JPH0554450A - Production of magneto-optical recording medium - Google Patents

Abstract

PURPOSE:To rewrite the recording marks to be recorded by a laser beam of a high level by flattening the surface of a 2nd magneto-optical layer by sputter etching and by using NdGdFeCoTi as the 2nd magneto-optical layer. CONSTITUTION:An NdGdFeCoTi target is sputtered by gaseous argon, by which the 2nd magneto-optical layer 312 consisting of the NdGdFeCoTi and having 50 angstrom thickness is formed in a 2nd magneto-optical layer film forming stage. The surface of this 2nd magneto-optical layer 312 is then sputter etched by the gaseous argon, by which the surface of the 2nd magnetooptical layer is relatively flattened in a 2nd magneto-optical layer sputter etching stage. The NdGdFeCoTi target is then sputtered by the gaseous argon to form the amorphous 3rd magneto-optical layer 313 consisting of the NdGdFeCoTi and having 600 angstrom thickness in a 3rd magneto-optical layer film forming stage. The recording marks recorded by the laser light of the high level are well rewritten to the recording marks to be recorded by a laser beam of a low level.

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 in which information is recorded / reproduced by a laser beam by utilizing a magnetic force effect, and more particularly, a magneto-optical recording medium utilizing exchange coupling force. The present invention relates to a recording medium manufacturing method.

[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 small recording power in a high coercive force magneto-optical layer having a low Curie temperature. Since it is transferred to the magneto-optical layer, it is possible to read with a large magnetic Kerr effect by reading the transferred recording mark.

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

An overwritable magneto-optical recording medium which does not require a preceding auxiliary magnetic field has also been proposed (13th aspect).
Annual Meeting of the Japan Society for Applied Magnetics Lecture number 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 designed 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 like it behaves.

The present inventors have also found that neodymium (Nd), gadolinium (Gd) and iron (Fe) are additionally provided between the two layers of the magneto-optical layer.
A magneto-optical recording medium in which the exchange coupling force can be controlled by inserting a magneto-optical layer containing at least cobalt, cobalt (Co) and titanium (Ti) has already been proposed.

Next, a conventional method for manufacturing a 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 by 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 layers 5 are heat dissipation layers. A polycarbonate resin plate or the like is used as the substrate 1, and silicon nitride or the like is used as the transparent interference layer 2. TbFe or the like is used for the first magneto-optical layer 3, and GdTbFeCo or the like is used for the third magneto-optical layer 303. Silicon nitride is used as the protective layer 40, and AlTi is used as the material of the heat dissipation layer 5.
Etc. are used. A sputtering apparatus is usually used to form each layer of such a magneto-optical recording medium.

A conventional method for manufacturing a magneto-optical recording medium is shown in FIG.
As shown in FIG. 5, after the substrate 1 is mounted in the sputtering apparatus in the substrate mounting step (a) and the sputtering apparatus vacuum exhaust step (b) is evacuated, the transparent interference layer deposition step (c) is performed. 2 is formed, then the first magneto-optical layer is formed in the first magneto-optical layer forming step (d), and then the second magneto-optical layer is formed in the second magneto-optical layer forming step (e). Magneto-optical layer (NdGdFeCoT
i) 302 is formed, then the third magneto-optical layer 303 is formed in the third magneto-optical layer forming step (g), and then the protective layer 40 is formed in the protective layer forming step (j). The film is formed, and finally the heat dissipation layer 5 is formed in the heat dissipation layer forming step (k). The magneto-optical recording medium manufactured in this manner is taken out from the sputtering apparatus in the magneto-optical recording medium taking-out step (l).

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

[0010]

However, the magneto-optical recording medium manufactured by the above-mentioned conventional method is as follows.
When the recorded information is read 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 in the recording layer by the low-level laser light is used. The recording mark having the magnetization is rewritten to the recording mark having the magnetization in the "reverse A direction",
(2) When the recording layer is of type A, the recording mark having the "inverse A direction" magnetization recorded on the recording layer by the low level laser beam is rewritten to the recording mark having the "A direction" magnetization. Further, when a bias magnetic field is applied in the same direction as the recording magnetic field and a low level laser beam is irradiated, (1) when the recording layer is a P type, the recording layer is irradiated with a high level laser beam. It becomes difficult to rewrite the recorded recording mark having the magnetization in the "reverse A direction" to the recording mark having the magnetization in the "A direction".
(2) When the recording layer is of A type, the recording mark having the "A direction" magnetization recorded on the recording layer by the high level laser beam is rewritten to the recording mark having the "reverse A direction" magnetization. There was a problem that it would be difficult.

As a result of intensive studies made by the present inventors to solve these problems, the cause of these problems is that the interaction between the first magneto-optical layer and the third magneto-optical layer is too weak. The inventors have found out that, and have reached the present invention.

[0012]

A method of manufacturing a magneto-optical recording medium according to the present invention comprises a transparent interference layer, a first magneto-optical layer, a second magneto-optical layer and a third magneto-optical layer on a substrate. Information is written by providing at least this order in order to focus and irradiate the laser beam on the first magneto-optical layer through the substrate, and focus the laser beam 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 higher and 50 ° C. or lower, 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 ferrimagnetic property at least 10 ° C. to 50 ° C. It is a film exhibiting magnetism, and 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 at least 10 ° C. and 50 ° C. or less, and the second magneto-optical layer and the third magneto-optical layer are at least 1
A method for manufacturing a magneto-optical recording medium, which is exchange-coupled at 0 ° C. or higher and 50 ° C. or lower, wherein the third magneto-optical layer is formed by flattening the surface of the second magneto-optical layer by sputter etching. By forming the film, the interaction between the first magneto-optical layer and the third magneto-optical layer is strengthened.

Also, in the method of manufacturing a magneto-optical recording medium of 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 in this order on a substrate. Writing information by converging and irradiating the first magneto-optical layer with laser light through the substrate, and irradiating laser light while converging and moving the first magneto-optical layer through the substrate. In this case, 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 10 ° C. or higher 50 The third magneto-optical layer is a vertically magnetizable film exhibiting ferrimagnetism below, 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 has a ferrimagnetism at least 10 ° C. to 50 ° C. Showing perpendicular magnetizable And the second magneto-optical layer is an amorphous alloy film containing at least neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (Ti). One of the magnetization direction of the first magneto-optical layer and the magnetization direction of the third magneto-optical layer is upward or downward with respect to the layer plane as "A direction", and the other is "reverse A direction". At this time, the magnetization of the first magneto-optical layer is kept as it is, and only the magnetization of the third magneto-optical layer is aligned in the “A direction” by the preceding auxiliary magnetic field immediately before writing.
When laser light 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 first magneto-optical layer, or the laser light is irradiated. The recording magnetic field that is not modulated acts in the process of decreasing the temperature to a temperature range of 10 ° C. to 50 ° C., and as a result, the third magneto-optical layer is subjected to “inverse A” in the temperature range of 10 ° C. to 50 ° C. The first magneto-optical layer is formed when a recording mark having "direction" magnetization and the first magneto-optical layer having "reverse A direction" magnetization is formed, and (2) the modulated laser light is at a low level. Rises to an intermediate temperature, and at least the magnetization of the third magneto-optical layer remains in that temperature state, and the residual magnetization of the third magneto-optical layer acts even if a non-modulated recording magnetic field acts. Possibly or Gone is the irradiation of the Za light 10
Even when a recording magnetic field that is not modulated acts in the process of lowering to a temperature range of 50 ° C. to 50 ° C., the residual magnetization of the third magneto-optical layer acts, resulting in 10 ° C. to 50 ° C.
In the following temperature range, the third magneto-optical layer has the “A-direction” magnetization, and the first magneto-optical layer forms the recording mark having the “A-direction” magnetization. A method of manufacturing a magneto-optical recording medium capable of being overwritten only by modulation of laser light such that a magnetic layer controls interaction between the first magneto-optical layer and the third magneto-optical layer, comprising: The third magneto-optical layer is formed by planarizing the surface of the second magneto-optical layer by sputter etching to planarize the surface of the second magneto-optical layer, thereby forming a film between the first magneto-optical layer and the third magneto-optical layer. The feature is to strengthen the action.

Also, in the method of manufacturing a magneto-optical recording medium of 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 in this order on a substrate. Writing information by converging and irradiating the first magneto-optical layer with laser light through the substrate, and irradiating laser light while converging and moving the first magneto-optical layer through the substrate. In this case, 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 10 ° C. or higher 50 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 ferrimagnetism at 10 ° C. or more and 50 ° C. or less. Perpendicular magnetization showing magnetism is possible The second 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 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 as “A direction”,
When the other is set in the "reverse A direction", the magnetization of the first magneto-optical layer is left unchanged and only the magnetization of the third magneto-optical layer is aligned in the "A direction" by the preceding auxiliary magnetic field immediately before writing. And when the laser light 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, In the process in which 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, or when the irradiation of the laser beam is stopped and the temperature falls to a temperature range of 10 ° C. to 50 ° C. As a result of the non-modulated recording magnetic field acting, as a result, the third magneto-optical layer is "reverse A direction" magnetized and the first magneto-optical layer is "reverse A direction" in the temperature range of 10 ° C. to 50 ° C. Recording marks having magnetization are 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 state, at least the magnetization of the third magneto-optical layer remains. Even if an unmodulated recording magnetic field acts, the residual magnetization of the third magneto-optical layer acts, or the irradiation of the laser beam is stopped and
Even if a recording magnetic field that is not modulated acts in the process of decreasing to a temperature range of 0 ° C. or more and 50 ° C. or less, the residual magnetization of the third magneto-optical layer acts, resulting in 10 ° C. or more and 50 ° C.
In the following temperature range, the third magneto-optical layer has the “A-direction” magnetization, and the first magneto-optical layer has the “reverse A-direction” magnetization, so that the second mark is formed. A method of manufacturing a magneto-optical recording medium capable of being overwritten only by modulation of laser light 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 to planarize the surface,
It is characterized in that the interaction between the first magneto-optical layer and the third magneto-optical layer is strengthened.

The method of manufacturing a magneto-optical recording medium according to the present invention comprises 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 on a substrate. A layer is provided at least in this order, and information is written by focusing and irradiating the first magneto-optical layer with laser light through the substrate, and the laser light is passed through the substrate to the first magneto-optical layer. A magneto-optical recording medium for reading information 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. And a perpendicular magnetizable film exhibiting ferrimagnetism at least at 10 ° C. or more and 50 ° C. or less,
Is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal and is at least 10 ° C. and 50 ° C.
The fourth magneto-optical layer is a vertically magnetizable film exhibiting ferrimagnetism below, 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. or more 5
A vertically magnetizable film that exhibits ferrimagnetism at 0 ° C. or below,
The second magneto-optical layer comprises neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), titanium (T).
i), which is an amorphous alloy film containing at least the direction of magnetization of the first magneto-optical layer and the direction of magnetization of the third magneto-optical layer either upward or downward with respect to the layer plane. When one of them is set to "A direction" and the other is set to "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 in that temperature state, or Irradiation is gone, 10 ℃ or more 50 ℃
An unmodulated recording magnetic field acts in the process of decreasing to the temperature range below, and as a result, the third magneto-optical layer is “A-oriented” magnetization in the temperature range of 10 ° C. to 50 ° C. Of the magneto-optical layer of the "reverse A direction" magnetization,
The magnetization direction of the fourth magneto-optical layer is invariable and a recording mark having the "A direction" is formed. (2) When the modulated laser light is at a low level, The temperature rises to an intermediate temperature, and at least the magnetization of the third magneto-optical layer remains in that temperature state, and the residual magnetization of the third magneto-optical layer acts even if a non-modulated recording magnetic field acts. Or the residual magnetization of the third magneto-optical layer acts even if an unmodulated recording magnetic field acts in the process of lowering the temperature range of 10 ° C. or more and 50 ° C. or less due to the disappearance of the laser light irradiation. As a result, the third magneto-optical layer has the “A direction” magnetization, the first magneto-optical layer has the “A direction” magnetization, and the fourth magneto-optical layer has a temperature range of 10 ° C. or higher and 50 ° C. or lower. The direction of magnetization of the layer is unchanged and "A
So that a recording mark having a “direction” is formed.
Of a magneto-optical recording medium which does not have a preceding auxiliary magnetic field for controlling the interaction between the first magneto-optical layer and the third magneto-optical layer and which can be overwritten only by modulation of laser light. In the manufacturing method, the third magneto-optical layer and the third magneto-optical layer are formed by planarizing the surface of the second magneto-optical layer by sputter etching to planarize the surface of the second magneto-optical layer and the third magneto-optical layer. It is characterized by strengthening the interaction with the magneto-optical layer.

The method for manufacturing a magneto-optical recording medium according to the present invention comprises 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 on a substrate. A layer is provided at least in this order, and information is written by focusing and irradiating the first magneto-optical layer with laser light through the substrate, and the laser light is passed through the substrate to the first magneto-optical layer. A magneto-optical recording medium for reading information 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. And a perpendicularly magnetizable film exhibiting ferrimagnetism at least at 10 ° C. or higher and 50 ° C. or lower.
Is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal and is at least 10 ° C. and 50 ° C.
The fourth magneto-optical layer is a vertically magnetizable film exhibiting ferrimagnetism below, 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. or more 5
A vertically magnetizable film that exhibits ferrimagnetism at 0 ° C. or below,
The second magneto-optical layer comprises neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), titanium (T).
i), which is an amorphous alloy film containing at least the direction of magnetization of the first magneto-optical layer and the direction of magnetization of the third magneto-optical layer either upward or downward with respect to the layer plane. When one of the laser beams is "A direction" and the other is "reverse A direction", the first magneto-optical layer is irradiated with laser light pulse-modulated between high level and 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 non-modulated recording magnetic field acts in the process of lowering the temperature to the range of 10 ° C. to 50 ° C. due to no irradiation, and as a result, the third magneto-optical layer is operated in the temperature range of 10 ° C. to 50 ° C. "Direction" magnetization, and the first magneto-optical The layer has "A direction" magnetization, the magnetization direction of the fourth magneto-optical layer does not change, and a recording mark having "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 at that temperature state, at least the magnetization of the third magneto-optical layer remains and the third magnetic field does not modulate, and the third magnetic field acts on the third magneto-optical layer. Even if the recording magnetic field that is not modulated acts due to the residual magnetization of the magneto-optical layer or in the process of decreasing the temperature range of 10 ° C. to 50 ° C. due to the disappearance of the laser light irradiation, the third light beam is applied. As a result of the residual magnetization of the magnetic layer acting, as a result, 10 ° C or higher 5
In the temperature range of 0 ° C. or less, the third magneto-optical layer is “A direction”
Magnetization so that the first magneto-optical layer is "inverse A direction" magnetization, and the magnetization direction of the fourth magneto-optical layer is invariable, so that a recording mark is formed in "A direction". 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 the magneto-optical can be overwritten only by modulation of laser light. A method of manufacturing a recording medium, wherein the third magneto-optical layer includes the second magneto-optical layer.
It is characterized in that the surface of the magneto-optical layer is sputter-etched to be planarized and then deposited to strengthen the interaction between the first magneto-optical layer and the third magneto-optical layer.

The method of manufacturing a magneto-optical recording medium according to the present invention comprises 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 on a substrate. At least a layer and a fifth magneto-optical layer are provided in this order, and information is written by focusing and irradiating the first magneto-optical layer with laser light through the substrate, and writing laser light through the substrate. First
Is a magneto-optical recording medium in which information is read out by irradiating while focusing and moving the magneto-optical layer of the first magneto-optical layer, wherein the first magneto-optical layer contains at least an iron group transition metal and a rare earth transition metal. An amorphous alloy containing and at least 10
It is a perpendicular magnetizable film exhibiting ferrimagnetism at ℃ or more and 50 ℃ 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 at least 10 ℃ or more 50 ℃ The fourth magneto-optical layer is a vertically magnetizable film exhibiting ferrimagnetism below, 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 has a ferrimagnetism at least 10 ° C. to 50 ° C. And 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 a ferrimagnetism at 10 ° C. or more and 50 ° C. or less. The second magneto-optical layer is a film of an amorphous alloy containing at least neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (Ti). ,Previous 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 as "A direction", and the other is "reverse A direction". When the laser light pulse-modulated between a high level and a low level according to the 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 a recording magnetic field that is not modulated acts on the first magneto-optical layer, or the irradiation of the laser beam is stopped and the temperature falls to a temperature range of 10 ° C. or more and 50 ° C. or less. As a result of the action of the recording magnetic field that is not modulated in the process, 1
In the temperature range of 0 ° C. or more and 50 ° C. or less, the first magneto-optical layer has “inverse A direction” magnetization, and the magnetization of the third magneto-optical layer is the fifth magneto-optical layer because of the fourth magneto-optical layer. Is not influenced by the magnetization of the magneto-optical layer and becomes the “A direction” magnetization, and the magnetization direction of the fifth magneto-optical layer does not change, and a recording mark having the “A direction” is formed, and (2) the modulation is performed. When the laser light is at a low level, the temperature of the first magneto-optical layer rises to an intermediate temperature, and at that temperature state, at least the magnetization of the third magneto-optical layer remains and a recording magnetic field that is not modulated is generated. Even if it acts, the residual magnetization of the third magneto-optical layer acts, or the irradiation of the laser beam is stopped and the temperature is 10 ° C.
Even if a recording magnetic field that is not modulated acts in the process of lowering to the temperature range of 50 ° C. or less, the residual magnetization of the third magneto-optical layer acts, resulting 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 magnetization direction of the fifth magneto-optical layer is invariable and "A-direction". Modulation of the laser light without a 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 so that a recording mark is formed. A method of manufacturing a magneto-optical recording medium capable of overwriting only by the method, wherein the third magneto-optical layer is formed by flattening 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.

The method of manufacturing a magneto-optical recording medium according to the present invention comprises 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 on a substrate. At least a layer and a fifth magneto-optical layer are provided in this order, and information is written by focusing and irradiating the first magneto-optical layer with laser light through the substrate, and writing laser light through the substrate. First
Is a magneto-optical recording medium in which information is read out by irradiating while focusing and moving the magneto-optical layer of the first magneto-optical layer, wherein the first magneto-optical layer contains at least an iron group transition metal and a rare earth transition metal. An amorphous alloy containing and at least 10
It is a perpendicular magnetizable film exhibiting ferrimagnetism at ℃ or more and 50 ℃ or less, 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 ℃ or more 50 ℃ The fifth magneto-optical layer is a vertically magnetizable film exhibiting ferrimagnetism below, and 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 ferrimagnetism at least 10 ° C to 50 ° C. And the second magneto-optical layer is neodymium (N).
d), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (Ti), and the magnetization direction of the first magneto-optical layer and the third direction. When the direction of the magnetization of the magneto-optical layer is set to "A direction", either upward or downward with respect to the plane of the layer, and the other is set to "reverse A direction", between the high level and the low level 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 when the pulse-modulated laser light is irradiated onto the first magneto-optical layer. However, an unmodulated recording magnetic field acts in that temperature state, or an unmodulated recording magnetic field acts in the process of decreasing to a temperature range of 10 ° C. or more and 50 ° C. or less due to the disappearance of the laser light, resulting in 1
In the temperature range of 0 ° C. or more and 50 ° C. or less, the first magneto-optical layer has “inverse A direction” magnetization, and the magnetization of the third magneto-optical layer is the fifth magneto-optical layer because of the fourth magneto-optical layer. Is not influenced by the magnetization of the magneto-optical layer and becomes the “A direction” magnetization, and the magnetization direction of the fifth magneto-optical layer does not change, and a recording mark having the “A direction” is formed, and (2) the modulation is performed. When the laser light is at a low level, the temperature of the first magneto-optical layer rises to an intermediate temperature, and at that temperature state, at least the magnetization of the third magneto-optical layer remains and a recording magnetic field that is not modulated is generated. Even if it acts, the residual magnetization of the third magneto-optical layer acts, or the irradiation of the laser beam is stopped and the temperature is 10 ° C.
Even if a recording magnetic field that is not modulated acts in the process of lowering to the temperature range of 50 ° C. or less, the residual magnetization of the third magneto-optical layer acts, resulting in the temperature range of 10 ° C. or more and 50 ° C. or less. The third magneto-optical layer is "A-oriented" magnetization, and the first magneto-optical layer is "reverse A-oriented"magnetization;
The second magneto-optical layer and the third magneto-optical layer are formed so that a recording mark having an invariable direction of magnetization of the fifth magneto-optical layer and having an “A direction” is formed. A method for manufacturing a magneto-optical recording medium capable of overwriting only by modulating laser light without a preceding auxiliary magnetic field for controlling interaction with a layer, wherein the third magneto-optical layer is the second optical layer. It is characterized in that the surface of the magnetic layer is sputter-etched to be planarized and then deposited to strengthen the interaction between the first magneto-optical layer and the third magneto-optical layer.

[0019]

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 an 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 is a first magneto-optical layer formed thereon, and 312 is N.
After the film of the second magneto-optical layer of dGdFeCoTi is formed, the second magneto-optical layer 313, which has been flattened to some extent by sputter etching the surface thereof, is the third magneto-optical layer formed thereon, 41 is a protective layer formed on it,
Reference numeral 5 is a heat dissipation layer formed thereon.

The inventors of the present invention used the magneto-optical recording medium manufactured by the manufacturing method of the present invention to form a third magneto-optical layer by NdGdF.
The surface of the second magneto-optical layer of eCoTi is sputter-etched to planarize the surface, and
The present invention was accomplished by discovering a phenomenon in which the interaction between the magneto-optical layer and the third magneto-optical layer is strengthened.

When the film surface is sputter-etched, it seems that the film surface is generally flat in the range of the experiments conducted by the present inventors. This confirmation was performed by a transmission electron microscope photograph of about 200,000 times by the replica method. The reason for flattening is considered to be that the incident angle of the argon gas which is being sputter-etched on the film surface has various angles other than the vertical angle.

When the third magneto-optical layer is formed after the second magneto-optical layer is flattened by sputter etching, the first magneto-optical layer and the third magneto-optical layer are formed more than when the third magneto-optical layer is not sputter-etched. Although the reason why the interaction with is strong is not clear, it is considered that the magnetic characteristics that are induced and formed differ depending on the surface shape of the underlayer during the film growth of the third magneto-optical layer.

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 board mounting step (a), the diameter is 130 mm, and the thickness is 1.20 mm.
The substrate 1 made of polycarbonate resin of No. 1 is mounted in the sputter device, and 5 × 10 ^{−7 is used} in the sputter mounting vacuum exhaust step (b).
After vacuum evacuation to below Torr, a transparent interference layer 2 of 800 Å thick is formed by reactive sputtering of a silicon target by introducing a mixed gas of argon and nitrogen in the transparent interference layer forming step (c). did. Next, in the first magneto-optical layer forming step (d), a TbFeTi target was sputtered with an argon gas to obtain 2
00 Å thick TbFeTi amorphous 1st
The magneto-optical layer 311 was formed. Next, in the second magneto-optical layer forming step (e), a second magneto-optical layer 312 of NdGdFeCoTi having a thickness of 50 angstroms is formed by sputtering an NdGdFeCoTi target with argon gas.
Formed. Next, in the second magneto-optical layer sputter etching step (f), this surface is sputter-etched with argon gas for about 10 angstroms to form the second magneto-optical layer 312.
The surface of was made relatively flat. Next, in the third magneto-optical layer forming step (g), a GdTbFeCoTi target was sputtered with argon gas to form a 600 angstrom-thick amorphous third magneto-optical layer 313 of GdTbFeCoTi. Next, in the protective layer forming step (j), a silicon target was reactively sputtered with a mixed gas of argon and nitrogen to form a protective layer 41 of silicon nitride having a thickness of 800 Å. Next, in the heat dissipation layer forming step (k), an AlNi target is sputtered with argon gas to form a 400 Å thick A film.
A heat dissipation layer 5 of 1Ni was provided to form a structure as shown in FIG. The magneto-optical recording medium manufactured in this manner is taken out of the sputtering apparatus in the magneto-optical recording medium taking-out step (l).
This magneto-optical recording medium was rotated at 3600 rpm to obtain a wavelength of 8
A semiconductor laser beam of 300 angstrom was irradiated through the substrate 1 on the first magneto-optical layer 311 with a diameter of about 1.4 μm. 3. At a radius of 30.0 mm, a signal with a recording frequency of 2.12 MHz is subjected to ternary optical modulation with a duty ratio of 50%, a high level recording power of 9 mW and a low level recording power
After overwriting with 5 mW, the preceding auxiliary magnetic field of 6.5 kOe, and the recording magnetic field of 350 oersted, even if the reproduction is performed by applying the bias magnetic field of 350 oersted in the same direction as the recording magnetic field at the time of reproducing, the unrecorded area remains. Good reproduction characteristics can be obtained without changing to the recorded state,
Further, 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 by the high level recording power can be favorably rewritten to a recording mark to be recorded by the low level recording power. Was confirmed.

For comparison, the magneto-optical recording medium manufactured by forming the third magneto-optical layer 303 on the surface of the second magneto-optical layer 302 as shown in FIG. When a reproduction was performed by applying a bias magnetic field of 350 Oersted in the same direction as the recording magnetic field during reproduction, the region in the non-recorded state was changed to the recorded state and good reproduction characteristics were obtained. When the low level recording power is applied while applying the bias magnetic field in the same direction as the recording magnetic field, the recording mark recorded by the high level recording power is good as the recording mark to be recorded by the low level recording power. Was not rewritten to.

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

As the material of the transparent interference layer 2, silicon nitride, silicon nitride oxide, zinc sulfide, a mixture of zinc sulfide and a metal oxide, a mixture of zinc sulfide and a metal nitride, a mixture of zinc sulfide and a metal carbide, A mixture of zinc sulfide and a metal fluoride, a mixture of zinc sulfide and a metal boride, a mixture of zinc sulfide and another metal sulfide, a high refractive index multi-component metal oxide, aluminum nitride, and sialon are preferable.
The transparent interference layer 2 may be formed of 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 is used, 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 are 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 a boride, a mixture of zinc sulfide and another metal sulfide, a multi-element metal oxide having a high refractive index, aluminum nitride and sialon are preferable. The protective layer 41 may be formed of a multilayer film.

As the material of the heat dissipation layer 5, Al, AiTi,
AlNi, an alloy containing a metal having a high thermal conductivity is desirable. Although it is not necessary to provide the heat dissipation layer 5, it is preferable to provide the heat dissipation layer 5 because the provision of the heat dissipation layer 5 increases the margin of recording power.

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 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 which has been flattened to some extent by forming a film of a second magneto-optical layer of NdGdFeCoTi and then sputter etching the surface thereof a little, and 323 is a third magneto-optical layer formed thereon. , 42 is a protective layer formed thereon, and 5 is a heat dissipation layer formed thereon.

As shown in FIG. 4, the diameter 2 where the guide groove is formed by the photopolymer in the substrate mounting step (a).
The glass substrate 1 having a thickness of 00 mm and a thickness of 1.18 mm is mounted in the sputtering apparatus, and the sputter mounting vacuum evacuation step (b) is performed.
After vacuum evacuation to × 10 ^-7 Torr or less, in the transparent interference layer forming step (c), a mixed gas of argon and nitrogen is introduced to reactively sputter a silicon target, thereby transparent interference of 800 Å thick silicon nitride. Layer 2 was formed. Next, in the first magneto-optical layer forming step (d), GeFeC
An amorphous first magneto-optical layer 321 of GeFeCo having a thickness of 200 angstrom was formed by sputtering an o target with argon gas. Next, in the second magneto-optical layer forming step (e), an NdGdFeCoTi target is sputtered with an argon gas to form a second magneto-optical layer 322 of NdGdFeCoTi with a thickness of 50 Å, and then a second magneto-optical layer is formed. In the layer sputter etching step (f), the surface of the second magneto-optical layer 322 of silicon nitride was made relatively flat by sputter etching this surface with argon gas for about 10 Å. Next, in the third magneto-optical layer forming step (g), a TbFeTi target was sputtered with argon gas to produce 600
An amorphous third magneto-optical layer 323 of TbFeTi having an angstrom thickness was formed. Next, in the protective layer forming step (j), a silicon target was reactively sputtered with a mixed gas of argon and nitrogen to form a protective layer 42 of silicon nitride having a thickness of 800 Å. Next, in the heat dissipation layer forming step (k), an AlTi target was sputtered with an argon gas to provide a heat dissipation layer 5 of AlTi having a thickness of 400 Å, and the structure as shown in FIG. 4 was obtained. The magneto-optical recording medium manufactured in this manner is taken out of the sputtering apparatus in the magneto-optical recording medium taking-out step (l). Next, 10 μm of UV curable resin is placed on this heat dissipation layer 5.
A thick laminated protective film was formed, and such two discs were laminated 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 angstrom was irradiated onto the first magneto-optical layer 321 through the substrate 1 with a diameter of about 1.4 μm.
A signal with a recording frequency of 10 MHz is recorded at a radius of 87.5 mm by a binary optical modulation with a duty ratio of 50% and a recording power of 9 mW.
After recording with a recording magnetic field of 400 Oersted, even when reproducing by applying a bias magnetic field of 400 Oersted in the same direction as the recording magnetic field at the time of reproduction, an unrecorded area does not change to a recorded state, which is excellent. It was confirmed that the 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 is used, 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 are 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 a boride, a mixture of zinc sulfide and another metal sulfide, a multi-element metal oxide having a high refractive index, aluminum nitride and sialon are preferable. The protective layer 42 may be formed of 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 using the embodiment shown in FIG.

In FIG. 6, 1 is a substrate, 2 is a transparent interference layer, and 331 is a first magneto-optical layer formed thereon.
Is a second magneto-optical layer formed by forming a film of the second magneto-optical layer of NdGdFeCoTi and then flattening the surface to some extent by sputter etching, and 333 is a third magneto-optical layer formed thereon. Reference numeral 334 denotes a fourth magneto-optical layer formed thereon, 43 denotes a protective layer formed thereon, and 5 denotes a heat dissipation layer formed thereon.

As shown in FIG. 5, the guide groove is formed in the substrate mounting step (a), the diameter is 130 mm, and the thickness is 1.20 mm.
Substrate 1 made of polycarbonate resin of No. 1 was mounted in the sputtering apparatus, and 5 × 10 ⁻⁷ was used in the vacuum exhaust step (b) of the sputtering apparatus.
After evacuation to below Torr, in the transparent interference layer forming step (c), a mixed gas of argon and nitrogen was introduced to reactively sputter a silicon target to form a transparent interference layer 2 of silicon having a thickness of 800 Å. . Then the first
In the magneto-optical layer forming step (d), the TbFeTi target was sputtered with argon gas to form the amorphous first magneto-optical layer 331 of TbFeTi having a thickness of 200 angstroms. Next, in the second magneto-optical layer forming step (e), NdGdFeCoTi cadat is sputtered with argon gas to form a second magneto-optical layer 332 of NdGdFeCoTi with a thickness of 50 Å, and then the second magneto-optical layer. In the sputter etching step (f), the surface of the second magneto-optical layer 332 was made relatively flat by sputter etching this surface with argon gas for about 10 Å. Then, in the third magneto-optical layer forming step (g), a GdTbFeCoTi target was sputtered with an argon gas to form an amorphous third magneto-optical layer 333 of GdTbFeCoTi having a thickness of 1000 angstrom. Next, in the fourth magneto-optical layer forming step (h), a TbCoTi target is sputtered with argon to form a 400 angstrom thick GdT film.
An amorphous third magneto-optical layer 333 of bFeCoTi was formed. Next, in the protective layer forming step (j), a silicon target was reactively sputtered with a mixed gas of argon and nitrogen to form a protective layer 43 of silicon nitride having a thickness of 800 Å. Next, in the heat dissipation layer forming step (k), A
An AlNi heat dissipation layer 5 having a thickness of 400 angstroms was provided by sputtering an lNi target with an argon gas, and the structure shown in FIG. 6 was obtained. The magneto-optical recording medium manufactured in this manner 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 semiconductor laser beam having a wavelength of 8300 angstrom is passed through the substrate 1 for the first time.
The light was focused on the magneto-optical layer 331 of 1. After performing overwriting recording with a recording magnetic field of 350 Oersted without a preceding auxiliary magnetic field by ternary optical modulation at a radius of 30.0 mm, 3 in the same direction as the recording magnetic field during reproduction.
Even when reproducing by applying a bias magnetic field of 50 Oersted, good reproducing 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. However, it was confirmed that when the low-level recording power was applied, the recording marks recorded by the high-level recording power were successfully rewritten into the recording marks to be recorded by 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 is used, 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 are desirable, and the Curie temperature is set higher in the third magneto-optical layer 333.

The fourth magneto-optical layer 334 is a film having a Curie temperature higher than that of the third magneto-optical layer 333 so that the magnetization is not inverted even when the high-level laser beam is irradiated, and the low-level laser beam is irradiated. Third that acts as an auxiliary layer when
The magnetization of the fourth magneto-optical layer 333 is aligned with the magnetization of the fourth magneto-optical layer 334 which functions as an initialization layer, and when the high-level laser light is irradiated, the magnetization of the fourth magneto-optical layer 334 becomes the third light. Physical properties are selected so as not to affect the magnetic layer 333. 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 a boride, a mixture of zinc sulfide and another metal sulfide, a multi-element metal oxide having a high refractive index, aluminum nitride and sialon are preferable. The protective layer 43 may be formed of 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 an 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 film of a second magneto-optical layer of NdGdFeCoTi and then flattening the surface to some extent by sputter etching, and 343 is a third magneto-optical layer formed thereon. Reference numeral 344 denotes a fourth magneto-optical layer formed thereon, 345 denotes 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, the guide groove is formed in the substrate mounting step (a), the diameter is 130 mm, and the thickness is 1.20 mm.
Substrate 1 made of polycarbonate resin of No. 1 was mounted in the sputtering apparatus, and 5 × 10 ⁻⁷ was used in the vacuum exhaust step (b) of the sputtering apparatus.
After vacuum evacuation to below Torr, a transparent interference layer 2 of 800 Å thick is formed by reactive sputtering of a silicon target by introducing a mixed gas of argon and nitrogen in the transparent interference layer forming step (c). did. Next, in the first magneto-optical layer forming step (d), a TbFeTi target is sputtered with argon gas to obtain 200
An amorphous TbFeTi amorphous first magneto-optical layer 341 was formed. Next, in the second magneto-optical layer forming step (f), an NdGdFeCoTi target was sputtered with an argon gas to form a second magneto-optical layer 342 of NdGdFeCoTi with a thickness of 50 angstroms. Next, in the second magneto-optical layer sputter etching step (f), this 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. In the layer forming step (g), a GdTbFeCoTi target was sputtered with an argon gas to form an amorphous third magneto-optical layer 343 of GdTbFeCoTi having a thickness of 1400 angstroms. Next, in the fourth magneto-optical layer forming step (h), a TbFeTi target is sputtered with argon to form a 250 angstrom thick TbF target.
An amorphous fourth magneto-optical layer 344 of eTi was formed. Next, in the fifth magneto-optical layer forming step (i), a TbCoTi target was sputtered with argon to form an amorphous fifth magneto-optical layer 345 of TbCoTi having a thickness of 400 Å. Next, in the protective layer forming step (j), a silicon target was reactively sputtered with a mixed gas of argon and nitrogen to form a protective layer 44 of silicon nitride having a thickness of 800 Å. Next, in the heat dissipation layer forming step (k), an AlNi target was sputtered with argon gas to provide a heat dissipation layer 5 of AlNi having a thickness of 400 angstroms, and the structure shown in FIG. 8 was obtained.
The magneto-optical recording medium manufactured in this manner is taken out of the sputtering apparatus in the magneto-optical recording medium taking-out step (l). This magneto-optical recording medium was rotated at 3600 rpm, and a semiconductor laser beam having a wavelength of 8300 angstrom was passed through the substrate 1 and then about φ1.4 μ on the first magneto-optical layer 341.
I focused on m and irradiated. After performing overwriting recording with a recording magnetic field of 350 Oersted without a preceding auxiliary magnetic field by ternary optical modulation at a radius of 30.0 mm, at the time of reproduction, a bias magnetic field of 350 Oersted was applied in the same direction as the recording magnetic field for reproduction. Also, good reproduction characteristics can be obtained without changing the unrecorded area to the recorded state,
Further, 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 by the high level recording power can be favorably rewritten to a recording mark to be recorded by the 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 is used, 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 are desirable, and the Curie temperature is set higher in the third magneto-optical layer 343.

The fifth magneto-optical layer 345 is a film having a Curie temperature higher than that of the third magneto-optical layer 343 so that the magnetization is not reversed even when the high-level laser beam is irradiated.
The Curie temperature of the magneto-optical layer 344 of the first magneto-optical layer 34 is
It is the lowest film among the first, third magneto-optical layer 343, and fifth magneto-optical layer 345. Irradiation of high-level laser light by aligning the magnetization of the third magneto-optical layer 343, which functions as an auxiliary layer when the low-level laser light is irradiated, with the magnetization of the fifth magneto-optical layer 345, which functions as an initialization layer. 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 behaves so that the magnetization of the magneto-optical layer 345 of the third magneto-optical layer 345 does not affect the third magneto-optical layer 343. Select 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 materials for the fifth magneto-optical layer 345 include GdTbFeCo and 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 preferred.

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 a boride, a mixture of zinc sulfide and another metal sulfide, a multi-element metal oxide having a high refractive index, aluminum nitride and sialon are preferable. The protective layer 44 may be formed of a multilayer film.

[0053]

As described above, according to the method of manufacturing a magneto-optical recording medium of the present invention, the surface of the second magneto-optical layer is sputter-etched to be flat, and NdGdFeCoTi is used as the second magneto-optical layer. By using, the interaction between the first magneto-optical layer and the third magneto-optical layer is moderately strong, and when the recorded information is read by applying the bias magnetic field in the same direction as the recording magnetic field, it 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 changing the area in the non-recorded state to the recorded state, the recording mark recorded by the high level laser beam becomes 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 rewritten favorably.

[Brief description of drawings]

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

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

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

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

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

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

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

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

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

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

[Explanation 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 layer Layer 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 device vacuum exhaust 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 Step (h) Fourth magneto-optical layer forming step (i) Fifth magneto-optical layer forming step (j) Protective layer forming step (k) Heat dissipation layer forming step (l) Magneto-optical recording medium ejecting step

Claims (7)

[Claims] 1. 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 laser light is passed through the substrate to produce the first light. Light for writing information by converging and irradiating the magnetic layer, and reading information by irradiating laser light while converging and moving the first magneto-optical layer through the substrate. In the magnetic recording medium, 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. to 50 ° C. 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 10 ° C. or higher and 50 ° C. or lower, and the second magneto-optical layer is neodymium. (Nd) and gadolinium (Gd ), Iron (Fe), cobalt (Co), and titanium (T
i) is an amorphous alloy film containing at least 10 and at least 10 of the first magneto-optical layer and the second magneto-optical layer
In the method for producing a magneto-optical recording medium, the second magneto-optical layer and the third magneto-optical layer are exchange-coupled at not less than 10 ° C. and not more than 50 ° C. The third magneto-optical layer is formed by planarizing the surface of the second magneto-optical layer by sputter etching to planarize the surface of the second magneto-optical layer, thereby forming a film between the first magneto-optical layer and the third magneto-optical layer. A method for manufacturing a magneto-optical recording medium, characterized in that the interaction is strengthened. 2. 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 laser light is passed through the substrate to produce the first light. Light for writing information by converging and irradiating the magnetic layer, and reading information by irradiating laser light while converging and moving the first magneto-optical layer through the substrate. 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 perpendicular magnetizable film exhibiting ferrimagnetism at least at 10 ° C to 50 ° C. 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 is a perpendicular magnetizable film exhibiting ferrimagnetism at least at 10 ° C. to 50 ° C., The second magneto-optical layer is neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (T
i) is an amorphous alloy film containing at least, and the magnetization direction of the first magneto-optical layer and the magnetization direction of the third magneto-optical layer are either upward or downward with respect to the layer plane. When one is set in the “A direction” and the other is set in the “reverse A direction”, the magnetization of the first magneto-optical layer remains as it is and only the magnetization of the third magneto-optical layer precedes by just before writing. When the first magneto-optical layer is irradiated with laser light that is aligned in the “A direction” by the auxiliary magnetic field and pulse-modulated between high level and 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 a recording magnetic field that is not modulated acts on the first magneto-optical layer or the irradiation of the laser beam is stopped and the temperature is 10 ° C. or higher and 50 ° C. Recording magnetic field that is not modulated in the process of falling into the temperature range below As a result, the third magneto-optical layer has the “reverse A direction” magnetization and the first magneto-optical layer has the “reverse A direction” magnetization in the temperature range of 10 ° C. or more and 50 ° C. or less. A recording mark is formed, and (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 state, at least the third magneto-optical layer is formed. The remaining magnetization remains and the residual magnetization of the third magneto-optical layer acts even when an unmodulated recording magnetic field acts, or the temperature of 10 ° C. or more and 50 ° C. or less due to the disappearance of the laser light irradiation. The residual magnetization of the third magneto-optical layer acts even when a recording magnetic field that is not modulated acts on the third magneto-optical layer in the temperature range of 10 ° C. to 50 ° C. Is the "A direction" magnetization, Note that the second magneto-optical layer is formed on the first magneto-optical layer and the third magneto-optical layer so that the first magneto-optical layer forms a recording mark having "A direction" magnetization. In a method of manufacturing a magneto-optical recording medium capable of overwriting only by modulating a laser beam so as to control the action, the surface of the third magneto-optical layer is flattened by sputter etching the surface of the third magneto-optical layer. A method of manufacturing a magneto-optical recording medium, characterized in that the interaction between the first magneto-optical layer and the third magneto-optical layer is strengthened by forming a film after that. 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 laser light is passed through the substrate to produce the first light. Light for writing information by converging and irradiating the magnetic layer, and reading information by irradiating laser light while converging and moving the first magneto-optical layer through the substrate. 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 perpendicular magnetizable film exhibiting ferrimagnetism at least at 10 ° C to 50 ° C. 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 is a perpendicular magnetizable film exhibiting ferrimagnetism at least at 10 ° C. to 50 ° C., The second magneto-optical layer is neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (T
i) is an amorphous alloy film containing at least, and the magnetization direction of the first magneto-optical layer and the magnetization direction of the third magneto-optical layer are either upward or downward with respect to the layer plane. When one is set in the “A direction” and the other is set in the “reverse A direction”, the magnetization of the first magneto-optical layer remains as it is and only the magnetization of the third magneto-optical layer precedes by just before writing. When the first magneto-optical layer is irradiated with laser light that is aligned in the “A direction” by the auxiliary magnetic field and pulse-modulated between high level and 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 a recording magnetic field that is not modulated acts on the first magneto-optical layer or the irradiation of the laser beam is stopped and the temperature is 10 ° C. or higher and 50 ° C. Recording magnetic field that is not modulated in the process of falling into the temperature range below As a result, recording in which the third magneto-optical layer has "inverse A direction" magnetization and the first magneto-optical layer has "A direction" magnetization in a temperature range of 10 ° C. or more and 50 ° C. or less. A mark is formed, and (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 state, at least the temperature of the third magneto-optical layer is increased. The temperature range of 10 ° C. or more and 50 ° C. or less, either due to the residual magnetization of the third magneto-optical layer acting even when the recording magnetic field which remains and is not modulated acts, or when the irradiation of the laser beam is stopped. The residual magnetization of the third magneto-optical layer acts even if a recording magnetic field which is not modulated acts on the third magneto-optical layer in the temperature range of 10 ° C. or more and 50 ° C. or less. A direction "magnetization, 1
The second magneto-optical layer interacts with the first magneto-optical layer and the third magneto-optical layer such that a recording mark having a "reverse A direction" magnetization is formed in the second magneto-optical layer. In a method of manufacturing a magneto-optical recording medium capable of overwriting only by controlling the modulation of laser light, the surface of the second magneto-optical layer of the third magneto-optical layer is flattened by sputtering etching. A method for manufacturing a magneto-optical recording medium, wherein the interaction between the first magneto-optical layer and the third magneto-optical layer is strengthened by forming a film on the magneto-optical recording medium. 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. Information is written by focusing and irradiating the first magneto-optical layer through the substrate, and by irradiating laser light while focusing and moving the laser beam through the substrate to the first magneto-optical layer. A magneto-optical recording medium for 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 is ferrimagnetic at least at 10 ° C. to 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 exhibits perpendicular magnetization at least 10 ° C. and 50 ° C. Possible film, the 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 perpendicular magnetizable film exhibiting ferrimagnetism at 10 ° C. to 50 ° C., and the second magneto-optical layer is neodymium. (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (T
i) is an amorphous alloy film containing at least, and the magnetization direction of the first magneto-optical layer and the magnetization direction of the third magneto-optical layer are either upward or downward with respect to the layer plane. When one of the laser beams is "A direction" and the other is "reverse A direction", the first magneto-optical layer is irradiated with laser light pulse-modulated between high level and 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 on the first magneto-optical layer, or the temperature of the laser light is increased. The non-modulated recording magnetic field acts in the process of lowering the temperature to the range of 10 ° C. to 50 ° C. due to no irradiation, and as a result, the third magneto-optical layer is operated in the temperature range of 10 ° C. to 50 ° C. "Direction" magnetization, and the first magneto-optical The air layer has "inverse A direction" magnetization, the magnetization direction of the fourth magneto-optical layer does not change, and a recording mark in "A direction" is formed, and (2) the modulated laser beam is at a low level. , The temperature of the first magneto-optical layer rises to an intermediate temperature, and at that temperature state, at least the magnetization of the third magneto-optical layer remains and the unmodulated recording magnetic field acts on the first magneto-optical layer. The residual magnetic field of the third magneto-optical layer acts, or even if a recording magnetic field that is not modulated acts in the process of decreasing the temperature range of 10 ° C. to 50 ° C. due to the disappearance of the laser light irradiation, As a result of the residual magnetization of the magneto-optical layer of FIG.
The second magneto-optical layer is magnetized in the “A direction”, and the second magneto-optical layer is formed so that a recording mark in which the magnetization direction of the fourth magneto-optical layer does not change and the “A direction” is formed. A method for manufacturing a magneto-optical recording medium capable of overwriting only by modulation of 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 planarizing the surface of the second magneto-optical layer by sputter etching to planarize the surface of the second magneto-optical layer, thereby forming a film between the first magneto-optical layer and the third magneto-optical layer. A method for manufacturing a magneto-optical recording medium, which is 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 laser light is applied to the substrate. Information is written by focusing and irradiating the first magneto-optical layer through the substrate, and by irradiating laser light while focusing and moving the laser beam through the substrate to the first magneto-optical layer. A magneto-optical recording medium for 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 is ferrimagnetic at least at 10 ° C. to 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 exhibits perpendicular magnetization at least 10 ° C. and 50 ° C. Is a possible film, the fourth light Air layer is an amorphous alloy comprising at least iron group transition metals and rare earth-transition metal and at least 10
The second magneto-optical layer is a vertically magnetizable film exhibiting ferrimagnetism at temperatures above 50 ° C. and below 50 ° C., and the second magneto-optical layer is neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co), and titanium (Ti). And a magnetization direction of the first magneto-optical layer and a magnetization direction of the third magneto-optical layer either upward or downward with respect to the layer plane. Is set to be “A direction” and the other is set to “reverse A direction”, when the first magneto-optical layer is irradiated with laser light pulse-modulated between high level and 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 in that temperature state, or the irradiation of the laser beam is Temperature above 10 ℃ and below 50 ℃ As a result of the non-modulated recording magnetic field acting in the process of lowering the ambient temperature, the third magneto-optical layer is magnetized in the “A direction” in the temperature range of 10 ° C. to 50 ° C., and the first magneto-optical layer is magnetized. The layer has the “A direction” magnetization, the magnetization direction of the fourth magneto-optical layer does not change, and the recording mark having the “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 at that temperature state, at least the magnetization of the third magneto-optical layer remains and the third magnetic field does not modulate, and the third magnetic field acts on the third magneto-optical layer. Even if the recording magnetic field that is not modulated acts due to the residual magnetization of the magneto-optical layer or in the process of decreasing the temperature range of 10 ° C. to 50 ° C. due to the disappearance of the laser light irradiation, the third light beam is applied. That 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 so that the magneto-optical layer of the second magneto-optical layer has "inverse A direction" magnetization and the recording direction of the fourth magneto-optical layer does not change and the "A direction" is formed. In a method of manufacturing a magneto-optical recording medium capable of overwriting only by modulation of 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 after the surface of the second magneto-optical layer is sputter-etched to planarize the surface, whereby the first magneto-optical layer and the third magneto-optical layer are mutually formed. A method for manufacturing a magneto-optical recording medium, which is 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 on a substrate in this order. Information is written by providing at least laser light focused on the first magneto-optical layer through the substrate to move the laser light focused on the first magneto-optical layer through the substrate. In the magneto-optical recording medium, information is read out by irradiating the medium while 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 10 ° C. A perpendicular magnetizable film exhibiting ferrimagnetism at 50 ° C. or lower, 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. to 50 ° C. A vertically magnetizable film that exhibits ferrimagnetism at The fourth magneto-optical layer is an amorphous alloy that contains at least an iron group transition metal and a rare earth transition metal, and is a perpendicular magnetizable film that exhibits ferrimagnetism at least 10 ° C. and 50 ° C., Is a vertically magnetizable film that is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal and exhibits ferrimagnetism at least at 10 ° C. or higher and 50 ° C. or lower. Is neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co) and titanium (T
i), which is an amorphous alloy film containing at least the direction of magnetization of the first magneto-optical layer and the direction of magnetization of the third magneto-optical layer either upward or downward with respect to the layer plane. When one of the laser beams is "A direction" and the other is "reverse A direction", the first magneto-optical layer is irradiated with laser light pulse-modulated between high level and 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 An unmodulated recording magnetic field acts in the process of decreasing the temperature range of 10 ° C. or more and 50 ° C. or less due to no irradiation, and as a result, the first magneto-optical layer is “reverse” in the temperature range of 10 ° C. or more and 50 ° C. or less. A direction ”magnetization, and the third magneto-optical Due to the fourth magneto-optical layer, the magnetization of the gas layer is not influenced by the magnetization of the fifth magneto-optical layer and becomes “A direction” magnetization, and the magnetization direction of the fifth magneto-optical layer does not change. (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 above-mentioned The residual magnetization of the third magneto-optical layer remains and even if an unmodulated recording magnetic field acts, the residual magnetization of the third magneto-optical layer acts, or the irradiation of the laser beam is stopped and the temperature is 10 ° C. Even if a recording magnetic field that is not modulated acts in the process of lowering to the temperature range of 50 ° C. or less, the residual magnetization of the third magneto-optical layer acts, resulting in the temperature range of 10 ° C. or more and 50 ° C. or less. The third magneto-optical layer is "A" oriented magnetization , The first magneto-optical layer is magnetized in the "A direction", and the magnetization direction of the fifth magneto-optical layer is invariable so that a recording mark in the "A direction" is formed. Manufacture of a magneto-optical recording medium capable of being overwritten only by modulation of laser light without a preceding auxiliary magnetic field for controlling the interaction between the first magneto-optical layer and the third magneto-optical layer. In the method, the third magneto-optical layer is formed after the surface of the second magneto-optical layer is sputter-etched to planarize the surface, thereby forming the first magneto-optical layer and the third magneto-optical layer. A method for manufacturing a magneto-optical recording medium, characterized in that the interaction with a layer is strengthened. 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 provided on a substrate in this order. Information is written by providing at least laser light focused on the first magneto-optical layer through the substrate to move the laser light focused on the first magneto-optical layer through the substrate. In the magneto-optical recording medium, information is read out by irradiating the medium while 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 10 ° C. A perpendicular magnetizable film exhibiting ferrimagnetism at 50 ° C. or lower, wherein 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. A vertically magnetizable film that exhibits ferrimagnetism at The fourth magneto-optical layer is an amorphous alloy that contains at least an iron group transition metal and a rare earth transition metal, and is a perpendicular magnetizable film that exhibits ferrimagnetism at least 10 ° C. and 50 ° C., Is a vertically magnetizable film that is an amorphous alloy containing at least an iron group transition metal and a rare earth transition metal and exhibits ferrimagnetism at least at 10 ° C. or higher and 50 ° C. or lower. Is neodymium (Nd), gadolinium (Gd), iron (Fe), cobalt (Co) and titanium (T
i), which is an amorphous alloy film containing at least the direction of magnetization of the first magneto-optical layer and the direction of magnetization of the third magneto-optical layer either upward or downward with respect to the layer plane. When one of the laser beams is "A direction" and the other is "reverse A direction", the first magneto-optical layer is irradiated with laser light pulse-modulated between high level and 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 An unmodulated recording magnetic field acts in the process of lowering the temperature range from 10 ° C. to 50 ° C. due to no irradiation, and as a result, the first magneto-optical layer in the temperature range from 10 ° C. to 50 ° C. "Direction" magnetization,
The magnetization of the third magneto-optical layer is not influenced by the magnetization of the fifth magneto-optical layer due to the fourth magneto-optical layer and becomes “A direction” magnetization, and the magnetization of the fifth magneto-optical layer. A recording mark whose direction is invariable and is "A direction" is formed. (2) When the modulated laser beam is at a low level, the temperature of the first magneto-optical layer rises to an intermediate temperature, In the temperature state, at least the magnetization of the third magneto-optical layer remains and even if the unmodulated recording magnetic field acts, the residual magnetization of the third magneto-optical layer acts, or the irradiation of the laser beam is performed. Even if a recording magnetic field that is not modulated acts in the process of decreasing the temperature range from 10 ° C. to 50 ° C., the residual magnetization of the third magneto-optical layer acts, resulting in 10 ° C. to 50 ° C. In the temperature range of So that the first magneto-optical layer has "inverse A direction" magnetization, and the magnetization direction of the fifth magneto-optical layer does not change so that a recording mark having "A direction" is formed. In addition, there is no preceding auxiliary magnetic field for controlling the interaction between the first magneto-optical layer and the third magneto-optical layer by the second magneto-optical layer, and overwriting is possible only by modulating laser light. In the method of manufacturing a magneto-optical recording medium, the third magneto-optical layer is formed after the surface of the second magneto-optical layer is sputter-etched to be planarized to form the first magneto-optical layer. A method for manufacturing a magneto-optical recording medium, characterized in that the interaction with the third magneto-optical layer is strengthened.