JP3454813B2 - Recording method for magneto-optical recording medium - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording method for a magneto-optical recording medium, and more particularly to an optical disk suitable for a method for recording information by modulating the length of a magnetic domain represented by mark edge recording. The present invention relates to a recording method for a magnetic recording medium.

[0002]

2. Description of the Related Art In magneto-optical recording, as shown in FIG. 16, a method of recording corresponding to information at the center of a recording magnetic domain (hereinafter abbreviated as pit position recording) and recording as shown in FIG. There is a method of recording information by modulating the length of the magnetic domain (hereinafter abbreviated as magnetic domain length recording).

This magnetic domain length recording has a feature that it is possible to perform recording at a higher density than the pit position recording, and a typical method therefor is to change the magnetization direction. That is, information is recorded by modulating a fine magnetic domain length on the premise of a method of recording information at the end of the magnetic domain (hereinafter, referred to as mark edge recording), a partial response method and reproduction by the maximum likelihood decoding method (PRML). There are methods such as recording.

In this magnetic domain length recording, the stability of the magnetic domain shape becomes more important than in the pit position recording. The signal recorded / reproduced on / from the medium fluctuates due to various factors. For example, variations in medium sensitivity, temperature changes during recording / playback, variations in equipment, laser beam defocus,
These are changes in characteristics due to repeated rewriting, and these are factors that cause variations in the recording magnetic domain length.

However, in pit position recording, information is made to correspond to the center of the recording magnetic domain.
As shown in FIG. 8 (a), even if the length of the recording magnetic domain fluctuates to some extent, the center position is hardly affected. In addition, in the figure, between the solid line and the dotted line is a line showing the width of fluctuation,
The same applies to FIG. 19.

Therefore, in the pit position recording, if the time differential processing of the reproduction signal [see FIG. 18 (b)] is performed, the intersection with the 0 point hardly moves as shown in FIG. Is relatively stable and has a high S / N
It was only necessary to form a recording magnetic domain having a uniform shape.

However, in the case of magnetic domain length recording, even if a recording magnetic domain having a uniform shape can be formed, there are the following fundamental problems. That is, first, since the lengths of recorded magnetic domains are different, the influence of heat from the magnetic domains recorded before the formation of each magnetic domain is not constant. Since this thermal state is varied, a problem peculiar to this method occurs that the position of the recorded magnetic domain end is not stable as shown in FIG. 19A during recording. Moreover, this remains as a movement (shift) of the detection point when the slice at the 0 level is applied even if the differential processing is performed twice. As a result, this causes an increase in jitter and an increase in errors with respect to the fluctuation of the recording laser power. Again, this leads to instability with respect to environmental temperature fluctuations.

Secondly, when rewriting is repeated, the magnetic film, which is an amorphous alloy of a rare earth transition metal, undergoes structural relaxation due to heat, and the magnetic characteristics change accordingly. Therefore, the recorded position of the magnetic domain end becomes unstable depending on the usage history.

Regarding the magneto-optical recording medium, there are, for example, Patent Documents 1 and 2.

[0010]

[Patent Document 1] Japanese Patent Laid-Open No. 4-305834

[0011]

[Patent Document 2] Japanese Patent Application Laid-Open No. 3-241549

[0012]

Although there is a great advantage that the recording density can be improved in magnetic domain length recording,
As described above, the fluctuation of the recording laser power, the fluctuation of the environmental temperature, and the like cause the fluctuation of the end portion of the recording magnetic domain, which causes a fundamental problem that the recording is unstable.

This is because the recorded magnetic domains have different lengths, so that the thermal state of each magnetic domain during recording is not constant. In particular, due to changes in characteristics due to repeated rewriting, since the history of rewriting differs for each recording point on the medium, there is a situation where the correction by the device cannot be supported.
This was a problem in magnetic domain length recording.

Further, conventionally, the magnetic characteristics of the magnetic film have been discussed for the purpose of reducing the modulation noise by forming the recording magnetic domain having a uniform shape. Until now, the fluctuation of the recording magnetic domain edge due to indefiniteness, the stability after repeated rewriting, etc. have not been taken into consideration at all, and the optimum characteristic relationship has not been examined.

An object of the present invention is to solve the above-mentioned problems that the conventional magnetic domain length recording has, and to be suitable for magnetic domain length recording, that is, even when the thermal state at the time of recording is indefinite, the magnetic domain end portion is recorded. It is an object of the present invention to provide a highly reliable recording method of a magneto-optical recording medium which can stably form the magnetic domain edge portion even after repeated rewriting and further reduce the jitter.

[0016]

In order to achieve this object, the present inventors have developed a large number of rare earth elements having different magnetic properties.
A magneto-optical recording medium was prepared using a transition metal amorphous alloy,
When we performed magnetic domain length recording on all of them, examined their stability, and compiled them, we found out the surprising fact that only those that satisfy the following conditions can make stable recording.

That is, the first means of the present invention is a rare earth-
A transition metal amorphous alloy recording material with magnetic properties
Q (T / Tc) = Hc / 4πMs for temperature T [K] where Hc: coercive force [Oe], Ms: saturation magnetization [emu / cc], Tc: Curie temperature [K], The value of q (T / Tc) given by
c) A magneto-optical recording medium provided with a magnetic film having a characteristic that a region of T satisfying ≧ 1 exists in a temperature range represented by at least 1 ≧ T / Tc ≧ 0.7. A recording method of a magneto-optical recording medium, which modulates the length of a magnetic domain according to the information to be recorded when irradiating a laser on the medium to record information, comprising a reproduction light pulse Pr, a preheat pulse Pa, Laser pulse Pw1, Pw for magnetic domain formation
The strength relationship of w2 is set to Pr <Pa <Pw1 <Pw2.

The second means of the present invention is a recording material of rare earth-transition metal amorphous alloy, which has a magnetic property of temperature T.
Q (T / Tc) = Hc / 4πMs for [K] where Hc: coercive force [Oe], Ms: saturation magnetization [emu / cc], Tc: Curie temperature [K], The value of q (T / Tc) is q (T / T
c) A magneto-optical recording medium provided with a magnetic film having a characteristic that a region of T satisfying ≧ 1 exists in a temperature range represented by at least 1 ≧ T / Tc ≧ 0.7. When the information is recorded by irradiating the laser with the laser beam, the length of the magnetic domain is modulated according to the information to be recorded, and the information signal is modulated so that the shortest recorded magnetic domain length of the magnetic domain is 0.75 μm or less. A recording method for a magnetic recording medium, comprising a reproducing light pulse P
r, preheat pulse Pa, and intensity relationships of laser pulses Pw1 and Pw2 for forming magnetic domains are Pr <Pa <
It is characterized in that Pw1 <Pw2.

The third means of the present invention is the information according to the first means, wherein the length of the magnetic domain is modulated according to the information to be recorded, and the shortest recorded magnetic domain length of the magnetic domain is 0.75 μm or less. It is characterized in that the signal is modulated.

A fourth means of the present invention is to record a magneto-optical recording medium in which the length of a magnetic domain is modulated according to the information to be recorded when the magneto-optical recording medium is irradiated with a laser to record information. A reproducing light pulse Pr, a preheat pulse Pa, a laser pulse Pw1 for forming a magnetic domain,
The strength relationship of Pw2 is set to Pr <Pa <Pw1 <Pw2.

A fifth means of the present invention is characterized in that, in the first means, the second means or the fourth means, information is recorded at an end of the magnetic domain.

[0022]

FIG. 20 is a schematic diagram showing a temperature distribution of a magnetic film in a portion irradiated with a laser beam during recording, in which the temperature varies between the solid line and the alternate long and short dash line due to the variation of the recording laser power. It shows the state. Note that Tc in the figure indicates the Curie temperature of the magnetic film (rare earth-transition metal amorphous alloy).

FIG. 21 shows changes in coercive force with respect to temperature changes.
In the comparatively gentle magnetic film as shown in (a), the coercive force distribution of the portion irradiated with the laser light is as shown in (b) of the same figure. In this profile, the intersection with the applied external magnetic field becomes the boundary of the magnetic domain, that is, the edge portion, and a recording magnetic domain as shown in FIG.

As described above, the fluctuation of the magnetic domain edge during recording is caused by various factors such as the temperature profile during recording, the magnetic characteristics of the magnetic film, and the environmental temperature. When the magnetic domain length recording is performed, since the size of the magnetic domain recorded immediately before the formation of each magnetic domain is different, the influence of heat from the magnetic domain is not constant, which is the greatest influence. These can be treated as a variation of the irradiation laser power during recording as a whole. FIG. 20 and FIGS. 21 (a) to 21 (c) show how the magnetic domain end moves when each fluctuation is assumed to occur.
It is schematically shown by a dotted line and a one-dot chain line.

In order to reduce the amount of movement (displacement), the temperature characteristic of the coercive force of the magnetic film is shown in FIG.
It is more suitable that the temperature rises rapidly from the Curie temperature Tc toward the low temperature side as shown in FIG.
It can be seen from the result of (c).

Regarding the spontaneous magnetization, a magnetic field proportional to its magnitude is generated inside the magnetic film. Since it is considered that the domain wall becomes unstable when this is large near the recording temperature, it can be said that a smaller spontaneous magnetization near the Curie temperature is more suitable.

The respective temperature characteristics of the coercive force and the saturation magnetization are intricately related to each other and affect the stability of the recording magnetic domain. According to various experiments by the inventors, this is q (T / Tc). ) = Hc / 4πMs It was inductively clarified that it can be arranged by one simple factor.

Then, the ratio of the magnetic field 4πMs generated by the spontaneous magnetization inside the magnetic film to Hc which is the domain wall coercive force showing the maximum magnetic field value capable of preventing the movement of the domain wall is 1 or less (Hc / 4π).
It was confirmed that by setting Ms ≧ 1), the movement of the domain wall due to spontaneous magnetization can be suppressed.

From these experimental results, FIG. 9 shows the temperature change characteristics of the q value for typical magneto-optical recording media A to E having different magnetic characteristics. These examples are the data of the recording medium shown in the section of the embodiment, and details regarding the configuration will be described later. The temperature on the horizontal axis of the figure is normalized by the Curie temperature (T / Tc), and the vertical axis indicates the q value.

FIG. 10 is a diagram showing the results of measuring the fluctuation of the reproduced signal with respect to the detection window, that is, the jitter, by performing mark edge recording on the recording media A to E shown in FIG. This is to evaluate the stability of jitter by changing the recording laser power.

In FIG. 9, it can be seen that the steeper the q value rises, the smaller the change in the jitter with respect to the recording power, as shown in FIG. Above all, the recording media D and E obviously have a larger jitter than the other recording media A to C, and the change in the jitter with respect to the recording power is also large.

FIG. 11 is a diagram showing the results of measuring the change in jitter as compared with the initial state, by performing mark edge recording after repeating rewriting 10 6 times for each of the recording media A to E.

Also in this result, the stability of the magnetic domain end corresponds to the order of FIG. That is, the recording media A and B are
Even after repetitive rewriting, the edge of the magnetic domain hardly changes and the jitter does not increase. The recording medium C has a slightly increased jitter, but is about 1 ns, which is well within the allowable range for the detection window. On the other hand, recording media D and E
Is changing drastically. A recording medium having an increase in jitter after rewriting 10 6 times within about 1 ns can be evaluated as a highly reliable recording medium.

When the data of many recording media is organized in this way, q (T / T /
The area of T in which the value of Tc) is 1 or more is at least 1 ≧ T
For a medium existing in the temperature range represented by /Tc≧0.7, the stability of jitter with respect to the change in recording laser power is good, and the recording magnetic domain edge after rewriting is repeated. It was found that the change in was small.

Among these, q (T
/ Tc) has a value of 1 or more, the region of T is 1 ≧ T / Tc ≧
A medium that exists in the temperature range of 0.8 has almost no change in the recording magnetic domain edge after repeated rewriting, and optimum recording is possible. Q near T / Tc = 1
Regarding the value being 1 or less, it is considered that there is no problem because the magnetic domain edge is in a higher temperature region than the determined temperature.

Further, in the present invention, the magneto-optical recording medium having the above-mentioned features is used, and the laser pulse is divided when information is recorded, and the laser intensity and the irradiation time are adjusted to form the layer. The width of the magnetic domain can be made uniform and the length of the magnetic domain can be modulated to fully exhibit the characteristics of this type of magneto-optical recording medium, further reduce the jitter, and improve the reliability.

Next, specific examples of the present invention will be described. (Embodiment 1) FIG. 1 shows the configuration of a recording medium according to Embodiment 1. A SiON dielectric film (film thickness of about 100 is formed on a substrate made of polycarbonate with laser light guide grooves and prepits.
0Å), Tb ₂₉ Fe ₅₃ Co ₁₃ Nb ₅ magnetic film (film thickness of about 20)
0 Å), SiON dielectric film (thickness of about 300 Å), and Al reflection film (thickness of about 700 Å) were vacuum-formed by magnetron sputtering, and a resin for protection was applied and cured.

As the magnetic film, a Tb ₂₉ Fe ₅₃ Co ₁₃ Nb ₅ amorphous perpendicular magnetization film as a typical example of a material containing at least Tb, Fe and Co was used. This magnetic film has a Curie temperature T
c is about 200 ° C. and the compensation temperature Tcomp is about 80 ° C. The magnetic characteristics are as shown in FIG. 2, and show the temperature change of q corresponding to the recording medium A of FIGS.

Example 2 As shown in FIG. 3, a recording medium having the same laminated structure as in Example 1 was used except that Tb ₃₁ Fe ₅₃ Co ₁₆ was used as the magnetic film.

This magnetic film has a Curie temperature Tc of about 240.
In ° C, the compensation temperature Tcomp is about 80 ° C. Its magnetic characteristics are as shown in FIG. 4, and show the temperature change of q corresponding to the recording medium B of FIGS.

Example 3 As shown in FIG. 5, a recording medium having the same laminated structure as in Example 1 was used except that Tb ₁₉ Fe ₆₄ Co ₉ Nb ₈ rich in transition metal was used as the magnetic film.

This magnetic film has a Curie temperature Tc of about 180.
In ° C, the compensation temperature Tcomp is below room temperature. Its magnetic characteristics are as shown in FIG. 6, and show the temperature change of q corresponding to the recording medium C of FIGS.

Comparative Example 1 As shown in FIG. 7, a recording medium having the same laminated structure as in Example 1 was used except that Tb ₁₈ Fe ₆₃ Co ₁₆ Nb ₃ rich in transition metal was used as the magnetic film.

This magnetic film has a Curie temperature Tc of about 240.
In ° C, the compensation temperature Tcomp is below room temperature. Its magnetic characteristics are as shown in FIG. 8, and show the temperature change of q corresponding to the recording medium D of FIGS.

FIG. 10 shows the jitter characteristics when mark edge recording is performed on each of these recording media. The recording conditions are as follows: laser wavelength 780 nm, lens N.V. A. But
Using an optical head of 0.55 at a linear velocity of 9.42 m / sec,
Shortest magnetic domain length 0.75 μm, shortest gap length 0.75 μm
1-7 modulated random data was recorded, and the reproduced signal was measured 10 4 times to measure the fluctuation within the detection window to obtain the standard deviation value of jitter.

FIG. 10 is a diagram showing changes in the standard deviation of jitter with respect to changes in the recording laser power. The fluctuation of the recording power causes an increase in jitter due to the fluctuations of the magnetic domain ends which occur because the recorded magnetic domains have different lengths and the thermal state of each magnetic domain during recording is not constant. This is also an index of stability against changes in environmental temperature.

Further, FIG. 11 shows that rewriting (10
It is a figure which shows the change of the standard deviation value of the jitter by ⁶ times. This is because the magnetic film, which is an amorphous alloy, undergoes structural relaxation due to heat, and the magnetic characteristics change accordingly. As in Examples 1 to 3 of the present invention, the q value is at least 1 ≧ T / Tc ≧ 0.7 for both the increase of the jitter with respect to the fluctuation of the recording power and the increase of the jitter due to the repeated rewriting.
In the range of 1 or more, it is suppressed to be small in the recording medium. Further, even in the composition rich in transition metal elements as in Example 3, when the value of q is within the range of the present invention, the increase of jitter is suppressed, and stable formation of magnetic domain edge portions is possible.

FIG. 12 is a view for explaining a recording method suitable for the above-mentioned magneto-optical recording medium, particularly a technique for controlling the recording magnetic domain edge. In the figure, (a) is a diagram showing a laser pulse output state at the time of information recording. Pr on the vertical axis is a reproducing light pulse, Pa is a preheat pulse for making the writing start state of each magnetic domain constant, and Pw1 and Pw2 is a laser pulse for substantially forming a magnetic domain, and the magnetic domain width W is kept constant by the balance between the two. As shown in the figure, the laser pulse intensity relationship is Pr <Pa <Pw1 <Pw2.

FIG. 7B shows the laser pulse Pa,
It is a figure which shows the shape of the recording magnetic domain formed of Pw1 and Pw2. A recording magnetic domain having a minimum magnetic domain length L is formed only by the laser pulse Pw1, and by combining the laser pulse Pw1 and the laser pulse Pw2,
The length of the magnetic domain length L can be arbitrarily adjusted by the number of laser pulses Pw2 (that is, the irradiation time).

As shown in this figure, by applying the recording method of dividing the laser pulse at the time of recording and adjusting the intensity and irradiation time to the magneto-optical recording medium of the present invention,
Further, the jitter can be reduced and the reliability at the time of recording is improved.

In the present invention, the relationship between the Curie temperature Tc and the compensation temperature Tcomp of the rare earth-transition metal amorphous alloy that constitutes the magnetic film is particularly equal to the compensation temperature Tcomp>
Curie temperature Tc> compensation temperature Tcomp at 50 ° C.
It is desirable that the relationship be

FIG. 13 is a block diagram of a magneto-optical recording medium showing a first modification of the present invention. In the case of this modification, TbF
In addition to the first magnetic film made of eCo, a second magnetic film made of GdFeCo having a large Kerr rotation angle is provided on the substrate side to increase the reproduction signal.

FIG. 14 is a block diagram of a magneto-optical recording medium showing a second modification of the present invention. In the case of this modification, TbD
In addition to the first magnetic film made of yFeCo, GdFeCo
The second magnetic film made of TbFeCo and the third magnetic film made of TbFeCo are formed so that direct overwrite is possible.

FIG. 15 is a block diagram of a magneto-optical recording medium showing a third modification of the present invention. In the case of this modification, TbF
A second magnetic film made of GdFeCo is formed in addition to the first magnetic film made of eCo, and TbFeCo is formed between both films.
A cutting layer made of Nb is provided to enable magnetic super-resolution reproduction.

Even in the structure in which various magnetic films are laminated as shown in these modified examples, the q value of the magnetic characteristics of at least one magnetic film is 1 ≧ T / Tc ≧ 0.7, preferably 1 ≧.
If T / Tc ≧ 0.8 in the range of 1 or more, the effect of stabilizing the magnetic domain end portion can be obtained when the magnetic domain length recording is performed, and the jitter is increased and the rewriting is repeated due to the variation of the recording power. The increase in jitter is suppressed.

In a recording medium in which a plurality of magnetic films are magnetically coupled and laminated, if at least one magnetic film is laminated with a magnetic film having the magnetic characteristics of the present invention, the magnetic film ends the magnetic domain end portions. Is stabilized. Then, due to the exchange coupling force of the magnetic film, this end is transferred to another magnetic film, and as a result, the magnetic domains of the entire multilayer film are aligned with the magnetic domains of this magnetic film. That is, no matter where the magnetic film having the magnetic properties of the present invention is arranged in the laminated film, this effect can be obtained through the exchange coupling force between the magnetic films.

The partial response method and the maximum likelihood decoding method (PRML) are one of the signal processing techniques for lowering the error rate when increasing the recording density. Using this technique, the recording density can be improved 1.2 times or more. Even when these are used, the size of the recording magnetic domain is further miniaturized as the density is increased. Along with this, the influence of fluctuations at the ends of the recording magnetic domains also appears significantly. However, the recording medium of the present invention is suitable even when recording is performed in a minute magnetic domain on the assumption that these signal processing methods are used. The gist of the present invention is that, as a magnetic property, the value of q (T / Tc) given by the equation of q (T / Tc) = Hc / 4πMs with respect to temperature T [K] is q (T / Tc). For a magneto-optical recording medium, a region of T satisfying ≧ 1 exists in a temperature range represented by at least 1 ≧ T / Tc ≧ 0.7, and the length of a magnetic domain represented by mark edge recording. Is to record information by modulating, and is not limited to the configurations shown in the embodiment and the modification of the book.

[0058]

According to the present invention, by adopting the above-mentioned constitution, the fluctuation of the end portion of the recording magnetic domain which is caused by the non-uniform thermal state during recording of each magnetic domain is suppressed, and even after the rewriting is repeated. It is possible to provide a highly reliable recording method for a magneto-optical recording medium that enables stable formation of magnetic domain edge portions and further reduces jitter.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining a magneto-optical recording medium according to a first embodiment of the invention.

FIG. 2 is a magnetic characteristic diagram of the magneto-optical recording medium according to the first embodiment.

FIG. 3 is a configuration diagram for explaining a magneto-optical recording medium according to a second embodiment of the present invention.

FIG. 4 is a magnetic characteristic diagram of the magneto-optical recording medium according to the second embodiment.

FIG. 5 is a configuration diagram for explaining a magneto-optical recording medium according to a third embodiment of the invention.

FIG. 6 is a magnetic characteristic diagram of the magneto-optical recording medium according to the third embodiment.

FIG. 7 is a configuration diagram for explaining a magneto-optical recording medium according to a comparative example.

FIG. 8 is a magnetic characteristic diagram of a magneto-optical recording medium according to the comparative example.

FIG. 9 is a characteristic diagram showing the relationship between temperature and q value of each magneto-optical recording medium.

FIG. 10 is a characteristic diagram showing the relationship between the amount of change in recording power and the jitter of each magneto-optical recording medium.

FIG. 11 is a characteristic diagram showing changes in jitter of each magneto-optical recording medium after repeated rewriting.

FIG. 12 is a diagram for explaining a recording method for the magneto-optical recording medium of the present invention.

FIG. 13 is a configuration diagram for explaining a magneto-optical recording medium according to a first modified example of the present invention.

FIG. 14 is a configuration diagram for explaining a magneto-optical recording medium according to a second modification of the present invention.

FIG. 15 is a configuration diagram for explaining a magneto-optical recording medium according to a third modified example of the present invention.

FIG. 16 is a diagram for explaining pit position recording on a magneto-optical recording medium.

FIG. 17 is a diagram for explaining magnetic domain length recording in a magneto-optical recording medium.

FIG. 18 is a diagram showing states of a recording magnetic domain, a reproduction signal, and a first-order differential signal in pit position recording.

FIG. 19 is a diagram showing states of recorded magnetic domains and reproduced signals in magnetic domain length recording.

FIG. 20 is a schematic diagram showing a temperature distribution of a magnetic film portion irradiated with laser light during recording.

FIG. 21 is a diagram showing a variation state of coercive force with respect to a temperature change, a distribution state of coercive force in a portion irradiated with laser light, and a state of a recording magnetic domain formed thereby.

FIG. 22 is a diagram showing a variation state of coercive force with respect to a temperature change, a distribution state of coercive force in a portion irradiated with laser light, and a state of a recording magnetic domain formed thereby.

[Explanation of symbols]

L Length of recording domain Width of W recording domain Pr reproduction light pulse Pa preheat pulse Pw1, Pw2 Laser pulse for magnetic domain formation

Front page continuation (72) Inventor Satoru Onuki 1-88, Torora, Ibaraki-shi, Osaka, Hitachi Maxell Co., Ltd. (72) Inventor, Kazuko Ishizuka 1-88, Torora, Ibaraki, Osaka (72) Inventor Norio Ohta 1-88, Tora-tora, Ibaraki-shi, Osaka, Hitachi Maxell Co., Ltd. (56) References JP-A-4-305834 (JP, A) JP-A-2-278546 (JP, A) JP-A-6-68534 (JP, A) JP-A-3-241549 (JP, A) JP-A-4-117645 (JP, A) JP-A-3-178038 (JP, A) JP-A-63-175230 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G11B 11/105

Claims (5)

(57) [Claims] 1. A rare earth-transition metal amorphous alloy-based recording material having a magnetic property of q (T / Tc) = Hc / 4πMs with respect to temperature T [K], where Hc: coercive force [Oe]. ], Ms: saturation magnetization [emu / cc], Tc: Curie temperature [K], and the value of q (T / Tc) is q (T / T).
c) A magneto-optical recording medium provided with a magnetic film having a characteristic that a region of T satisfying ≧ 1 exists in a temperature range represented by at least 1 ≧ T / Tc ≧ 0.7. A recording method of a magneto-optical recording medium, which modulates a length of a magnetic domain according to information to be recorded when irradiating a laser on the medium to record information, comprising a reproduction light pulse Pr, a preheat pulse Pa, A recording method for a magneto-optical recording medium, wherein the intensity relationship between the laser pulses Pw1 and Pw2 for forming magnetic domains is Pr <Pa <Pw1 <Pw2. 2. A rare earth-transition metal amorphous alloy recording material having a magnetic property of q (T / Tc) = Hc / 4πMs with respect to temperature T [K], where Hc: coercive force [Oe ], Ms: saturation magnetization [emu / cc], Tc: Curie temperature [K], and the value of q (T / Tc) is q (T / T).
c) A magneto-optical recording medium provided with a magnetic film having a characteristic that a region of T satisfying ≧ 1 exists in a temperature range represented by at least 1 ≧ T / Tc ≧ 0.7. When the information is recorded by irradiating the laser with the laser beam, the length of the magnetic domain is modulated according to the information to be recorded, and the information signal is modulated so that the shortest recorded magnetic domain length of the magnetic domain is 0.75 μm or less. A recording method of a magnetic recording medium, characterized in that the intensity relationship among a reproduction light pulse Pr, a preheat pulse Pa, and laser pulses Pw1 and Pw2 for forming magnetic domains is set to Pr <Pa <Pw1 <Pw2. Recording method for magneto-optical recording medium. 3. The recording method for a magneto-optical recording medium according to claim 1, wherein the length of the magnetic domain is modulated according to information to be recorded, and the shortest recording magnetic domain length of the magnetic domain is 0.75 μm.
A recording method for a magneto-optical recording medium, which comprises modulating the following information signal. 4. A recording method for a magneto-optical recording medium, wherein a length of a magnetic domain is modulated according to the information to be recorded when the magneto-optical recording medium is irradiated with a laser to record information. A recording method for a magneto-optical recording medium, wherein the intensity relationship among the pulse Pr, the preheat pulse Pa, and the laser pulses Pw1 and Pw2 for forming magnetic domains is set to Pr <Pa <Pw1 <Pw2. 5. The recording method for a magneto-optical recording medium according to claim 1, claim 2, or claim 4,
A recording method for a magneto-optical recording medium, characterized in that information is recorded at an end of the magnetic domain.