JP2815034B2 - Method for manufacturing magneto-optical recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a magneto-optical recording medium for recording / reproducing information by laser light utilizing a magnetic force-effect, and more particularly to a magneto-optical recording medium utilizing an exchange coupling force. The present invention relates to a method for manufacturing a recording medium.

[0002]

2. Description of the Related Art Conventionally, for the purpose of improving the recording characteristics and recording signal-to-noise signal ratio characteristics of a magneto-optical recording medium, a magneto-optical recording film using a two-layer magneto-optical film having an exchange coupling force has been used. It has been proposed (Japanese Patent Publication No. 2-35371). This magneto-optical recording medium can be written with a low recording power on a high coercivity magneto-optical layer having a low Curie temperature, and the written recording mark has a low Curie temperature and a low coercive force having a large magnetic Kerr effect. Since the data is transferred to the magneto-optical layer, by reading the transferred recording marks, it is possible to perform a read with a large magnetic Kerr effect.

On the other hand, a so-called overwritable magneto-optical device having an overwrite function capable of writing new information on the spot, regardless of the presence or absence of written information, has been added as another additional function to the magneto-optical recording medium. A recording medium has also been proposed (for example, JP-A-2-158939).
This overwritable magneto-optical recording medium is formed by laminating a perpendicularly magnetizable recording layer and a perpendicularly magnetizable auxiliary layer. (The direction of magnetization is defined as “upward” or “downward” with respect to the layer plane, and the other is defined as “reverse A direction”). When the recording layer is irradiated with the laser light pulse-modulated between the high level and the low level according to the information, (1) when the room temperature is returned by the high level laser light, Is "inverse A direction" magnetization, and when the recording layer is a P type, "inverse A direction"
In the case of type A or A type, a recording mark having magnetization of direction A is formed. (2) When the temperature is returned to room temperature by a low-level laser beam, the auxiliary layer is When the recording layer is of a P type, a recording mark having a magnetization of “A direction” is formed, and when the recording layer is of an A type, a recording mark having a magnetization of “Reverse A direction” is formed. Here, the P type means the spin of the iron group transition metal (TM) of the auxiliary layer and the rare earth transition metal (R
The spin of E) is the case where the metal which is more dominant to the whole magnetization and that of the recording layer are the same, and is different from the A type.

There has also been proposed a magneto-optical recording medium capable of overwriting that does not require a preceding auxiliary magnetic field (No. 13).
Of the Annual Meeting of the Japan Society of Applied Magnetics, Lecture No. 23aC
-4 (1989)). This overwritable magneto-optical recording medium is further laminated with a switch layer / initialization layer on the recording layer / auxiliary layer so that the magnetization of the initialization layer is not reversed even by irradiation with a high-level laser beam, The switch layer is arranged so that the magnetization of the auxiliary layer aligns with the magnetization of the initialization layer during low-level laser light irradiation, and the magnetization of the initialization layer does not affect the auxiliary layer during high-level laser light irradiation. It behaves.

[0005] The present inventors have also disclosed that neodymium (Nd), gadolinium (Gd) and iron (Fe) are further provided between the two magneto-optical layers.
There has already been proposed a magneto-optical recording medium capable of controlling the exchange coupling force by inserting a magneto-optical layer containing at least cobalt, cobalt (Co) and titanium (Ti).

Next, a method for manufacturing a conventional magneto-optical recording medium will be described with reference to the drawings. FIG. 9 is a manufacturing process diagram for explaining an example of the related art, and FIG. 10 is a schematic sectional view of a magneto-optical recording medium manufactured using the conventional example shown in FIG.

In FIG. 10, 1 is a substrate, 20 is a transparent interference layer, 301 is a first magneto-optical layer, 302 is a second magneto-optical layer (NdGdFeCoTi film), 303 is a third magneto-optical layer, and 40 is The protective layer 5 is a heat radiation layer. As the substrate 1, a polycarbonate resin plate or the like is used, and as the transparent interference layer 2, silicon nitride or the like is used. For the first magneto-optical layer 3, TbFe or the like is used, and for the third magneto-optical layer 303, GdTbFeCo or the like is used. Silicon nitride is used as the protection layer 40, and AlTi is used as the material of the heat radiation layer 5.
Are used. For forming each layer of such a magneto-optical recording medium, a sputtering apparatus is usually used.

FIG. 9 shows a conventional method of manufacturing a magneto-optical recording medium.
As shown in (a), after mounting the substrate 1 in the sputtering apparatus in the substrate mounting step (a) and evacuating it in the sputtering apparatus evacuation step (b), the transparent interference layer is formed in the transparent interference layer forming step (c). 2, a first magneto-optical layer 301 is formed in a first magneto-optical layer forming step (d), and a second magneto-optical layer is formed in a second magneto-optical layer forming step (e). Magneto-optical layer (NdGdFeCoT)
i) forming a film 302, then forming a third magneto-optical layer 303 in a third magneto-optical layer forming step (g), and then forming a protective layer 40 in a protective layer forming step (j) The heat radiation layer 5 is formed in a heat radiation layer forming step (k). The magneto-optical recording medium thus manufactured is taken out of the sputtering apparatus in the magneto-optical recording medium take-out step (l).

Before forming the transparent interference layer 2, the substrate 1
In some cases, the surface of the substrate 1 is slightly sputter-etched in order to increase the adhesive force between the substrate 1 and the transparent interference layer 2. Further, the heat radiation layer 5 may be omitted in some cases.

[0010]

However, such a magneto-optical recording medium manufactured by the above-described conventional method has the following problems.
When reading information recorded by applying a bias magnetic field in the same direction as the recording magnetic field, (1) when the recording layer is a P type, the “A direction” recorded on the recording layer by a low-level laser beam is used. The recording mark having the magnetization is rewritten to the recording mark having the magnetization of “reverse A direction”,
(2) When the recording layer is of the A type, the recording mark having the “reverse A direction” magnetization recorded on the recording layer by the low-level laser light is replaced with the recording mark having the “A direction” magnetization. When a low-level laser beam is applied by applying a bias magnetic field in the same direction as the recording magnetic field, (1) when the recording layer is a P-type, the high-level laser beam is applied to the recording layer. It becomes difficult to rewrite the recorded recording mark having the “reverse A direction” magnetization to the recording mark having the “A direction” magnetization,
(2) When the recording layer is of the A type, the recording mark having the “A direction” magnetization recorded on the recording layer by the high-level laser light is rewritten to the recording mark having the “reverse A direction” magnetization. There was a problem that it became difficult.

The present inventors have conducted intensive studies to solve these problems, and as a result, the cause of these problems is that the interaction between the first and third magneto-optical layers is too weak. This led to the present invention.

[0012]

According to a method of manufacturing a magneto-optical recording medium of the present invention, a transparent interference layer, a first magneto-optical layer, a second magneto-optical layer, and a third magneto-optical layer are formed on a substrate. At least in this order, information is written by focusing and irradiating the first magneto-optical layer with the laser light through the substrate, and focusing the laser light on the first magneto-optical layer through the substrate. A magneto-optical recording medium for reading information by irradiating while moving, wherein the first magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and at least A film exhibiting ferrimagnetism at 10 ° C. or more and 50 ° C. or less, wherein the third magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and at least 10 ° C. or more and 50 ° C. or less. A film exhibiting magnetism, wherein the second The magneto-optical layer is a film of an amorphous alloy containing at least neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (Ti). The second magneto-optical layer is exchange-coupled to the second magneto-optical layer at a temperature of 10 ° C. or more and 50 ° C. or less, and the second magneto-optical layer and the third magneto-optical layer
A method for manufacturing a magneto-optical recording medium which is exchange-coupled at 0 ° C. or more and 50 ° C. or less, wherein said third magneto-optical layer is formed by flattening a surface of said second magneto-optical layer by sputter etching. By forming a film, the interaction between the first magneto-optical layer and the third magneto-optical layer is strengthened.

In the method of manufacturing a magneto-optical recording medium according to the present invention, at least a transparent interference layer, a first magneto-optical layer, a second magneto-optical layer, and a third magneto-optical layer are provided on a substrate in this order. Writing information by focusing and irradiating the laser beam on the first magneto-optical layer through the substrate, and irradiating the laser beam while focusing and moving the laser beam on the first magneto-optical layer through the substrate; The first magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and is at least 10 ° C. or higher. The third magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and has a ferrimagnetic property of at least 10 ° C. to 50 ° C. Showing perpendicular magnetization possible Wherein the second magneto-optical layer is an amorphous alloy film containing at least neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (Ti). Regarding the direction of magnetization of the first magneto-optical layer and the direction of magnetization of the third magneto-optical layer, one of an upward direction and a downward direction with respect to a layer plane is defined as “A direction”, and the other is defined as “reverse A direction”. At this time, only the magnetization of the third magneto-optical layer is aligned in the “A direction” by the preceding auxiliary magnetic field just before writing, while the magnetization of the first magneto-optical layer remains unchanged.
When a laser beam pulse-modulated between a high level and a low level according to information is applied to the first magneto-optical layer,
(1) When the modulated laser light is at a high level, the temperature of the first magneto-optical layer rises to a high temperature, and an unmodulated recording magnetic field acts on the temperature, or the laser light is irradiated. As a result, the unmodulated recording magnetic field acts in the process of dropping to a temperature range of 10 ° C. or more and 50 ° C. or less, and as a result, the third magneto-optical layer becomes “inverse A” (2) when the modulated laser beam is at a low level, the first magneto-optical layer is formed with a recording mark having a "direction" magnetization and the first magneto-optical layer having a "reverse A direction" magnetization. Rises to an intermediate temperature, and in that temperature state, at least the magnetization of the third magneto-optical layer remains, and the residual magnetization of the third magneto-optical layer acts even when a non-modulated recording magnetic field acts. By or above Gone is the irradiation of the Za light 10
The residual magnetization of the third magneto-optical layer acts even when a recording magnetic field that is not modulated in the process of decreasing to a temperature range of not less than 50 ° C.
In the following temperature range, the second magneto-optical layer has the “A-direction” magnetization, and the first magneto-optical layer has a recording mark having the “A-direction” magnetization. A method for manufacturing a magneto-optical recording medium, wherein a magnetic layer can be overwritten only by modulating a laser beam so as to control an interaction between the first magneto-optical layer and the third magneto-optical layer, The third magneto-optical layer is formed by flattening the surface of the second magneto-optical layer by sputter etching to form the third magneto-optical layer. It is characterized by enhancing the action.

In the method of manufacturing a magneto-optical recording medium according to the present invention, at least a transparent interference layer, a first magneto-optical layer, a second magneto-optical layer, and a third magneto-optical layer are provided on a substrate in this order. Writing information by focusing and irradiating the laser beam on the first magneto-optical layer through the substrate, and irradiating the laser beam while focusing and moving the laser beam on the first magneto-optical layer through the substrate; The first magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and is at least 10 ° C. or higher. The third magneto-optical layer is an amorphous alloy containing at least an iron-group transition metal and a rare-earth transition metal, and has a ferrimagnetic property of at least 10 ° C. to 50 ° C. Permanent magnetizable indicating magnetism The second magneto-optical layer is an amorphous alloy film containing at least neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (Ti); The direction of the magnetization of the first magneto-optical layer and the direction of the magnetization of the third magneto-optical layer are either “A” or “up” with respect to the layer plane.
When the other is set to the "inverse A direction", only the magnetization of the third magneto-optical layer is aligned in the "A direction" by the preceding auxiliary magnetic field just before writing, while keeping the magnetization of the first magneto-optical layer unchanged. When the first magneto-optical layer is irradiated with laser light pulse-modulated between a high level and a low level according to information, (1) when the modulated laser light is at a high level, The temperature of the first magneto-optical layer rises to a high temperature, and a recording magnetic field that is not modulated in the temperature state acts on the first magneto-optical layer, or the temperature is reduced to a temperature range of 10 ° C. or more and 50 ° C. or less after the irradiation of the laser beam stops. When the unmodulated recording magnetic field acts, as a result, the third magneto-optical layer has a “reverse A direction” magnetization and the first magneto-optical layer has a “reverse A direction” in a temperature range of 10 ° C. or more and 50 ° C. or less. A recording mark having magnetization is formed, 2) When the modulated laser light is at a low level, the temperature of the first magneto-optical layer rises to an intermediate temperature, and at that temperature, at least the magnetization of the third magneto-optical layer remains. Even if the unmodulated recording magnetic field acts, the residual magnetization of the third magneto-optical layer acts, or the laser beam is no longer irradiated, and
Even if a recording magnetic field which is not modulated in the process of decreasing to a temperature range of 0 ° C. or more and 50 ° C. or less acts, the residual magnetization of the third magneto-optical layer acts to result in 10 ° C. or more and 50 ° C.
In the following temperature range, the second magneto-optical layer has the “A-direction” magnetization, and the first magneto-optical layer has a recording mark having the “reverse A-direction” magnetization. A method of manufacturing a magneto-optical recording medium capable of overwriting only by modulating a laser beam such that the magneto-optical layer controls the interaction between the first magneto-optical layer and the third magneto-optical layer, The third magneto-optical layer is formed by flattening the surface of the second magneto-optical layer by sputter etching, thereby forming a film.
It is characterized in that the interaction between the first magneto-optical layer and the third magneto-optical layer is strengthened.

Further, the method of manufacturing a magneto-optical recording medium according to the present invention is characterized in that a transparent interference layer, a first magneto-optical layer, a second magneto-optical layer, a third magneto-optical layer, and a fourth magneto-optical layer are formed on a substrate. Layers are provided at least in this order, and information is written by focusing and irradiating the laser beam to the first magneto-optical layer through the substrate, and writing the laser beam to the first magneto-optical layer through the substrate. A magneto-optical recording medium wherein information is read out by irradiating while focusing and moving, wherein the first magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal. A perpendicularly magnetizable film exhibiting ferrimagnetism at least at 10 ° C. or more and 50 ° C. or less,
Layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and is at least 10 ° C. or more and 50 ° C.
The fourth magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and is at least 10 ° C. or higher.
A perpendicularly magnetizable film exhibiting ferrimagnetism at 0 ° C. or lower,
The second magneto-optical layer is composed of neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (T
i) wherein the direction of magnetization of the first magneto-optical layer and the direction of magnetization of the third magneto-optical layer are either upward or downward with respect to the layer plane. When one is set to “A direction” and the other is set to “reverse A direction”, the first magneto-optical layer is irradiated with a laser beam pulse-modulated between a high level and a low level according to information. (1) When the modulated laser beam is at a high level, the temperature of the first magneto-optical layer rises to a high temperature, and an unmodulated recording magnetic field acts at that temperature, or No more than 10 ℃ and no more than 50 ℃
When the recording magnetic field which is not modulated in the process of lowering to the following temperature range acts, as a result, the third magneto-optical layer has the “A direction” magnetization in the temperature range of 10 ° C. or more and 50 ° C. or less, and Of the magneto-optical layer is "reverse A direction" magnetization,
A recording mark in which the direction of magnetization of the fourth magneto-optical layer is invariable and “A direction” is formed, and (2) when the modulated laser light is at a low level, The temperature rises to an intermediate temperature, and in that temperature state, at least the magnetization of the third magneto-optical layer remains, and the residual magnetization of the third magneto-optical layer operates even when a non-modulated recording magnetic field acts. Or the residual magnetization of the third magneto-optical layer acts even if a recording magnetic field that is not modulated in the process of decreasing to a temperature range of 10 ° C. or more and 50 ° C. or less after the irradiation of the laser beam is stopped. As a result, in the temperature range of 10 ° C. or more and 50 ° C. or less, the third magneto-optical layer has “A-direction” magnetization, the first magneto-optical layer has “A-direction” magnetization, and the fourth magneto-optical layer has The direction of magnetization of the layer is invariable and "A
The second direction so that a recording mark having the “direction” is formed.
Of a magneto-optical recording medium capable of overwriting only by modulating a laser beam without a preceding auxiliary magnetic field such that the magneto-optical layer controls the interaction between the first magneto-optical layer and the third magneto-optical layer. In a manufacturing method, the third magneto-optical layer is formed by flattening the surface of the second magneto-optical layer by sputter etching to form the first magneto-optical layer and the third magneto-optical layer. Is characterized in that the interaction with the magneto-optical layer is strengthened.

Further, the method of manufacturing a magneto-optical recording medium according to the present invention is characterized in that a transparent interference layer, a first magneto-optical layer, a second magneto-optical layer, a third magneto-optical layer, and a fourth magneto-optical layer are formed on a substrate. Layers are provided at least in this order, and information is written by focusing and irradiating the laser beam to the first magneto-optical layer through the substrate, and writing the laser beam to the first magneto-optical layer through the substrate. A magneto-optical recording medium wherein information is read out by irradiating while focusing and moving, wherein the first magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal. A perpendicularly magnetizable film exhibiting ferrimagnetism at least at 10 ° C. or more and 50 ° C. or less,
Layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and is at least 10 ° C. or more and 50 ° C.
The fourth magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and is at least 10 ° C. or higher.
A perpendicularly magnetizable film exhibiting ferrimagnetism at 0 ° C. or lower,
The second magneto-optical layer is composed of neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (T
i) wherein the direction of magnetization of the first magneto-optical layer and the direction of magnetization of the third magneto-optical layer are either upward or downward with respect to the layer plane. When one is set to the “A direction” and the other is set to the “reverse A direction”, the first magneto-optical layer is irradiated with laser light pulse-modulated between a high level and a low level according to information. (1) When the modulated laser beam is at a high level, the temperature of the first magneto-optical layer rises to a high temperature, and an unmodulated recording magnetic field acts at that temperature, or The unmodulated recording magnetic field acts in the process of dropping to a temperature range of 10 ° C. or more and 50 ° C. or less after irradiation disappears, and as a result, the third magneto-optical layer becomes “A” in a temperature range of 10 ° C. or more and 50 ° C. or less. Orientation "magnetization, said first magneto-optical A recording mark is formed in which the layer has “A direction” magnetization, the magnetization direction of the fourth magneto-optical layer is invariable and “A direction” is formed, and (2) the modulated laser light is at a low level. At this time, the temperature of the first magneto-optical layer rises to an intermediate temperature, and in that temperature state, at least the magnetization of the third magneto-optical layer remains, and even if a non-modulated recording magnetic field acts on the third magneto-optical layer, Due to the residual magnetization of the magneto-optical layer acting, or even if a recording magnetic field that is not modulated acts during the process of decreasing the temperature range from 10 ° C. to 50 ° C. due to the elimination of the laser beam irradiation, the third light As a result of the residual magnetization of the magnetic layer acting, as a result,
In the temperature range of 0 ° C. or less, the third magneto-optical layer is “A-oriented”.
The first magneto-optical layer has a magnetization of “reverse A direction”, and the direction of magnetization of the fourth magneto-optical layer is invariable and a recording mark of “A direction” is formed. Magneto-optical that can be overwritten only by modulating laser light without a preceding auxiliary magnetic field in which the second magneto-optical layer controls the interaction between the first and third magneto-optical layers. A method of manufacturing a recording medium, wherein the third magneto-optical layer is
By forming a film after flattening the surface of the magneto-optical layer by sputter etching, the interaction between the first magneto-optical layer and the third magneto-optical layer is strengthened.

Further, the method of manufacturing a magneto-optical recording medium according to the present invention is characterized in that a transparent interference layer, a first magneto-optical layer, a second magneto-optical layer, a third magneto-optical layer, and a fourth magneto-optical layer are formed on a substrate. A layer and a fifth magneto-optical layer are provided at least in this order, and information is written by focusing and irradiating the first magneto-optical layer with the laser light through the substrate, and writing the laser light through the substrate. First
A magneto-optical recording medium for reading information by irradiating while focusing and moving the magneto-optical layer, wherein the first magneto-optical layer comprises at least an iron group transition metal and a rare earth transition metal. An amorphous alloy comprising at least 10
A film capable of perpendicular magnetization exhibiting ferrimagnetism at a temperature of at least 10 ° C. and at least 50 ° C., wherein the third magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal. The fourth magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal and has a ferrimagnetic property of at least 10 ° C. to 50 ° C. Wherein the fifth magneto-optical layer is an amorphous alloy containing at least an iron-group transition metal and a rare-earth transition metal, and exhibits ferrimagnetism at least from 10 ° C. to 50 ° C. The second magneto-optical layer is an amorphous alloy film containing at least neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (Ti). ,Before Either the direction of magnetization of the first magneto-optical layer and the direction of magnetization of the third magneto-optical layer are “A direction”, one of which is upward or downward with respect to the layer plane, and the other is “inverse A direction”. When the first magneto-optical layer is irradiated with laser light pulse-modulated between a high level and a low level according to information, (1) when the modulated laser light is at a high level The temperature of the first magneto-optical layer rises to a high temperature, and an unmodulated recording magnetic field acts in that temperature state, or the temperature falls to a temperature range of 10 ° C. or more and 50 ° C. or less after the irradiation of the laser beam stops. The effect of the recording magnetic field which is not modulated in the process results in 1
In a temperature range of 0 ° C. or more and 50 ° C. or less, the first magneto-optical layer has “reverse A direction” magnetization, and the magnetization of the third magneto-optical layer is the fifth magneto-optical layer due to the fifth magneto-optical layer. (5) The recording mark becomes “A-direction” without being affected by the magnetization of the magneto-optical layer, and the direction of magnetization of the fifth magneto-optical layer is invariable and “A-direction” is formed. When the laser light is at a low level, the temperature of the first magneto-optical layer rises to an intermediate temperature, and in that temperature state, at least the magnetization of the third magneto-optical layer remains and an unmodulated recording magnetic field is generated. The residual magnetization of the third magneto-optical layer acts even if it acts, or 10 ° C.
The residual magnetization of the third magneto-optical layer acts even when a recording magnetic field that is not modulated in the process of decreasing to a temperature range of not less than 50 ° C. or less acts as a result. The third magneto-optical layer has “A-direction” magnetization, the first magneto-optical layer has “A-direction” magnetization, and the magnetization direction of the fifth magneto-optical layer is invariable and “A-direction”. Modulation of laser light without a preceding auxiliary magnetic field such that the second magneto-optical layer controls the interaction between the first and third magneto-optical layers so that a recording mark is formed. A method of manufacturing a magneto-optical recording medium capable of overwriting only by using the method, wherein the third magneto-optical layer is formed by planarizing the surface of the second magneto-optical layer by sputter etching. Interaction between the first magneto-optical layer and the third magneto-optical layer It is characterized in that strongly.

Further, the method of manufacturing a magneto-optical recording medium according to the present invention is characterized in that a transparent interference layer, a first magneto-optical layer, a second magneto-optical layer, a third magneto-optical layer, and a fourth magneto-optical layer are formed on a substrate. A layer and a fifth magneto-optical layer are provided at least in this order, and information is written by focusing and irradiating the first magneto-optical layer with the laser light through the substrate, and writing the laser light through the substrate. First
A magneto-optical recording medium for reading information by irradiating while focusing and moving the magneto-optical layer, wherein the first magneto-optical layer comprises at least an iron group transition metal and a rare earth transition metal. An amorphous alloy comprising at least 10
The fourth magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and is at least 10 ° C. to 50 ° C. The fifth magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and has a ferrimagnetic property at least at 10 ° C. or more and 50 ° C. or less. And the second magneto-optical layer is neodymium (N
d) a film of an amorphous alloy containing at least gadolinium (Gd), iron (Fe), cobalt (Co) and titanium (Ti), wherein the direction of magnetization of the first magneto-optical layer and the third When the direction of magnetization of the magneto-optical layer is upward or downward with respect to the layer plane, one of which is "A direction" and the other is "reverse A direction", the direction between the high level and the low level is determined according to the information. (1) When the modulated laser light is at a high level, the temperature of the first magneto-optical layer rises to a high temperature. Then, a recording magnetic field that is not modulated in the temperature state acts, or a recording magnetic field that is not modulated acts in a process in which the irradiation of the laser beam stops and the temperature falls to a temperature range of 10 ° C. or more and 50 ° C. or less, and as a result, 1
In a temperature range of 0 ° C. or more and 50 ° C. or less, the first magneto-optical layer has “reverse A direction” magnetization, and the magnetization of the third magneto-optical layer is the fifth magneto-optical layer due to the fifth magneto-optical layer. (5) The recording mark becomes “A-direction” without being affected by the magnetization of the magneto-optical layer, and the direction of magnetization of the fifth magneto-optical layer is invariable and “A-direction” is formed. When the laser light is at a low level, the temperature of the first magneto-optical layer rises to an intermediate temperature, and in that temperature state, at least the magnetization of the third magneto-optical layer remains and an unmodulated recording magnetic field is generated. The residual magnetization of the third magneto-optical layer acts even if it acts, or 10 ° C.
The residual magnetization of the third magneto-optical layer acts even when a recording magnetic field that is not modulated in the process of lowering to a temperature range of not less than 50 ° C. acts as a result. A third magneto-optical layer having an "A-direction" magnetization, the first magneto-optical layer having a "reverse A-direction" magnetization,
The second magneto-optical layer is formed of the first magneto-optical layer and the third magneto-optical layer so that a recording mark in which the direction of magnetization of the fifth magneto-optical layer is invariable and “A direction” is formed. A method for manufacturing a magneto-optical recording medium capable of overwriting only by modulating a laser beam without a preceding auxiliary magnetic field for controlling interaction with a layer, wherein the third magneto-optical layer includes the second magneto-optical layer. By forming the film after flattening the surface of the magnetic layer by sputter etching, the interaction between the first magneto-optical layer and the third magneto-optical layer is enhanced.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the overwritable magneto-optical recording medium of the present invention will be described with reference to the drawings.

FIG. 1 is a manufacturing process diagram for explaining one embodiment of the present invention, and FIG. 2 is a schematic sectional view of a magneto-optical recording medium manufactured by using the embodiment shown in FIG.

In FIG. 2, 1 is a substrate, 2 is a transparent interference layer 311, a first magneto-optical layer formed thereon, and 312 is N
After forming a second magneto-optical layer of dGdFeCoTi, the surface of the second magneto-optical layer is flattened to some extent by sputter etching, 313 is a third magneto-optical layer formed thereon, 41 is a protective layer formed thereon,
Reference numeral 5 denotes a heat radiation layer formed thereon.

The present inventors have found that the magneto-optical recording medium manufactured by the manufacturing method of the present invention can form the third magneto-optical layer into NdGdF.
The first step is performed after the surface of the second magneto-optical layer of eCoTi is planarized by sputter etching.
The present inventors have found out that the interaction between the magneto-optical layer and the third magneto-optical layer becomes stronger, and have reached the present invention.

When the film surface is sputter-etched, the film surface generally seems to be flat within the scope of the experiments performed by the present inventors. This was confirmed by a transmission electron microscope photograph of about 200,000 times by the replica method. It is considered that the reason why the surface becomes flat is that the angle of incidence of the argon gas being sputter-etched on the film surface has various angles other than vertical.

When the third magneto-optical layer is formed after flattening the second magneto-optical layer by sputter etching, the first and third magneto-optical layers are formed more than when no sputter etching is performed. The reason for the strong interaction with is not clear, but it is considered that the magnetic properties induced and formed by the surface shape of the underlayer during the film growth of the third magneto-optical layer are different.

Next, embodiments of the present invention will be specifically described with reference to the drawings.

As shown in FIG. 1, the guide groove is formed in the substrate mounting step (a) in a diameter of 130 mm and a thickness of 1.20 mm.
The substrate 1 made of polycarbonate resin is mounted in a sputtering apparatus, and in the sputter mounting vacuum evacuation step (b), 5 × 10 ^{−7 is used.}
After evacuating to a pressure of Torr or less, a transparent interference layer 2 of 800 angstrom thick is formed by introducing a mixed gas of argon and nitrogen in the transparent interference layer forming step (c) and reactively sputtering the silicon target. did. Next, in the first magneto-optical layer forming step (d), a TbFeTi target is
The first amorphous of TbFeTi having a thickness of 00 Å
Was formed. Next, in a second magneto-optical layer forming step (e), an NdGdFeCoTi target is sputtered with argon gas to form a second magneto-optical layer 312 of 50 Å thick NdGdFeCoTi.
Was formed. Next, in a second magneto-optical layer sputter etching step (f), this surface is sputter-etched with argon gas for about 10 angstroms to form a second magneto-optical layer 312.
Was made relatively flat. Next, in the third magneto-optical layer forming step (g), a GdTbFeCoTi target was sputtered with an argon gas to form a 600 angstrom thick amorphous third magneto-optical layer 313 of GdTbFeCoTi. Next, in a protective layer forming step (j), a silicon target was reactively sputtered with a mixed gas of argon and nitrogen to provide a 800 angstrom thick silicon nitride protective layer 41. Next, in the heat radiation layer forming step (k), the AlNi target is sputtered with argon gas to form a 400 Å thick A.
A heat radiation layer 5 of 1Ni was provided, and the structure was as shown in FIG. The magneto-optical recording medium thus manufactured is taken out of the sputtering apparatus in the magneto-optical recording medium taking-out step (l).
This magneto-optical recording medium is rotated at 3600 rpm, and a wavelength of 8
A 300 angstrom semiconductor laser beam was irradiated through the substrate 1 on the first magneto-optical layer 311 to a diameter of about 1.4 μm. 3. At a radius of 30.0 mm, a high-level recording power of 9 mW and a low-level recording power of a signal having a recording frequency of 2.12 MHz by ternary light modulation with a duty ratio of 50%.
After performing overwrite recording with 5 mW, a preceding auxiliary magnetic field of 6.5 kOe, and a recording magnetic field of 350 Oersted, even when the data is reproduced by applying a bias magnetic field of 350 Oersted in the same direction as the recording magnetic field at the time of reproduction, the unrecorded area remains. Good reproduction characteristics can be obtained without changing to the recorded state,
When a low level recording power is applied while applying a bias magnetic field in the same direction as the recording magnetic field, a recording mark recorded with a high level recording power can be satisfactorily rewritten to a recording mark to be recorded with a low level recording power. Was confirmed.

For comparison, a magneto-optical recording medium manufactured by forming the third magneto-optical layer 303 on the surface of the second magneto-optical layer 302 without sputter etching as shown in FIG. As a result, when a bias field of 350 Oe is applied in the same direction as the recording magnetic field at the time of reproduction, the non-recorded area changes to the recorded state, and good reproduction characteristics are obtained. When a low-level recording power is applied while applying a bias magnetic field in the same direction as the recording magnetic field, a recording mark recorded with a high-level recording power is excellent in a recording mark to be recorded with a low-level recording power. Was not rewritten.

As the substrate 1, a polycarbonate resin plate,
A glass plate with a photopolymer, an acrylic resin plate with a photopolymer, or the like is used. It is desirable that guide grooves and guide pits are formed on the substrate 1 for tracking servo.

Examples of the material of the transparent interference layer 2 include silicon nitride, silicon nitride oxide, zinc sulfide, a mixture of zinc sulfide and metal oxide, a mixture of zinc sulfide and metal nitride, a mixture of zinc sulfide and metal carbide, A mixture of zinc sulfide and metal fluoride, a mixture of zinc sulfide and metal boride, a mixture of zinc sulfide and another metal sulfide, a multi-component metal oxide having a high refractive index, aluminum nitride, and sialon are desirable.
The transparent interference layer 2 may be formed by a multilayer film.

The material of the first magneto-optical layer 311 is G
dFeCo, GdFeCoTi, GdFeCoCr, G
dFeCoNi, GdFeCoNiCr, GdFeCo
Ta, GdFeCoNb, GdFeCoPt, GdTb
FeCo, GdTbFeCoTi, GdTbFeCoC
r, GdTbFeCoNi, GdTbFeCoNiC
r, GdTbFeCoTa, GdTbFeCoNb, G
dTbFeCoPt, GdDyFeCo, GdDyFe
CoTi, GdDyFeCoCr, GdDyFeCoN
i, GdDyFeCoNiCr, GdDyFeCoT
a, GdDyFeCoNb, GdDyFeCoPt, T
bFeCo, TbFeCoTi, TbFeCoCr, T
bFeCoNi, TbFeCoNiCr, TbFeCo
Ta, TbFeCoNb, and TbFeCoPt are desirable, and the material of the second magneto-optical layer 312 is NdGdFeCo.
Ti, and the material of the third magneto-optical layer 313 is Tb
Fe, TbFeTi, TbFeCr, TbFeNi, T
bFeNiCr, TbFeTa, TbFeNb, TbF
ePt, TbFeCo, TbFeCoTi, TbFeC
oCr, TbFeCoNi, TbFeCoNiCr, T
bFeCoTa, TbFeCoNb, TbFeCoP
t, TbDyFeCo, TbDyFeCoTi, TbD
yFeCoCr, TbFeCoNi, TbDyFeCo
NiCr, TbDyFeCoTa, TbDyFeCoN
b, TbDyFeCoPt is desirable, and the Curie temperature is set higher in the third magneto-optical layer 313.

The material of the protective layer 41 is silicon nitride,
Silicon nitride oxide, zinc sulfide, mixture of zinc sulfide and metal oxide, mixture of zinc sulfide and metal nitride, mixture of zinc sulfide and metal carbide, mixture of zinc sulfide and metal fluoride, zinc sulfide and metal A mixture with boride, a mixture with zinc sulfide and another metal sulfide, a multi-component metal oxide having a high refractive index, aluminum nitride, and sialon are preferable. The protective layer 41 may be formed by a multilayer film.

The material of the heat radiation layer 5 is Al, AiTi,
AlNi, an alloy containing a metal with high thermal conductivity is desirable. There is no necessity to provide the heat radiation layer 5, but it is preferable to provide the heat radiation layer because the margin of the recording power becomes large.

Next, another embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a manufacturing process diagram for explaining one embodiment of the present invention, and FIG. 4 is a schematic sectional view of a magneto-optical recording medium manufactured by using the embodiment shown in FIG.

In FIG. 4, 1 is a substrate, 2 is a transparent interference layer, 321 is a first magneto-optical layer formed thereon, 322
Is a second magneto-optical layer formed by forming a second magneto-optical layer of NdGdFeCoTi and then slightly sputter-etching the surface to a certain extent, and 323 is a third magneto-optical layer formed thereon. , 42 are a protective layer formed thereon and 5 is a heat dissipation layer formed thereon.

As shown in FIG. 4, in the substrate mounting step (a), a guide groove having a diameter of 2
A glass substrate 1 having a thickness of 00 mm and a thickness of 1.18 mm was mounted in a sputtering apparatus, and a vacuum evacuation step (b) for mounting a spatter was performed.
After evacuating to a pressure of 10 ^-7 Torr or less, a transparent interference of 800 angstrom thick silicon nitride is performed by introducing a mixed gas of argon and nitrogen in the transparent interference layer forming step (c) and reactively sputtering the silicon target. Layer 2 was formed. Next, in the first magneto-optical layer forming step (d), GeFeC
The target was sputtered with argon gas to form a 200 Å thick GeFeCo amorphous first magneto-optical layer 321. Next, in a second magneto-optical layer forming step (e), an NdGdFeCoTi target is sputtered with argon gas to form a 50 angstrom thick second magneto-optical layer 322 of NdGdFeCoTi, and then the second magneto-optical layer is formed. In the layer sputter etching step (f), the surface was sputter-etched with argon gas for about 10 angstroms to make the surface of the second magneto-optical layer 322 made of silicon nitride relatively flat. Next, in a third magneto-optical layer film forming step (g), a TbFeTi target is
An amorphous third magneto-optical layer 323 of TbFeTi having a thickness of Å was formed. Next, in a protective layer forming step (j), a silicon target was reactively sputtered with a mixed gas of argon and nitrogen to provide a 800 angstrom thick silicon nitride protective layer 42. Next, in the heat radiation layer forming step (k), an AlTi heat radiation layer 5 having a thickness of 400 angstroms was provided by sputtering an AlTi target with argon gas, and the structure as shown in FIG. 4 was obtained. The magneto-optical recording medium thus manufactured is taken out of the sputtering apparatus in the magneto-optical recording medium taking-out step (l). Next, a UV curable resin of 10 μm
A thick bonding protective film was formed, and such two disks were bonded by hot melt so that the substrate 1 was on the outside and each film was on the inside. The thus produced magneto-optical recording medium was rotated at 3600 rpm, and a semiconductor laser beam having a wavelength of 8300 angstroms was irradiated onto the first magneto-optical layer 321 through the substrate 1 to a diameter of about 1.4 μm.
At a radius of 87.5 mm, a signal having a recording frequency of 10 MHz is subjected to binary optical modulation with a duty ratio of 50% to have a recording power of 9 mW,
After recording with a recording magnetic field of 400 Oersteds, even if a reproduction is performed by applying a bias magnetic field of 400 Oersteds in the same direction as the recording magnetic field at the time of reproduction, the unrecorded area does not change to the recorded state. It was confirmed that reproduction characteristics could be obtained.

The material of the first magneto-optical layer 321 is G
dFeCo, GdFeCoTi, GdFeCoCr, G
dFeCoNi, GdFeCoNiCr, GdFeCo
Ta, GdFeCoNb, GdFeCoPt, GdTb
FeCo, GdTbFeCoTi, GdTbFeCoC
r, GdTbFeCoNi, GdTbFeCoNiC
r, GdTbFeCoTa, GdTbFeCoNb, G
dTbFeCoPt, GdDyFeCo, GdDyFe
CoTi, GdDyFeCoCr, GdDyFeCoN
i, GdDyFeCoNiCr, GdDyFeCoT
a, GdDyFeCoNb, GdDyFeCoPt, T
bFeCo, TbFeCoTi, TbFeCoCr, T
bFeCoNi, TbFeCoNiCr, TbFeCo
Ta, TbFeCoNb, and TbFeCoPt are desirable, and the material of the second magneto-optical layer 322 is NdGdFeCo.
Ti, and the material of the third magneto-optical layer 323 is Tb
Fe, TbFeTi, TbFeCr, TbFeNi, T
bFeNiCr, TbFeTa, TbFeNb, TbF
ePt, TbFeCo, TbFeCoTi, TbFeC
oCr, TbFeCoNi, TbFeCoNiCr, T
bFeCoTa, TbFeCoNb, TbFeCoP
t, TbDyFeCo, TbDyFeCoTi, TbD
yFeCoCr, TbFeCoNi, TbDyFeCo
NiCr, TbDyFeCoTa, TbDyFeCoN
b, TbDyFeCoPt is desirable, and the Curie temperature is set to be lower in the third magneto-optical layer 323.

The material of the protective layer 42 is silicon nitride,
Silicon nitride oxide, zinc sulfide, mixture of zinc sulfide and metal oxide, mixture of zinc sulfide and metal nitride, mixture of zinc sulfide and metal carbide, mixture of zinc sulfide and metal fluoride, zinc sulfide and metal A mixture with boride, a mixture with zinc sulfide and another metal sulfide, a multi-component metal oxide having a high refractive index, aluminum nitride, and sialon are preferable. The protective layer 42 may be formed by a multilayer film.

Next, another embodiment of the overwritable magneto-optical recording medium of the present invention will be described with reference to the drawings.

FIG. 5 is a manufacturing process diagram for explaining one embodiment of the present invention, and FIG. 6 is a schematic sectional view of a magneto-optical recording medium manufactured by using the embodiment shown in FIG.

In FIG. 6, 1 is a substrate, 2 is a transparent interference layer, 331 is a first magneto-optical layer formed thereon, 332
Is a second magneto-optical layer formed of a second magneto-optical layer of NdGdFeCoTi and then slightly sputter-etched on its surface to a certain extent, and 333 is a third magneto-optical layer formed thereon. Numeral 334 denotes a fourth magneto-optical layer formed thereon, 43 denotes a protective layer formed thereon, and 5 denotes a heat radiation layer formed thereon.

As shown in FIG. 5, the guide groove is formed in the substrate mounting step (a) in a diameter of 130 mm and a thickness of 1.20 mm.
The substrate 1 made of polycarbonate resin is mounted in a sputtering apparatus, and the sputtering apparatus is evacuated to 5 × 10 ⁻⁷ in the evacuation step (b) (b).
After evacuation to Torr or less, in a transparent interference layer forming step (c), a mixed gas of argon and nitrogen was introduced, and a silicon target was reactively sputtered to form a 800 nm thick silicon transparent interference layer 2. . Then the first
In the step (d) of forming a magneto-optical layer, a TbFeTi target was sputtered with argon gas to form an amorphous first magneto-optical layer 331 of TbFeTi having a thickness of 200 angstroms. Next, in a second magneto-optical layer forming step (e), a 50 angstrom thick second magneto-optical layer 332 of NdGdFeCoTi is formed by sputtering NdGdFeCoTi cadat with argon gas, and then the second magneto-optical layer is formed. In the sputter etching step (f), the surface was sputter-etched with argon gas for about 10 angstroms to make the surface of the second magneto-optical layer 332 relatively flat. Next, in a third magneto-optical layer forming step (g), a GdTbFeCoTi target was sputtered with argon gas to form a 1000 angstrom thick amorphous third magneto-optical layer 333 of GdTbFeCoTi. Next, in a fourth magneto-optical layer forming step (h), a TbCoTi target is sputtered with argon to form a 400 angstrom thick GdT.
An amorphous third magneto-optical layer 333 of bFeCoTi was formed. Next, in a protective layer forming step (j), a silicon target was reactively sputtered with a mixed gas of argon and nitrogen to provide a 800 angstrom thick silicon nitride protective layer 43. Next, in the heat radiation layer forming step (k), A
An AlNi heat dissipation layer 5 having a thickness of 400 angstroms was provided by sputtering the 1Ni target with argon gas, and the structure as shown in FIG. 6 was obtained. The magneto-optical recording medium thus manufactured is taken out of the sputtering apparatus in the magneto-optical recording medium taking-out step (l). The magneto-optical recording medium is rotated at 3600 rpm, and a semiconductor laser beam having a wavelength of 8300 Å is passed through the substrate 1 for the first time.
On the magneto-optical layer 331 of. After performing overwrite recording with a recording magnetic field of 350 Oersted without precedence auxiliary magnetic field by ternary light modulation at a radius of 30.0 mm, three-valued light is modulated in the same direction as the recording magnetic field during reproduction.
Even when a 50 Oersted bias magnetic field is applied for reproduction, good reproduction characteristics can be obtained without changing the unrecorded area to the recorded state, and the bias magnetic field is applied in the same direction as the recording magnetic field. While irradiating the recording medium with the low-level recording power, it was confirmed that the recording marks recorded with the high-level recording power could be satisfactorily rewritten to the recording marks to be recorded with the low-level recording power.

The material of the first magneto-optical layer 331 is G
dFeCo, GdFeCoTi, GdFeCoCr, G
dFeCoNi, GdFeCoNiCr, GdFeCo
Ta, GdFeCoNb, GdFeCoPt, GdTb
FeCo, CdTbFeCoTi, GdTbFeCoC
r, GdTbFeCoNi, GdTbFeCoNiC
r, GdTbFeCoTa, GdTbFeCoNb, G
dTbFeCoPt, GdDyFeCo, GdDyFe
CoTi, GdDyFeCoCr, GdDyFeCoN
i, GdDyFeCoNiCr, GdDyFeCoT
a, GdDyFeCoNb, GdDyFeCoPt, T
bFeCo, TbFeCoTi, TbFeCoCr, T
bFeCoNi, TbFeCoNiCr, TbFeCo
Ta, TbFeCoNb, and TbFeCoPt are desirable, and the material of the second magneto-optical layer 332 is NdGdFeCo.
Ti, and the material of the third magneto-optical layer 333 is Tb
Fe, TbFeTi, TbFeCr, TbFeNi, T
bFeNiCr, TbFeTa, TbFeNb, TbF
ePt, TbFeCo, TbFeCoTi, TbFeC
oCr, TbFeCoNi, TbFeCoNiCr, T
bFeCoTa, TbFeCoNb, TbFeCoP
t, TbDyFeCo, TbDyFeCoTi, TbD
yFeCoCr, TbFeCoNi, TbDyFeCo
NiCr, TbDyFeCoTa, TbDyFeCoN
b, TbDyFeCoPt is desirable, and the Curie temperature is higher in the third magneto-optical layer 333.

The fourth magneto-optical layer 334 is a film having a higher Curie temperature than that of the third magneto-optical layer 333 so that the magnetization is not reversed even by irradiation with a high-level laser beam, and is irradiated with a low-level laser beam. The third that works as an auxiliary layer at the time of
The magnetization of the fourth magneto-optical layer 334 is aligned with the magnetization of the fourth magneto-optical layer 334 that functions as an initialization layer. When a high-level laser beam is irradiated, the magnetization of the fourth magneto-optical layer 334 changes to the third light. A physical property that does not affect the magnetic layer 333 is selected. The material of the fourth magneto-optical layer 334 is GdTbF
eCo, GdTbFeCoTi, GdTbFeCoC
r, GdTbFeCoNi, GdTbFeCoTa, G
dTbFeCoNb, GdTbFeCoPt, GdTb
FeCoNiCr, TbFeCo, TbFeCoTi,
TbFeCoCr, TbFeCoNi, TbFeCoT
a, TbFeCoNb, TbFeCoPt, TbDyF
eCo, TbDyFeCoTi, TbDyFeCoN
b, TbCo, TbCoTi, TbCoCr, TbCo
Ni, TbCoTa, TbCoNb, and TbCoPt are desirable.

The material of the protective layer 43 is silicon nitride,
Silicon nitride oxide, zinc sulfide, mixture of zinc sulfide and metal oxide, mixture of zinc sulfide and metal nitride, mixture of zinc sulfide and metal carbide, mixture of zinc sulfide and metal fluoride, zinc sulfide and metal A mixture with boride, a mixture with zinc sulfide and another metal sulfide, a multi-component metal oxide having a high refractive index, aluminum nitride, and sialon are preferable. The protective layer 43 may be formed by a multilayer film.

Next, another embodiment of the overwritable magneto-optical recording medium of the present invention will be described with reference to the drawings.

FIG. 7 is a manufacturing process diagram for explaining one embodiment of the present invention, and FIG. 8 is a schematic sectional view of a magneto-optical recording medium manufactured by using the embodiment shown in FIG.

In FIG. 8, 1 is a substrate, 2 is a transparent interference layer, 341 is a first magneto-optical layer formed thereon, 342
Is a second magneto-optical layer formed by forming a second magneto-optical layer of NdGdFeCoTi and then slightly sputter-etching the surface thereof to a certain extent, and 343 is a third magneto-optical layer formed thereon. 344 is a fourth magneto-optical layer formed thereon, 345 is a fifth magneto-optical layer formed thereon, 44 is a protective layer formed thereon, and 5 is formed thereon. It is a heat dissipation layer.

As shown in FIG. 7, in the substrate mounting step (a), a guide groove is formed and has a diameter of 130 mm and a thickness of 1.20 mm.
The substrate 1 made of polycarbonate resin is mounted in a sputtering apparatus, and the sputtering apparatus is evacuated to 5 × 10 ⁻⁷ in the evacuation step (b) (b).
After evacuating to a pressure of Torr or less, a transparent interference layer 2 of 800 angstrom thick is formed by introducing a mixed gas of argon and nitrogen in the transparent interference layer forming step (c) and reactively sputtering the silicon target. did. Next, in a first magneto-optical layer forming step (d), a TbFeTi target is sputtered with an argon gas to form a target.
An amorphous first magneto-optical layer 341 of TbFeTi having a thickness of Å was formed. Next, in a second magneto-optical layer forming step (f), a NdGdFeCoTi target was sputtered with argon gas to form a second magneto-optical layer 342 of 50 Å thick NdGdFeCoTi. Next, in the second magneto-optical layer sputter etching step (f), the surface is sputter-etched with argon gas for about 10 angstroms to make the surface of the second magneto-optical layer 342 relatively flat, and then the third magneto-optical layer is formed. In the layer forming step (g), a GdTbFeCoTi target was sputtered with argon gas to form a GdTbFeCoTi amorphous third magneto-optical layer 343 having a thickness of 1400 angstroms. Next, in a fourth magneto-optical layer forming step (h), a TbFeTi target is sputtered with argon to form a 250 angstrom thick TbF.
An amorphous fourth magneto-optical layer 344 of eTi was formed. Next, in a fifth magneto-optical layer forming step (i), a TbCoTi amorphous fifth magneto-optical layer 345 having a thickness of 400 Å was formed by sputtering a TbCoTi target with argon. Next, in the protective layer forming step (j), a silicon target was reactively sputtered with a mixed gas of argon and nitrogen to provide a 800 angstrom thick silicon nitride protective layer 44. Next, in the heat radiation layer forming step (k), an AlNi heat radiation layer 5 having a thickness of 400 angstroms was provided by sputtering an AlNi target with argon gas, to obtain a configuration as shown in FIG.
The magneto-optical recording medium thus manufactured is taken out of the sputtering apparatus in the magneto-optical recording medium taking-out step (l). The magneto-optical recording medium is rotated at 3600 rpm, and a semiconductor laser beam having a wavelength of 8300 angstroms is applied to the first magneto-optical layer 341 through the substrate 1 to approximately φ1.4 μm.
m and irradiation. After performing overwrite recording with a recording magnetic field of 350 Oersted without precedence auxiliary magnetic field by ternary light modulation at a radius of 30.0 mm, reproduction is performed by applying a bias magnetic field of 350 Oersted in the same direction as the recording magnetic field during reproduction. Also, good reproduction characteristics can be obtained without changing the unrecorded area to the recorded state,
When a low level recording power is applied while applying a bias magnetic field in the same direction as the recording magnetic field, a recording mark recorded with a high level recording power can be satisfactorily rewritten to a recording mark to be recorded with a low level recording power. Was confirmed.

The material of the first magneto-optical layer 341 is G
dFeCo, GdFeCoTi, GdFeCoCr, G
dFeCoNi, GdFeCoNiCr, GdFeCo
Ta, GdFeCoNb, GdFeCoPt, GdTb
FeCo, CdTbFeCoTi, GdTbFeCoC
r, GdTbFeCoNi, GdTbFeCoNiC
r, GdTbFeCoTa, GdTbFeCoNb, G
dTbFeCoPt, GdDyFeCo, GdDyFe
CoTi, GdDyFeCoCr, GdDyFeCoN
i, GdDyFeCoNiCr, GdDyFeCoT
a, GdDyFeCoNb, GdDyFeCoPt, T
bFeCo, TbFeCoTi, TbFeCoCr, T
bFeCoNi, TbFeCoNiCr, TbFeCo
Ta, TbFeCoNb, and TbFeCoPt are desirable, and the material of the second magneto-optical layer 342 is NdGdFeCo.
Ti, and the material of the third magneto-optical layer 343 is Tb
Fe, TbFeTi, TbFeCr, TbFeNi, T
bFeNiCr, TbFeTa, TbFeNb, TbF
ePt, TbFeCo, TbFeCoTi, TbFeC
oCr, TbFeCoNi, TbFeCoNiCr, T
bFeCoTa, TbFeCoNb, TbFeCoP
t, TbDyFeCo, TbDyFeCoTi, TbD
yFeCoCr, TbFeCoNi, TbDyFeCo
NiCr, TbDyFeCoTa, TbDyFeCoN
b, TbDyFeCoPt is desirable, and the Curie temperature is higher in the third magneto-optical layer 343.

The fifth magneto-optical layer 345 is a film having a higher Curie temperature than the third magneto-optical layer 343 so that the magnetization is not reversed even by irradiation with a high-level laser beam.
Curie temperature of the first magneto-optical layer 34
1, the lowest film among the third magneto-optical layer 343 and the fifth magneto-optical layer 345. When the low-level laser light is irradiated, the magnetization of the third magneto-optical layer 343 serving as the auxiliary layer is aligned with the magnetization of the fifth magneto-optical layer 345 serving as the initialization layer, and the high-level laser light is irradiated. When is the fifth
Of the fourth magneto-optical layer 344 and the fifth magneto-optical layer 345 so that the fourth magneto-optical layer 344 acts so that the magnetization of the first magneto-optical layer 345 does not affect the third magneto-optical layer 343. Choose physical properties. The material of the fourth magneto-optical layer 344 is Tb
Fe, TbFeTi, TbFeCr, TbFeNi, T
bFeTa, DyFeCo, DyFeCoTi, DyF
eCoNi, DyFeCoNb, TbFeCo, TbF
eCoTi, TbFeCoCr, TbFeCoNi, T
bFeCoTa, TbFeCoNb, TbFeCoP
t, TbDyFeCo, TbDyFeCoTi, TbD
yFeCoNb is desirable, and the material of the fifth magneto-optical layer 345 is GdTbFeCo, GdTbFeCoT
i, GdTbFeCoCr, GdTbFeCoNi, G
dTbFeCoNiCr, GdTbFeCoTa, Tb
FeCo, TbFeCoTi, TbFeCoCr, Tb
FeCoPt, TbDyFeCo, TbDyFeCoT
i, TbDyFeCoCr, TbDyFeCoTa, T
bCo, TbCoTi, TbCoCr, TbCoNb,
TbCoPt is desirable.

The material of the protective layer 44 is silicon nitride,
Silicon nitride oxide, zinc sulfide, mixture of zinc sulfide and metal oxide, mixture of zinc sulfide and metal nitride, mixture of zinc sulfide and metal carbide, mixture of zinc sulfide and metal fluoride, zinc sulfide and metal A mixture with boride, a mixture with zinc sulfide and another metal sulfide, a multi-component metal oxide having a high refractive index, aluminum nitride, and sialon are preferable. The protective layer 44 may be formed by a multilayer film.

[0053]

As described above, the method of manufacturing a magneto-optical recording medium according to the present invention comprises flattening the surface of the second magneto-optical layer by sputter etching, and forming NdGdFeCoTi as the second magneto-optical layer. Is used, the interaction between the first magneto-optical layer and the third magneto-optical layer is moderately strong, and when a bias magnetic field is applied in the same direction as the recording magnetic field to read the recorded information, the information is recorded. When a low-level laser beam is irradiated by applying a bias magnetic field in the same direction as the recording magnetic field without irradiating the recording mark with the high-level laser beam without changing the area in the absence state to the recorded state. It is possible to manufacture a magneto-optical recording medium in which a recording mark to be recorded by a low-level laser beam can be satisfactorily rewritten.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram for explaining an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a magneto-optical recording medium manufactured by using the embodiment shown in FIG.

FIG. 3 is a manufacturing process diagram for explaining another embodiment of the present invention.

FIG. 4 is a schematic sectional view of a magneto-optical recording medium manufactured using the embodiment shown in FIG.

FIG. 5 is a manufacturing process diagram for explaining another embodiment of the present invention.

6 is a schematic sectional view of a magneto-optical recording medium manufactured by using the embodiment shown in FIG.

FIG. 7 is a manufacturing process diagram for explaining another embodiment of the present invention.

8 is a schematic sectional view of a magneto-optical recording medium manufactured by using the embodiment shown in FIG.

FIG. 9 is a manufacturing process diagram for explaining one embodiment of a conventional magneto-optical recording medium.

FIG. 10 is a schematic sectional view of a magneto-optical recording medium manufactured using the embodiment shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate 2 Transparent interference layer 311,321,331,341,301 First magneto-optical layer 312,322,332,342,302 Second magneto-optical layer 313,323,333,343,303 Third magneto-optical Layers 334, 344 Fourth magneto-optical layer 345 Fifth magneto-optical layer 41, 42, 43, 44, 40 Protective layer 5 Heat dissipation layer (a) Substrate mounting step (b) Sputtering apparatus vacuum evacuation step (c) Transparent interference Layer forming step (d) First magneto-optical layer (e) Second magneto-optical layer forming step of NdGdFeCoTi (f) Second magneto-optical layer sputter etching step (g) Third magneto-optical layer forming Step (h) Fourth magneto-optical layer forming step (i) Fifth magneto-optical layer forming step (j) Protective layer forming step (k) Heat radiating layer forming step (l) Magneto-optical recording medium take-out step

Claims (7)

(57) [Claims] At least a transparent interference layer, a first magneto-optical layer, a second magneto-optical layer, and a third magneto-optical layer are provided on a substrate in this order, and laser light is transmitted through the substrate to the first light layer. Light for writing information by focusing and irradiating the magnetic layer, and reading information by irradiating the laser light while focusing and moving the laser light through the substrate to the first magneto-optical layer. A magnetic recording medium, wherein the first magneto-optical layer is an amorphous alloy containing at least an iron-group transition metal and a rare-earth transition metal, and is a film exhibiting ferrimagnetism at least at 10 ° C or more and 50 ° C or less; The third magneto-optical layer is an amorphous alloy containing at least an iron-group transition metal and a rare-earth transition metal, and is a film exhibiting ferrimagnetism at least from 10 ° C. to 50 ° C., and the second magneto-optical layer is neodymium. (Nd) and gadolinium (Gd ), Iron (Fe), cobalt (Co), and titanium (T
i), wherein the first magneto-optical layer and the second magneto-optical layer are at least 10
The second magneto-optical layer and the third magneto-optical layer are exchange-coupled at least at least 10 ° C. and no more than 50 ° C. The third magneto-optical layer is formed by flattening the surface of the second magneto-optical layer by sputter etching and forming a film. A method for manufacturing a magneto-optical recording medium, characterized by enhancing interaction. 2. A method according to claim 1, wherein at least a transparent interference layer, a first magneto-optical layer, a second magneto-optical layer, and a third magneto-optical layer are provided on the substrate in this order, and the first light is transmitted through the substrate. Light for writing information by focusing and irradiating the magnetic layer, and reading information by irradiating the laser light while focusing and moving the laser light through the substrate to the first magneto-optical layer. A magnetic recording medium, wherein the first magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and is at least 10 ° C.
A film capable of perpendicular magnetization exhibiting ferrimagnetism at a temperature of not less than 50 ° C. or less, and the third magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal and at least 10 ° C.
A film capable of perpendicular magnetization exhibiting ferrimagnetism at a temperature of 50 ° C. or less, and the second magneto-optical layer is composed of neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (Ti). Wherein the direction of magnetization of the first magneto-optical layer and the direction of magnetization of the third magneto-optical layer are either upward or downward with respect to the layer plane. Is set in the “A direction” and the other is set in the “reverse A direction”, the magnetization of the first magneto-optical layer is not changed and the third
Only the magnetization of the magneto-optical layer is aligned in the “A direction” by the preceding auxiliary magnetic field immediately before writing, and the laser light pulse-modulated between the high level and the low level in accordance with the information is the first laser beam.
(1) When the modulated laser beam is at a high level, the temperature of the first magneto-optical layer rises to a high temperature, and a recording magnetic field that is not modulated at that temperature state is increased. Acts or the recording magnetic field that is not modulated in the process of decreasing to the temperature range of 10 ° C. or more and 50 ° C. or less after the irradiation of the laser beam is removed, and as a result, the temperature is reduced to 10 ° C. or more and 50 ° C. or less. A third magneto-optical layer having a "reverse A direction" magnetization and a recording mark having the first magneto-optical layer having a "reverse A direction"; and (2) the modulated laser light is at a low level. At this time, the temperature of the first magneto-optical layer rises to an intermediate temperature, and in that temperature state, at least the magnetization of the third magneto-optical layer remains, and even if a non-modulated recording magnetic field acts on the third magneto-optical layer, The residual magnetization of the magneto-optical layer acts Either by Rukoto, or irradiation of the laser light is gone 10 ° C. to 50
The residual magnetization of the third magneto-optical layer acts even when a recording magnetic field that is not modulated in the process of lowering to a temperature range of 10 ° C. or less acts as a result.
The second magneto-optical layer is formed of the first magneto-optical layer so that a recording mark having the “A-directional” magnetization is formed in the first magneto-optical layer. In a method for manufacturing a magneto-optical recording medium capable of overwriting only by modulating a laser beam so as to control the interaction between a magnetic layer and the third magneto-optical layer, Forming a film after flattening the surface of the magneto-optical layer by sputter etching to enhance the interaction between the first magneto-optical layer and the third magneto-optical layer. A method for manufacturing a magnetic recording medium. 3. A transparent interference layer, a first magneto-optical layer, a second magneto-optical layer, and a third magneto-optical layer are provided at least in this order on a substrate, and a laser beam is transmitted through the substrate to the first light layer. Light for writing information by focusing and irradiating the magnetic layer, and reading information by irradiating the laser light while focusing and moving the laser light through the substrate to the first magneto-optical layer. A magnetic recording medium, wherein the first magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and is a perpendicularly magnetizable film exhibiting ferrimagnetism at least at least 10 ° C. and not more than 50 ° C. Wherein the third magneto-optical layer is an amorphous alloy containing at least an iron-group transition metal and a rare-earth transition metal and is a perpendicularly magnetizable film exhibiting ferrimagnetism at least at 10 ° C. or more and 50 ° C. or less, The second magneto-optical layer is neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (T
i) wherein the direction of magnetization of the first magneto-optical layer and the direction of magnetization of the third magneto-optical layer are either upward or downward with respect to the layer plane. When one is set to the “A direction” and the other is set to the “reverse A direction”, only the magnetization of the third magneto-optical layer precedes immediately before writing while the magnetization of the first magneto-optical layer remains unchanged. When the first magneto-optical layer is irradiated with a laser beam aligned in the “A direction” by an auxiliary magnetic field and pulse-modulated between a high level and a low level according to information, (1) the modulated laser When the light is at a high level, the temperature of the first magneto-optical layer rises to a high temperature, and an unmodulated recording magnetic field acts on the temperature state, or the laser light irradiation stops and the temperature is 10 ° C. or more and 50 ° C. Recording magnetic field not modulated in the process of decreasing to the following temperature range As a result, in the temperature range from 10 ° C. to 50 ° C., the third magneto-optical layer has “reverse A-direction” magnetization and the first magneto-optical layer has “A-direction” magnetization. (2) when the modulated laser light is at a low level, the temperature of the first magneto-optical layer rises to an intermediate temperature, at which temperature at least the third magneto-optical layer The magnetization remains due to the residual magnetization of the third magneto-optical layer acting even when a non-modulated recording magnetic field acts, or the temperature range of 10 ° C. or more and 50 ° C. or less after the laser beam irradiation stops. The residual magnetization of the third magneto-optical layer acts even when a recording magnetic field that is not modulated in the process of lowering the magnetic field acts on the third magneto-optical layer. A direction ”magnetization, 1
The second magneto-optical layer interacts with the first and third magneto-optical layers such that a recording mark having a "reverse A direction" magnetization is formed in the magneto-optical layer of the second type. In a method of manufacturing a magneto-optical recording medium capable of overwriting only by controlling the modulation of a laser beam, the third magneto-optical layer is formed by flattening the surface of the second magneto-optical layer by sputter etching. A method of manufacturing a magneto-optical recording medium, characterized in that the first magneto-optical layer and the third magneto-optical layer have a stronger interaction by being formed on the first magneto-optical layer. 4. A transparent interference layer, a first magneto-optical layer, a second magneto-optical layer, a third magneto-optical layer, and a fourth magneto-optical layer are provided at least in this order on a substrate, and laser light is applied to the substrate. The information is written by focusing and irradiating the first magneto-optical layer through the substrate, and irradiating the laser light while focusing and moving the laser light through the substrate to the first magneto-optical layer. A magneto-optical recording medium for performing reading, wherein the first magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal and has a ferrimagnetic property at least at 10 ° C or more and 50 ° C or less. Wherein the third magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and has a perpendicular magnetization exhibiting ferrimagnetism at least from 10 ° C. to 50 ° C. A possible film, said fourth light The magnetic layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and is a perpendicularly magnetizable film exhibiting ferrimagnetism at least from 10 ° C. to 50 ° C., and the second magneto-optical layer is neodymium. (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (T
i) wherein the direction of magnetization of the first magneto-optical layer and the direction of magnetization of the third magneto-optical layer are either upward or downward with respect to the layer plane. When one is set to the “A direction” and the other is set to the “reverse A direction”, the first magneto-optical layer is irradiated with laser light pulse-modulated between a high level and a low level according to information. (1) When the modulated laser beam is at a high level, the temperature of the first magneto-optical layer rises to a high temperature, and an unmodulated recording magnetic field acts at that temperature, or The unmodulated recording magnetic field acts in the process of dropping to a temperature range of 10 ° C. or more and 50 ° C. or less after irradiation disappears, and as a result, the third magneto-optical layer becomes “A” in a temperature range of 10 ° C. or more and 50 ° C. or less. Orientation "magnetization, said first magneto-optical A recording mark in which the air layer has a “reverse A direction” magnetization, the magnetization direction of the fourth magneto-optical layer is invariable and the “A direction” is formed, and (2) the modulated laser light is at a low level. , The temperature of the first magneto-optical layer rises to an intermediate temperature, and at that temperature, at least the magnetization of the third magneto-optical layer remains, and even if a non-modulated recording magnetic field acts, The third magnetic field is not affected by the residual magnetization of the magneto-optical layer of No. 3 or the non-modulated recording magnetic field in the process of declining to a temperature range of 10 ° C. or more and 50 ° C. or less after the irradiation of the laser beam stops. As a result, the third magneto-optical layer has the “A direction” magnetization in a temperature range of 10 ° C. or more and 50 ° C. or less due to the action of the residual magnetization of the first magneto-optical layer.
The second magneto-optical layer is formed such that the magneto-optical layer of “No. A method of manufacturing a magneto-optical recording medium capable of overwriting only by modulating a laser beam without a preceding auxiliary magnetic field for controlling an interaction between the first magneto-optical layer and the third magneto-optical layer, The third magneto-optical layer is formed by flattening the surface of the second magneto-optical layer by sputter etching to form the third magneto-optical layer. A method for manufacturing a magneto-optical recording medium, characterized by enhancing the action. 5. A transparent interference layer, a first magneto-optical layer, a second magneto-optical layer, a third magneto-optical layer, and a fourth magneto-optical layer are provided at least in this order on a substrate, and a laser beam is emitted. The information is written by focusing and irradiating the first magneto-optical layer through the substrate, and irradiating the laser light while focusing and moving the laser light through the substrate to the first magneto-optical layer. A magneto-optical recording medium for performing reading, wherein the first magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal and has a ferrimagnetic property at least at 10 ° C or more and 50 ° C or less. Wherein the third magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and has a perpendicular magnetization exhibiting ferrimagnetism at least from 10 ° C. to 50 ° C. A possible film, said fourth light Air layer is an amorphous alloy comprising at least iron group transition metals and rare earth-transition metal and at least 10
A perpendicularly magnetizable film exhibiting ferrimagnetism at a temperature of not less than 50 ° C. and not more than 50 ° C., wherein the second magneto-optical layer is composed of neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (Ti) And a direction of magnetization of the first magneto-optical layer and the direction of magnetization of the third magneto-optical layer are either upward or downward with respect to the layer plane. When “A direction” is set to “A direction” and the other is set to “inverse A direction”, when the laser light pulse-modulated between the high level and the low level according to the information is irradiated on the first magneto-optical layer, 1) When the modulated laser light is at a high level, the temperature of the first magneto-optical layer rises to a high temperature, and an unmodulated recording magnetic field acts at that temperature, or the laser light irradiation Temperature of 10 ℃ or more and 50 ℃ or less As a result, the third magneto-optical layer is "A-oriented" in the temperature range of 10 ° C. or more and 50 ° C. or less due to the action of the recording magnetic field which is not modulated in the process of decreasing the temperature. A recording mark in which the layer has "A direction" magnetization and the magnetization direction of the fourth magneto-optical layer is invariable and "A direction" is formed, and (2) the modulated laser beam is at a low level. At this time, the temperature of the first magneto-optical layer rises to an intermediate temperature, and in that temperature state, at least the magnetization of the third magneto-optical layer remains, and even if a non-modulated recording magnetic field acts on the third magneto-optical layer, Due to the residual magnetization of the magneto-optical layer acting, or even if a recording magnetic field that is not modulated acts during the process of decreasing the temperature range from 10 ° C. to 50 ° C. due to the elimination of the laser beam irradiation, the third light The residual magnetization of the magnetic layer acts Ri is the result as the temperature range of 10 ° C. or higher 50 ° C. or less third magnetooptical layer "A direction" magnetization, the first
The second magneto-optical layer is formed such that the magneto-optical layer of the second magneto-optical layer has a "reverse A direction" magnetization, and the recording direction of the fourth magneto-optical layer is invariable and "A direction" is formed. A method of manufacturing a magneto-optical recording medium capable of overwriting only by modulating laser light without a preceding auxiliary magnetic field for controlling the interaction between the first magneto-optical layer and the third magneto-optical layer, The third magneto-optical layer is formed by flattening the surface of the second magneto-optical layer by sputter etching to form a film between the first magneto-optical layer and the third magneto-optical layer. A method for manufacturing a magneto-optical recording medium, characterized by enhancing the action. 6. A transparent interference layer, a first magneto-optical layer, a second magneto-optical layer, a third magneto-optical layer, a fourth magneto-optical layer, and a fifth magneto-optical layer are formed on a substrate in this order. At least provided, information writing is performed by focusing and irradiating the laser beam to the first magneto-optical layer through the substrate, and focusing and moving the laser beam to the first magneto-optical layer through the substrate. Wherein the first magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and is at least 10 ° C. A film capable of perpendicular magnetization exhibiting ferrimagnetism at a temperature of not less than 50 ° C. or less, and the third magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and at least 10 ° C. to 50 ° C. Perpendicularly magnetizable film showing ferrimagnetism The fourth magneto-optical layer is an amorphous alloy containing at least an iron-group transition metal and a rare-earth transition metal, and is a perpendicularly magnetizable film exhibiting ferrimagnetism at least from 10 ° C. to 50 ° C .; The magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and is a perpendicularly magnetizable film exhibiting ferrimagnetism at least from 10 ° C. to 50 ° C .; Is neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (T
i) wherein the direction of magnetization of the first magneto-optical layer and the direction of magnetization of the third magneto-optical layer are either upward or downward with respect to the layer plane. When one is set to the “A direction” and the other is set to the “reverse A direction”, the first magneto-optical layer is irradiated with laser light pulse-modulated between a high level and a low level according to information. (1) When the modulated laser light is at a high level, the temperature of the first magneto-optical layer rises to a high temperature, and an unmodulated recording magnetic field acts at that temperature, or The unmodulated recording magnetic field acts during the process of decreasing the temperature to a temperature range of 10 ° C. or more and 50 ° C. or less due to the elimination of the irradiation. A direction "magnetization, said third magneto-optical The magnetization of the air layer is "A direction" without being affected by the magnetization of the fifth magneto-optical layer because of the fourth magneto-optical layer, and the direction of the magnetization of the fifth magneto-optical layer is unchanged. (2) When the modulated laser light is at a low level, the temperature of the first magneto-optical layer rises to an intermediate temperature, and in that temperature state, at least the The magnetization of the third magneto-optical layer remains at 10 ° C. due to the remaining magnetization of the third magneto-optical layer acting even when a non-modulated recording magnetic field acts, or the laser beam irradiation disappears. The residual magnetization of the third magneto-optical layer acts even when a recording magnetic field that is not modulated in the process of lowering to a temperature range of not less than 50 ° C. acts as a result. The third magneto-optical layer is “A-oriented” magnetization The second magneto-optical layer is formed such that the first magneto-optical layer has “A direction” magnetization and the fifth magneto-optical layer has a constant magnetization direction and a “A direction” recording mark. Manufacture of a magneto-optical recording medium in which a magneto-optical layer controls an interaction between the first magneto-optical layer and the third magneto-optical layer without a preceding auxiliary magnetic field and can be overwritten only by modulating laser light. In the method, the third magneto-optical layer is formed by flattening the surface of the second magneto-optical layer by sputter etching to form the first magneto-optical layer and the third magneto-optical layer. A method for producing a magneto-optical recording medium, characterized by strengthening interaction with a layer. 7. A transparent interference layer, a first magneto-optical layer, a second magneto-optical layer, a third magneto-optical layer, a fourth magneto-optical layer, and a fifth magneto-optical layer are formed on a substrate in this order. At least provided, information writing is performed by focusing and irradiating the laser beam to the first magneto-optical layer through the substrate, and focusing and moving the laser beam to the first magneto-optical layer through the substrate. Wherein the first magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and is at least 10 ° C. A film capable of perpendicular magnetization exhibiting ferrimagnetism at a temperature of 50 ° C. or less, and the fourth magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and at least 10 ° C. to 50 ° C. Perpendicularly magnetizable film showing ferrimagnetism The fourth magneto-optical layer is an amorphous alloy containing at least an iron-group transition metal and a rare-earth transition metal, and is a perpendicularly magnetizable film exhibiting ferrimagnetism at least from 10 ° C. to 50 ° C .; The magneto-optical layer is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal, and is a perpendicularly magnetizable film exhibiting ferrimagnetism at least from 10 ° C. to 50 ° C .; Is neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (T
i) wherein the direction of magnetization of the first magneto-optical layer and the direction of magnetization of the third magneto-optical layer are either upward or downward with respect to the layer plane. When one is set to the “A direction” and the other is set to the “reverse A direction”, the first magneto-optical layer is irradiated with laser light pulse-modulated between a high level and a low level according to information. (1) When the modulated laser light is at a high level, the temperature of the first magneto-optical layer rises to a high temperature, and an unmodulated recording magnetic field acts at that temperature, or The unmodulated recording magnetic field acts in the process of dropping to a temperature range of 10 ° C. or more and 50 ° C. or less due to the elimination of the irradiation. Orientation ”magnetization,
Because of the fourth magneto-optical layer, the magnetization of the third magneto-optical layer becomes "A direction" without being affected by the magnetization of the fifth magneto-optical layer, and becomes the "A direction" magnetization. (2) When the modulated laser light is at a low level, the temperature of the first magneto-optical layer rises to an intermediate temperature, and In a temperature state, at least the magnetization of the third magneto-optical layer remains, and the residual magnetization of the third magneto-optical layer acts even when an unmodulated recording magnetic field acts, or the laser light irradiation The residual magnetization of the third magneto-optical layer acts even when a recording magnetic field that is not modulated in the process of dropping to a temperature range of 10 ° C. or more and 50 ° C. or less occurs, resulting in 10 ° C. or more and 50 ° C. or less. When the third magneto-optical layer is in the “A And the first magneto-optical layer has a "reverse A direction" magnetization, and the recording direction of the fifth magneto-optical layer does not change and a "A direction" recording mark is formed. In addition, there is no preceding auxiliary magnetic field such that the second magneto-optical layer controls the interaction between the first magneto-optical layer and the third magneto-optical layer, and overwriting can be performed only by modulating laser light. In the method for manufacturing a magneto-optical recording medium, the third magneto-optical layer is formed by flattening the surface of the second magneto-optical layer by sputter etching to form the third magneto-optical layer. A method for manufacturing a magneto-optical recording medium, wherein the interaction with the third magneto-optical layer is strengthened.