JPH11259921A - Magneto-optical record medium and magneto-optical recording method using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magneto-optical record medium easily manufacturing it with good yield and reliably reproducing it with magnetic wall movement detection. SOLUTION: In this record medium, first, second and third magnetic layers 11-13 are provided on a substrate. At this time, the Curie temp. (Tc1 , Tc2 and Tc3 ) of the first, second and third magnetic layers 11-13 are Tc1 >Tc2 , Tc3 >Tc2 , and the magnetic wall coercive force of the first magnetic layer 11 is smaller than the magnetic wall coercive force of the third magnetic layer 13 in the temp. of Tc2 or above, and the temp. that exchange connection force affected to the first magnetic layer 11 through the second magnetic layer 12 from the third magnetic layer 13 exceeds the coercive force energy of the first magnetic layer 11 exists within the temp. range from an ambient temp. to Tc2 . The third magnetic layer 13 is a vertical magnetized film, and an area 23 arranged in the upward magnetization direction and the area arranged in the downward magnetization direction exist in an intertrack area 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording medium for recording information as a magnetic domain pattern of a magnetic film and reproducing information using a magneto-optical effect, and a magneto-optical recording method using the same.

[0002]

2. Description of the Related Art To record information on a magneto-optical recording medium,
Information is recorded as a magnetic domain pattern on a magnetic film which is easily perpendicularly magnetized by a thermomagnetic recording method. For example, by setting the initial magnetization state to downward magnetization, and forming a recording mark including an upward magnetization region in this state, the recording magnetic domain pattern can be formed. At the time of reproduction, the magnetization direction of the magnetic film is converted into an electric signal by the magneto-optical effect and detected.

In recent years, there has been an increasing demand for higher recording densities of magneto-optical recording media, and in order to meet the demand, extremely fine recording marks exceeding the optical resolution of the wavelength of light used for reproduction and the reproduction optical system. The technology to play back has been developed. A magnetic super-resolution reproducing method is known as a method of achieving this by devising a recording medium. In this method, in the magnetic multilayer film, the recording mark is transferred only to the detection area smaller than the spot diameter of the reproducing laser, and the other area is magnetically masked in one direction. Reproduction that is limited and exceeds the resolution of the optical system becomes possible. However, in order to improve the reproduction resolution in the magnetic super-resolution reproduction method, it is necessary to narrow a signal detection area to be used effectively, so that there is a disadvantage that the reproduction signal amplitude itself decreases.

As a method for solving the above problem, a method of reproducing a recorded mark by enlarging it instead of narrowing a signal detection area has been proposed, for example, in Japanese Patent Laid-Open No. Hei 6-290496. That is, when reproducing the recorded information of the magneto-optical recording medium on a magneto-optical recording medium basically composed of three magnetic layers, the magnetic domain wall of the recording mark is moved by the temperature gradient formed by the reproducing beam. And a method for enlarging and reproducing a recording mark. (Hereinafter, this reproduction method is referred to as a domain wall movement detection method in this specification.)

[0005] In this specification, the "recording mark" means a magnetic domain magnetized in a direction opposite to the surroundings.
The description has been made assuming that the periphery is downward magnetization and the recording mark is upward magnetization. However, the same holds true if the periphery is upward and the recording mark is downward.

In order to obtain a good reproduction signal with less noise in a magneto-optical recording medium using the above-described conventional domain wall motion detection method, it was necessary to break the magnetic coupling of the magnetic layer between adjacent information tracks. This is because when the magnetic film between the information tracks is a uniform film that is physically and physically continuous, the recording mark is enlarged because the recording mark exists as a magnetic domain surrounded by a closed domain wall. It is considered that when the domain wall is moved in the direction, the domain wall area inevitably increases and the energy of the domain wall increases, resulting in an unstable operation of the domain wall movement.

[0007] In order to break the magnetic coupling, the above publication discloses three methods. That is, as a first method, a rectangular guide groove is provided between information tracks to reduce the magnetic film thickness on the side of the guide groove, and as a second method, a space between the information tracks is formed. The third method involves annealing the magnetic film in the guide groove portion with a high-power laser to change the magnetic properties. A third method is a method of patterning by etching. As a modification of the first method, a method in which the land and the rectangular groove are formed to have substantially the same width, and both the land and the rectangular groove are used for the information track (a so-called land / groove recording method) can be considered. These methods all attempt to separate adjacent information tracks by a method involving a change in physical shape and physical properties, and to enlarge a recording mark without increasing the domain wall area.

[0008]

However, in order to cut off the magnetic coupling by the rectangular groove in the first method, it is necessary to make the groove extremely deep and to reduce the magnetic film thickness on the side surface of the groove. For this purpose, a special film formation method such as perpendicular incidence of magnetic atoms on the substrate is required during film formation. Also, since the depth of the groove greatly affects the groove signal for tracking servo control for positioning the light beam on the information track, it is not desirable to add a condition to the depth due to other factors. . Furthermore, in the land / groove recording method, the amount of crosstalk from the adjacent track is reduced by controlling the phase difference of the reproduction light of the adjacent track by the depth of the groove. Adding conditions is not desirable.

In the second method, there is a problem that high-power laser irradiation may cause a physical defect in the film, thereby impairing the reliability as a recording medium.
Further, in the third method, there is a problem that whether the etching process is wet etching or dry etching, the magnetic film is degraded or defective, and the manufacturing yield may be significantly reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to provide a magneto-optical recording medium which can be easily manufactured with a high yield and can be reproduced with high reliability by detecting a domain wall movement. It is another object of the present invention to provide a magneto-optical recording method capable of reproducing data by detecting domain wall motion using the magneto-optical recording medium and obtaining a good reproduced signal with less noise.

[0011]

According to a first magneto-optical recording medium of the present invention, at least first, second and third magnetic layers are provided in this order on a substrate, and the Curie temperature of the i-th magnetic layer is increased. Is Tc _i (i = 1, 2, 3), the Curie temperature of these magnetic layers satisfies the following condition: Tc ₁ > Tc ₂ Tc ₃ > Tc ₂ , and the first magnetic layer at a temperature equal to or higher than Tc ₂ The magnetic domain wall coercive force of the layer is smaller than the magnetic domain wall coercive force of the third magnetic layer, and the exchange applied to the first magnetic layer from the third magnetic layer via the second magnetic layer within a temperature range between ambient temperature and Tc _2. In a magneto-optical recording medium in which the coupling force exceeds the coercive force energy of the first magnetic layer and the third magnetic layer is a perpendicular magnetization film, a region between adjacent information tracks of the third magnetic layer ( In the area between tracks), the area aligned with the upward magnetization direction and the downward And a region aligned with the magnetization direction.

A second magneto-optical recording medium according to the present invention is the first magneto-optical recording medium, wherein the inter-track region of the third magnetic layer is aligned with the upward magnetization direction and the downward magnetization direction. The regions aligned in the upward magnetization direction are provided on either the inside or the outside of each inter-track region.

According to a third magneto-optical recording medium of the present invention, in the above-mentioned first magneto-optical recording medium, the magnetization directions of adjacent track regions of the third magnetic layer are alternately aligned in opposite directions. Things.

In a fourth magneto-optical recording medium according to the present invention, at least first, second, third, fourth, fifth and sixth magnetic layers containing a transition metal are provided in this order on a substrate. ,
The Curie temperature of the i-th magnetic layer is defined as Tc _i (i = 1, 2, 3,
When a 4,5,6), the Curie temperature of the magnetic layer satisfies the condition of the following equation _{Tc 1> Tc 2 Tc 4>} Tc 3> Tc 2 Tc 6> Tc 4> Tc 5, Tc 2 or more At temperature, the domain wall coercive force of the first magnetic layer is smaller than the domain wall coercive force of the third magnetic layer, and the first magnetic layer passes through the second magnetic layer via the second magnetic layer within a temperature range between ambient temperature and Tc _2. The temperature at which the exchange coupling force exerted on the layer exceeds the coercive force energy of the first magnetic layer, the third magnetic layer is a perpendicular magnetization film, and the transition metal sublattice magnetization of the third magnetic layer near ambient temperature. The direction is not reversed by the magnetization reversal of the second magnetic layer or the magnetization reversal of the fourth magnetic layer, and the fourth magnetic layer and the fourth magnetic layer in the region where the transition metal sublattice magnetization direction of the sixth magnetic layer is upward at around ambient temperature. The transition metal sublattice magnetization directions of the five magnetic layers are aligned upward. In a region where the transition metal sublattice magnetization direction of the sixth magnetic layer is downward, the transition metal sublattice magnetization directions of the fourth magnetic layer and the fifth magnetic layer are aligned downward, and the transition metal sublattice magnetization direction of the sixth magnetic layer is downward. In the magneto-optical recording medium in which the magnetization is not reversed during recording / reproducing, the lattice magnetization direction is the third, fourth, fifth
And a region aligned with the direction of the transition metal sublattice magnetization of the information track regions of the fourth, fifth, and sixth magnetic layers in a region between adjacent information tracks (inter-track region) of the sixth magnetic layer. , The fourth, fifth, and sixth magnetic layers have regions aligned in the direction opposite to the direction of the transition metal sublattice magnetization in the information track regions.

According to a fifth magneto-optical recording medium of the present invention, in the above-mentioned fourth magneto-optical recording medium, the third, fourth, fifth and sixth magnetic layers have fourth, fifth and sixth inter-track regions. The direction of the transition metal sublattice magnetization of the information track region of the sixth magnetic layer is aligned with the direction of the transition metal sublattice magnetization of the information track regions of the fourth, fifth, and sixth magnetic layers. The regions aligned in the direction of the transition metal sublattice magnetization of the information track regions of the fourth, fifth, and sixth magnetic layers are one of the inner and outer regions of each inter-track region. It is provided in.

A sixth magneto-optical recording medium according to the present invention is the above-mentioned fourth magneto-optical recording medium, wherein the transition metal sublattice in the inter-track region adjacent to the third, fourth, fifth and sixth magnetic layers is provided. The directions of magnetization are alternately aligned in opposite directions.

The first magneto-optical recording method according to the present invention is characterized in that the third magnetic layer of the information track of any of the first to sixth magneto-optical recording media is provided on one of the tracks of the third magnetic layer. This is a method of forming a recording mark which is in contact with the region and which is magnetized in the same direction as the magnetization direction of the portion in contact with the inter-track region.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is an explanatory view for explaining a magneto-optical recording medium according to a first embodiment of the present invention and a magneto-optical recording method using the same. FIG. 1A shows the thickness of the medium on which recording marks are formed. 1 (b) schematically shows a state from the first magnetic layer side of the medium, in which two information tracks have oblong and substantially circular recording marks, respectively. Is recorded, and this recording mark is transferred to the first magnetic layer. FIG. 1A shows AA ′ in FIG. 1B.
The cross section of the line is shown.

In the figure, 30 is a transparent substrate, 31 is a first dielectric layer, 32 is a second dielectric layer, 11 is a first magnetic layer, 12 is a second magnetic layer, and 13 is a third magnetic layer. The arrow in the middle represents the direction of the transition metal sublattice magnetization. 24 is a recording mark, 21 is an information track, and 25 is an inter-track area, which is an area between adjacent information tracks 21. In the present invention, in particular, in the present invention, the inter-track area 25 of the third magnetic layer is magnetized upward and downward. Area is provided. FIG.
In (b), the inter-track area 25 is indicated by a line, but is not shown structurally but is shown for convenience. Reference numeral 23 denotes an upwardly magnetized region in the inter-track region 25 (in the present specification, an upwardly magnetized region is hatched along the surface normal of the magnetic film).
Reference numeral 22 denotes a guide groove for tracking the light beam on the information track 21, and the recording mark 24 denotes the information track 2.
1 is recorded.

FIG. 1 shows a case in which each of the inter-track regions 25 is composed of an upwardly magnetized region and a downwardly magnetized region.
In some cases, upwardly magnetized inter-track regions and downwardly magnetized inter-track regions may be provided alternately. In FIG. 1, the boundary between the upwardly magnetized region that is hatched and the downwardly magnetized region that is not hatched is separated by a thick line, indicating that a domain wall exists at this boundary. The domain wall is a transition region in which the magnetization changes from downward to upward, and magnetic energy (domain wall energy) is stored. In addition, in the following drawings, in order to avoid complication, the magnetization direction may be represented only by a hatched area and arrows may be omitted.

As shown in FIG. 1, a magneto-optical recording medium according to a first embodiment of the present invention
In some cases, a dielectric layer 31 is provided, first, second and third magnetic layers are provided in this order, and a third dielectric layer 32 is further provided with a second dielectric layer 32. The magneto-optical recording medium is first,
The Curie temperatures of the second and third magnetic layers are set to Tc ₁ and Tc ₁ , respectively.
If c ₂ and Tc ₃ are satisfied, the condition of Tc ₁ > Tc ₂ Tc ₃ > Tc ₂ is satisfied.

The material of the first to third magnetic layers will be described later, but a transition metal alloy or a rare earth-transition metal alloy can be used. In a rare earth-transition metal alloy, the sublattice magnetization of the rare earth metal and the sublattice magnetization of the transition metal are coupled in opposite directions, and the subtraction magnetization of both is observed as magnetization outside. In the present specification, the direction of the magnetization shall be represented by the direction of the transition metal magnetization or the direction of the transition metal sublattice magnetization, and unless otherwise specified, the magnetization shall mean the transition metal magnetization or the transition metal sublattice magnetization, The term “total magnetization” will be used to particularly indicate the subtraction magnetization observed outside.

The first, second and third magnetic layers 11, 1
2, 13 are rare earth-transition metal alloys composed of a rare earth metal element such as Gd, Tb, Dy, Ho, Nd or Sm, and an iron group transition metal such as Fe, Co or Ni (the rare earth metal content is 10%). -40 at%) materials, including Al, Ti, Cr, Pt, Au, Ag,
An element such as In, Mn, Pb or Bi may be added in a small amount.

The first magnetic layer 11 and the third magnetic layer 13 may further include a layer mainly composed of Pt or Pd and
An artificial lattice film in which layers mainly composed of o are alternately laminated, or a material constituted by combining this artificial lattice film with a rare earth metal or an iron group metal may be used.

The first to third magnetic layers are formed with the Curie temperature defined as described above. To adjust the Curie temperature to a predetermined value, for example, the F
It is well known that it can be adjusted by the ratio of e, Co or Ni. Fine adjustment can also be made by the amount of the added element or the amount of the rare earth metal. In an artificial lattice film in which layers mainly composed of Pt or Pd and layers mainly composed of Co are alternately laminated, the Curie temperature can be adjusted by adjusting the thickness or the ratio of the thickness of both layers.

The domain wall coercive force of the first magnetic layer 11 of the magneto-optical recording medium according to the first embodiment of the present invention is
At a temperature equal to or higher than the Curie temperature of 2, the domain wall coercive force of the third magnetic layer is smaller than the first magnetic layer 11 or the third magnetic layer.
It can be realized by adjusting the domain wall coercive force of the magnetic layer 13. For example, in a rare earth-transition metal alloy, the domain wall coercive force becomes weaker in the order of Tb, Dy, and Gd (or Ho) of the main rare earth element. It is known that when a magnetic film is formed by a sputtering method, a vapor deposition method, or the like, the domain wall coercive force can be adjusted by film forming conditions such as atmospheric gas pressure.
Also, since the magnetic wall has better smoothness and the domain wall moves more easily without resistance, and the domain wall coercive force decreases, the domain wall coercive force can be adjusted by controlling the film smoothness under film forming conditions.

In a multilayer magnetic film such as the magneto-optical recording medium of the present invention, an exchange force acts to align the direction of the same type of sublattice magnetization between adjacent magnetic layers in the same direction. Magnetic coupling is called exchange coupling.
In the magneto-optical recording medium according to the first embodiment of the present invention, the exchange coupling force exerted on the first magnetic layer from the third magnetic layer via the second magnetic layer depends on the coercive force energy of the first magnetic layer. temperatures above exists within a temperature range of between ambient temperature Tc _2. Therefore, by passing through this temperature during the temperature raising / lowering operation, the ambient temperature or Tc
_At a temperature between ₂ , the magnetization directions of the first magnetic layer 11 and the second magnetic layer 12 can be aligned with the magnetization direction of the third magnetic layer. In this specification, "ambient temperature" refers to the temperature of the magneto-optical recording medium during operation.

The first to third magnetic layers satisfying the above conditions are specifically shown below. That is, the first magnetic layer is made of a material having a relatively small domain wall coercivity, for example, GdFe, Gd
A material containing FeCo, GdNdFeCo, GdDyFe, or the like as a main component, or an artificial lattice film in which a layer mainly containing Pt or Pd and a layer mainly containing Co are alternately stacked can be used. The thickness of the first magnetic layer is 10 to obtain a required signal amplitude and perform a stable reproducing operation.
nm to 100 nm is desirable. The Curie temperature Tc ₁ of the first magnetic layer needs to be higher than the Curie temperature Tc ₂ of the second magnetic layer, and is desirably 180 ° C. or higher so that the Kerr rotation angle does not decrease significantly due to the temperature rise by the reproduction light beam ( The upper limit of the Curie temperature of the first magnetic layer is not specified because there is no upper limit of what degree of operation the temperature must be below.

The second magnetic layer is made of a material whose Curie temperature can be adjusted to a relatively low temperature, for example, Dy.
Fe, DyFeCo, TbFe, TbFeCo, TbD
A material containing yFe or TbDyFeCo or a material obtained by adding Gd or Ni to them as a main component can be used. The thickness of the second magnetic layer is desirably 3 nm to 80 nm so that the exchange coupling between the first magnetic layer and the third magnetic layer can be sufficiently cut at a Curie temperature Tc ₂ or higher and a stable reproducing operation is performed. Second Curie temperature Tc ₂ of the magnetic layer is required to be lower than the Curie temperature Tc ₃ Curie temperature Tc ₁ and the third magnetic layer of the first magnetic layer, and in order to perform a stable reproducing operation 60 ° C. or higher 25
0 ° C. or less is desirable.

The third magnetic layer is desirably a perpendicular magnetization film having a large perpendicular magnetic anisotropy in order to stably retain recorded information. As the material, for example, DyFe, DyFeCo, T
bFe, TbFeCo, TbDyFe or TbDy
Material containing FeCo as a main component or Pt or P
An artificial lattice film in which layers mainly composed of d and layers mainly composed of Co are alternately laminated can be used. The thickness of the third magnetic layer is set to 10 in order to stably hold recorded information against changes such as domain wall motion and magnetization disappearance of the first magnetic layer and the second magnetic layer.
nm to 250 nm is desirable. The Curie temperature Tc ₃ of the third magnetic layer needs to be higher than the Curie temperature Tc ₂ of the first magnetic layer, has a practical recording sensitivity, and is 120 ° C. or more and 360 ° C. for performing a stable reproducing operation. C or lower is desirable.

As shown in FIG. 1A, in the magneto-optical recording medium according to the first embodiment of the present invention, the first dielectric layer 31 and the second dielectric layer 32 protect the magnetic layer. For example, Al, Si, Ge, Ta or Y
For example, an oxide, a nitride, or an oxynitride can be used. In particular, the first dielectric layer 31 on the light incident side is
Since it is used to adjust the reflectance by the light interference effect, a highly transparent material is used. As the substrate 30, for example, a transparent substrate such as glass or polycarbonate can be used, and the guide groove 22 may be V-shaped or U-shaped.

That is, the magneto-optical recording medium of the present invention does not require any additional conditions for the depth of the guide groove, and therefore has good tracking and crosstalk characteristics, and is inexpensive without requiring a special film forming method. It can be manufactured without using a process that causes changes in the shape and properties of the film, such as annealing and etching.Therefore, there is no risk of causing defects or deterioration in the physical properties of the magnetic film. Can be performed.

Embodiment 2 FIG. FIG. 9 is an explanatory diagram illustrating a magneto-optical recording medium according to a second embodiment of the present invention.
9A schematically shows a cross section in the thickness direction of the medium on which a recording mark is formed, and FIG. 9B schematically shows a state of the medium from the first magnetic layer side. It is shown that oblong and substantially circular recording marks are recorded on the information tracks of the book, respectively, and are transferred to the first magnetic layer. FIG. 9A shows a cross section taken along line AA ′ in FIG. 9B. In the drawing, reference numeral 14 denotes a fourth magnetic layer, 15 denotes a fifth magnetic layer, 16 denotes a sixth magnetic layer, and the others are the same as those in FIG. In particular, in the present invention, the inter-track region 25 of the third, fourth, fifth, and sixth magnetic layers has a transition metal sublattice magnetization of the information track region of the fourth, fifth, and sixth magnetic layers. There is a region aligned in the direction and a region aligned in the direction opposite to the direction of the transition metal sublattice magnetization of the information track regions of the fourth, fifth and sixth magnetic layers. 23 is the fourth in the inter-track area 25;
This is a region aligned in the direction of the transition metal sublattice magnetization in the information track regions of the fifth and sixth magnetic layers. Note that FIG. 9 shows a state in which oval and substantially circular recording marks 24 are recorded on two information tracks. An obliquely upward magnetized region and a non-obliquely downward magnetized region are shown. The boundary is separated by a bold line, indicating that a domain wall exists at this boundary.

The magneto-optical recording medium according to the second embodiment of the present invention is, as shown in FIG. 9, a third magneto-optical recording medium having the three magnetic layers shown in the first embodiment. The fourth magnetic layer 14, the fifth magnetic layer 15, and the sixth magnetic layer 16 are provided on the magnetic layer 13. Information is stored in the third magnetic layer 1
3 and transferred to the first magnetic layer 11, and the Curie temperature Tc ₂ of the second magnetic layer 12 is recorded.
The point that the domain wall of the magnetic domain of the first magnetic layer is moved in the region where the temperature is increased to the above temperature, and the domain is enlarged and reduced and reproduced by the domain wall movement detection method is that the magneto-optical recording according to the first embodiment of the present invention is performed. Same as the medium.

In the magneto-optical recording medium according to the second embodiment of the present invention, the Curie temperatures of the first, second, third, fourth, fifth, and sixth magnetic layers are set to Tc ₁ , Tc ₂ , and Tc ₂ , respectively. Tc ₃ , T
If c ₄ , Tc ₅ and Tc ₆ are satisfied, the condition of Tc ₁ > Tc ₂ Tc ₄ > Tc ₃ > Tc ₂ Tc ₆ > Tc ₄ > Tc ₅ is satisfied.

The domain wall coercive force of the first magnetic layer 11 of the magneto-optical recording medium according to the second embodiment of the present invention is
At a temperature equal to or higher than the Curie temperature of 2, the magnetic wall coercive force of the third magnetic layer is smaller than that of the third magnetic layer, but this can be realized by adjusting the magnetic wall coercive force similarly to the magneto-optical recording medium having the three magnetic layers.

In the magneto-optical recording medium according to the second embodiment of the present invention, the exchange coupling force exerted on the first magnetic layer from the third magnetic layer via the second magnetic layer is different from that of the first magnetic layer. The temperature at which the coercive force energy exceeds Tc
Lies in the temperature range between ₂ .

In the magneto-optical recording medium according to the second embodiment of the present invention, the third magnetic layer is a perpendicular magnetic film, and the transition metal sublattice magnetization direction of the third magnetic layer is near the ambient temperature. It is not reversed by the magnetization reversal of the second magnetic layer and the magnetization reversal of the fourth magnetic layer. In the vicinity of the ambient temperature, the sixth
In the region where the transition metal sublattice magnetization direction of the magnetic layer is upward, the transition metal sublattice magnetization directions of the fourth magnetic layer and the fifth magnetic layer are aligned upward, and the transition metal sublattice magnetization direction of the sixth magnetic layer is upward. In the downward region, the transition metal sublattice magnetization directions of the fourth magnetic layer and the fifth magnetic layer are aligned downward. Further, the magnetization direction of the transition metal sublattice of the sixth magnetic layer does not reverse during recording and reproduction. Further, the fourth magnetic layer 14,
The fifth magnetic layer 15 and the sixth magnetic layer 16 can be overwritten with new information without going through a process for erasing old recording marks when information is recorded. This is a magnetic layer that enables overwriting.

Specific examples of the magnetic layer satisfying the above conditions are shown below. The fourth magnetic layer is a magnetic layer having a role of determining the magnetization direction of the third magnetic layer since the magnetization direction is transferred to the third magnetic layer when recording. As a material,
For example, TbFeCo, DyFeCo or TbDyF
A material containing eCo or the like or a material to which Gd is added as a main component can be used. The thickness of the fourth magnetic layer is from 10 nm to 100 n in order to perform a stable recording operation.
m is desirable. As described above, the Curie temperature Tc ₄ of the _fourth magnetic layer needs to be higher than the Curie temperature Tc ₃ of the _third magnetic layer and the Curie temperature Tc ₅ of the fifth magnetic layer, and in order to obtain good recording characteristics. Is preferably 180 ° C. or more and 360 ° C. or less.

The fifth magnetic layer disconnects the exchange coupling between the fourth magnetic layer and the sixth magnetic layer at the time of overwriting so that the fourth magnetic layer is directed by the external magnetic field without being bound by the sixth magnetic layer. And a material capable of adjusting the Curie temperature to a relatively low temperature, for example, Dy.
Fe, DyFeCo, TbFe, TbFeCo, TbD
A material containing yFe or TbDyFeCo or a material obtained by adding Ni to these as a main component can be used. The thickness of the fifth magnetic layer is 3 nm to 50 nm so that the exchange coupling between the fourth magnetic layer and the sixth magnetic layer can be sufficiently cut at a Curie temperature Tc ₅ or higher and a stable overwrite recording operation is performed. desirable. The Curie temperature Tc ₅ of the fifth magnetic layer needs to be lower than the Curie temperature Tc ₄ of the fourth magnetic layer, and is preferably 70 ° C. or more and 250 ° C. or less for performing a stable overwrite recording operation.

The sixth magnetic layer is a layer for initializing the magnetization direction of the fourth magnetic layer downward by exchange coupling via the fifth magnetic layer after overwrite recording so that overwriting can be repeatedly performed. It is necessary to keep the downward magnetization at all times during recording and reproduction. Therefore, as a material, a material that can adjust the Curie temperature relatively high,
For example, TbCo, TbFeCo, DyCo, DyFeC
A material containing o or TbDyFeCo as a main component can be used. The thickness of the sixth magnetic layer is preferably 1 in order to obtain good recording characteristics and stably maintain downward magnetization.
5 nm to 250 nm is desirable. The Curie temperature Tc ₆ of the sixth magnetic layer needs to be higher than the Curie temperature Tc ₄ of the fourth magnetic layer, and is preferably 220 ° C. or higher in order to perform a stable recording / reproducing operation (the Curie temperature of the sixth magnetic layer). The upper limit of the temperature is not specified because there is no upper limit that the temperature must be below what operating temperature.)

For the layers other than the fourth, fifth and sixth magnetic layers, the same materials as those described in the first embodiment can be used.

That is, the magneto-optical recording medium according to the second embodiment of the present invention allows direct overwriting as compared with the magneto-optical recording medium according to the first embodiment.

Embodiment 3 FIG. Next, a third embodiment of the present invention will be described with reference to FIG. 1, in which a recording mark is formed on an information track of a magneto-optical recording medium according to the first embodiment of the present invention. Information is stored in the third magnetic layer 1
3 is recorded and held as the direction of magnetization. In the magneto-optical recording medium of the first embodiment, the exchange coupling force exerted on the first magnetic layer from the third magnetic layer via the second magnetic layer exceeds the coercive force energy of the first magnetic layer. By passing through this temperature during the temperature raising / lowering operation, since the temperature is in the temperature range between the ambient temperature and Tc ₂ , at the ambient temperature or at the temperature between the ambient temperature and Tc ₂ The magnetization directions of the first magnetic layer 11 and the second magnetic layer 12 can be aligned with the magnetization direction of the third magnetic layer.

It should be noted that the recording mark 24 is
Of the two inter-track regions 25 formed above and sandwiching the information track 21, one of the inter-track regions on which the third magnetic layer is aligned upward is in contact with the upward magnetized region 23. It is magnetized upward in the same direction as the contacting region 23. As a result, only one of the two left and right side surfaces along the information track of the recording mark is in contact with the area 23.

Next, a third embodiment of the present invention will be described with reference to FIG. 9 for a case where a recording mark is formed on an information track of a magneto-optical recording medium according to the second embodiment of the present invention. I do. Information is recorded and held as the direction of magnetization of the third magnetic layer 13, and the first magnetic layer 11, the second magnetic layer 11, and the second magnetic layer 13 are stored in the same manner as in the case of using the magneto-optical recording medium of the first embodiment of the present invention. The magnetization direction of the magnetic layer 12 can be aligned with the magnetization direction of the third magnetic layer.

The recording mark is formed on the information track 21 and, among the two inter-track areas 25 sandwiching the information track 21, the recording mark is formed between one track on which the third magnetic layer is aligned upward. The region is in contact with the upward magnetized region 23 and is magnetized upward in the same direction as the contacted region 23. As a result, only one of the two left and right side surfaces along the information track of the recording mark is the area 2
It touches 3.

The exchange coupling force from the sixth magnetic layer 16 causes the fourth magnetic layer 14 and the fifth magnetic layer 1 in the region where the sixth magnetic layer 16 has an upward magnetization near the ambient temperature.
5 is aligned with upward magnetization, and in the region where the sixth magnetic layer 16 has downward magnetization, the fourth magnetic layer 14 and the fifth magnetic layer 15
Are aligned with downward magnetization. Information Track Part Six
The magnetic layer is initialized to downward magnetization, and a part of the inter-track region is initialized to be aligned with upward magnetization.
When the magnetic film is heated while applying an external external magnetic field to initialize the inter-track region to upward magnetization, the third magnetic layer is also aligned to upward magnetization, and as a result, is aligned to upward magnetization in the inter-track region. In the initialized portion, at least the third, fourth, fifth, and sixth magnetic layers are all aligned with upward magnetization.

That is, in the third embodiment of the present invention, the magneto-optical recording method is an optimal recording method that can obtain a good reproduction signal with less noise, and deteriorates even when recording and reproduction are repeated. And good recording / reproducing characteristics can be obtained.

Hereinafter, the present invention will be described in more detail with reference to specific examples. The present invention is not limited to the following examples without departing from the gist thereof, regardless of the specific examples in the description.

[0051]

[Embodiment 1] 40nm depth, 0.2μ width on the surface
A transparent disk 1.2 mm thick and 13 cm in diameter having a substantially V-shaped spiral guide groove 22 having a track pitch of 0.85 μm and having a diameter of 13 cm was used as the substrate 30, and the thin film shown in Table 1 was placed thereon. Films are sequentially formed by a sputtering method, and U is formed on the second dielectric layer 32 for mechanical protection.
By forming a V-cured resin layer, a magneto-optical recording medium shown in FIG.

[0052]

[Table 1]

For this magneto-optical recording medium, an optical disk tester having an optical pickup using a laser diode having a wavelength of 650 nm as a light source was used.
m, and a recording / reproducing experiment described below was performed at a radial position of 30 mm on the disk.

<Initialization of inter-track area> The light beam is tracked on the guide groove 22 having a width of 0.2 μm, and an offset voltage is applied to the tracking control signal so that the light beam is moved from the center line of the guide groove 22 to the outer periphery. About 0.1 on the side
Tracking was performed with a shift of μm. Next, while applying an external magnetic field of 300 Oe upward, the light beam is DC at 6 mW.
Lighted. As a result, the temperature of the magnetic film becomes about Tc ₃ or higher, and the magnetization of the third magnetic layer 13 becomes upward in the same direction as the external magnetic field when the temperature is lowered. Further, when the temperature of the magnetic film becomes equal to or lower than Tc ₂ , the magnetization of the second magnetic layer 12 is aligned upward by exchange coupling from the third magnetic layer 13, and further within the temperature range between ambient temperature and Tc ₂ , Since the temperature at which the exchange coupling force exerted on the first magnetic layer via the second magnetic layer exceeds the coercive force energy of the first magnetic layer exists, the first magnetic layer 11 is also aligned with upward magnetization. As a result, as shown in FIG.
The upward magnetized region 23 is formed so as to be biased toward the outer peripheral side of. This operation is called initialization.

<Erase> Next, a light beam is applied to the information track 21.
And the light beam was DC-lit at 7 mW while applying an external magnetic field of 300 Oe downward. As a result, the magnetization direction of the magnetic layer in the region of the information track 21 sandwiched between the inter-track regions 25 is aligned downward.

<Recording> Next, the light beam is applied to the information track 21.
Then, while applying an external magnetic field of 300 Oe upward, the light beam intensity was irradiated to the recording signal frequency of 15 MHz while being intensity-modulated to 1 mW and 8 mW. As a result, only the portion irradiated with 8 mW becomes a recording mark of upward magnetization, and a pattern in which a mark and a space having a length of about 0.25 μm alternately appear is recorded. Note that this is a recording method based on the light intensity modulation recording method, and a similar recording pattern could be recorded even by a recording method based on the magnetic field modulation recording method.

<Reproduction> Next, a reproduction operation based on the domain wall motion detection method will be described. FIG. 2 shows a substantially circular recording mark 2 recorded on one information track of the magneto-optical recording medium shown in FIG.
FIG. 4 is an explanatory diagram showing a case of reproducing No. 4; FIG. 2 (a),
(B) and (c) are illustrations showing the operation of the upward magnetized region over time with time, and the magneto-optical recording medium moves downward from above in the drawing. The mark x drawn at the center of the recording mark 24 indicates the position of the recording mark recorded and held in the third magnetic layer 13, and the position of the recording mark is shifted downward in the drawing with the movement of the magneto-optical recording medium. Moving towards. FIG. 2D schematically shows a cross section in the thickness direction of the medium in which a recording mark is formed on one information track. FIG.
In (d), the shaded area is a region where the first magnetic layer 11 has upward magnetization, 26 is a light beam, and 40 is a temperature rising region by the light beam 26.

That is, the temperature of the magnetic layer is raised by the irradiation of the light beam 26, and a part of the second magnetic layer 12 having the lowest Curie temperature among the first to third magnetic layers has a Curie temperature T.
It is heated to c ₂ or more in a non-magnetic material. Magnetic layer temperature is T
In Figure 2 the raised portion surrounded by an isothermal line is a c ₂ is shown as a raised region 40. The heating region 40 is originally
Although it occurs immediately below the light beam 26, since the magneto-optical recording medium is moving, the temperature rising area 40 and the highest temperature position shift in the moving direction of the magneto-optical recording medium from immediately below the light beam. ing.

In FIG. 2A, the recording mark 24 does not enter the temperature rising area 40. In FIG. 2B, the leading edge of the recording mark 24 is inside the temperature rising area 40. At the leading edge position of the recording mark 24, the second magnetic layer 12 becomes non-magnetic and the exchange coupling between the first magnetic layer 11 and the third magnetic layer 13 is cut off.
The first domain wall moves away from the binding by exchange coupling from the third magnetic layer 13 to a position that is energetically stable.

In the magneto-optical recording medium of the present invention, the domain wall coercive force of the first magnetic layer 11 is higher than the third magnetic layer 1 at a temperature of Tc ₂ or higher.
3 is smaller than the domain wall coercive force of the first magnetic layer 11.
When the binding due to exchange coupling from the third magnetic layer 13 has disappeared, the domain wall of the recording mark 24 becomes extremely easy to move. In this case, the domain wall energy density per unit area decreases as the temperature increases, so that the energetically stable position is the highest temperature portion near the center of the temperature rising region 40. FIGS. 2B and 2D illustrate a state where the domain wall of the first magnetic layer 11 at the leading edge of the recording mark moves to the vicinity of the center of the temperature-raising region 40. Due to the domain wall movement, the upward magnetic domain of the first magnetic layer 11 expands, and the reproduction signal level sharply increases. Record mark 2 after more time
When the trailing edge of the recording mark 24 enters the temperature rising area 40 as shown in FIG. 2C, the domain wall of the first magnetic layer 11 at the trailing edge of the recording mark 24 becomes the third as in the case of the leading edge. It moves away from the binding due to exchange coupling from the magnetic layer 13 toward the vicinity of the center of the temperature-rising region 40 that is stable in terms of energy. At this time, the upward magnetic domain of the first magnetic layer 11 is reduced, and the reproduction signal is rapidly reduced to zero.
FIG. 2C illustrates a state in which the upward magnetic domains of the first magnetic layer 11 are reduced. However, depending on the balance between the linear velocity of the magneto-optical recording medium and the moving speed of the domain wall, the state is not limited to the reduction. The upward magnetic domains of the first magnetic layer 11 may disappear (collapse).

In the above-described reproducing operation, the reproduced signal greatly changes at the time when the domain wall at the leading edge and the trailing edge of the recording mark 24 moves, and is called domain wall movement detection. In the domain wall moving operation described above, the change in which the magnetic domain expands from FIG. 2A to FIG.
Even when the magnetic domain decreases, the domain wall length or the total area of the domain walls obtained by multiplying the domain wall length by the film thickness of the first magnetic layer 11 does not change. For example, when changing from FIG. 2A to FIG. 2B, the domain wall on the right side of the recording mark 24 becomes longer,
Upward magnetized area 2 between the tracks by the same length
This is because the domain wall length of No. 3 is shortened and both are canceled out.
2B to 2C, the recording marks 24 are similarly formed.
However, the domain wall length of the upward magnetization region 23 between the tracks becomes longer by the same length, but the two walls cancel each other. Since the domain wall energy is obtained by multiplying the domain wall energy density by the domain wall area, the domain wall can be moved to a position which is energetically stable only by the temperature distribution without changing the domain wall area.

In the above description of the operation, the magnetization directions of the first magnetic layer and the second magnetic layer are always aligned with the magnetization directions of the recording mark patterns recorded on the third magnetic layer due to exchange coupling near the ambient temperature. I explained that it was
Depending on the delicate energy balance that also takes into account items such as the decrease in magnetostatic energy due to the formation of fine magnetic domains, a part of the recording mark of the first magnetic layer may become downwardly magnetized. In the case of one magnetic layer, the recording domain may not be maintained in the first magnetic layer at the ambient temperature, and the first magnetic layer may be collapsed. In any case, the recording information itself is held as a recording mark pattern of the third magnetic layer. In such a case, the temperature is such that the exchange coupling force exerted on the first magnetic layer from the third magnetic layer via the second magnetic layer by the reproduction light beam irradiation exceeds the coercive force energy of the first magnetic layer. By raising the temperature of the magnetic layer to a temperature at which the recording magnetic domain can be maintained in the first magnetic layer, the recording mark can be completely raised on the first magnetic layer. This is because, for example, the exchange coupling force adjusting layer that strengthens the exchange coupling between the first magnetic layer and the third magnetic layer when the temperature is increased is combined with the first magnetic layer and the second magnetic layer or the second magnetic layer. It is also possible to interpose between the third magnetic layers.

When a recorded mark of 15 MHz was reproduced at a reproducing power of 2.2 mW without applying an external magnetic field, the optical recording and crosstalk characteristics were good.
The CN ratio, which is the ratio between the MHz carrier signal level and the noise level near the frequency, is considered to be almost a practical level.
8 dB was obtained. At this time, an external magnetic field was applied within the range of ± 500 Oe and adjusted.
With Oe, the maximum value of the CN ratio was 48.5 dB. This is considered to be because the application of an external magnetic field has improved the energy balance when moving the domain wall.There is no practical problem if there is no external magnetic field during reproduction, but if the external magnetic field is adjusted and applied, This indicates that higher performance can be obtained. In a normal reproduction method other than the domain wall movement detection method, discrimination of such a fine recording mark as a reproduction signal cannot exceed the limit of optical resolution.

Comparative Example 1 FIG. 3 shows a magneto-optical recording medium according to the first embodiment, which is different from the magneto-optical recording medium according to the first embodiment only in that no upward magnetization region 23 is provided in the inter-track region. FIG. 9 is a diagram illustrating a change over time in a magnetization region when it is assumed that a substantially circular recording mark 24 can be reproduced by the domain wall movement detection method.
3 (a), 3 (b) and 3 (c) are explanatory diagrams showing the operation of the upward magnetized region with the passage of time over time. , The cross mark drawn at the center of the recording mark 24 indicates the position of the recording mark recorded and held on the third magnetic layer. Accordingly, it is moving downward in the drawing. in this case,
The substantially circular recording mark 24 recorded on one information track changes the domain wall area with the change from FIG. 3A to FIG.
Since the domain wall energy increases, the movement of the domain wall at the leading edge of the recording mark from FIG. 3 (a) to FIG. 3 (b) requires a reduction in domain wall energy density due to a large temperature distribution exceeding the increase in domain wall energy. Yes, not easily realized. Even if it can be realized, the operation becomes unstable due to the small width of the domain wall energy reduction. Therefore, Japanese Patent Application Laid-Open No. Hei 6-290496 (see p.
(2nd column, first to third lines) states that "because there is a magnetic domain surrounded by a closed magnetic domain wall, the operation becomes unstable when the magnetic domain wall is moved in a direction in which the magnetic domain is enlarged, and noise increases". As described above, problems such as an increase in noise of a reproduced signal occur. Actually, when the recording and reproduction were performed under the same conditions as in Example 1, the noise was high, and the maximum C / N ratio was only 25 dB.

Comparative Example 2 FIG. 4 shows a magneto-optical recording medium according to the first embodiment, which is different from the magneto-optical recording medium of the first embodiment only in that only the upward magnetization region 23 is provided in the inter-track region 25. FIG. 6 is a diagram for explaining a change with time of a magnetization region when it is assumed that a substantially circular recording mark 24 recorded on the magnetic recording medium can be reproduced by the domain wall movement detection method.
Example FIG. 7B corresponds to FIG. 7B. FIGS. 4A, 4B, and 4C are explanatory views showing the operation of the upward magnetized region with the passage of time over time. The mark x drawn at the center of the recording mark 24 indicates the position of the recording mark 24 recorded and held on the third magnetic layer. Is moving downward in the drawing. In this case, the substantially circular recording marks 24 recorded on one information track show that the domain wall area and the domain wall energy increase with the change from FIG. 4B to FIG. 4C. In order to realize the movement of the domain wall at the trailing edge of the recording mark in c), it is necessary to reduce the domain wall energy density due to the temperature distribution so as to exceed the increase in domain wall energy. Further, even if it can be realized, the operation becomes unstable due to the small range of the reduction of the domain wall energy, and problems such as an increase in noise of the reproduced signal occur. Actually, when the recording and reproduction were performed under the same conditions as in Example 1, the noise was still high and the CN ratio was only 29 dB at the maximum.

Embodiment 2 FIG. FIG. 5 is an explanatory view for explaining a magneto-optical recording medium of the present invention and a magneto-optical recording method using the same. FIG. 5 (a) schematically shows a cross section in the thickness direction of the medium on which recording marks are formed. FIG. 5B schematically shows a state of the medium from the side of the first magnetic layer, in which oblong and substantially circular recording marks are recorded on two information tracks, respectively. Have been. FIG. 5 (a)
Shows a cross section taken along line AA ′ in FIG.
The magneto-optical recording medium shown in FIG. 5 is different from the magneto-optical recording medium of the first embodiment in that the guide groove is formed along the center line of the guide groove without biasing the upward magnetized portion 23 between the tracks 25 from the guide groove 22. It is magnetized upward so as to cover it and the other is magnetized downward. The only difference from the first embodiment is that the recording mark 24 is recorded with the recording mark 24 deviated slightly inward from the center line of the information track 21 of the medium. Also in this case, as in the first embodiment, only one of the two side surfaces of the recording mark 24 is in a recording state in contact with the upwardly magnetized region 23 between the inter-track regions 25, so that good reproduction characteristics were obtained as in the first embodiment. When recording and reproduction were performed under the same conditions as in Example 1, the CN ratio was 47.7 dB.

Embodiment 3 FIG. FIG. 6 shows a magneto-optical recording medium according to the second embodiment, which is different from the magneto-optical recording medium according to the second embodiment only in that the entire adjacent inter-track region 25 is alternately aligned in the upward magnetization and the downward magnetization every one turn. FIG. 6 is an explanatory view for explaining a magneto-optical recording method using the same, and FIG.
6A schematically shows a cross section in the thickness direction of the medium on which the recording mark 24 is formed, and FIG. 6B schematically shows a state of the medium from the first magnetic layer side. Oval and substantially circular recording marks 2 are provided on the two information tracks 21 respectively.
4 is recorded. FIG.
FIG. 6A shows a cross section taken along line AA ′ in FIG. Also in this case, as in the second embodiment, only one of the two side surfaces of the recording mark 24 is in a recording state in contact with the upward magnetized region 23 between the tracks, so that good reproduction characteristics were obtained as in the second embodiment. When recording and reproduction were performed under the same conditions as in Example 1, the CN ratio was 47.9 dB.

Embodiment 4 FIG. FIG. 7 shows that V
Description of a magneto-optical recording medium and a magneto-optical recording method using the same in that a transparent substrate having land tracks and groove tracks having substantially the same width is used instead of a letter-shaped guide groove, which is different from the first embodiment. FIG. 7A schematically shows a cross section in the thickness direction of the medium on which recording marks are formed, and FIG. 7B schematically shows a state of the medium from the first magnetic layer side. The figure shows a state in which oval and substantially circular recording marks are recorded on two information tracks, respectively, in which 41 is a land track and 42 is a groove track. Note that FIG. 7A shows A in FIG. 7B.
The section along the line A 'is shown. This embodiment is an embodiment in the case where the present invention is applied to a so-called land / groove recording system for recording information on both land tracks and groove tracks. The width of each of the land track 41 and the groove track 42 is 0.5 μm, and the depth of the groove track is 48 nm. The upward magnetized portion 23 of the inter-track region 25 has a width of about 0.1 μm, is provided at the end of the land track and the end of the groove track, and the recording mark 24 recorded at the center of each track is one side. Only the side surface is in contact with the upward magnetized portion 23.
As a result, good reproduction characteristics were obtained as in Example 1. When recording and reproduction were performed under the same conditions as in Example 1, the CN ratio was 47.4 dB.

Embodiment 5 FIG. FIG. 8 shows a magneto-optical recording medium according to the fourth embodiment which differs from the magneto-optical recording medium according to the fourth embodiment in that adjacent inter-track regions are alternately aligned with upward magnetization and downward magnetization every turn. FIG. 8A schematically shows a cross section in the thickness direction of the medium on which recording marks are formed, and FIG. FIG. 4 schematically shows a state from one magnetic layer side, in which oblong and substantially circular recording marks are recorded on two information tracks, respectively. FIG. 8A shows a cross section taken along line AA ′ in FIG. 8B. Inter-track area 25
The upward magnetized portion 23 has a width of about 0.15 μm, and is provided at every other boundary portion between the land track 41 and the groove track 42, and the recording mark 24 recorded at the center of each track has one side. Only the side surface is in contact with the upward magnetized portion 23. As a result, good reproduction characteristics were obtained as in Example 4. When recording and reproduction were performed under the same conditions as in Example 1, the CN ratio was 48.1 dB.

Embodiment 6 FIG. 40nm depth, 0.2 width on the surface
1.2 mm thick, 13 mm in diameter having a substantially V-shaped spiral guide groove 22 of μm and a track pitch of 0.85 μm.
cm of polycarbonate disc as a transparent substrate 30, and thin films shown in Table 2 are sequentially formed thereon by a sputtering method, and further a second dielectric layer 3 is provided for mechanical protection.
A UV curable resin layer was formed on No. 2 to produce a magneto-optical recording medium shown in FIG.

[0071]

[Table 2]

For this magneto-optical recording medium, an optical disk tester having an optical pickup using a laser diode having a wavelength of 650 nm as a light source was used.
m, and a recording / reproducing experiment described below was performed at a radial position of 30 mm on the disk.

<Initialization of Sixth Magnetic Layer> The rare earth transition metal alloy is a ferrimagnetic material in which the rare earth metal sublattice magnetization and the transition metal sublattice magnetization are coupled in opposite directions. Are oriented in the same direction as the total magnetization, and the non-dominant sublattice magnetization is oriented in the opposite direction to the total magnetization. In the alloy system used for the sixth magnetic layer 16, when Tb is about 21 atomic% at ambient temperature, the transition metal sublattice magnetization and the rare earth metal sublattice magnetization just balance, and the compensation composition becomes such that the total magnetization becomes zero. The sixth magnetic layer 16 of the magneto-optical recording medium of the present embodiment has a rare earth metal sublattice magnetization predominance because the Tb composition is 26 atomic% and Tb is larger than the compensation composition, and at the ambient temperature, the direction of the transition metal sublattice magnetization is The direction is opposite to the direction of the total magnetization. Upward to the magneto-optical recording medium of the present embodiment (upward in FIG. 9B)
And the reversal magnetic field at an ambient temperature of the sixth magnetic layer 16 is 10
When an external magnetic field of 15 kOe exceeding kOe was applied, the total magnetization of the sixth magnetic layer 16 was aligned upward with the external magnetic field, and the transition metal sublattice magnetization was aligned downward and initialized. At this time, the magnetizations of the fourth magnetic layer 14 and the fifth magnetic layer 15 were also aligned upward by exchange coupling from the sixth magnetic layer 16. If the reversal magnetic field at the ambient temperature of the sixth magnetic layer 16 is extremely large, the magneto-optical recording medium may be heated to a temperature at which the reversal magnetic field decreases, and an external magnetic field may be applied to initialize the medium. For example, the Curie temperature T of the sixth magnetic layer 16 is changed by a light beam.
When the temperature was raised to around c _6, the sixth magnetic layer 16 of the magneto-optical recording medium of this embodiment is the total magnetization by applying a downward external magnetic field since the vicinity of the Curie temperature is dominant transition metal sublattice magnetization of a transition metal Both the sub-magnetizations are aligned downward, and the transition metal sub-lattice magnetization is initialized downward when the temperature is lowered to the ambient temperature.

<Initialization of Inter-Track Area> Next, the light beam is tracked on the guide groove 22 having a width of 0.2 μm, and an offset voltage is applied to the tracking control signal so that the light beam is centered on the guide groove 22. From the outside to the outer peripheral side by about 0.1 μm. Then 300O
e, while applying an external magnetic field upward, the light beam
W turned on DC. As a result, the temperature of the magnetic film becomes Tc ₆
The area of the sixth magnetic layer 16 irradiated with the light beam was initialized to upward magnetization. After the sixth magnetic layer 16 is aligned with the upward magnetization, the fifth magnetic layer 15, the fourth magnetic layer 14,
The third magnetic layer 13, the second magnetic layer 12, and the first magnetic layer 11 are sequentially aligned in the upward magnetization. As a result, as shown in FIG. 9B, an upward magnetized region 23 is formed biased toward the outer peripheral side of the inter-track region 25. The initialization of the sixth magnetic layer and the initialization of the inter-track region 25 need only be performed once at first. In the magneto-optical recording medium having six magnetic layers shown in the present embodiment, the erasing step is not necessary as in the magneto-optical recording medium having three magnetic layers as shown in the above-mentioned first to fifth embodiments. You can overwrite directly as shown.

<Recording> The light beam is tracked on the center line of the information track 21 and the intensity of the light beam is adjusted to the recording signal frequency 1 while applying an external magnetic field of 300 Oe upward.
Irradiation was performed at 5 MHz with intensity modulated into two values of 5 mW and 11 mW. As a result, the third magnetic layer 13 in the region irradiated with 5 mW is magnetized downward and is in an erased state.
In the third magnetic layer in the region irradiated with mW, a recording mark 24 having an upward magnetization was formed, and a pattern in which a recording mark having a length of about 0.25 μm and a space appeared alternately was overwritten. Recording with this high power (here, 11 mW, hereinafter represented by PH) is called a high process, and erasing with low power (here, 5 mW, hereafter represented by PL) is called a low process, which will be further described below.

<< High Process >> FIG. 10 is an explanatory diagram for explaining a recording process at a high power on the magneto-optical recording medium of the present invention. FIG. 10A shows a magnetization state when PH is irradiated. By the PH irradiation, the temperature of the magnetic film is raised to a temperature of Tc ₄ or more and Tc ₆ or less, and the second, third, fourth,
The temperature of the fifth magnetic layer becomes higher than the Curie temperature, and the fifth magnetic layer becomes a non-magnetic material (indicated by a cross in the figure). When the PH irradiation is stopped and the temperature of the magnetic film becomes Tc ₄ or less, the magnetization of the fourth magnetic layer 14 becomes upward in the same direction as the external magnetic field as shown in FIG. 10B. When the temperature of the magnetic film further falls below Tc ₃ , the magnetization of the third magnetic layer 13 appears upward as shown in FIG. 10C, and when the temperature of the magnetic film further falls below Tc ₅ , FIG.
As shown in (d), the magnetization of the fifth magnetic layer 15 appears. At this time, the exchange coupling force from the fourth magnetic layer 14 to the fifth magnetic layer 15 causes the magnetization from the sixth magnetic layer 16 to the fifth magnetic layer 15 to change. If the exchange coupling force is set to be larger, the magnetization of the fifth magnetic layer becomes upward in line with the upward magnetization of the sixth magnetic layer 16. Further, the downward magnetization of the fourth magnetic layer 14 also becomes upward due to the exchange coupling force from the fifth magnetic layer (this is called initialization of the fourth magnetic layer). Further, when the temperature of the magnetic film becomes Tc ₂ or less, FIG.
As shown in 0 (e), the magnetization of the second magnetic layer 12 appears to be aligned with the upward magnetization of the third magnetic layer. By the high process described above, a recording mark of upward magnetization is formed on the third magnetic layer.

<< Low Process >> FIG. 11 is an explanatory view for explaining a recording process at a low power on the magneto-optical recording medium of the present invention. FIG. 11A shows a magnetization state when PL is irradiated. The magnetic film temperature is Tc ₃ or more by PL irradiation,
The temperature is raised to a temperature of Tc ₄ or less. When the PL irradiation is stopped and the temperature of the magnetic film becomes equal to or lower than Tc _3, the magnetization of the third magnetic layer 13 is downwardly aligned with the magnetization of the fourth magnetic layer 14 which has been initialized to downward magnetization as shown in FIG. Becomes Furthermore appeared on the magnetization of the fifth magnetic layer 15 is downward as the magnetic film temperature is Tc ₅ below shown in FIG. 11 (c), the as shown in further when the magnetic film temperature is Tc _2: Figure 11 (d) The magnetization of the second magnetic layer 12 appears downward along with the third magnetic layer 13, and subsequently or simultaneously with the first magnetic layer 13 as shown in FIG.
The magnetic layer is also aligned with downward magnetization. By the above-described low process, the third magnetic layer is in an erased state of downward magnetization.

After the high process and the low process, the magnetization of the fourth magnetic layer 14 is initialized downward by exchange coupling from the sixth magnetic layer 16 in both cases.
It is possible to repeat direct overwrite any number of times. In the above description, Tc ₂ <Tc _{5 has} been described, but the same operation can be performed even if the reverse is true.

<Reproduction> The reproduction operation using the domain wall motion detection method is performed at a temperature at which neither a high process nor a low process occurs due to the reproduction light beam, that is, a temperature equal to or lower than Tc ₃ .
In addition, the temperature of the magnetic film is raised to a temperature at which a temperature range of Tc ₂ or more can be formed. Therefore, since the fourth, fifth, and sixth magnetic layers do not participate in the reproducing process, the magnetizations of the first, second, and third magnetic layers are described with reference to FIGS. 2A, 2B, and 2C. The operation is performed in exactly the same manner as in the case of the reproducing operation, and the domain wall movement detecting and reproducing can be performed.

Actually, when a 15 MHz recording mark recorded on the magneto-optical recording medium of the present embodiment was reproduced at a reproduction power of 2.7 mW without applying an external magnetic field, the 15 MHz carrier signal level and the noise near the frequency were reproduced. The CN ratio, which is the level ratio, is considered to be almost a practical level of 47.9 dB.
was gotten. At this time, the external magnetic field is plus or minus 500
When the voltage was applied and adjusted in the range of Oe, the maximum value of CN ratio was 48.9 dB at 70 Oe upward. This is the fourth,
It is considered that the effect of stray magnetic fields from the fifth and sixth magnetic layers and the balance of energy when moving the domain wall by applying an external magnetic field have been improved. Although it does not matter above, it shows that higher performance can be obtained by adjusting and applying the external magnetic field.

This embodiment not only allows overwriting by the light intensity modulation method as described above, but also has the following features. In the high process and the low process, the light beam is tracked at the center of the information track 21, the intensity distribution of the light beam itself has a substantially Gaussian distribution, and heat is diffused in the radial direction. A temperature distribution is formed below the light beam such that the temperature is highest at the center of the light beam and the temperature gradually decreases in the radial direction. For example, in the high process, recording is performed at the center of the information track, and a recording mark having a certain width is formed.

On the other hand, there is a portion where the magnetic film temperature is equal to or higher than Tc ₃ and equal to or lower than Tc ₄ at the outer edge surrounding the area where the recording mark is formed, and a low process occurs. This is generally called a self-sharpening effect. However, in the magneto-optical recording medium of the present invention, one of the side surfaces of the recording mark along the information track is in contact with the region 23 where the fourth, fifth, and sixth magnetic layers are aligned in the upward magnetization. On the other side surface, the fourth, fifth, and sixth magnetic layers are aligned with downward magnetization. The low process is essentially the third magnetic layer 1
Since the magnetization direction of the third magnetic layer is aligned with the magnetization direction of the fourth magnetic layer, the third magnetic layer in the former region (region 23) in contact with one side surface of the recording mark has an upward magnetization and the third magnetic layer on the opposite side of the recording mark. The latter region in contact with the side surface will be realigned to downward magnetization. That is, even if, for some reason, the magnetization direction of the third magnetic layer in the inter-track region, which has been initialized to be aligned with the upward magnetization and the downward magnetization, is disturbed, as long as the magnetization direction of the sixth magnetic layer is not disturbed. Is re-aligned in a predetermined direction during recording and is automatically re-initialized. As a result, an extremely reliable recording / reproducing operation can be guaranteed. Even after actually recording over 1,000,000 times or more on the same track, a good CN ratio equivalent to that at the first time is obtained.

Embodiment 7 FIG. In the magneto-optical recording medium of the sixth embodiment, the upwardly magnetized portion 23 between the tracks 25 is magnetized upward so as to cover the guide groove along the center line of the guide groove without being deviated from the guide groove 22, and the recording mark is formed. A magneto-optical recording medium different from that of Example 6 was prepared only in that the recording was performed with a slight deviation from the center line of the information track 21 toward the inner peripheral side. In this case, the state of the medium from the side of the first magnetic layer is the same as that in FIG. 5B. In this case, as in the sixth embodiment, only one of the two sides of the recording mark is in a recording state in contact with the upward magnetized region 23 between the tracks.
In the same manner as in the above, good reproduction characteristics were obtained. When recording and reproduction were performed under the same conditions as in Example 6, the CN ratio was 48.1 dB.

Embodiment 8 FIG. In the magneto-optical recording medium according to the seventh embodiment, only the fourth, fifth, and sixth magnetic layers in the adjacent inter-track region are alternately aligned with the upward magnetization and the downward magnetization every one rotation, which is different from the sixth embodiment. Different magneto-optical recording media were created. In this case, the state of the medium from the side of the first magnetic layer is the same as that in FIG. 6B. Also in this case, the embodiment 7
Similarly, only one of the two side surfaces of the recording mark is in a recording state in contact with the upward magnetized region 23 between the tracks, so that good reproduction characteristics were obtained as in Example 7. When recording and reproduction were performed under the same conditions as in Example 6, the CN ratio was 48.2 dB.

Embodiment 9 FIG. The magneto-optical recording medium according to the sixth embodiment differs from the sixth embodiment in that a transparent substrate having land tracks and groove tracks having substantially the same width is used instead of the V-shaped guide groove on the surface of the transparent substrate 30. A magneto-optical recording medium having a layered magnetic film structure was prepared. In this case, the state of the medium from the side of the first magnetic layer is the same as that in FIG. 7A. This embodiment is an embodiment in a case where the present invention is applied to a so-called land / groove recording system in which information is recorded on both a land track 41 and a groove track 42.
The width of both the land track and the groove track is 0.
5 μm, and the depth of the groove track is 48 nm. The upwardly magnetized portion 23 in the inter-track region is approximately 0.1 μm.
It has a width of m and is provided at the end of the land track and the end of the groove track. The recording mark 24 recorded at the center of each track has only one side surface in contact with the upward magnetized portion 23. As a result, good reproduction characteristics were obtained as in Example 6. When recording and reproduction were performed under the same conditions as in Example 6, the CN ratio was 48.4 dB.

Embodiment 10 FIG. In the magneto-optical recording medium of the sixth embodiment, a magneto-optical recording medium different from that of the ninth embodiment in that the adjacent inter-track regions are alternately aligned with the upward magnetization and the downward magnetization every round is produced. In this case, the state of the medium from the side of the first magnetic layer is the same as FIG. 8A. The upwardly magnetized portion 23 of the inter-track region 25 has a thickness of about 0.5 mm.
It has a width of 15 μm, and is provided at every other boundary portion between the land track 41 and the groove track 42, and only one side of the recording mark 24 recorded at the center of each track is in contact with the upward magnetized portion 23. ing. As a result, good reproduction characteristics were obtained as in Example 9. When recording and reproduction were performed under the same conditions as in Example 6, the CN ratio was 4
It was 8.8 dB.

In the first to tenth embodiments, the recording was performed by the light intensity modulation method. However, the magnetic field modulation was applied to these, including the magneto-optical recording media in which the light modulation direct overwrite of the sixth to tenth embodiments can be performed. The effect of the present invention does not change even if recording is performed.

As a recording method, there are a mark position recording method in which information is carried at a position where a recording mark exists, and a mark edge recording method in which information is carried at a leading edge and a trailing edge of the recording mark. In the recording medium, since both recording methods have the same effect, the recording methods are not separately described in the above embodiment.

When performing the magnetic field modulation recording on the magneto-optical recording medium of the sixth to tenth embodiments, the light beam intensity is set to the recording power PH at which the high process can be performed. The magnetization direction of the magnetic layer is realigned each time recording is performed, and a highly reliable recording / reproducing operation can be obtained.

In any of the embodiments, a layer for adjusting the exchange force may be interposed between the magnetic layers, and a metal layer having a high thermal conductivity may be used to adjust the thermal characteristics of the recording film. It may be provided on the two dielectric layers on the side opposite to the substrate. Further, in the present invention, it is described that light is incident from the side of the transparent substrate. However, if the order of laminating each dielectric layer and magnetic layer is reversed, recording and reproduction may be performed from the side opposite to the transparent substrate. Absent. Further, in the magneto-optical recording method of the present invention, when information is recorded, the second light beam is caused to track the inter-track region adjacent to the recording track to emit DC light to initialize the inter-track region to upward magnetization. That is, the recording and the initialization of the inter-track area may be performed simultaneously. Also,
It goes without saying that test recording and test reproduction for optimally adjusting the recording power, the reproduction power, and the magnitude of the reproduction magnetic field can be used immediately before recording or reproduction on the magneto-optical recording medium of the present invention.

[0091]

According to the first magneto-optical recording medium of the present invention, at least the first, second and third magnetic layers are provided in this order on the substrate, and the Curie temperature of the i-th magnetic layer is set to Tc.
_i (i = 1, 2, 3), the Curie temperature of these magnetic layers satisfies the following condition: Tc ₁ > Tc ₂ Tc ₃ > Tc ₂ , and at a temperature equal to or higher than Tc ₂ , The domain wall coercive force is smaller than the domain wall coercive force of the third magnetic layer, and the exchange coupling force exerted on the first magnetic layer from the third magnetic layer via the second magnetic layer within a temperature range between ambient temperature and Tc _2. However, in a magneto-optical recording medium in which the temperature exceeds the coercive force energy of the first magnetic layer and the third magnetic layer is a perpendicular magnetization film, the area between adjacent information tracks of the third magnetic layer (inter-track distance) Region), there are a region aligned with the upward magnetization direction and a region aligned with the downward magnetization direction, and it can be easily manufactured with high yield, and the reproduction by the domain wall movement detection can be performed with high reliability. There is an effect of obtaining a magneto-optical recording medium.

According to the second magneto-optical recording medium of the present invention,
In the first magneto-optical recording medium, the inter-track region of the third magnetic layer includes a region aligned with an upward magnetization direction and a region aligned with a downward magnetization direction, and is aligned with the upward magnetization direction. The area provided is provided on one of the inside and outside of the above-mentioned inter-track area, so that a magneto-optical recording medium that can be easily manufactured with high yield and that can be reproduced with high reliability by detecting domain wall motion can be obtained. There is.

According to the third magneto-optical recording medium of the present invention,
In the first magneto-optical recording medium, the magnetization directions of the inter-track regions of the third magnetic layer are alternately aligned in the opposite direction, so that the magnetic head can be easily manufactured with a high yield, and reproduction by domain wall motion detection is performed. However, there is an effect that a magneto-optical recording medium which can be performed with high reliability can be obtained.

According to the fourth magneto-optical recording medium of the present invention,
On a substrate, at least a first, a second,
Third, fourth, fifth, and sixth magnetic layers are provided in this order, and the Curie temperature of the ith magnetic layer is set to Tc _i (i = 1, 2,
3, 4, 5, 6), the Curie temperatures of these magnetic layers satisfy the following condition: Tc ₁ > Tc ₂ Tc ₄ > Tc ₃ > Tc ₂ Tc ₆ > Tc ₄ > Tc ₅ , and Tc ₂ At the above temperature, the domain wall coercive force of the first magnetic layer is smaller than the domain wall coercive force of the third magnetic layer, and within the temperature range from ambient temperature to Tc ₂ , the third magnetic layer passes through the second magnetic layer via the second magnetic layer. There is a temperature at which the exchange coupling force exerted on the first magnetic layer exceeds the coercive force energy of the first magnetic layer, the third magnetic layer is a perpendicular magnetization film, and near the ambient temperature, the transition metal sub-electrode of the third magnetic layer The lattice magnetization direction is not reversed by the magnetization reversal of the second magnetic layer or the magnetization reversal of the fourth magnetic layer, and in the region where the transition metal sublattice magnetization direction of the sixth magnetic layer is upward at around ambient temperature, the fourth magnetic layer And the magnetization directions of the transition metal sublattice of the fifth magnetic layer are aligned upward. In a region where the transition metal sublattice magnetization direction of the sixth magnetic layer is downward, the transition metal sublattice magnetization directions of the fourth magnetic layer and the fifth magnetic layer are aligned downward, and the transition metal In the magneto-optical recording medium in which the magnetization of the sublattice does not reverse during recording and reproduction,
And a region aligned with the direction of the transition metal sublattice magnetization of the information track regions of the fourth, fifth, and sixth magnetic layers in a region between adjacent information tracks (inter-track region) of the sixth magnetic layer. , The fourth, fifth, and sixth magnetic layers have regions aligned in the direction opposite to the direction of the transition metal sublattice magnetization in the information track regions. There is an effect that a magneto-optical recording medium capable of performing reproduction by detection with high reliability and enabling direct overwrite is obtained.

According to the fifth magneto-optical recording medium of the present invention,
In the fourth magneto-optical recording medium, the third, fourth, fifth
A region in which the inter-track region of the sixth magnetic layer is aligned with the direction of the transition metal sublattice magnetization of the information track region of the fourth, fifth, and sixth magnetic layers; and a fourth, fifth, and sixth magnetic layer. And the fourth and fifth regions of the information track region are aligned in the direction opposite to the direction of the transition metal sublattice magnetization.
And a region aligned in the direction of the transition metal sublattice magnetization of the information track region of the sixth magnetic layer is provided on one of the inside and outside of each of the inter-track regions, and can be easily manufactured with good yield. In addition, there is an effect that a magneto-optical recording medium capable of performing reproduction by domain wall motion detection with high reliability and enabling direct overwrite is obtained.

According to the sixth magneto-optical recording medium of the present invention,
In the fourth magneto-optical recording medium, the third, fourth, fifth
In addition, the direction of the transition metal sublattice magnetization in the adjacent track region of the sixth magnetic layer is alternately aligned in the opposite direction, so that it can be easily manufactured with a good yield, and the reproduction by the domain wall movement detection is reliable. There is an effect that a magneto-optical recording medium capable of performing direct overwriting can be obtained.

According to the first magneto-optical recording method of the present invention,
The third magnetic layer of the information track of any one of the first to sixth magneto-optical recording media is in contact with one of the inter-track regions of the third magnetic layer. This is a method for forming recording marks magnetized in the same direction. It is an object of the present invention to provide a magneto-optical recording method capable of reproducing by detecting domain wall motion and obtaining a good reproduced signal with less noise.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a magneto-optical recording medium of the present invention and a magneto-optical recording method using the same.

FIG. 2 is an explanatory diagram for explaining recording and reproduction of a magneto-optical recording medium of the present invention.

FIG. 3 is an explanatory diagram for explaining recording and reproduction on a magneto-optical recording medium of a comparative example.

FIG. 4 is an explanatory diagram for explaining recording and reproduction of a magneto-optical recording medium of a comparative example.

FIG. 5 is an explanatory diagram illustrating a magneto-optical recording medium of the present invention and a magneto-optical recording method using the same.

FIG. 6 is an explanatory diagram illustrating a magneto-optical recording medium of the present invention and a magneto-optical recording method using the same.

FIG. 7 is an explanatory diagram illustrating a magneto-optical recording medium of the present invention and a magneto-optical recording method using the same.

FIG. 8 is an explanatory diagram illustrating a magneto-optical recording medium of the present invention and a magneto-optical recording method using the same.

FIG. 9 is an explanatory diagram illustrating a magneto-optical recording medium of the present invention and a magneto-optical recording method using the same.

FIG. 10 is an explanatory diagram illustrating a recording process at a high power on a magneto-optical recording medium according to the present invention.

FIG. 11 is an explanatory diagram illustrating a recording process at a low power on a magneto-optical recording medium according to the present invention.

[Explanation of symbols]

11 first magnetic layer, 12 second magnetic layer, 13 third magnetic layer, 14 fourth magnetic layer, 15 fifth magnetic layer, 16 sixth magnetic layer
Magnetic layer, 21 information tracks, 23 upward magnetization portions in the inter-track region, 24 recording marks, 25 inter-track regions, 41 land tracks, 42 groove tracks.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Koichi Yamada 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (7)

[Claims] At least a first, a second and a third magnetic layer are provided in this order on a substrate, and when the Curie temperature of the i-th magnetic layer is Tc _i (i = 1, 2, 3), The Curie temperature of the magnetic layer satisfies the following condition: Tc ₁ > Tc ₂ Tc ₃ > Tc ₂ , and at a temperature equal to or higher than Tc ₂ , the domain wall coercive force of the first magnetic layer is smaller than the domain wall coercive force of the third magnetic layer, Within a temperature range between ambient temperature and Tc ₂ , a temperature at which the exchange coupling force exerted on the first magnetic layer from the third magnetic layer via the second magnetic layer exceeds the coercive force energy of the first magnetic layer. In the magneto-optical recording medium in which the third magnetic layer is a perpendicular magnetization film, a region (an inter-track region) between information tracks adjacent to the third magnetic layer has a region aligned with an upward magnetization direction. It is noted that there is a region aligned with the downward magnetization direction. Magneto-optical recording medium according to. 2. A region in which an inter-track region of the third magnetic layer includes a region aligned with an upward magnetization direction and a region aligned with a downward magnetization direction, and a region aligned with an upward magnetization direction. 2. The magneto-optical recording medium according to claim 1, wherein the magneto-optical recording medium is provided inside or outside each of the inter-track regions. 3. The magneto-optical recording medium according to claim 1, wherein the magnetization directions of adjacent track regions of the third magnetic layer are alternately aligned in opposite directions. 4. At least first, second, third, fourth, fifth and sixth magnetic layers containing a transition metal are provided in this order on a substrate, and the Curie temperature of the i-th magnetic layer is set to Tc.
_{When i} (i = 1, 2, 3, 4, 5, 6), the Curie temperature of these magnetic layers is expressed by the following equation: Tc ₁ > Tc ₂ Tc ₄ > Tc ₃ > Tc ₂ Tc ₆ > Tc ₄ > Tc ₅ At a temperature equal to or higher than Tc ₂ , the domain wall coercive force of the first magnetic layer is smaller than the domain wall coercive force of the third magnetic layer, and within a temperature range between ambient temperature and Tc ₂ , There is a temperature at which the exchange coupling force exerted on the first magnetic layer via the second magnetic layer exceeds the coercive force energy of the first magnetic layer, and the third magnetic layer is a perpendicular magnetization film. The magnetization direction of the transition metal sublattice of the third magnetic layer is not inverted by the magnetization reversal of the second magnetic layer or the magnetization reversal of the fourth magnetic layer, and the magnetization direction of the transition metal sublattice of the sixth magnetic layer is directed upward at around ambient temperature. Region, the transition metal sublattice magnetization directions of the fourth magnetic layer and the fifth magnetic layer Are aligned upward, and in the region where the transition metal sublattice magnetization direction of the sixth magnetic layer is downward, the transition metal sublattice magnetization directions of the fourth magnetic layer and the fifth magnetic layer are aligned downward. In the magneto-optical recording medium in which the magnetization direction of the transition metal sublattice of the layer does not reverse during recording and reproduction, the third, fourth, and fifth layers may be used.
And a region aligned with the direction of the transition metal sublattice magnetization of the information track regions of the fourth, fifth, and sixth magnetic layers in a region between adjacent information tracks (inter-track region) of the sixth magnetic layer. A magneto-optical recording medium characterized in that the information track regions of the fourth, fifth and sixth magnetic layers have regions aligned in the direction opposite to the direction of the transition metal sublattice magnetization. 5. The inter-track regions of the third, fourth, fifth and sixth magnetic layers are aligned in the direction of the transition metal sublattice magnetization of the information track regions of the fourth, fifth and sixth magnetic layers. And a region in which the direction of the transition metal sublattice magnetization of the information track region of the fourth, fifth and sixth magnetic layers is aligned in a direction opposite to that of the fourth, fifth and sixth magnetic layers. 5. The magneto-optical recording medium according to claim 4, wherein a region of the information track region aligned in the direction of the transition metal sublattice magnetization is provided inside or outside each of the inter-track regions. 6. The transition metal sublattice magnetization directions in adjacent inter-track regions of the third, fourth, fifth, and sixth magnetic layers are alternately aligned in opposite directions. 4
3. The magneto-optical recording medium according to claim 1. 7. The third magnetic layer of an information track of the magneto-optical recording medium according to claim 1, wherein said third magnetic layer is in contact with one of the inter-track regions of said third magnetic layer. A magneto-optical recording method for forming a recording mark magnetized in the same direction as the magnetization direction of a portion in contact with.