may be oriented substantially obliquely with respect to the substrate surface. In this case, the particles do not necessarily have to be uniformly oriented obliquely with respect to the film thickness direction, and the effect of the present invention is exhibited if the oblique magnetic anisotropy is exhibited on the average of the entire film.

In the case of the latter plate-like particles, the magnetic anisotropy generally depends on the crystal magnetic anisotropy. Therefore, the oblique magnetic anisotropic film should be formed by appropriately adjusting the orientation direction of the crystal main axis. You can

[0018]

EXAMPLES The present invention will be illustrated by the following examples. Example 1 Using a PET (polyethylene terephthalate) film having a thickness of 9 μm as the substrate 5, the Co—Ni alloy 6 was vapor-deposited by using the winding vapor deposition apparatus shown in FIG. In addition, by introducing oxygen gas through the gas introduction hole 8 during vapor deposition, the magnetic characteristics and mechanical characteristics were improved. The principal axis of magnetic anisotropy of the Co—Ni—O film thus produced stood on average about 35 degrees above the film surface as shown in FIG. The anisotropic principal axis azimuth θ was obtained from the torque curve corrected for demagnetization. The oblique magnetic anisotropy Co—Ni—O film produced in this manner was cut into a 1/2 inch tape, and the recording characteristics were measured with a drum tester. The magnetic heads used in the experiment were the ferrite head, MIG head, and one-sided MIG head shown in Table 1. MIG and M on one side
The high saturation magnetic flux density material used for the IG head is Co-Nb.
It was a -Zr amorphous body, and its saturation magnetic flux density was 9300 gauss. On the other hand, the low saturation magnetic flux density material is Mn-Zn.
It was ferrite, and its saturation magnetic flux density was 5500 gauss.

[0019]

[Table 1] Table 1 Head No. Structure Gap length Track width A Ferrite head 0.19 μm 26 μm B MIG head 0.18 μm 26 μm C One-sided MIG head 0.19 μm 26 μm

The evaluation results are shown in Table 2. In addition, all CN
The measurement result of the ratio was based on the value of 0 dB in the forward recording of the ferrite head (head A). In the table,
C (L) of the head used is a case where the one-sided MIG head C is set to run at the head of the gap end on the high saturation magnetic flux density side and C (T) is set to the rear end.

[0021]

[Table 2]                                 Table 2                                               CN ratio (dB)             Used head     Head running direction    Recording density 10kFCI    100kFCI       A forward direction 0 0     B Forward direction +0.6 +3.5     B reverse direction -0.1 -1.7   C (L) forward direction +2.7 +6.4   C (L) reverse direction −0.5 −2.3   C (T) Forward +0.5 +1.6

Example 2 Three kinds of recording layers were formed on a polyimide film substrate having a thickness of 10 μm by a vacuum vapor deposition method. Table 3 below summarizes their configurations and the inclination θ of the principal axis of magnetic anisotropy. In addition, only the medium a in the table was manufactured under the condition of oblique incidence, and the other medium was assumed to be perpendicular incidence.

[0023]

[Table 3]                                 Table 3                                                         Magnetic anisotropy principal axis Sample name   Recording layer  Underlayer  Slope of θ (degrees)   Medium a 0.2 μm thick Co—Cr layer --- 65 Medium b 0.2 μm thick Co—Cr layer 0.03 μm thick Ti layer 90 Medium c 0.2 μm thick Co—Cr layer 0.10 μm thick Cr layer 0

The recording characteristics of each of the above media were evaluated. The same recording method as that used in Example 1 was used for the evaluation of recording characteristics. However, a one-sided MIG head (head C) was used as the magnetic head for forward recording. Further, in any case, the gap end on the high saturation magnetic flux density side of the head is set to be the leading end. The evaluation results are summarized in Table 4 below. The CN ratio in the table is based on the CN ratio of medium a.

[0025]

[Table 4] Table 4 CN ratio of the medium 10 kFCI, CN ratio of 100 kFCI a 0 dB 0 dB b -4.7 dB -3.8 dB c +0.2 dB -10.4 dB

EXAMPLE 3 Needle-like iron fine particles having an axial ratio of 10 were dispersed in a binder to prepare PE.
It was coated on a T film substrate and dried. The orientation direction of the particles was changed by applying an external magnetic field to the coating layer before drying. The principal axis direction of the oblique magnetic anisotropy of the coating layer was measured with a torque meter in the same manner as described in Example 1. The measurement results of the recording characteristics are summarized in Table 5 below.
It should be noted that the CN ratios in the table are for MIG head (head B) and
The value when the medium of = 0 was combined was set to 0 dB, and this value was used as a reference.

[0027]

[Table 5] Table 5 Head magnetic anisotropy main axis azimuth θ (degree) 100 kFCI CN ratio B 0 0 dB 15 +0.5 dB 60 +0.2 dB C (L) 0 +0.1 dB 15 +4.3 dB 60 +2.8 dB C (T) 0 ± 0.1 dB 15 +0.1 dB 60 −0.3 dB

[0028]

As described above, when recording a magnetic recording medium having a unidirectional oblique magnetic anisotropy with respect to the film surface, the edge of the one-sided MIG head on the high saturation magnetic flux density material side is used as the leading edge. By recording the recording medium by traveling in the forward direction, the recording characteristics can be greatly improved.

[Brief description of drawings]

FIG. 1A is a schematic view showing a magnetic recording / reproducing system of the present invention, and FIG. 1B shows a state in which a head is run in a reverse direction to a recording medium for recording / reproducing, unlike the present invention. It is a schematic diagram which shows.

FIG. 2 (a) is a schematic cross-sectional view of an example of a batch-type vacuum vapor deposition apparatus used for producing a magnetic recording medium suitable for the magnetic recording / reproducing system of the present invention, and (b) is a magnetic recording medium of the present invention. FIG. 3 is a schematic cross-sectional view of an example of a continuous vacuum vapor deposition device used for producing a magnetic recording medium suitable for a recording / reproducing system.

FIG. 3 is a schematic cross-sectional view showing a state in which acicular magnetic particles are oriented obliquely with respect to the substrate surface.

FIG. 4 is a conceptual diagram showing the direction of the magnetic anisotropy principal axis of the Co—Ni—O film manufactured in Example 1.

[Explanation of symbols]

1 Low saturation magnetic flux density material side of MIG head 2 High saturation magnetic flux density material side of MIG head 3 Oblique magnetic anisotropic recording film 4 Magnetic anisotropy principal axis direction 5 substrates 7 electron gun 8 Variable leak valve 9 exhaust holes 10 rolls 11 can roll 13 Needle-like magnetic particles 14 binder 15 substrates

Claims (3)

[Claims] 1. When recording a magnetic recording medium having an oblique magnetic anisotropy substantially unidirectional with respect to a film surface, a high saturation of a ring head including a high saturation magnetic flux density material on only one side of a gap portion. A magnetic recording / reproducing system characterized in that the gap edge on the magnetic flux density material side is set as a head, and the recording and / or reproduction is performed by traveling in a forward direction with respect to the oblique magnetic anisotropic recording medium. 2. The magnetic recording / reproducing system according to claim 1, wherein the gap edge on the high saturation magnetic flux density material side has a saturation magnetic flux density intensity difference of at least 1.2 times or more that of the other gap edge. 3. The magnetic recording / reproducing system according to claim 1, wherein the substantial direction of the principal axis of magnetic anisotropy rises from the film surface by 10 to 80 °.