JP2001143335A - Method for information reproduction, device for recording and reproducing information and information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such problem that conventional technology has a limit to control over the distribution of crystal particle sizes of an information recording magnetic film by a seed layer on a magnetic disk and very-high-density recording exceeding 40 Gb/inch2 can not be performed stably and to further improve the reproduction sensitivity for magnetooptic recording since the magnetic domain sizes abruptly become much smaller by the progress of higher density. SOLUTION: An information recording device which has at least a very small light source and an information recording medium for recording information uses a reproduction system for reproduction information recorded on an information recording medium by irradiating the information recording medium surface with the light emitted from the very small light source, modulating the frequency (or wavelength) or light intensity through optical interaction between the light before the irradiation and the light reflected by the medium surface, and detecting the modulated frequency or light intensity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording apparatus for rapidly and accurately storing a large amount of information, and more particularly to a high-performance and highly reliable recording medium for information recording. And an information recording apparatus using the recording medium.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable progress in the advanced information society, and multimedia in which various forms of information are integrated has rapidly spread. There are a magnetic disk device and an optical disk device as information recording devices supporting this.
These devices are used in fields that take advantage of their respective characteristics.

At present, in a magnetic disk drive, the recording density is increased.
It is being downsized while improving. In parallel,
The cost reduction of disk devices is rapidly progressing. Toko
In order to increase the density of magnetic disks,
1) Reducing the distance between the disk and the magnetic head 2)
Increase the coercive force of the medium;
Husband is an essential technology. Above all, magnetic recording
In media, coercive force is used to achieve high-density recording.
Is essential. In addition to this, 40 Gb / inch ^TwoOver
To achieve high-density recording, magnetization reversal
Units must be reduced. To do this,
It is necessary to reduce the size of the conductive particles, which is achieved
As a method of providing, a seed layer is provided under the magnetic film.
Proposed. One example is USP-4652499
be able to.

On the other hand, in an optical disk device that performs recording, reproduction, or erasing using a laser beam, it is effective to form a minute magnetic domain using a laser beam having a short wavelength in order to perform high-density recording. In this case, the wavelength of the laser beam becomes shorter, and the Kerr effect exhibited by the amorphous alloy of the rare earth element and the iron group element, which is the recording medium, decreases, so that the reproduction output-to-noise ratio (S / N) decreases. In some cases, stable information recording cannot be performed. To solve this problem, P that exhibits a large Kerr effect even in the short wavelength region of 400 nm or less
An artificial lattice film in which t and Co are alternately stacked has been proposed.
As an example, JP-A-1-251356 can be mentioned.
In addition, a recording method using a lens having a large aperture ratio has been proposed. Further, in the reproducing method, a reproducing method using a magnetic super-resolution method (MSR) has been proposed in addition to the reproducing method using the short wavelength light. In addition, there has been proposed a magnetic domain enlarging method in which a magnetic domain formed at the time of reproduction is enlarged to increase a reproduction signal.

[0005]

In the above prior art,
First, in a magnetic disk, there is a limit in controlling the crystal grain size distribution of an information recording magnetic film by a seed layer, and fine particles and coarse particles may coexist. These fine particles and coarse particles are
When recording information (when reversing the magnetization), it is affected by the leakage magnetic field from the surrounding magnetic particles, and conversely, for large particles, it has an ultra-high density exceeding 40 Gb / inch ² to give an interaction. When performing recording, there were cases where stable recording could not be performed. This tendency is the same in a Co—Cr-based magnetic film for perpendicular magnetic recording.

On the other hand, in the magneto-optical recording, when an artificial lattice film in which Pt and Co are alternately laminated is used as a recording film, a large Kerr rotation angle can be obtained in a short wavelength region of 400 nm or less.
The moving speed of the domain wall is high, and particularly when performing mark length recording, it causes jitter, and stable recording and reproduction cannot be performed. Further, although minute recording is possible, the resolution can be improved by the MSR method, but it is sometimes difficult to improve the reproduction signal output. In the magnetic domain expansion reproduction technology, the reproduction output can be increased by enlarging the magnetic domain at the time of reproduction.
The miniaturization of the magnetic domain size has rapidly progressed, and further improvement in the reproduction sensitivity has been desired.

Therefore, a first object of the present invention is to provide a method for reproducing a minute magnetic domain with high sensitivity. A second object of the present invention is to provide a high-performance information recording medium and an information recording device by providing a method for forming a minute magnetic domain and a method for reproducing the formed magnetic domain with high sensitivity. As described above, an object of the present invention is to provide an information reproducing method and an information recording medium suitable for performing ultra-high-density recording exceeding 40 Gb / inch ² and an information recording apparatus using them.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an information recording apparatus having at least a very small light source and an information recording medium for recording information. The frequency (or wavelength) or light intensity is modulated by optical interaction between the light after the light is reflected on the medium surface and the light before irradiation, and the modulated frequency or light intensity Can be realized by using a reproducing method for reproducing the information recorded on the information recording medium by detecting the information. Here, as a result of the optical change that occurs on the surface of the information recording medium, the frequency of the light generated due to the optical interaction with the light before irradiation
In the modulation of (or wavelength) or light intensity, it is most preferable to use a method of reproducing information in which the modulation is caused by the magneto-optical effect of the information recording medium.

As the information recording medium, it is most preferable to use a material having perpendicular magnetic anisotropy and a magneto-optical effect, and more specifically, to use an amorphous alloy of a rare earth element and an iron group element. It is. More preferably, in this medium, the magnetic layer is composed of a plurality of magnetic layers via a non-magnetic layer. In this case, one of them is a recording layer for recording information, and the other magnetic layer is a magnetic domain recorded on the recording layer at the time of reproduction is transferred to the reproducing layer, and the magnetic domain is a magnetic domain larger than the recording layer. It is particularly preferable to reproduce information by using Further, of the magnetic layers, the magnetic layer on the reproduction light irradiation side uses a material whose perpendicular magnetic anisotropy is induced by light irradiation and / or application of a magnetic field. Furthermore, when the light irradiated from the minute light source to the reproduction layer during the reproduction is reflected by the reproduction layer, the polarization plane changes to Kerr.
The rotation is effected by the effect and / or the Faraday effect, whereby the reproduction is performed using the optical interaction that occurs between the reflected light and the incident light. In that case, the frequency
It is most preferable to detect a change in (or wavelength) or a change in light intensity. By the way, the above-mentioned amorphous alloy of a rare earth element and an iron group element is used as a rare earth element as Tb, Gd, Ho.D.
It comprises at least one element selected from y and at least one element selected from Fe, Co, and Ni as iron group elements. In addition, as a nonmagnetic material, an oxide or nitride of silicon, tantalum, aluminum, titanium, or chromium is used. Further, as a very small light source, it is most effective that a minute pinhole is provided in the course of the light source, and the diameter of the pinhole is 300 nm or less.

[0010] By the way, considering the whole process from recording to reproduction of information, at least an information recording medium formed on a circular substrate, a laser light source narrowed down to a certain spot size by a lens, a micro light source, and a magnetic field are applied. Using an information recording device equipped with an electromagnet, a disk drive system, and an electric circuit, as a recording / reproducing method, a laser light source and a magnetic field narrowed down to a certain spot size by at least a lens in order to record information on a magnetic recording medium. The information is reproduced using an electromagnet for applying the information, and the reproduction of information is performed using an extremely small light source. Alternatively, reproduction of information from a magnetic recording medium may be performed using an extremely small light source and an electromagnet for applying a magnetic field. In any case, the frequency (or wavelength) of light or the intensity of the light changes as a result of the optical interaction between the light reflected from the extremely small laser light source and the light from the light source and the light from the light source. Is detected by comparing light from a light source with light that has undergone optical interaction after reflection. Here, in this reproduction method, the size of the magnetic domain of the information recorded on the information recording medium has a width measured in the moving direction of the information recording medium of 0.3.
The greatest effect is exhibited when it is less than μm.

[0011] Such a magnetic domain is formed by using at least a laser light source and a magnetic head. In this case, at least the magnetic domain formed by performing recording using the laser light source and the magnetic head has a width of the magnetic domain measured in a direction in which the information recording medium moves, the width being shorter than the magnetic gap length in the magnetic head. It is unique.
More preferably, the size of the magnetic domain of the information recorded on the recording layer of the information recording medium is most preferably 0.1 μm or less as measured in the direction in which the information recording medium moves. It is most preferable to record, reproduce, or erase various types of information using an information recording medium, an information reproducing method, and an information recording device. In particular, the information to be recorded or reproduced
It is preferably at least one of audio information, code data, image information, and control information for controlling the magnetic disk drive.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to embodiments.

[0013]

<Embodiment 1> This embodiment is directed to a case where an information recording apparatus is configured by using one magnetic film as an information recording layer. FIG. 1 shows a schematic diagram of a cross-sectional structure of the manufactured disk. First, a 3.5 ″ diameter glass substrate was used as the disk substrate (1). The substrate used here is only one example, and any size disk substrate can be used.
It goes without saying that the effects of the present invention are not affected even if a resin such as polycarbonate or amorphous polyolefin is used. Further, it is needless to say that a substrate having an uneven guide groove may be used for positioning the magnetic head or the optical head, or the uneven guide groove may be formed after forming the information recording medium. On this substrate (1), a 30 nm thick Al-Ti film was formed as a light reflection film (2). Pure Ar was used as a discharge gas and Al ₉₀ Ti ₁₀ alloy was used as a target. The sputtering pressure is 15mTorr and the input RF power is 0.5kW
/ 150mmφ. Here, no difference was found between the composition of the obtained thin film and the composition of the target.

Next, as an inorganic compound thin film (3), a silicon nitride film was formed by a sputtering method. Ar / N ₂ was used for the discharge gas, with Si as the target. The pressure during sputtering is 10 mTorr, and the input RF power is 0.7 kW / 150 mmφ.
The thickness of the formed inorganic compound thin film is 15 nm. On this film, a Tb-Fe-Co film was formed as a magnetic film (4) to a thickness of 25 nm by a sputtering method. Tb ₂₆ Fe ₆₂ Co ₁₂ prepared by hot static pressure press (HIP) was used as a target for sputtering.
Using an alloy, the pressure during sputtering is 5 mTorr, and the input RF power is
1.5kW / 150mmφ. Here, when the target is manufactured by the HIP method, it has an effect that the oxygen content in the target can be reduced and the composition difference between the target and the film can be significantly reduced. Finally, as an inorganic compound thin film (3),
A silicon nitride film was formed to a thickness of 65 nm by a sputtering method. Ar / O ₂ was used for the discharge gas, with Si as the target. The pressure during sputtering is 10 mTorr, and the input RF power is
0.7kW / 150mmφ. Here, the thickness of the formed inorganic compound thin film is determined by the wavelength of light used for reproduction.

Next, the magnetic characteristics of the magnetic film were measured.
The obtained magnetic properties are as follows: coercive force is 10.0 kOe, perpendicular magnetic anisotropy energy is 5 × 10 ⁷ erg / ml, saturation magnetization is 120 emu
/ ml, the Kerr rotation angle was 0.89 °. The Curie temperature is 210 ° C and the compensation temperature is 80 ° C.

The reproduction characteristics of the disk using the magnetic film having the above magnetic characteristics were evaluated. FIG. 2 shows an outline of the apparatus used for the evaluation. As the information recording medium (104), a medium in which a magnetic domain having a width of 0.30 μm in the track direction and 0.5 μm in the direction perpendicular to the track was formed in advance was used. For reproduction, laser light (100) with a wavelength of 680 nm is used, and the light is
The information recording medium was irradiated through a slit (101) having a pinhole (102) having an m diameter. Here, a part of the light coming out of the pinhole is collected by a half mirror (103) and used as reference light, and the light reflected from the information recording medium and returned is referred to as a reference light from a light source. An optical interaction occurs between the light, the light is separated by a half mirror (103), each light is converted to an electric signal by a detector (105), and these are differentially converted by a comparator (106). By detecting, information can be reproduced. here,
The change in light frequency (change in wavelength) was detected by using the wavelength dependency of the signal output of the detector, and the change in light intensity was detected by using the light intensity dependency of the signal output of the detector. By using this method, the width in the track direction is 0.3 μm
Magnetic domain (0.4 μm in the direction perpendicular to the track) was successfully reproduced. When the playback signal output was measured, C / N = 55
It was ~ 58dB.

In this embodiment, the information recording film is made of Tb-Fe-Co
Although the case where a system was used was described, in addition to this material system, Dy-Fe-C
o, Ho-Fe-Co, Gd-Tb-Fe-Co, Gd-Dy-Fe-Co, Gd-Ho-Fe-Co, Tb-
Similar effects can be obtained by using Dy-Fe-Co, Tb-Ho-Fe-Co, and Dy-Ho-Fe-Co. In particular, in a system containing Gd, the perpendicular magnetic anisotropy is reduced, but a large magneto-optical effect is obtained. here,
In a system containing two or more rare earth elements, the composition of the rare earth element is determined by the total amount without depending on the kind of the element. Needless to say, the same effect can be obtained even if a part of Fe is replaced with Ni.

<Embodiment 2> Using the information recording medium (104) of Embodiment 1, continuous light is irradiated from an optical head, and at the same time, information is recorded by applying a magnetic field by a flying magnetic head (110). A magnetic field modulation recording method was used. FIG. 3 shows a schematic diagram of the magnetic field recording method used. Here, a very small light source for reproduction is
It may be attached to this flying magnetic head. Recording was performed on the information recording film (104) using the flying magnetic head (110). At the same time, a laser beam focused down to 0.6μm with a lens
(Continuous light). Here, a pulse light of about 20 ns to 60 ns may be used. In this case, the area where the temperature rises effectively becomes narrow, which is suitable for high-density recording. The formed magnetic domain had a width measured in the track direction of about 0.15 μm.
The width, measured perpendicular to the track, was 0.7 μm. When the magnetic domains formed on this information recording medium were reproduced using the ultra-small light source system shown in FIG. 2 as in Example 1, good reproduction was possible. When the reproduced signal output was measured, it was C / N = 54 dB. The S / N was found to be 34 dB. As described above, it was found that information recorded by using an extremely small light source can be favorably reproduced.

<Embodiment 3> In this embodiment, recording is performed on the information recording medium of the previous embodiment 1 by using both a thin film magnetic head and a laser light source. This is the case where an extremely small light source is used. FIG. 4 shows an outline of the recording system.
The magnetic head used for recording is attached to a support spring (202). FIG. 5 shows the details of the recording head used. For recording, a soft magnetic film with a high saturation magnetic flux density of 2.1T was used for the magnetic core.
The thin-film magnetic head used in (302) was used. The distance (flying distance) between the head surface and the magnetic recording medium is 12 nm and the gap width
(301) is 0.20 μm. At the time of recording, a magnetic field was applied from the thin-film magnetic head, and at the same time, a pulse light was applied from the laser light source (111) through the lens (112). The pulse width to be applied varies depending on the width of the magnetic domain to be formed. Here, a laser pulse of 40 ns was applied. According to the magnetic domain observation, the width of the formed magnetic domain was 0.1 μm measured in the track direction.
Met. As described above, it was found that a magnetic domain narrower than the gap width of the magnetic head can be formed by using the magnetic head and the laser light source together for recording.

Next, a signal (700 kFCI) corresponding to 40 Gb / inch ² was recorded on this disk. When the recorded signal was reproduced, the S / N was 30 dB. When the defect rate of this disk was measured, the value was 1 × 10 ⁻⁵ or less when no signal processing was performed.

<Embodiment 4> This embodiment is directed to a case where a magnetic domain recorded on an information recording medium during reproduction is enlarged. FIG. 6 shows the structure of the manufactured information recording medium. A 3.5 ″ diameter glass substrate was used as the disk substrate (1). The substrate used here is only one example, and 2.
It goes without saying that the effect of the present invention is not affected by using a disk substrate of any size such as 5 ″ or by using a resin such as polycarbonate or amorphous polyolefin. Needless to say, a substrate having an uneven guide groove may be used for the positioning, or the uneven guide groove may be formed after forming the information recording medium.

On this substrate (1), an Al-T
An i film was formed to a thickness of 30 nm. Pure Ar as discharge gas, Al ₉₀ T
the i ₁₀ alloy was used, respectively to the target. The pressure during sputtering is 15 mTorr, and the input RF power is 0.5 kW / 150 mmφ.
Here, no difference was found between the composition of the obtained thin film and the composition of the target. Next, a silicon nitride film was formed by a sputtering method as the inorganic compound thin film (3). Ar / N ₂ was used for the discharge gas, with Si as the target.
The pressure during sputtering is 10mTorr, and the input RF power is 0.7kW / 150mm
φ. The thickness of the formed inorganic compound thin film is 15 nm. Next, a magnetic film composed of two layers was formed via a nonmagnetic layer. As the magnetic film I (5), a Tb-Fe-Co film was formed to a thickness of 100 nm by a sputtering method. Tb ₂₆ Fe ₆₂ Co prepared by hot static pressure press (HIP) was used as a sputtering target.
_{Using 12} alloy, the pressure during sputtering is 5 mTorr, and the input RF power is 1.5 kW / 150 mmφ. Here, when the target is manufactured by the HIP method, the oxygen content in the target can be reduced, and at the same time, the composition difference between the target and the film can be significantly reduced. On this, a non-magnetic layer (6)
A silicon nitride film was formed to a thickness of 10 nm. Ar / N ₂ was used for the discharge gas, with Si as the target. The pressure during sputtering is 10mTorr and the input RF power is 0.7kW / 150mmφ
It is. Subsequently, a Gd-Fe-Co film was formed as a magnetic layer II (7) by a sputtering method. A Gd _{2 6} Fe ₆₄ Co ₁₀ alloy produced by a hot static pressure press (HIP) method was used as a sputtering target, and Ar was used as a discharge gas. The sputtering conditions were as follows: the sputtering pressure was 5 mTorr, and the input RF power was 1.5 kW / 15
0 mmφ. The thickness of the magnetic layer II is 20 nm. As described above, when the magnetic film was formed via the nonmagnetic layer, the magnetic layers were magnetostatically coupled to each other. Finally, the inorganic compound thin film
As (3), a silicon nitride film was formed to a thickness of 65 nm by a sputtering method. Ar / O ₂ was used for the discharge gas, with Si as the target. The pressure during sputtering is 10 mTorr, and the input RF power is 0.7 kW / 150 mmφ. Here, the thickness of the formed inorganic compound thin film is determined by the wavelength of light used for reproduction.

An 800 kFCI signal was recorded on the above disk using a laser light source (optical head) and an electromagnet. Here, recording is performed by raising the magnetic layer I and the magnetic layer II to the Curie temperature and applying a magnetic field from the outside in the process of cooling the portions to direct the magnetization in a desired direction. The recorded information is stored in the magnetic layer I. At the time of reproduction, an extremely small light source and a magnetic head are used. When a magnetic field is applied from the outside by the magnetic head, the information of the magnetic layer I is transferred to the magnetic layer I.
It is enlarged and transcribed to I. This information was reproduced using laser light from a very small light source. A part of the light coming out of the pinhole is fractionated and used as a reference light, and the light reflected from the information recording medium and returned returns an optical interaction between the light from the light source, The information is reproduced by comparing the light with the light (differential detection). Where the change in light frequency
The detection of (change in wavelength) was performed using the wavelength dependency of the signal output of the detector, and the change in light intensity was detected using the light intensity dependency of the signal output of the detector. By using this method, when the reproduction signal output was measured, C / N = 53 to 56
dB.

<Embodiment 5> In this embodiment, using the information recording medium of Embodiment 4, continuous light is irradiated from an optical head, and at the same time, information is recorded by applying a magnetic field by a floating magnetic head. This is a case where a magnetic field modulation recording method is used. The schematic diagram is as shown in FIG. Here, it goes without saying that an extremely small light source for reproduction may be attached to the flying magnetic head. First, recording was performed on the information recording film using a flying magnetic head. The formed magnetic domain was about 0.1 μm. The magnetic domain formed on this information recording medium is referred to as Embodiment 4.
When reproduction was performed using the same ultra-small light source system as described above, good reproduction was possible. When the playback signal output was measured, C / N = 56dB
Met. When the S / N was determined, it was 35 dB. As described above, it was found that information recorded by using an extremely small light source can be favorably reproduced.

<Embodiment 6> In this embodiment, recording is performed on the information recording medium of the previous embodiment 4 by using both a thin film magnetic head and a laser light source. This is the case where an extremely small light source is used. FIG. 4 shows an outline of the recording system.
For recording, a thin-film magnetic head using a soft magnetic film having a high saturation magnetic flux density of 2.1 T was used. The distance (flying distance) between the head surface and the magnetic recording medium is 12 nm, and the gap width is 0.20 μm
It is. At the time of recording, a magnetic field was applied from the thin-film magnetic head and pulse light was applied from a laser light source.
The pulse width to be applied varies depending on the width of the magnetic domain to be formed. Here, a laser pulse of 40 ns was applied. According to the magnetic domain observation, the width of the formed magnetic domain was 0.1 μm as measured in the track direction. As described above, it was found that a magnetic domain narrower than the gap width of the magnetic head can be formed by using the magnetic head and the laser light source together for recording.

Next, a signal (700 kFCI) corresponding to 40 Gb / inch ² was recorded on this disk. When the recorded signal was reproduced, the S / N was 35 dB. When the defect rate of this disk was measured, the value was 1 × 10 ⁻⁵ or less when no signal processing was performed. Here, for comparison, when reproduction was performed using the optical head used for recording, S /
N was 28 dB. Thus, the S / N was low. this is,
This was due to low reproduction sensitivity. Further, in this case, the crosstalk was large and the resolution was low. The reason may be that the light spot cannot be made small and that the temperature of the information recording medium increases due to light irradiation. Conversely, this is a feature of the present invention.

[0027]

According to the present invention, a laser beam (extremely small light source) passing through a slit of 300 nm or less is used as a light source for reproduction,
Due to the optical interference between the polarized light on the surface of the information recording medium having a magneto-optical effect and the light from the light source, the frequency of the light
A large light reproduction output can be obtained by detecting a change (or a wavelength) or a change in light intensity. As a result, it was possible to provide a reproducing method capable of reproducing data with good resolution and sensitivity even with a domain size of 0.1 μm or less. In particular, when the magnetic domain expansion reproducing method is used as a reproducing method for a magneto-optical disk, the effect obtained is large.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a cross-sectional structure of an information recording medium.

FIG. 2 is a diagram showing an information reproducing method using a minute light source.

FIG. 3 is a diagram showing an information recording method using a flying magnetic head.

FIG. 4 is a diagram showing an information recording method in which a magnetic head and an optical head are combined.

FIG. 5 is a diagram showing a structure of a thin-film magnetic head.

FIG. 6 is a schematic diagram showing a cross-sectional structure of an information recording medium.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Light reflection film 3 ... Inorganic compound film 4 ... Magnetic film 5 ... Magnetic layer I 6 ... Non-magnetic layer 7 ... Magnetic layer II 100 ... Laser light source 101 ... Slit 102 ... Pinhole 103 ... Half mirror 104 ... Information Recording medium 105 Detector 106 Comparator 110 Floating magnetic head 111 Laser light 112 Lens 201 Magnetic head 202 Support spring 301 Magnetic gap 302 Magnetic core 303 Insulator 304 Current terminal 305 Thin film coil

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G11B 11/105 551 G11B 11/105 551Q 7/18 7/18 (72) Inventor Koichiro Wakabayashi 1-chome Ushitora, Ibaraki-shi, Osaka No. 1-88 Hitachi Maxell Co., Ltd. (72) Inventor Teruaki Takeuchi 1-88 Ushitora, Ibaraki-shi, Osaka F-term within Hitachi Maxell Co., Ltd. 5D075 BB05 BB06 BB08 BB10 CC11 EE03 FF04 FF12 5D119 AA11 AA22 BA01 FA05 JA70

Claims (14)

[Claims] 1. An information reproducing method for reproducing an information recording medium using a very small light source, wherein the very small light source comprises:
A semiconductor package having at least a slit having a pinhole having a diameter of 50 nm or more and 300 nm or less provided in the course of a semiconductor laser and a laser beam emitted from the semiconductor laser, and transmitting the light emitted from the pinhole to the information recording medium. Irradiating the surface of the information recording medium, and irradiating the surface of the information recording medium with an optical interaction generated between light reflected from the medium surface and light before reflection, and detecting a modulation degree thereof. Reproducing information from the information recording medium by using the method. 2. The information reproducing method according to claim 1, wherein the modulated optical interaction is at least one selected from a frequency, a wavelength, and a light intensity. 3. The information reproducing method according to claim 1, wherein the modulated optical interaction occurs due to a magneto-optical effect of the information recording medium. 4. The information reproducing method according to claim 1, wherein a width of the recording mark measured in a moving direction of the information recording medium is smaller than a diameter of the pinhole. 5. The information reproducing method according to claim 1, wherein the information recording medium has a magnetic layer made of a material having perpendicular magnetic anisotropy and having a magneto-optical effect. 6. The information reproducing method according to claim 5, wherein said magnetic layer is an amorphous alloy of a rare earth element and an iron group element. 7. The magnetic layer transfers a magnetic domain recorded on the recording layer during reproduction via the recording layer for recording information and the recording layer and the non-magnetic layer, and the magnetic domain is shifted from the recording layer. 7. The information reproducing method according to claim 6, comprising a plurality of magnetic layers including at least a reproducing layer that forms a large magnetic domain. 8. The information reproducing method according to claim 7, wherein a perpendicular magnetic anisotropy is induced in the reproducing layer by light irradiation and / or application of a magnetic field. 9. The polarization plane is rotated by the Kerr effect and / or the Faraday effect when the light applied to the reproduction layer from the extremely small light source is reflected by the reproduction layer. Information reproduction method described. 10. A laser light source, a lens for narrowing laser light emitted from the laser light source to a fixed spot size, a magnetic head for applying a magnetic field, and a disk drive for rotating an information recording medium. An information recording / reproducing apparatus comprising at least a unit and an electric circuit, characterized in that a slit having a pinhole having a diameter of 50 nm or more and 300 nm or less is provided on the way of laser light emitted from the laser light source. 11. The information recording / reproducing apparatus according to claim 10, wherein the electric circuit includes a circuit for detecting at least one optical interaction selected from a frequency, a wavelength, and a light intensity. 12. The information recording method according to claim 1, wherein the information recorded on the information recording medium is at least one of audio information, code data, image information, and control information for controlling a magnetic disk drive. apparatus. 13. A semiconductor laser and a laser beam emitted from the semiconductor laser having a diameter of 50 n provided on the way.
irradiating light emitted from a semiconductor package having at least a slit having a pinhole of m or more and 300 nm or less,
In an information recording medium that reproduces information by detecting an optical interaction that occurs between light after reflection of the irradiated light and light before reflection, the information recording medium is Tb, Gd,
Information characterized by comprising a recording layer made of an amorphous alloy of at least one rare earth element selected from Ho.Dy and at least one iron group element selected from Fe, Co, and Ni recoding media. 14. The information recording medium according to claim 1, wherein the information on the information recording medium is at least one of audio information, code data, image information, and control information for controlling a magnetic disk drive.