JPH0233745A - Magneto-optical recording medium and magneto-optical recording method - Google Patents

Abstract

PURPOSE:To impart high corrosion resistance to the above recording medium and to allow high-speed recording by forming a recording layer which is specified in the contents of Tb, Dy and Co and consists of the balance substantially e on a substrate and providing a protective layer consisting of borosilicate glass on the recording layer. CONSTITUTION:This magneto-optical recording medium 1 is formed by providing the protective layer 3, an intermediate layer 4, the recording layer 5, the protective layer 6, and a protective coat 7 successively on the substrate 2. The recording layer 5 is constituted of the Tb, Dy and Co the contents of which, expressed by atomic %, are expressed by the formula I, II and III, and the balance substantially Fe. Either one or both of the protective layer 3 and the protective layer 6, more preferably the layer 6 and further preferably the two protective layers are constituted of the borosilicate glass. The high corrosion resistance is thus imparted to the recording medium and the high-speed recording is attained by impressing modulated magnetic fields thereto under irradiation of light.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a magneto-optical recording medium such as a magneto-optical recording disk, which records and reproduces information using heat and light such as a laser beam, and a magneto-optical recording medium. The present invention relates to a magneto-optical recording method for performing magneto-optical recording.

<Prior Art> An amorphous magnetic thin film of a rare earth element transition metal is used in the recording layer of a magneto-optical recording medium.

As rare earth elements, Gd, Tb, Dy, etc. are preferably used, as transition metals, Fe, Co, etc. are preferably used, and in particular, C/
Since the N ratio is high, GdDyFeCo, TbDyFe
A recording layer made of Co has been proposed.

For example, in Japanese Patent Application Laid-Open No. 60-83305, Fe-C
In the o-Dy system, Dy is partially substituted with Tb or Gd, and examples thereof include (Fe+-b Cob )
7sTbe Gd+9 (however, o<b≦0.4)
is listed. The effect is an improvement in the C/N ratio due to an increase in the Kerr rotation angle.

Furthermore, in Japanese Patent Application Laid-Open No. 60-9855, TbDyFe
Co is disclosed, examples thereof include C03s5F
e3e5Dy+3. aTb92, CO+7. aF e
62. SD y5.7 T b 10.2 is stated. The effect is an improvement in the S/N ratio due to the synergistic effect of the decrease in the magnetostriction value and the increase in the Kerr rotation angle.

Furthermore, in the example of JP-A-60-107751, (D yo, 3 T b 0.7)
0.2(F e O,7COO,3)o,e, ie Dy6Tt)+<Fe5aCOz4.

The effect is an improvement in the S/N ratio due to a decrease in the Curie temperature and an increase in the Kerr rotation angle.

Furthermore, in JP-A-60-233810, as a comparative example (Feo9COo, lo, a(Tbo,
Dyoyama and (Fe.

COO, l) 0.79 (T b o, a D ”J
o, s) o, z+, i.e. Fet2COa, respectively
Tt)+oDy+o and F e 71COs T
b 10.6D y+o,s is described.

In addition to these, Japanese Patent Application Laid-open No. 60-98611,
9-'217249 also discloses TbDyFeCo, but its effects include an increase in Kerr rotation angle,
These include improved saturation magnetization and lowered Curie temperature.

However, in the composition range described in the above publication, C/
The improvement in the N ratio may be insufficient, or the magnetic field strength required when recording/erasing information becomes large.

In other words, a magnetic field is externally applied to a magneto-optical recording medium when recording and erasing information, and the magnetic field strength (hereinafter referred to as "Hext") required for these is determined by the composition described in each of the above-mentioned publications. However, since a relatively large magnetic field, for example, 3000 e or more is required, the magnetic field generating device becomes large in size, and therefore the recording/reproducing device for the magneto-optical recording medium also becomes large. Furthermore, in the recording layer having the above composition, the magnetic field strength necessary for erasing information is naturally high.

In addition, in recent years, magnetic field modulation recording, which performs recording using a modulated magnetic field while irradiating light with a constant intensity, has attracted attention due to the demand for the so-called override method, which erases information by overwriting information without providing an independent erasing process. However, in this case, since the recording layer described in each of the above-mentioned publications requires a large applied magnetic field strength, it is necessary to use a coil with a large inductance. High-speed recording is difficult because a coil with large inductance cannot shorten the magnetic field reversal time.

Therefore, the present inventors determined that the content expressed in atomic percent of Tb, Dy, and co is 20.5≦Tb+Dy≦310 0.088≦Tb/ (Tb+Dy)≦0,226.0
≦CO≦15.0, and the remainder is substantially Fe, and a magneto-optical recording medium having a recording layer and a magnetic field modulation type magneto-optical recording method capable of high-speed recording using this magneto-optical recording medium are proposed. (Patent Application No. 1983-77394). This magneto-optical recording medium is C
/N ratio is high, and Hext can be kept low.

Since the recording layer of the magneto-optical recording medium described in Japanese Patent Application No. 63-77394 has a small Hext, a coil with small inductance can be used and high-speed recording is possible.
Furthermore, when a coil with a smaller inductance is used to perform high-speed recording, the distance between the coil and the recording layer must be made close.

However, a double-sided recording type magneto-optical recording medium is constructed by laminating a pair of substrates each having a recording layer with the recording layer on the inside, or even in a single-sided recording type, the recording layer is placed on the same substrate as the substrate. In a magneto-optical recording medium having a protective plate with a certain thickness, it is difficult to bring the coil and the recording layer close to each other due to the thickness of the substrate or the protective plate. Therefore, when using a coil with a smaller inductance, for example, a 1 to 1 layer thick layer made of an organic material is placed on the recording layer.
It is preferable to use it as a single-sided recording type magneto-optical recording medium provided with a protective coat of 00 μm. However, such a protective coat cannot be said to have sufficient corrosion resistance.

For this reason, the present inventors added a group 4A element, a group 5A element, a group 6A element, a group 8 element, a group 3B element, C, A magneto-optical recording medium has been proposed in which at least one element selected from Si and P is added as an additive element (Japanese Patent Application No. 140764/1982). In this magneto-optical recording medium, the corrosion resistance of the recording layer is improved by adding the above-mentioned additive elements.

In addition, the present inventors have proposed a magneto-optical recording medium in which Ge and/or Sr is added as an additive element to the recording layer of the magneto-optical recording medium described in Japanese Patent Application No. 63-77394 and Japanese Patent Application No. 63-140764. (Patent application 1986-1)
No. 42462). In this magneto-optical recording medium, the change in sensitivity of the recording layer is extremely small even after storage under high temperature and high humidity conditions or after repeated reproduction.

Furthermore, the present inventors have disclosed that
In the recording layer of the magneto-optical recording medium described in No. 62, Bi, Cu
has proposed a magneto-optical recording medium in which one or more elements selected from , Sn, and Pb are added as an additive element (Japanese Patent Application No. 143335/1983). This magneto-optical recording medium has further improved C/N ratios.

<Problems to be Solved by the Invention> However, there are strict requirements for improving the corrosion resistance of magneto-optical recording media, and in particular, when used as a single-sided recording type for magnetic field modulation recording, higher corrosion resistance is required.

The present invention provides high corrosion resistance to a magneto-optical recording medium that can suppress the strength of an externally applied magnetic field when recording and erasing information, thereby achieving sufficient corrosion resistance even for a single-sided recording type configuration. An object of the present invention is to provide a magneto-optical recording medium having the present invention and a magnetic field modulation type magneto-optical recording method that enables high-speed recording using the magneto-optical recording medium.

Means to solve problems〉 Such objects are achieved by the invention described below.

That is, the present invention includes the following (1) to (7).

(1) The content expressed in atomic percent of Tb, Dy and Go is 205≦Tb+Dy≦31.0 0.088≦Tb/ (Tb+Dy)≦0.2260≦
Co≦150 and the remainder is substantially Fe on a substrate, and a protective layer made of borosilicate glass is provided on the recording layer and/or between the substrate and the recording layer. A magneto-optical recording medium comprising:

(2) For the recording layer of the magneto-optical recording medium described in (1) above, a group 4A element, a group 5A element, a group 6A element, a group 8 element,
1. A magneto-optical recording medium characterized in that at least one element selected from Group 3B elements, C, Si, and P is added as an additive element.

(3) the Group 4A elements are Ti, Zr and Hf;
The 5A group elements are ■, Nb and Ta, and the 6A group elements are
The group elements are Cr, Mo and W, and the group 8 element is N.
i and Pt, and the group 3B elements are B and A42
The magneto-optical recording medium according to (2) above.

(4) A magneto-optical recording medium characterized in that Ge and/or Sr are added as additional elements to the recording layer of the magneto-optical recording medium according to any one of (1) to 3) above.

(5) For the recording layer of the magneto-optical recording medium according to any one of (1) to 4) above, B], Cu, Sn and P
A magneto-optical recording medium characterized in that one or more of the elements selected from b. is added as an additive element.

(6) The total content of the additive elements in the recording layer is j~
The magneto-optical recording medium according to any one of (2) to 5) above, wherein the content is 20 at%.

(7) A method for performing magneto-optical recording on the magneto-optical recording medium according to any one of (1) to 6) above, wherein the magneto-optical recording is performed by applying a modulated magnetic field while irradiating light. A magneto-optical recording method characterized by performing the following.

Hereinafter, the specific configuration of the present invention will be explained in detail.

FIG. 1 shows a preferred embodiment of the magneto-optical recording medium of the present invention.

The magneto-optical recording medium 1 shown in FIG. 1 has a protective layer 3, an intermediate layer 4, a recording layer 5, a protective layer 6, and a protective coat 7 on a substrate 2 in this order.

The protective layer 3 and the protective layer 6 are provided to improve the corrosion resistance of the recording layer 5.
Preferably both are provided.

In the present invention, either one of the protective layer 3 and the protective layer 6,
Preferably the protective layer 6 and more preferably both are composed of borosilicate glass. Borosilicate glass is a glass containing boron oxide and silicon oxide.

In the present invention, there is no particular restriction on the borosilicate glass used, but in order to obtain a magneto-optical recording medium with higher corrosion resistance, it is preferable to use a borosilicate glass having the following composition. Note that the atomic percentages shown below are values in metals and semimetals in glass.

Silicon 20-70 at%, more preferably 30-60
at%.

Boron: 5 to 40 at%, more preferably 5 to 30 at%
%.

Aluminum: 5 to 30 at%, more preferably 10 to 30 at%
20at%.

Alkaline earth metal = 5 to 50 at%, more preferably 5
~40at%. As alkaline earth metals, Ba, C
It is preferable to use one or more of a, Mg, and Sr, preferably Ba and/or Ca.

The above-mentioned metal or metalloid is usually contained in the glass as a stoichiometric oxide, but it may be contained in a stoichiometric composition. In particular, in the present invention, the content of oxygen in the glass is preferably lower than the stoichiometric composition.

In addition to the above-mentioned compounds, an alkali metal oxide may be contained, but the content thereof is less than 0.5 wt%.

A particularly preferable borosilicate glass is, for example, Sing 50wt%, B203:1
0wt%, Al2103: 10wt%, BaO:
Glass having a composition of 25 wt% and CaO: 5 wt% (
7059) manufactured by Corning Incorporated.

The thickness of the protective layer is preferably about 30 to 300 nm from the viewpoint of improving corrosion resistance. These are preferably provided by a vapor phase film forming method such as a sputtering method.

In the present invention, the recording layer 5 has the above composition.

The reason why the composition ranges of Tb, Dy, and CO are limited as described above is as follows.

When Tb+Dy is less than the above range, the magnetic field sensitivity decreases and Hext becomes 300. Oe level or more is required, and
Hc decreases, leading to a decrease in C/N ratio.

When Tb+Dy exceeds the above range, magnetic field sensitivity decreases, Hext needs to be about 3000e or more, and Hc
This causes a decrease in the C/N ratio (and a decrease in reliability).

When Tb/(Tb+py) is less than the above range, He
xt becomes approximately 3000e or more, and the Curie point decreases, resulting in a decrease in thermal stability.

When Tb/(Tb+Dy) exceeds the above range, Hex
t is about 3000e or more.

In addition, 2.5≦Tb≦50 and 18. O≦Dy≦26.
When it is 0, even better characteristics can be obtained, and especially Hext is reduced.

If the Co content is less than the above range, the corrosion resistance of the recording layer will be insufficient and reliability will decrease. In addition, the Curie point is lowered and the thermal stability is lowered.

When CO exceeds the above range, the C/N ratio decreases and Hex
t also increases.

The remainder after removing these elements is substantially Fe.

In the present invention, the following X group and Y group are added to the recording layer having such a configuration.
At least one element selected from Group 7 and Group 7 may be added.

Group X = a small number of elements selected from group 4A elements, group 5A elements, group 6A elements, group 8 elements, group 3B elements, C, Si, and P (both are one or more elements).

In this case, the 4A group elements are Ti, Zr and Hf, the 5A group elements are V, Nb and Ta, and the 6A group elements are V, Nb and Ta.
Group A elements include Cr, Mo, and W, Group 8 elements include Ni and Pt, and Group 3B elements include B and A.
j2 is preferred.

Y group: Ge and/or S r a Z group: one or more elements selected from Bi, Cu, Sn and Pb.

By adding the above group X, the corrosion resistance of the recording layer is improved.

By adding the above Y group, the effect of stabilizing the amorphous state of the recording layer is realized.

In other words, changes in sensitivity of the recording layer (annealing effect) that occur when the recording layer is stored at high temperatures and under high temperature conditions are prevented. Furthermore, changes in sensitivity of the recording layer due to repeated reproduction are also prevented. Note that this effect can also be achieved by adding B and/or Si among the above-mentioned group X.

By adding the above 7 groups, the Kerr rotation angle increases,
C/N ratio improves. Note that this effect can also be achieved by adding Cr and/or Ni among the above-mentioned group X.

The content ratio of these additive elements in the recording layer, that is, the ratio of the content of the additive element to the total content of Tb, Dy, Go, Fe, and the additive element is 1 to 20 at%.
, particularly preferably 2 to 10 at%. When the content is within this range, each of the above effects will be extremely high.

Such a recording layer 5 is preferably formed by a vapor phase deposition method, particularly a sputtering method, and is usually in an amorphous state.

Moreover, the layer thickness of the recording layer 5 is usually about 10 to 11000 nm.

The substrate 2 is made of glass or resin, especially Acnor resin,
It is preferably made of polycarbonate resin, epoxy resin, polyolefin resin, etc., and is transparent to recording light and reproduction light. Further, the thickness thereof is usually about 0.5 to 3 mm, and the external shape is selected to be disc-shaped or other depending on the purpose.

The intermediate layer 4 is provided to improve the C/N ratio, and is made of various dielectric materials such as various oxides, nitrides,
It is preferably formed from a sulfide or a mixture thereof, and the layer thickness is preferably about 30 to 150 nm. Further, as the layer forming method, it is preferable to use a vapor phase film forming method such as a sputtering method.

The protective coat 7 is provided to improve corrosion resistance, and is preferably made of various organic substances, but in particular, it is made of acrylic double bonds that can be cured by radiation such as electron beams and ultraviolet rays. A radiation-curable compound having
Preferably, it is constructed from radiation-cured material.

In addition, the thickness of the protective coat 1-7 is usually 1 to 1,000 mm.
It is preferable to set it to about jLm.

The magneto-optical recording medium 1 composed of these layers can be made into a double-sided recording medium by bonding two sets of magneto-optical recording media 1 with the recording layer 5 inside.
A protective plate can be adhered onto the surface of the medium to create a single-sided recording medium.

However, since the distance between the magnetic head and the medium can be reduced and high-speed recording is possible, it is preferable to use a single-sided recording type medium without a protective plate.

In addition, when a protective plate is provided, it is usually sufficient to use the same material as the substrate 2, but it does not have to be transparent, and other materials can also be used. Further, any known adhesive may be used for adhesion, such as a hot melt adhesive, a thermosetting adhesive, an anaerobic adhesive, etc.

Next, the magneto-optical recording method of the present invention using the magneto-optical recording medium of the present invention described above will be explained.

The magneto-optical recording method of the present invention is a magnetic field modulation type recording method in which recording is performed by applying a modulated magnetic field while irradiating light.

Usually, the magnetic field is applied from the side of the substrate on which the recording layer is provided.
In the present invention, the magnetic head for applying the magnetic field may be either a normal non-contact type magnetic head or an air floating type floating head, but the distance between the magnetic head and the medium can be reduced. It is preferable to use a floating type magnetic head because high-speed recording is possible.

The distance between the magnetic head and the recording layer is approximately 0.5 mm for a normal non-contact type head, and 5 to 20 μm for a floating type head.
Therefore, in the present invention, a single-sided recording medium without a protective plate is usually used.

In the present invention, the magnetic field strength on the recording layer surface of the medium is 3000
It is preferably less than e, preferably less than 2500e, more preferably less than 2000e.

By setting the magnetic field strength within this range, a coil with small inductance can be used. Therefore, the magnetic field reversal time can be shortened, and high-speed recording of, for example, 5 MHz or more is possible.

Light is typically emitted from the opposite side of the magnetic field.

The recording power is usually about 1 to 10 mW, and the spot diameter of the light on the surface of the recording layer is usually about 0.5 to 3 μm.

<Example> Hereinafter, the present invention will be explained in further detail by giving specific examples of the present invention.

[Example 1] A protective layer 3 made of borosilicate glass was formed to a thickness of 40 nm by high-frequency magnetron sputtering on a substrate 2 made of bisphenol A-based optical disk grade polycarbonate resin with a diameter of 130 mm and a thickness of 1.2 mm. Then, on this protective layer 3, an intermediate layer 4 made of SiNx was formed to a thickness of 80 nm by high frequency magnetron sputtering.

Next, on the intermediate layer 4, a recording layer 5 having a composition of the present invention shown in Table 1 below was formed to a thickness of 80 nm by sputtering. In addition, the content ratio (at%) of Tb, Dy and CO
is the total content of Tb, Dy, Co and Fe to 10
This is the value when it is set to 0. Further, the content ratio (at%) of the additive element is a value when the total content of Tb, Dy, Co, Fe, and the additive element is 100.

Further, on the recording layer 5, a protective layer 6 made of borosilicate glass is provided.
was formed to a thickness of 1100 nm by high-frequency magnetron sputtering, and a protective coat 7 was formed on this protective layer 6.

The protective coat 7 is formed by applying a coating composition containing a polyfunctional oligoester acrylate and a photosensitizer onto the protective layer 6 using a spinner coat, and then cross-linking and curing it by irradiating it with ultraviolet rays for 15 seconds. Layered. The thickness of the protective coat 7 was 5 μm.

In this way, samples of magneto-optical recording media of the present invention having various recording layers were obtained. Note that Sample No. 3 was a comparative sample in which the protective layers 3 and 6 were not provided.

In addition, samples Nos. 101 to 106 had recording layer compositions outside the range of the present invention.

As the borosilicate glasses constituting the protective layers 3 and 6, glasses Nos. 091 to 5 shown in Table 1 below were used. The content of metals or metalloids in these glasses is as follows. Note that the oxygen content in the glass was approximately the same level or lower than when the following metals or semimetals were contained in the stoichiometric composition.

Table glass Glass composition (at%) No, Si Ba An B Ca5
53 10 13 18 The following measurements were performed on these samples.

(1) Corrosion resistance initial pit error rate (BER) and 80°C/80%
The BER after storage at RH for 1000 hours was measured, and the amount of increase (ΔBER) was determined. The evaluation shown in Table 2 is
It is as follows.

0: No change ○: The amount of increase is 2 times or less △: The amount of increase is more than 2 times and less than 5 times X: The amount of increase is more than 5 times (2) C/N ratio linear velocity 4. Measured at Om/sec Frequency I MHz Recording power (830 nm) 2.0 to 6.0 mW Reproducing power (830 nm) 1.0 mW RB W 30 kHz V B W 100 Hz. The magnetic field strength during recording was 3000
It was set as e.

(3) Hext Among the following ■ and ■, the larger one was designated as Hext.

■ Recording is performed while increasing the applied magnetic field strength, and C
/Magnetic field strength when the N ratio reaches a certain value ■ A signal recorded with an applied magnetic field strength of 3000e at the optimum recording power is erased by changing the applied magnetic field at the same optimum recording power, and the remaining amount is 1. ．． Magnetic field strength when below d B (4)
) (5) Curie point (Tc) The results are shown in Table 1.

[Example 2] For each magneto-optical recording medium sample prepared in Example 1,
Override recording (erasing by overwriting without providing an independent erasing process) was performed by magnetic field modulation, and the C/N ratio of each sample after recording was measured.

Magnetic field modulation recording records a rectangular wave alternating magnetic field of 500 K, Hz using a small coil installed on the recording layer side of the substrate while irradiating a laser beam of constant intensity from the side opposite to the recording layer side of the substrate. This was done by applying it to the layer surface.

The distance between the recording layer surface and the small coil was 0.2 mm, the magnetic field strength at the recording layer surface was 2500 e, and the linear velocity was 4.0 m/s.

In addition, when the distance between the recording layer surface and the small coil was set to Q, 1 mm in order to increase the magnetic field strength on the recording layer surface, the small coil came into contact with the protective coat 7 due to deflection and warpage of the substrate, making recording impossible. Met.

Such magnetic field modulation recording was performed 10 times on the same track.

The C/N ratio is the same as in Example 1, with a reproduction power of 1.0 mW.
It was regenerated and measured.

A case where a C/N ratio of 45 dB or more was obtained was evaluated as ◯, and a case where the C/N ratio was less than 45 dB was evaluated as ×.

The results are shown in Table 2.

[Example 3] Using each sample prepared in Example 1, the reproduction power was set to 1.
．． A continuous reproduction test was conducted at 5 mW.

For sample No. 106, the C/N ratio began to deteriorate after approximately 500 continuous playbacks, but for the other samples, no deterioration in the C/N ratio was observed even after 1000 or more continuous playbacks. .

[Example 4] Samples were prepared in which one or more of the above-described additive elements X group, 7 group, and Z group were added to the recording layers of samples No. 1, 1, and 2, and the same corrosion resistance measurements and C/ The N ratio was measured. In addition, 1 at 80°C and 80%RH
The rate of change in sensitivity after storage for 000 hours and the rate of change in sensitivity after repeated playback were also measured.

Corrosion resistance was further improved when the additive element included an element selected from Group X.

Furthermore, when the additive element included an element selected from the Y group, the rate of change in sensitivity was extremely small. Note that this effect was also achieved by adding B and/or Si among the above-mentioned group X.

When an element selected from the above seven groups was included as an additive element, the C/N ratio was further improved.

Note that this effect was also achieved by adding Cr and/or Ni in Group 1.

The effects of the present invention are clear from the results of the above examples.

In other words, the samples of the present invention have extremely high corrosion resistance.

Moreover, Hext is low at 2500e or less, Hc is high, and Tc is higher than 100°C, so thermal stability is high.

Further, when override recording was performed by magnetic field modulation at a magnetic field strength of 2500e on the recording layer surface, the sample of the present invention showed a good C/N ratio even after overriding, indicating that erasing was performed well by overriding.

<Function> In a magneto-optical recording medium, information is recorded by increasing the temperature of a recording layer having a predetermined composition to near the Curie point by irradiation with laser light or the like, and applying a magnetic field from the outside at this time.

Information is recorded using optical modulation recording, which records using modulated light while applying a magnetic field of a certain intensity, or magnetic field modulation recording, which records using a modulated magnetic field while applying light of a certain intensity. Ru.

Information on a magneto-optical recording medium can be erased by externally applying Hc to the recording layer.
Either by the bulk erase method, which erases by applying a magnetic field similar to the one described above, or by raising the temperature of the recording layer by irradiating it with laser light, etc., an external magnetic field of the strength necessary to reverse the magnetization of the recording layer is applied. Apply it.

Further, when recording is performed by magnetic field modulation, recording and erasing can be performed by a so-called override method in which erasing is performed by overwriting information without providing an independent erasing process.

<Effects of the Invention> Since the magneto-optical recording medium of the present invention has a protective layer made of borosilicate glass, it has extremely high corrosion resistance.
Further, the magneto-optical recording medium of the present invention can suppress the intensity (Hext) of the magnetic field applied from the outside when recording and erasing information to a relatively low level. Therefore, according to the present invention, it is possible to downsize a recording/reproducing apparatus for a magneto-optical recording medium.

Further, according to the magneto-optical recording method of the present invention, which performs magnetic field modulation recording using the magneto-optical recording medium of the present invention, since Hext can be kept low, a coil with small inductance can be used, and the magnetic field reversal time It is possible to perform high-speed recording by shortening the length of the coil. Furthermore, since sufficient corrosion resistance is obtained by having the above-mentioned protective layer, there is no need to provide a thick protective plate on the recording layer, and the recording layer and coil can be placed close together. Therefore, a coil with extremely small inductance can be used, and even higher speed recording is possible.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a preferred embodiment of the magneto-optical recording medium of the present invention. Explanation of symbols 1... Magneto-optical recording medium, 2... Substrate, 3... Protective layer, 4... Intermediate layer, 5... Recording layer, 6... Protective layer, 7... Protective coat patent applicant TDT-K Co., Ltd. Agent Patent attorney Yo Ishii FIG, 1

Claims (1)

[Claims] (1) The content expressed in atomic % of Tb, Dy and Co is 20.5≦Tb+Dy≦31.0 0.088≦Tb/(Tb+Dy)≦0.226.0≦
Co≦15.0, the remainder being substantially Fe, the recording layer having a recording layer on the substrate, and a protection made of borosilicate glass on the recording layer and/or between the substrate and the recording layer. A magneto-optical recording medium characterized by having a layer. (2) For the recording layer of the magneto-optical recording medium according to claim 1, a group 4A element, a group 5A element, a group 6A element, a group 8 element, 3
A magneto-optical recording medium characterized in that at least one element selected from Group B elements, C, Si, and P is added as an additive element. (3) the Group 4A elements are Ti, Zr and Hf;
The 5A group elements are V, Nb and Ta, and the 6A
The group elements are Cr, Mo and W, and the group 8 element is N.
3. The magneto-optical recording medium according to claim 2, wherein the group 3B elements are B and Al. (4) A magneto-optical recording medium characterized in that Ge and/or Sr are added as additional elements to the recording layer of the magneto-optical recording medium according to any one of claims 1 to 3. (5) The recording layer of the magneto-optical recording medium according to any one of claims 1 to 4 is characterized in that one or more elements selected from Bi, Cu, Sn, and Pb are added as an additive element. magneto-optical recording medium. (6) The total content of the additive elements in the recording layer is 1 to
6. The magneto-optical recording medium according to claim 2, wherein the content is 20 at%. (7) A method for performing magneto-optical recording on the magneto-optical recording medium according to any one of claims 1 to 6, wherein the magneto-optical recording is performed by applying a modulated magnetic field while irradiating light. A magneto-optical recording method characterized by: