JPH03156753A - Optical recording medium - Google Patents

Abstract

PURPOSE:To improve recording sensitivity and to obtain the optical recording medium having good C/N and excellent durability by using an AgAu alloy obtained by incorporating Au into Ag for the metallic reflecting layer. CONSTITUTION:The metallic reflecting layer is formed with an AgAu alloy obtained by incorporating >=0.5 atomic percent of Au into Ag. Namely, the AgAu alloy film has low heat conductivity, the recording sensitivity of the medium is improved, the reflectivity is not significantly reduced as compared with an Ag film, etc., and hence the C/N of the medium is improved. Furthermore, the film itself is highly durable and has a good protecting function. Consequently, the durability of the medium is improved, and a magneto-optical recording medium excellent in recording sensitivity, C/N and durability is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application The present invention relates to an optical recording medium on which information is recorded, reproduced, erased, etc. using light such as a laser. More specifically, the present invention relates to an optical recording medium having a metal reflective layer, and is particularly preferably applicable to a magneto-optical recording medium in which the recording layer is a magneto-optical recording layer.

<Prior Art> Various research and developments are being conducted on optical recording media as high-density, large-capacity information recording media. In particular, magneto-optical recording media from which information can be erased have a wide range of applications, and numerous materials and systems have been announced, and their practical application is eagerly awaited.

As the above-mentioned magneto-optical recording material, for example, JP-A-52-
FeTb described in Publication No. 31703, JP-A-56-126
FeTbG4 described in Publication No. 907, JP-A-58-737
There have already been many proposals such as FeTbCo and FeCoDy described in Japanese Patent Application Laid-Open No. 165846/1984. However, in order to put these information erasable magneto-optical recording media into practical use, it is necessary to further improve recording and reproducing characteristics.

In contrast, a method has been proposed in which a metal reflective layer is provided on the magneto-optical recording layer or thereon via a dielectric layer.

This method is excellent in that a high C/N can be obtained by using both the Kerr effect and the Faraday effect. Conventionally, as this metal reflective layer, AI was used (JP-A-58-83346, JP-A-59-132434), Cm was used (JP-A-59-8150), AI-based Those using alloy (Japanese Unexamined Patent Publication No. 62-137743), those using stainless steel (Japanese Unexamined Patent Publication No. 59-171054)
, Taranoku using Te (Japanese Patent Application Laid-Open No. 62-52744)
, using an amorphous metal film (Japanese Patent Application Laid-Open No. 61-57053
Publication No. 2), etc. have been proposed. However, when materials such as Ag, AI, and eu with high reflectivity are used, recording sensitivity decreases significantly due to their high thermal conductivity, while when stainless steel and Te, which have relatively low thermal conductivity, are used, recording Although the sensitivity is improved, the reflectance is low, so there is a problem that a sufficient C/N ratio cannot be obtained.

Furthermore, the recording layer deteriorates due to high temperature and humidity, and it is necessary to protect the recording layer with these metal layers.

To solve these problems, Ta addition to AI (Japanese Unexamined Patent Application Publication No. 1983-1999)
No. 4938 Publication 1, Addition of Ti, Mg, and Rare Earths to An, Ag, AI, and Cu (JP-A-59-38781
No. Publication), Co-111g alloy to A1, Mg-3i
Addition of alloy, Cr, Sn, Mg (JP-A-62-23
9349), addition of Ti to AI (JP-A-62-1
Various alloy films have been proposed, such as those disclosed in Japanese Patent Laid-open No. 37743 and Japanese Unexamined Patent Publication No. 64-66847. However, although it is possible to improve thermal conductivity while maintaining high reflectance with these conventional alloy films, it is necessary to add significant amounts of additive elements to improve durability under high temperature and high humidity conditions. If it is added in the necessary amount, it will not be possible to maintain the high reflectance required for the reflective layer, and it will not be possible to obtain a layer that satisfies both the functions of a reflective layer and a protective layer.

<Objective of the Invention> The present invention was made in view of the current situation, and it is an object of the present invention to provide an optical recording medium that has characteristics of high sensitivity and high C/N ratio and excellent durability by improving the metal reflective layer. The purpose is to

<Structure and effects of the invention> The above objects are achieved by the invention as follows.

That is, the present invention is an optical recording medium having a metal reflective layer, characterized in that the metal reflective layer is made of an AgAu alloy containing 0.5 at% or more of Au in Ag.

The above-mentioned present invention was made as follows.

That is, as a result of intensive studies by the present inventors to overcome the above-mentioned drawbacks, by making the metal reflective layer an Ag-Au alloy in which Ag contains Au, the recording sensitivity is improved compared to the conventional Ag reflective film. discovered that it is possible to obtain an optical recording medium with a large improvement in C/N ratio, and excellent durability.
We have arrived at the present invention.

This will be explained in detail below.

The reason why the recording sensitivity of the optical recording medium provided with the AgAu alloy metal reflective film of the present invention is improved is that the recording sensitivity is closely related to the thermal conductivity of the metal reflective film. The thermal conductivity of AgAu alloy containing Ag
This is due to a surprising decrease compared to the membrane.

In view of the effect of reducing thermal conductivity, in other words, improving recording sensitivity, the content of Au in the AgAu alloy of the present invention is 0.5 at% or more, more preferably 2.0 at%.
This range is preferable from the viewpoint of durability of the medium, especially the magneto-optical recording medium. There is no particular restriction on the upper limit of the Au content in terms of recording sensitivity and durability, but in the magneto-optical recording medium of the example, due to the increase in Au, there is a slight increase in C, /
(This is thought to be related to a decrease in reflectance), and the effect of improving recording sensitivity (decreasing thermal conductivity) tends to reach saturation. Considering the price of Au, from a practical standpoint, 50 at% or less is preferable. . From the viewpoint of C/'N, that is, reflectance, and recording sensitivity, that is, thermal conductivity, it is preferably 30 at% or less, more preferably 15 at% or less.

It goes without saying that the AgAu alloy of the present invention may contain other metal elements within a range that does not impair its properties.

Furthermore, it has been found that by incorporating specific elements into this AgAu alloy, it is possible to improve recording sensitivity, that is, to lower thermal conductivity, to improve C/N, and to improve durability. This particular element is Ti, Ta, Zr, Y.

Ag such as Re, transition metals other than Au, In, Sn
, Zn, and Mg, and at least one of Ti, Ta, Zr, and Y is preferred. Furthermore, due to these elements, sufficient effects described above can be obtained even with a small Au content, and costs can be reduced by reducing the Au content. Among these, Ag and Au
The AgAu alloy containing 0.5 to 15 at% of 0.5 to 15 at% and further containing 0.3 to 8.0 at% of at least one of the above-mentioned specific elements has excellent recording sensitivity, durability under high temperature and high humidity,
It is preferable because it is excellent in the four points of C/N and cost, and in particular, the total content of Au and the specific element is 1.0 to 15
Preferred is an AgAu alloy having a composition of at%.

Incidentally, in order to further improve the stability over time, a small amount of other elements such as Cr, Nb, and Re may be added to the metal reflective film of the present invention.

The thickness of these metal reflective layers is preferably 100 to 200 OA, more preferably 300 to 800 OA. If it is too thick, the sensitivity will decrease, and if it is too thin, the reflectance of the reflective film will decrease and the C/N will deteriorate.

Possible methods for forming these metal reflective layers include well-known vacuum evaporation methods, sputtering methods, ion beam sputtering methods, and CVD methods; A sputtering method is preferred. Further, the film deposition rate, sputtering gas pressure, etc. are appropriately selected in consideration of productivity and film stress.

It is clear from the spirit of the present invention that the optical recording medium of the present invention is not particularly limited as long as it uses a reflective film, such as well-known compact disks and video disks, in addition to the above-mentioned magneto-optical recording medium.

Among them, it can be particularly preferably applied to a magneto-optical recording medium that uses a rare earth element that is easily oxidized as a recording layer.

By the way, in this magneto-optical recording medium, the recording layer may be any material as long as it can record by the photothermal magnetic effect, and may be a known magnetic metal having an easy magnetization direction perpendicular to the film surface and having a large magneto-optic effect. a thin film, such as the aforementioned FeTb alloy,
FeTbCo alloy, FeTbGd alloy and NdDyFe
Typical examples include amorphous alloys of rare earth elements and transition metal elements, such as Co alloys. The film thickness of the magneto-optical recording layer is 15
0 to 1000 people, preferably 200 to 500 A.

Further, the laminated structure is not particularly limited except that the metal reflective layer is formed on the side opposite to the light incident surface of the magneto-optical recording layer. Among these, a configuration in which a transparent dielectric layer is provided between the metal reflective layer and the magneto-optical recording layer is preferable from the viewpoint of improving sensitivity, C/N, and durability.

Furthermore, a structure in which a dielectric layer is also provided between the substrate and the magneto-optical recording layer, that is, a structure in which the magneto-optical recording layer is sandwiched between transparent dielectric layers, improves durability due to effects such as improving C/N of the layer and preventing moisture permeation. It is more preferable because improvement can be obtained.

On the other hand, even in a configuration in which the metal reflective layer is provided in direct contact with the magneto-optical recording layer, the metal reflective layer made of the AgAu alloy of the present invention exhibits practically sufficient performance. This configuration eliminates the need for a transparent dielectric layer, and is therefore preferable from the viewpoint of productivity and medium cost. Each of these configurations is selected depending on the purpose.

Both the transparent dielectric layers on the substrate side and the metal reflective layer side used in the above structure need to have effects such as optical interference effect and Kerr effect enhancement depending on their purpose, and must have a high refractive index above a certain level. preferable. In addition, it is necessary to be transparent to the laser beam used, and as a transparent dielectric layer, metal oxides, nitrides, sulfides,
Carbide, fluoride, or a composite thereof can be applied.

Specific examples include silicon oxide, indium oxide, tantalum oxide, aluminum oxide, silicon nitride, aluminum nitride, titanium nitride, zinc sulfide, magnesium fluoride, aluminum fluoride, silicon carbide, and composites thereof. , needless to say, is not limited to this. These dielectrics may contain metal elements in their films. Organic materials such as parylene, polyimide, and paraffin can also be used. A multilayer structure of these transparent dielectrics may be used.

The transparent dielectric material in contact with the oxidizable layer 5i, such as the magneto-optical recording layer, is preferably one that does not contain oxygen, such as nitride, from the viewpoint of preventing oxidative deterioration. Among them, aluminum nitride, silicon nitride, and aluminum-silicon nitride are preferably used in terms of film stress and film quality.

The optimum thickness of these transparent dielectric layers varies depending on the medium configuration and refractive index. For example, in the above-mentioned structure in which a magneto-optical recording layer is sandwiched between transparent dielectric layers, the thickness of the transparent dielectric layer between the substrate and the magneto-optical recording layer will depend on the thickness of the transparent dielectric layer between the magneto-optical recording layer and the metal reflective layer. The optimal thickness of the dielectric layer also varies, so it cannot be determined unambiguously, but usually the thickness of the transparent dielectric between the substrate and the magneto-optical recording layer is about 300 to 1,600, and the thickness of the magneto-optical recording layer The thickness of the transparent dielectric film between the metal reflective layer and the metal reflective layer is preferably 30 to 600 mm. However, of course, the film thickness is not limited to these ranges.

These transparent dielectric layers are formed by conventional methods.

For example, for those made of the above-mentioned inorganic substances, the known vacuum evaporation method,
Sputtering method, ion beam sputtering method, C
It is manufactured by VD method etc.

In addition, glass, acrylic resin, polycarbonate resin, epoxy resin, 4-methylpentene resin, and modified products thereof are preferably used as the substrate, but they are limited in mechanical strength, price, weather resistance, heat resistance, and moisture permeability. In this respect, polycarbonate resin is preferred.

By providing an inorganic protective layer made of an inorganic material on the metal reflective layer having the above-mentioned structure, durability such as resistance to high temperature and high humidity and gas resistance is further improved, which is more preferable. Especially AgAu
Although alloys may be degraded by H2S gas or the like and their properties may deteriorate, this inorganic protective layer can significantly improve this.

This inorganic protective layer is not particularly limited as long as it has good moisture permeability and gas barrier properties, but in terms of recording properties and durability, it is preferably applied that has a low thermal conductivity and is itself excellent in durability. . Such inorganic protective layers include metal films and dielectric films.

The metal film itself must have sufficiently high durability and low thermal conductivity so as not to reduce the recording sensitivity of the medium. There is no need to specifically limit the metal as long as it has such characteristics, but metal films made of Ti, Cr, Ni, and alloys thereof are particularly preferred. Note that the thickness of the metal film is preferably 10 to 300 people, more preferably 30 to 250 people, from the above points.

On the other hand, dielectric films are superior in that they have low thermal conductivity, have little effect on recording characteristics even if they are thick, and can provide sufficient protection. For such dielectric films, known transparent dielectrics can be used as they are as the aforementioned enhancement layer, but aluminum nitride, silicon nitride, nitride films of aluminum/silicon nitride, silicon oxide,
An oxide film of titanium Ride is preferable, and a nitride film is particularly preferable since oxygen is not involved.

The thickness of the dielectric film is determined by its effect on improving the thermal conductivity, productivity, and durability of the material.

Although it cannot be said unambiguously, 10 to 500 people, preferably 5
0 to 300 people are preferably used.

Furthermore, by covering not only the upper surfaces of the optical recording layer and the metal reflective layer but also the edges thereof, the inorganic protective layer becomes more effective.

As a method for forming the metal reflective layer and the inorganic protective layer, publicly known vacuum evaporation methods, sputtering methods, ion beam sputtering methods, CVD methods, etc. can be considered. A sputtering method is preferable in terms of distribution and the like. In addition, the film deposition rate, gas pressure, etc. are factors that affect productivity.

It is selected appropriately in consideration of membrane stress.

Furthermore, it is common to provide an organic protective layer made of an organic photo- and thermosetting resin or thermoplastic resin on this inorganic protective layer for the purpose of mechanical protection, further improvement of durability, and the like.

As is known, the optical recording medium with the above structure can be used as a single-sided recording medium by adding necessary protection such as a protective flat plate or a protective film, or by bonding the two sheets together with the metal reflective layer side. Used as a double-sided recording medium.

The present invention will be described below based on examples of magneto-optical recording media, but the present invention is not limited to the following examples.

<Example 1-4. Comparative Example 1 A magneto-optical recording medium having a structure in which a transparent dielectric layer 2, a magneto-optical recording layer 3, a metal reflective layer 4 are sequentially laminated on a substrate 1 shown in FIG. 1, and an organic protective layer 5 is further laminated is as follows. It was created and evaluated as follows.

1.6 μm in a disk with a diameter of 130 mm and a thickness of 1.2 mm.
Polycarbonate resin (PC) with pitch groups
A high-frequency magnetron sputtering device (manufactured by ANELVA 5PF-4
30H type) vacuum chamber, and 4 x 1O-7To
Do not exhaust until it reaches rr.

Next, a mixed gas of Ar and N2 (Ar: N2=70:
30 vo1%) was introduced into the vacuum chamber, and the pressure was 10 mT.
The A r /N2 mixed gas flow rate was adjusted so that the A r /N2 mixed gas flow rate was orr. The target is 100mm in diameter and 5mm thick.
mm of Al5oS! Using a disk made of a sintered body of 5o (hereinafter, the suffix indicates the composition (atomic %)), the discharge power was 5o.
Performing high frequency sputtering at 00W and discharge frequency of 13.561EZ, while rotating (rotating) the PC board,
As the transparent dielectric 2, 800 Al5iN films were deposited.

Subsequently, as the magneto-optical recording layer 3, Tb2□FeftCos
Approximately 300 TbFeCo alloy films were deposited by high-frequency sputtering using an alloy target under conditions of Ar gas pressure of 2 m Torr and discharge power of 150 W.

Subsequently, using an Ag target, appropriately placing an Au chip of 3 mm square and xi mm on the target, high frequency sputtering was performed under the conditions of Ar gas pressure of 2 m Torr and discharge power of 100 W, and the Au content was varied.Table 1 ,
400 made of AgAu alloys having the respective compositions of Examples 1 to 4.
Deposit the metal reflective layer 4 on the PC board/AIS
A magneto-optical disk having a laminated structure of iN/TbFeCo/metal reflective layer was obtained. Au of each AgAu alloy film of metal reflective layer 4
The amount was adjusted to each composition of Examples 1 to 4 in Table 1 by changing the number of Au chips on the Ag target.

During the formation of each of these layers, the PC board was rotated at 20 rpm.

The obtained magneto-optical disk was recorded with C,
/N and the optimum recording laser power, which is an index of recording sensitivity, were evaluated. The semiconductor laser power during writing was varied, and the optimal recording condition was set when the second harmonic of the reproduced signal was minimized.

[Recording conditions] Disk rotation speed: 1800 rpm, recording track position: 30 mm radius, recording frequency: 2 MHz,
Magnetic field applied during recording = 500 Oe [Reproduction conditions] Disk rotation speed: 1800 rpm, successive laser power + 1.2 mW Table 1 shows the measurement results of the optimum recording laser power and C/N.
Shown below.

Note that Example 1 in Table 1 is the same as Example 1 except for the metal reflective layer.
This magneto-optical disk has the same structure as Example 4, but has a metal reflective layer formed by removing the ku chips of Examples 1 to 4, and has a simple Ag reflective film that does not contain An.

Also, (20 mW or more) in the optimum recording laser power column means that recording was not possible with the maximum output of the laser used, 10 mW, and a small reproduction signal was obtained with the disk rotation speed halved to 10 mW.

Table 1 Furthermore, on the metal reflective layer 4 of the disks of Examples 1, 2.3 and Comparative Example 1, an ultraviolet curable phenol novolac epoxy acrylate resin was applied using a spin coater, and then cured by ultraviolet irradiation to a thickness of about 20 μm. An organic protective layer 5 was provided. These samples were heated to a temperature of 70°C and a humidity of 85°C.
When an accelerated deterioration test was conducted for 1000 hours under conditions of ．． There was no change in C/N or appearance in the disc No. 2.3, confirming that the metal reflective film of the present invention has excellent durability and also has a protective function to prevent deterioration of the recording film. .

<Examples 5 to 9> Unlike Examples 1 to 4, the metal reflective layer 4 was not only made of Au chips on the Ag target, but also contained Ti, Ta, Zr, and Y chips as specific elements. Magneto-optical disk samples having the same configuration as in Examples 1 to 4 were prepared in the same manner as in Examples 1 to 4, except that the AgAu alloy films were formed by adding the respective metals, and the same evaluations were performed. The results are shown in Table-2.

Table 2 In addition, on the samples of Examples 5 to 9, the above-mentioned Examples]・～
The same organic protective layer 5 as in 3 was provided, and the temperature was 80°C and the humidity was 85%.
An accelerated deterioration test was conducted for 1000 hours under the following conditions, but no change was observed in either C/N or appearance, confirming that the metal reflective layer of the example had the above-mentioned durability and protective performance.

As shown in the above examples, 0.5 at% of Au is added to Ag.
The Agh alloy film without any of the above additives has excellent C/N, recording sensitivity, and durability under high temperature and high humidity.
It can be seen that the recording sensitivity is further improved in the A g A, u alloy containing Ta, Zr, and Y.

<Examples 10-12. Comparative Example 2> A magneto-optical recording medium having the same laminated structure shown in FIG. 1 as in Examples 1 to 10 was prepared as follows, and evaluated at a recording density nearly twice that of Examples 1 to 10 and an accelerated deterioration test time.

1.6 for a disk with a diameter of 130 mm and a thickness of 1, 2 mm.
A disk substrate 1 made of polycarbonate resin ()) C) having groups with a pitch of c and zm was placed in a vacuum chamber of a high frequency magnetron sputtering device (Model 5PF-430H manufactured by Anelva ■) capable of installing 3 targets. 1
The exhaust was evacuated to O-7 Torr.

Next, a mixed gas of A, r, and N2 (Ar: N2 = 70
: 30 vo1%) was introduced into the vacuum chamber, and the pressure was 10
The A r /N2 mixed gas flow rate was adjusted so that it became m Torr. The target is 100mm in diameter,
Using a disk made of a sintered body of Al3oSi7o with a thickness of 5 mm, discharge power was 500W, discharge frequency was 13, and 56MH7.
While rotating (rotating) the PC board, an Al5iN film was deposited as the transparent dielectric 2 by high-frequency sputtering.
00 people piled up.

Subsequently, as the magneto-optical recording layer 3, Tb2□Fe7xCoB
Using an alloy target, high frequency sputtering was performed under the conditions of Ar gas pressure of 2 m Torr and discharge power of 150 W to deposit approximately 225 TbFeCo alloy films.

Subsequently, using an Ag target, a 3 mm square x 1 mm thick A1 chip, as well as Ti and Ta chips were placed on the target, and Ar gas pressure was set at 2 m Torr.
High-frequency sputtering was performed under the condition of LOW discharge power, and the contents of Au, Ti, and Ta were varied.
Deposit metal reflective layer 4 on PC board/Al5iN
To obtain a magneto-optical disk having a laminated structure of /TbFeCo/metal reflective layer.

Au, Ti, T of each AgAu alloy film of metal reflective layer 4
l of a was adjusted to each composition of Examples 10 to 12 in Table 3 by changing the number of An, Ti, and Ta chips on the Ag target.

During the formation of each of these layers, the PC board was rotated at 20 rpm.

Furthermore, an ultraviolet-curable phenol novolac epoxy acrylate resin was applied onto the metal reflective layer 4 using a spin coater, and then cured by ultraviolet irradiation to provide an organic protective layer of about 20 μm.

In addition to measuring the initial characteristics of the obtained magneto-optical disk, a durability test of 2000 hours, which is twice as long as in Examples 1 to 9, was conducted at a temperature of 80°C and a relative humidity of 85%, and the C/N was measured. The increase in number of was measured. The initial values of the magneto-optical characteristics are determined by the magneto-optical recording and reproducing device (0MS- manufactured by Nakamichi ■).
1000 type), the recording power was varied under the following conditions, and the optimum recording condition was when the second harmonic of the reproduced signal was at its minimum. As described below, the recording frequency was set to 3.7 MHz, which is nearly twice that of Examples 1 to 9.

[Recording conditions] Disc rotation speed: 1800 rpm, recording track position at 30 mm radius, recording frequency: 3.7 MHz
, Applied magnetic field during recording = 300 oersted, duty
: 50% [Reproduction conditions] Disc rotation speed: 1800 rpm, read laser power: 1.2 mW, optimum recording laser power, C/N and 2000 hr
Table 3 shows the increase in the number of pinholes for 7i.

Note that Comparative Example 2 in Table 3 is the same as Example 1 except for the metal reflective layer 4.
This is a magneto-optical disk having the same configuration as Nos. 0 to 12, with the metal reflection layer 4 being an Ag reflection film (400A) made of a simple Ag film. In Comparative Example 2, measurement could not be performed using the above-mentioned apparatus with a maximum recording power of 10 mW, so the required recording power was set to be 10 mW or more.

In Examples 10 to 12, the number of pinholes increased slightly, but
There was no change in C/N even after 2000 hours, and C/N
The recording laser power level is also sufficient and can be said to be at a level suitable for practical use.

Table 3 <Examples 13 to 21, Comparative Examples 3 and 4> In order to improve the durability of Examples 1 to 12, a transparent dielectric was added between the magneto-optical recording layer 3 and the metal reflective layer 4 in the laminated structure. A magneto-optical disk having the laminated structure shown in FIG. 2 in which the body layer 6 was inserted was prepared and evaluated.

In Examples 10 to 12, for the magneto-optical disk, following the formation of the magneto-optical recording layer 3, the transparent dielectric layer 6 on the rear surface was formed to a thickness of 120 nm in exactly the same manner as the transparent dielectric layer 3 on the front surface. Except for this, in exactly the same manner as in Examples 10 to 12, products having metal reflective layers made of various AgAu alloys shown in Table 4 were manufactured.

Also, evaluation of each obtained magneto-optical disk was also carried out in Example 10.
It was carried out in exactly the same manner as in 12.

Table 4 Comparative Example 3 has the same configuration as Examples 13 to 21 except for the metal reflective layer 4.
This is a magneto-optical disk which is formed by removing the Au chip of No. 21 and is simply an Ag reflective film that does not contain Au. Further, in Comparative Example 4, only the metal reflective layer 4 was formed using an AlTi alloy (Ti:2
at%) to a thickness of 600, and the rest was as in Example 1.
This is a magneto-optical disk having the same configuration as Nos. 3 to 21.

In Comparative Example 3), in which the metal reflective layer 4 was made of Ag, the recording power was so large that it could not be measured with this evaluation device (maximum performance: 10 mW). In addition, the increase in pinholes in accelerated aging tests is large. In the case of AlTi in Comparative Example 4, C
ZN is low and the number of pinholes increases significantly. On the other hand, in the examples of the present invention, the recording sensitivity and CZN are excellent, and even in the accelerated deterioration test results after 200 Ohr, there is no change in CZN at all, and the number of pinholes is small, and the durability is also good. It was confirmed that it was excellent.

From a comparison with Examples 10 to 12, it was found that although the layered structure becomes somewhat complicated by providing the transparent dielectric layer 6 between the magneto-optical recording layer 3 and the metal reflective layer 4, it can be used under high temperature and high humidity conditions. It was confirmed that the durability of CZN was greatly improved, and the recording and reproducing characteristics of CZN and recording sensitivity were also improved.

<Examples 22 to 27> In the configurations of Examples 13 to 21, a magneto-optical disk having the laminated configuration shown in FIG. Created and Example 13
- Evaluation was made in the same manner as in 21.

The magneto-optical disk of this example has the same structure as Examples 14 and 17, and has an Al5iN film of each thickness shown in Table 5 formed on the metal reflective layer 4 in the same manner as Examples 13 to 21. Ti metal films having the thicknesses shown in Table 5 were formed by sputtering a Ti target under the same conditions as those for the magneto-optical recording layer. The evaluation results are shown in Table-5.

Table 5 By providing an inorganic protective layer, both recording sensitivity and CZN are good, and durability can be further improved. In particular, those provided with an Al5iN film can improve durability without reducing recording sensitivity at all.

As described above, the present invention includes 0.5 at% or more of Au in Ag,
Furthermore, Ti, Ta, 7. This is an optical recording medium that uses an AgAu alloy film as a reflective film, which contains a predetermined amount of the above-mentioned specific elements such as r, Y, etc. The excellent properties of the AgAu alloy film realize an optical recording medium with the following excellent properties. It has the effect of In other words, the thermal conductivity of the AgAu alloy film decreases, improving the recording sensitivity of the medium, and the reflectance also increases.
The C/N ratio of the medium is also good, and the film itself is highly durable and has a good protective function, so the durability of the medium is also improved, and the recording sensitivity and C/
N. An optical recording medium with excellent durability can be obtained. Furthermore, by providing an inorganic protective layer, the durability of the negative layer can be improved without reducing recording sensitivity.

As described above, the present invention makes a significant contribution to improving the characteristics of optical recording media, especially magneto-optical recording media that use a recording layer that requires improvement of characteristics by a 6-metal reflective film and is susceptible to deterioration.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the laminated structure of Examples 1 to 12, FIG. 2 is an explanatory diagram of the laminated structure of Examples 13 to 21, and FIG. 3 is an explanatory diagram of the laminated structure of Examples 22 to 27. . 1: Substrate, 2, 6: Transparent dielectric layer, 3: Magneto-optical recording layer,
4: Metal reflective layer, 5: Organic protective layer, 7: Inorganic protective layer.

Claims (1)

[Scope of Claims] 1) In an optical recording medium having a metal reflective layer, the metal reflective layer contains Ag containing 0.5 at% or more of Au.
An optical recording medium characterized by being made of an Au alloy. 2) The Au content of the AgAu alloy is 0.5 to 50 at.
%. The optical recording medium according to claim 1. 3) The AgAu alloy contains 0.5 to 15 at% of Au, and further contains transition metal elements other than Ag and Au, In
AgAu containing 0.3 to 8.0 at% of at least one specific element selected from the group of , Sn, Zn, and Mg.
The optical recording medium according to claim 1 or 2, which is an alloy. 4) The optical recording medium according to claim 3, wherein the total content of Au and specific elements in the AgAu alloy is 1.0 to 15 at%. 5) The specific element is Ti, Ta, Zr, Y, Re, In
5. The optical recording medium according to claim 3, wherein the optical recording medium is at least one element selected from the group consisting of , Sn, Zn, and Mg. 6) The optical recording medium according to claim 5, wherein the specific element is at least one element selected from the group of Ti, Ta, Zr, and Y. 7) Claim 1, wherein the metal reflective layer is in contact with an optical recording layer.
6. The optical recording medium according to any one of items 6 to 6. 8) The optical recording medium according to any one of claims 1 to 6, characterized in that a transparent dielectric layer is provided between the metal reflective layer and the optical recording layer. 9) Claims 1 to 8, characterized in that a transparent dielectric layer is laminated on the side of the optical recording layer opposite to the metal reflective layer side.
Any of the optical recording media listed in Section 1. 10) The optical recording medium according to any one of claims 1 to 9, characterized in that an inorganic protective layer made of an inorganic material is provided on the metal reflective layer. 11) Claim 1, wherein the optical recording layer is a magneto-optical recording layer.
The optical recording medium according to any one of items 1 to 10.