JPH0644622A - Magneto-optical recording medium - Google Patents

Abstract

PURPOSE:To provide a magneto-optical recording medium capable of reproducing information with high precision and capable of overwriting with enhanced reliability. CONSTITUTION:A transparent substrate 1, a transparent dielectric layer 2, a nitrogen interstitial solid soln. layer 3, a readout layer 10, a recording layer 11, a transparent dielectric layer 5 and an overcoat layer 8 are successively laminated. The solid soln. layer 3 contains at least the same magnetic material as the magnetic material of the readout layer 10 and has perpendicular magnetic anisotropy. Since the solid soln. layer 3 has higher saturation magnetization than that of the readout layer 10, the magneto-optical effect is enhanced, the angle of magnetic Kerr rotation is increased and the level of a readout signal is increased.

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 such as a magneto-optical disk, a magneto-optical tape, a magneto-optical card which is applied to a magneto-optical recording device.

[0002]

2. Description of the Related Art The magneto-optical recording method is a method of recording and reproducing on / from a magneto-optical recording medium having a structure in which a perpendicularly magnetized film made of a magnetic material is formed on a substrate.

At the time of recording, first, the magneto-optical recording medium is initialized by a strong external magnetic field or the like. That is, the magnetization direction of the perpendicular magnetization film is aligned in one direction (upward or downward). After that, by irradiating a portion on the magneto-optical recording medium where recording is performed with a laser beam, the perpendicular magnetization film in that portion is heated to a temperature near the Curie temperature or above the compensation temperature. As a result, the coercive force of the heated portion becomes zero or almost zero. In this state, an external magnetic field (bias magnetic field) opposite to the initialized magnetization direction is applied. When the irradiation of the laser beam is stopped, the temperature of the perpendicularly magnetized film returns to room temperature, so the direction of magnetization is reversed and fixed, and information is thermomagnetically recorded.

During reproduction, a linearly polarized laser beam is applied to the perpendicularly magnetized film, and the phenomenon that the rotation of the plane of polarization of the reflected or transmitted light differs depending on the direction of magnetism (magnetic Kerr effect, magnetic Faraday effect). The information is optically read out by utilizing the information.

As described above, the magneto-optical recording medium is capable of recording and reproducing information, and is therefore attracting attention as a rewritable mass storage element.

[0006]

However, in the above-mentioned conventional magneto-optical recording medium, the perpendicular magnetization is made so that the perpendicular magnetization film composed of the recording layer and the reading layer can be easily heated above the Curie temperature or above the compensation temperature. Since the film uses a magnetic material having a low Curie temperature, the magneto-optical effect is small. Therefore, there are problems that the magnetic Kerr rotation angle is small and the read signal level is low.

A method has been proposed in which a magnetic material having a higher Curie temperature than that of the perpendicular magnetic film is laminated on the surface of the perpendicular magnetic film. This requires strict control, which complicates the manufacturing process of the magneto-optical recording medium, resulting in a new problem of lowering production efficiency.

Further, in order to prevent corrosion of the magneto-optical recording medium and improve reliability, both interfaces (upper and lower surfaces) of the recording layer are formed.
A magneto-optical recording medium having a structure in which a nitride layer made of a metal nitride containing the same magnetic material as that of the recording layer is formed is proposed (Journal of the Japan Institute of Metals, Vol. 55, No. 6 (199).
1) 696-705).

However, since the above-mentioned metal nitride is formed by combining nitrogen and metal, the structure of the nitride layer (atomic arrangement of magnetic material) is different from that of the recording layer. Therefore, the nitride layer is less likely to exhibit perpendicular magnetic anisotropy and has a smaller magneto-optical effect than the recording layer. That is, for the purpose of improving reliability, the structure of the nitride layer needs to be different from the structure of the recording layer, and it has been impossible to increase the signal level.

[0010]

In order to solve the above-mentioned problems, a magneto-optical recording medium according to the present invention has a recording layer for magneto-optically recording information, and at least the same magnetic property as that of the recording layer. It is characterized in that it is provided with a nitrogen intrusion type solid solution layer containing a material and exhibiting perpendicular magnetic anisotropy.

In order to solve the above-mentioned problems, a magneto-optical recording medium according to a second aspect of the present invention has a recording layer for magneto-optically recording information, and a Curie temperature lower than that of the recording layer. And a read layer having a coercive force at room temperature higher than that of the recording layer, and a nitrogen intrusion type solid solution layer containing at least the same magnetic material as the read layer and exhibiting perpendicular magnetic anisotropy. There is.

[0012]

According to the magneto-optical recording medium of the first aspect of the invention, at least the same magnetic material as that of the recording layer is contained, and the nitrogen-intrusion type solid solution layer exhibiting perpendicular magnetic anisotropy is provided. The nitrogen intrusion type solid solution layer has a larger saturation magnetization than the recording layer made of the same magnetic material, so that the magneto-optical effect is increased, the magnetic Kerr rotation angle is increased, and the read signal level is increased. Therefore, it is possible to obtain a magneto-optical recording medium with improved reliability that can reproduce information with high accuracy.

According to another aspect of the magneto-optical recording medium of the present invention, a read layer having a Curie temperature lower than that of the recording layer and having a coercive force higher than that of the recording layer at room temperature, and at least the above-mentioned read layer. Contains the same magnetic material as the layer,
And a nitrogen intrusion type solid solution layer exhibiting perpendicular magnetic anisotropy. This nitrogen-intrusion type solid solution layer has a larger saturation magnetization than the read layer made of the same magnetic material, so that the magneto-optical effect is increased, the magnetic Kerr rotation angle is increased, and the read signal level is increased. Therefore, it is possible to obtain an overwritable (rewritable without erasing) rewritable magneto-optical recording medium capable of reproducing information with high accuracy and having improved reliability.

[0014]

【Example】

[First Embodiment] The first embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, a magneto-optical disk, which is a magneto-optical recording medium according to this embodiment, has a transparent substrate 1, an adhesive layer 7, a transparent dielectric layer 2, a nitrogen intrusion type solid solution layer 3, and a recording layer 4. The transparent dielectric layer 5 and the substrate 6 are laminated in this order.

The recording layer 4 is, for example, Dy.
_0.23 Fe _0.63 Co _0.14 is used and the film thickness is 20 nm
It is about 200 nm, preferably 80 nm. Also,
The Curie temperature is set to 150 to 250 ° C. If the recording layer 4 is a magnetic material exhibiting perpendicular magnetic anisotropy that enables perpendicular magnetic recording, the above-mentioned Dy _0.23 Fe _{0.63 is used.}
It is not limited to Co _0.14 .

The transparent dielectric layer 2 is, for example, AlN.
It is made of nitride such as SiN, AlSiN, etc., and its film thickness is set to a value obtained by dividing 1/4 of the light beam wavelength during reproduction by the refractive index. For example, when reproducing light beam wavelength is 800n
m, the thickness of the transparent dielectric layer 2 is 10 nm to 200
The thickness is about nm, preferably about 80 nm. The transparent dielectric layer 5 is a protective layer made of, for example, a nitride such as AlN, SiN, or AlSiN, and has a film thickness of 10 nm to 20 nm.
It is about 0 nm, preferably 50 nm. The transparent dielectric layers 2 and 5 are not limited to AlN, SiN, AlSiN and the like as long as they are transparent to the light beam wavelength at the time of recording / reproducing.

As the material of the transparent substrate 1 and the substrate 6, glass or plastic such as polycarbonate is used. The adhesive layer 7 is made of, for example, an ultraviolet curable resin having a refractive index of about 1.5 and has a film thickness of 5 μm.

The above-mentioned nitrogen-penetrating solid solution layer 3 is, for example,
A nitrogen intrusion type solid solution in which N has infiltrated Dy _0.23 Fe _0.63 Co _0.14 is used, and the film thickness is 5 nm.

Next, an example of a method of making the magneto-optical disk having the above-mentioned structure will be described.

As shown in FIG. 2, first, the sufficiently cleaned substrate 6 is held at a predetermined position in a chamber 14 which is a sputtering device, and the inside of the chamber 14 is set to 5 × 10 ^-6 by an exhaust device (not shown). Make the vacuum below Torr. next,
Ar gas is introduced into the chamber 14, and the substrate 6 is reverse-sputtered under the conditions of Ar gas pressure of 9 mTorr and discharge power of 700 W to clean the surface of the substrate 6.

After that, Ar gas and N ₂ gas were introduced at a ratio of 4: 1 and the Al target 13 was used to carry out sputtering under the conditions of a mixed gas pressure of 8 mTorr and a discharge power of 1 kW. A transparent dielectric layer 5 made of AlN is formed on the surface of the substrate 6 with a film thickness of 50 nm.

After exhausting the mixed gas, Ar gas was introduced, and sputtering was performed using a Dy _0.23 Fe _0.63 Co _0.14 target 12 under the conditions of Ar gas pressure of 9 mTorr and discharge power of 1 kW to obtain a transparent dielectric layer. The recording layer 4 is formed on the surface 5 with a film thickness of 95 nm. Then, after exhausting the Ar gas, N ₂ gas is introduced, and the pressure of the N ₂ gas is changed to 9
By etching the surface of the recording layer 4 by about 10 nm under the conditions of mTorr and discharge power of 700 W, Dy _0.23 Fe
Nitrogen is infiltrated into _0.63 Co _0.14 to form a nitrogen intrusion type solid solution layer 3 having a film thickness of 5 nm. As a result, the recording layer 4 is formed with a film thickness of 80 nm on the surface of the transparent dielectric layer 5, and the nitrogen intrusion type solid solution layer 3 is formed with a film thickness of 5 nm on the surface of the recording layer 4.

Next, after evacuating the N ₂ gas, Ar gas and N ₂ gas were introduced at a ratio of 4: 1 and the same conditions as those for forming the transparent dielectric layer 5 described above were used. , A transparent dielectric layer 2 made of AlN on the surface of the nitrogen-penetrating solid solution layer 3
Is formed to a film thickness of 80 nm.

After that, the substrate 6 is taken out from the chamber 14, an ultraviolet curable resin (adhesive layer 7) is applied to the surface of the transparent dielectric layer 2, and the transparent substrate 1 is attached and cured. As a result, a magneto-optical disk is created.

FIG. 3 shows the relationship between the magnetic Kerr rotation angle measured using the above magneto-optical disk and the externally applied magnetic field.
In the figure, the horizontal axis represents the externally applied magnetic field H _c , and the vertical axis represents the magnetic Kerr rotation angle θ _k . For comparison, a magneto-optical disk in which the nitrogen-intrusion type solid solution layer 3 was omitted and the recording layer 4 had a thickness of 85 nm was manufactured under the same conditions as above, and the magnetic Kerr rotation angle measured was measured. The relationship with the externally applied magnetic field is shown in FIG.

In general, a nitrogen-penetrating solid solution has a larger saturation magnetization than a magnetic body made of the same magnetic material.
The magneto-optical effect is increased. For this reason, the magneto-optical disc without the nitrogen intrusion type solid solution layer 3 has a magnetic Kerr rotation angle θ _k of 1.05 deg, whereas the magneto-optical disc of the present embodiment has a magnetic Kerr rotation angle θ _k. Is as large as 1.26 deg. That is, in the magneto-optical disk of this embodiment, the read signal level becomes high.

With the above structure, it is possible to obtain a magneto-optical disk which can reproduce information with high accuracy and has improved reliability.

[Second Embodiment] The second embodiment of the present invention will be described below with reference to FIG. still,
For convenience of explanation, FIG. 2 used in the explanation of the first embodiment described above.
The same reference numerals are given to members having the same function as the members shown in the drawings of the first embodiment, and the description thereof will be omitted.

As shown in FIG. 5, a magneto-optical disk, which is a magneto-optical recording medium according to the present embodiment, has a transparent substrate 1, a transparent dielectric layer 2, a nitrogen intrusion type solid solution layer 3, a recording layer 4, and a transparent dielectric. The layer 5 and the overcoat layer 8 are laminated in this order. The overcoat layer 8 is made of, for example, an ultraviolet curable resin.

Next, an example of a method of making the magneto-optical disk having the above-mentioned structure will be described.

As shown in FIG. 2, first, the sufficiently cleaned transparent substrate 1 is held at a predetermined position in the chamber 14 and the inside of the chamber 14 is set to 5 × 10 by an exhaust device (not shown).
-Use a vacuum of ⁶ Torr or less. Next, in the chamber 14,
Introducing r gas, the transparent substrate 1 is subjected to reverse sputtering (Ar
The surface of the transparent substrate 1 is cleaned by applying a gas pressure of 9 mTorr and a discharge power of 700 W).

Then, Ar gas and N ₂ gas were introduced at a ratio of 4: 1 and sputtering (mixed gas pressure 8 mTorr, discharge power 1 kW) was performed using the Al target 13 to obtain a transparent substrate. A transparent dielectric layer 2 made of AlN is formed on the surface 1 with a thickness of 80 nm.

After exhausting the mixed gas, Ar gas was introduced, and sputtering (Ar gas pressure 9 mTorr, discharge power 1 kW) was performed using the Dy _0.23 Fe _0.63 Co _0.14 target 12 to obtain the surface of the transparent dielectric layer 2. To Dy
_0.23 Fe _0.63 Co _0.14 is formed to a film thickness of 15 nm. Then, after exhausting Ar gas, N ₂ gas was introduced, and the surface of Dy _0.23 Fe _0.63 Co _0.14 was etched by about 10 nm (pressure of N ₂ gas 9 mTorr, discharge power 700 W) to obtain Dy _0.23 Fe _0.63 Co _0.14. Intrudes N into
By using the nitrogen-penetrating solid solution, the nitrogen-penetrating solid solution layer 3 is formed with a thickness of 5 nm.

Next, after evacuating N ₂ gas, Ar gas was introduced, and again Dy _0.23 Fe _0.63 Co _0.14 target 12 was obtained.
Sputtering (Ar gas pressure 9 mTorr,
The discharge power is set to 1 kW) to form the recording layer 4 on the surface of the nitrogen-intrusion type solid solution layer 3 with a film thickness of 80 nm.

After the Ar gas was exhausted, Ar gas and N ₂ gas were introduced at a ratio of 4: 1, and the recording layer 4 was formed under the same conditions as the film forming conditions for the transparent dielectric layer 2 described above. A transparent dielectric layer 5 made of AlN is formed on the surface to a film thickness of 50 nm.

After that, the transparent substrate 1 is taken out from the chamber 14, and an ultraviolet curable resin (overcoat layer 8) is applied to the surface of the transparent dielectric layer 5 and cured. As a result, a magneto-optical disk is created.

The magneto-optical disk constructed as described above exhibited substantially the same performance as the magneto-optical disk of the first embodiment. Therefore, with the above configuration, it is possible to obtain a magneto-optical disk which can reproduce information with high accuracy and has improved reliability.

[Third Embodiment] The third embodiment of the present invention will be described below with reference to FIG. still,
For convenience of explanation, members having the same functions as those shown in the drawings of the second embodiment will be designated by the same reference numerals, and the description thereof will be omitted.

The magneto-optical disk, which is the magneto-optical recording medium according to the present embodiment, has a structure in which a reflecting layer is provided in addition to the structure of the second embodiment, and as shown in FIG.
Transparent substrate 1, transparent dielectric layer 2, nitrogen intrusion type solid solution layer 3,
The recording layer 4, the transparent dielectric layer 5, the reflective layer 9, and the overcoat layer 8 are laminated in this order.

The reflective layer 9 is made of, for example, Al and has a film thickness of about 10 nm to 200 nm, preferably 50 nm. The reflective layer 9 is not limited to Al, but may be made of a material such as Ni, Cr, Ag, Au, Pt or the like having a light beam reflectance of 50% or more during reproduction.

The present embodiment has the same structure and characteristics as those of the second embodiment except that the reflective layer 9 for enhancing the magneto-optical effect is provided, and therefore a detailed description will be given here. Omit it. However, the film thickness of the recording layer 4 is 1
It is about 0 nm to 50 nm, preferably about 20 nm, and the transparent dielectric layer 5 is about 10 nm to 200 nm, preferably about 30 nm.

According to the above-mentioned structure, the light beam (not shown) at the time of reproduction is irradiated from the transparent substrate 1 side through the condenser lens to the nitrogen-intrusion type solid solution layer 3. At this time,
Among the incident light beams, the light beam that has passed through the recording layer 4 and the transparent dielectric layer 5 is reflected by the reflection layer 9.

With the above structure, in addition to the effect of the structure of the second embodiment, the magneto-optical effect is enhanced by the reflection layer 9 and the magnetic Kerr rotation angle becomes larger, so that the read signal level is further improved. As a result, the quality of the reproduced signal is improved. Therefore, it is possible to obtain a magneto-optical disk which can reproduce information with high accuracy and which has improved reliability.

[Embodiment 4] The following description will discuss Embodiment 4 of the present invention with reference to FIGS. 7 to 10. For convenience of explanation, members having the same functions as the members shown in the drawings of the second embodiment will be designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 7, a magneto-optical disk, which is a magneto-optical recording medium according to the present embodiment, has a transparent substrate 1, a transparent dielectric layer 2, a nitrogen intrusion type solid solution layer 3, a reading layer 10,
The recording layer 11, the transparent dielectric layer 5, and the overcoat layer 8 are laminated in this order.

The readout layer 10 is, for example,
Tb ₁₈ Fe ₇₇ Co ₅ is used, and the film thickness is 10 nm-
The thickness is about 200 nm, preferably 50 nm. The readout layer 10 is not limited to the above Tb ₁₈ Fe ₇₇ Co ₅ as long as it is a magnetic material that can have a relatively large coercive force.

The recording layer 11 is, for example, Tb.
₂₅ Fe ₆₁ Co ₁₄ is used, and the film thickness is 10 nm to 20
It is about 0 nm, preferably 50 nm. Incidentally, the recording layer 1
No. 1 is not limited to the above Tb ₂₅ Fe ₆₁ Co ₁₄ as long as it is a magnetic material exhibiting perpendicular magnetic anisotropy that enables perpendicular magnetic recording.

Since the magneto-optical disk having the above-mentioned structure is composed of the exchange coupling two-layer film of the recording layer 11 for recording information and the reading layer 10 for reading information, the overwriting (erasing operation is performed by optical modulation). It is possible to rewrite without doing). Here, the procedure of overwriting will be described.

In the initialization, the recording layer 11 is aligned in one direction (downward in this case) by applying the initialization magnetic field H _ini in the direction shown in FIG. The initialization is always performed, or only during recording. At this time, as shown in FIG. 9, since the coercive force H ₂ of the recording layer 11 is smaller than the initializing magnetic field H _ini , the magnetization of the recording layer 11 is reversed. On the other hand, since the coercive force H ₁ of the read layer 10 is larger than the initializing magnetic field H _ini , the magnetization reversal of the read layer 10 does not occur.

Information is recorded on a magneto-optical disk by
It is performed by irradiating a light beam whose intensity is modulated into two levels of high and low while applying the recording magnetic field H _W. That is, when the high level of the light beam indicated by I in FIG. 10 is irradiated, the readout layer 10 and the recording layer 11 are both Curie temperature T _1, T ₂ near or above the to warm to a temperature T _H comprising It has become. On the other hand, when the low-level light beam indicated by II in FIG. 10 is irradiated, only the reading layer 10 has a temperature T around the Curie temperature T ₁ or higher.
It is designed to heat up to _L.

Therefore, when the light beam I is irradiated, the magnetization of the recording layer 11 is inverted upward (see FIG. 8) by the recording magnetic field H _W , and the magnetization direction of the reading layer 10 is changed during the cooling process. Due to the exchange coupling force acting on the interface, the direction of magnetization of the corresponding portion of the recording layer 11 matches. As a result, the magnetization direction of the read layer 10 becomes upward.

On the other hand, when the light beam II is irradiated, the magnetization of the recording layer 11 does not reverse under the influence of the recording magnetic field H _W (see FIG. 9), and in this case, the magnetization direction of the read layer 10 is Due to the exchange coupling force acting on the interface during the cooling process, the magnetization direction coincides with the magnetization direction of the corresponding portion of the recording layer 11.
Therefore, the magnetization direction of the read layer 10 is downward (see FIG. 8). As shown in FIG. 9, the recording magnetic field H _W is set to be sufficiently smaller than the initialization magnetic field H _ini . Also, as indicated by III in FIG. 10, the intensity of the light beam during reproduction is set to be sufficiently smaller than that during recording.

As described above, the read layer 10 has a coercive force H ₁ higher than the initialization magnetic field H _ini at room temperature, but the recording layer 11 has a small coercive force H ₂ at room temperature. Then, when the temperature of the reproducing portion of the reading layer 10 rises, the magnetization direction is influenced by the recording layer 11, and the direction of magnetization coincides with the direction of the recording layer 11. That is, the magnetization of the recording layer 11 is transferred to the reading layer 10 by the exchange coupling force between the two layers of the reading layer 10 and the recording layer 11.

In the magneto-optical disk of the present embodiment, the coercive force H ₁ of the reading layer 10 is about 10 kOe and the Curie temperature T.
₁ is about 200 ° C., while the coercive force H _{2 of the} recording layer 11 is
Is about 2 kOe, and the Curie temperature T ₂ is about 250 ° C.

In the magneto-optical disk having the above structure, although the read layer 10 is made of a magnetic material having a low Curie temperature, the nitrogen penetrating solid solution layer 3 is formed on the surface of the read layer 10.
Is formed, the magneto-optical effect is enhanced by the nitrogen intrusion type solid solution layer 3, the magnetic Kerr rotation angle is increased, and the read signal level is increased. Therefore, it is possible to obtain an overwritable magneto-optical disk capable of reproducing information with high accuracy and having improved reliability.

Although the magneto-optical disk has been described as the magneto-optical recording medium in the above-mentioned first to fourth embodiments, the present invention is not limited to this and can be applied to a magneto-optical tape, a magneto-optical card and the like. .

Further, the specific embodiments or examples made in the section of the detailed description of the invention are merely for clarifying the technical contents of the present invention, and are not limited to such specific examples. It should not be construed in a narrow sense, and various modifications can be made and implemented within the spirit of the present invention and the scope of the above claims.

[0059]

As described above, the magneto-optical recording medium according to the present invention comprises a recording layer for magneto-optically recording information, and at least the same magnetic material as that of the recording layer, and has a perpendicular magnetic field. And a nitrogen-introducing solid solution layer exhibiting a directionality.

Since the nitrogen intrusion type solid solution layer has a larger saturation magnetization than the recording layer made of the same magnetic material, the magneto-optical effect is increased, the magnetic Kerr rotation angle is increased, and the read signal level is increased.

As a result, it is possible to obtain a magneto-optical recording medium which can reproduce information with high accuracy and has improved reliability.

Further, since the solid solution layer of nitrogen intrusion type is provided, the effect of improving the environmental resistance is also obtained.

The magneto-optical recording medium according to the second aspect of the invention is
As described above, a recording layer for magneto-optically recording information, a read layer having a Curie temperature lower than that of the above recording layer and having a coercive force at room temperature higher than that of the recording layer, at least the same as the above read layer. And a nitrogen intrusion type solid solution layer exhibiting perpendicular magnetic anisotropy.

Since the nitrogen intrusion type solid solution layer has a larger saturation magnetization than the read layer made of the same magnetic material, the magneto-optical effect is increased, the magnetic Kerr rotation angle is increased, and the read signal level is increased.

As a result, it is possible to obtain an overwritable magneto-optical recording medium which can reproduce information with high accuracy and has improved reliability.

Further, since the solid solution layer of nitrogen intrusion is provided, the effect of improving the environment resistance is also obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a schematic configuration of a magneto-optical disk according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a method for producing the magneto-optical disc.

FIG. 3 is an explanatory diagram showing a relationship between an externally applied magnetic field applied to a recording layer of the magneto-optical disk and a magnetic Kerr rotation angle.

FIG. 4 shows a comparative example and is an explanatory diagram showing a relationship between an externally applied magnetic field applied to a recording layer of a magneto-optical disk having no nitrogen-intrusion type solid solution layer and a magnetic Kerr rotation angle.

FIG. 5 is a longitudinal sectional view showing a schematic configuration of a magneto-optical disk according to a second embodiment of the present invention.

FIG. 6 is a vertical sectional view showing a schematic configuration of a magneto-optical disk according to a third embodiment of the present invention.

FIG. 7 is a vertical sectional view showing a schematic configuration of a magneto-optical disk according to a fourth embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a magneto-optical recording method for a magneto-optical disk according to a fourth embodiment of the present invention.

FIG. 9 is an explanatory diagram showing the temperature dependence of the coercive force of the recording layer and the reading layer of the magneto-optical disk in the fourth example of the present invention.

FIG. 10 is an explanatory diagram showing the intensity of a light beam when recording / reproducing is performed using the magneto-optical disk according to the fourth embodiment of the present invention.

[Explanation of symbols]

 1 Transparent Substrate 2 Transparent Dielectric Layer 3 Nitrogen Penetration Type Solid Solution Layer 4 Recording Layer 5 Transparent Dielectric Layer 6 Substrate 7 Adhesive Layer 8 Overcoat Film 9 Reflective Layer 10 Readout Layer 11 Recording Layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroyuki Katayama 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Kenji Ota 22-22 Nagaike-cho, Abeno-ku, Osaka, Osaka Within the corporation

Claims (2)

[Claims] 1. A recording layer for magneto-optically recording information, and a nitrogen intrusion type solid solution layer containing at least the same magnetic material as the above recording layer and exhibiting perpendicular magnetic anisotropy. Magneto-optical recording medium. 2. A recording layer for magneto-optically recording information, a reading layer having a Curie temperature lower than that of the recording layer and having a coercive force higher than that of the recording layer at room temperature, at least the same as the reading layer. 2. A magneto-optical recording medium containing the magnetic material of 1. and a nitrogen-intrusion type solid solution layer exhibiting perpendicular magnetic anisotropy.