JPH03219446A - Magneto-optical recording medium - Google Patents

Abstract

PURPOSE:To enhance an adhesive strength, oxidation resistance and magneto- optical recording characteristics and the stability thereof by laminating a specified magneto-optical recording film on a substrate formed of a cyclic olefin random copolymer of ethylene and specified cyclic olefin. CONSTITUTION:The magneto-optical recording medium 1 is formed by laminating the magneto-optical recording film 3 on the substrate 2. The substrate 2 is formed of the cyclic olefin random copolymer of the ethylene and the cyclic olefin expressed by formula I. In the formula I, (n) is 0 or positive integer; R<1> to R<12> respectively denote a hydrogen atom, halogen atom or hydrocarbon group. The magneto-optical recording film 2 is formed of the thin film of an amorphous alloy which contains the element selected from 3d transition metals and the element selected from rare earths and has the axis of easy magnetization perpendicular to the film plane.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magneto-optical recording medium that has excellent adhesion between a substrate and a magneto-optical recording film, as well as excellent oxidation resistance and magneto-optical recording properties.

The targets and their properties include transition metals such as iron and cobalt, and terbium (Tb),
A magneto-optical recording film made of an alloy with a rare earth element such as cadrinium (G d) has an axis of easy magnetization in a direction perpendicular to the film surface, and the film surface is entirely magnetized in one direction. It is known that small inverted magnetic domains with opposite directions can be formed. The presence or absence of this inverted magnetic domain is set to "1", "
By making it compatible with "O", it becomes possible to record digital signals on the magneto-optical recording film as described above.

As a magneto-optical recording film made of such a transition metal and a rare earth element, for example, Japanese Patent Publication No. 57-20691 discloses a Tb--Fe based magneto-optical recording film containing 15 to 30 atom % of Tb. Also, Tb-Fe-Co',
Gd-Tb-Fe, Dy-Tb-Fe-C.

Magneto-optical recording films such as those based on the above are also known.

These magneto-optical recording films have excellent recording and reproducing properties.C) During use, these magneto-optical recording films undergo oxidation and their properties change over time, which is a major practical problem. Ta.

The mechanism of oxidative deterioration of such magneto-optical recording films containing transition metals and rare earth elements has been discussed, for example, in the Journal of the Japan Society of Applied Magnetics, Vol. 9, No. 2, pp. 93-96, and as follows: It has been reported that there are three types:

b) Pitting Pitting corrosion refers to the formation of pinholes in the magneto-optical recording film, and this corrosion mainly progresses in high temperature atmospheres, such as Tb-Fe and Tb-C.

The disease progresses markedly in some systems.

(a) A surface oxidation layer is formed on the surface oxidized magneto-optical recording film.Car rotation angle θk
changes over time, and eventually the Kerr rotation angle θk decreases.

c) Selective oxidation of rare earth metal ÷ (g) Rare earth metal in the magneto-optical recording film is selectively oxidized, and the coercive force Hc changes greatly over time.

In order to prevent the oxidative deterioration of the magneto-optical recording film as described above,
Juto: Various methods have been tried. Even if,
The magneto-optical recording film is made of Si3N4, 5iO1Si02, AI
A method of creating a three-layer structure sandwiched with an oxidation-preventing protective film such as N is being considered.

Furthermore, various methods have been attempted to add a third metal to a magneto-optical recording film such as a Tb-Fe system or a Tb-Co system in order to improve the oxidation resistance of this thin film.

For example, in the above-mentioned Journal of the Japanese Society of Applied Magnetics, T b-F
e or Tb-Co, Co, NiPt,
3 tertiary metals such as Al, Cr, Ti, Pd, etc.
．． By adding up to 5 at%, Tb-F
Attempts have been made to improve the oxidation resistance of e-based or Tb--Co based magneto-optical recording films.

Also, the 9th Academic Lecture Summary of the Japanese Society of Applied Magnetics (1985)
(November 2013), page 209, there is a Tb-F
e or T b-F e-Co, Pt, At, Cr
, magneto-optical recording films doped with up to 10 atomic % of Ti have been taught.

Furthermore, in JP-A No. 61-255546, a magneto-optical recording film made of a rare earth element and a transition element is coated with Pt, Au.
, Ag SRu , Rh , Pd , Os .

A magneto-optical recording film with improved oxidation resistance is disclosed in which a noble metal element such as Ir is added within a range that provides the Kerr rotation angle necessary for reproduction.

In this way, conventional Tb-Fe or Tb-Co is
, NiS Pt, AI, CrS TiS Pd, etc. are added to the magneto-optical recording film with known power\ These magneto-optical recording films are laminated on a normal substrate, for example, a substrate made of polycarbonate resin. Magneto-optical recording media still do not have sufficient oxidation resistance and long-term stability of magneto-optical recording characteristics, and due to the large birefringence of the substrate, the C/N ratio is low and the noise level is high. Furthermore, the adhesion between the substrate and the film was also insufficient. Therefore, when using polycarbonate resin as a substrate, it is necessary to thoroughly remove moisture from the polycarbonate substrate by heat treatment.In order to improve adhesion with the film, it is necessary to perform plasma treatment on the surface of the substrate. The inventors of the present invention have conducted intensive research to improve the performance of magneto-optical recording media as described above, and have found that the oxidation and deterioration of the magneto-optical recording film is caused by the composition of the magneto-optical recording film as well as by the light. The cause lies in the substrate itself, which is conventionally used for laminating magnetic recording films, and the conventionally used substrates such as polycarbonate have poor adhesion with magneto-optical recording films. The inventors of the present invention discovered that the problem lies in the fact that the oxidation of , and a specific magneto-optical recording film is laminated on the above-mentioned substrate (this is convenient for improving the adhesion between the substrate and the magneto-optical recording film, and has excellent magneto-optical recording properties such as oxidation resistance and high C/N ratio). The present invention was completed by discovering that a magneto-optical recording medium with excellent long-term stability of magneto-optical recording characteristics can be obtained.

The present invention is intended to solve the problems associated with the prior art as described above, and it is an object of the present invention to improve the adhesion between the substrate and the magneto-optical recording film. The object of the present invention is to provide a magneto-optical recording medium with excellent long-term stability in properties and magneto-optical recording properties.

A magneto-optical recording medium according to the present invention is a magneto-optical recording medium in which a magneto-optical recording film is laminated on a substrate. One of its characteristics is that it is formed from a cyclic olefin random copolymer consisting of a copolymer with an olefin.

÷ 10-... [I] (In formula [I], n is 0 or a positive integer,
R1 to R12 each represent a hydrogen atom, a halogen atom, or a hydrocarbon group, and R9 to R12 may be bonded to each other to form a monocyclic or polycyclic group, and the monocyclic or polycyclic group may have a double bond, and R9 and Rle or R11 and RI2 may form an alkylidene group).

In such a cyclic olefin random copolymer, the cyclic olefin component forms a structure represented by the general formula [n].

11- ... [n] (In formula [n], n is 0 or a positive integer,
R1 to R12 each represent a hydrogen atom, a halogen atom, or a hydrocarbon group, and R9 to RI2 may be bonded to each other to form a monocyclic or polycyclic group, and the monocyclic or polycyclic group may have a double bond, and R9 and R19, Mataha RII and R12,
(may form an alkylidene group).

Further, in the present invention, on the substrate as described above, as a magneto-optical recording film, (i) at least one selected from 3d transition metals is provided.
The present invention is characterized in that it uses an amorphous alloy thin film having an axis of easy magnetization perpendicular to the film surface, which contains at least one element selected from rare earths as an essential element.

The magneto-optical recording medium according to the present invention will be specifically explained below.

A magneto-optical recording medium 1 according to the present invention has a structure in which a magneto-optical recording film 3 is laminated on a substrate 2, as shown in FIG.

Further, the magneto-optical recording medium 1 according to the present invention may have a structure in which a magneto-optical recording film 3 and a reflective film 4 are laminated in this order on a substrate 2, as shown in FIG. .

Further, the magneto-optical recording medium 1 according to the present invention may have a structure in which an enhancement film 5 is provided between the substrate 2 and the magneto-optical recording film 3, as shown in FIG.

Furthermore, as shown in FIG. 4, the magneto-optical recording medium 1 according to the present invention has an enhancement film 5 provided between the substrate 2 and the magneto-optical recording film 3, and a magneto-optical recording film 3 and a reflective film 4. It may have a structure in which the enhancement film 5 is received between. As the enhancement film, for example, Si3N4
．． Silicon nitride, AIN, such as 5iNx (0<x<4/3).

Examples include ZnSe, ZnS, and Si.

In the present invention, the substrate 2 as described above is formed from a cyclic olefin-based random copolymer consisting of a copolymer of ethylene and a cyclic olefin represented by the following symbol [■].

... [I] (In formula [I], n is 0 or a positive integer,
R1 to RI2 each represent a hydrogen atom, a halogen atom, or a hydrocarbon group, and R9 and R12 may be bonded to each other to form a cyclic or polycyclic group, and the monocyclic Alternatively, the polycyclic group may have a double bond, and R9 and R1[+, or Lk RI I and RI2
may form an alkylidene group).

To explain in more detail about the cyclic olefin represented by -Sakura [■] above, the cyclic olefin represented by -Sakura [r] is represented by the formula [r- a].

RITI each independently represents an atom or group selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group.

RI6 to Roe may be bonded to each other to form a monocyclic or polycyclic group, and the monocyclic or polycyclic group may have a double bond.

Furthermore, RI5 and Rle or RIT and R18 may form an alkylidene group.

In such cyclic olefin random copolymers [A] and [B], the cyclic olefin component forms a structure represented by the general formula "r1".

... [r -a] However, in the above [I-a], n is 0 or 1, m is 0 or a positive integer, and R1 to 5 -l t [■ ko (formula [n ], n is O or a positive integer,
R1 to Rb2 each represent a hydrogen atom, a halogen atom, or a hydrocarbon group, and R9 to R12 may be bonded to each other to form a monocyclic or polycyclic group, and the monocyclic or polycyclic group may have a double bond, and R9 and Rle or R11 and RI2 may form an alkylidene group).

Incidentally, when the cyclic olefin is represented by [I-a] as described above, in the cyclic olefin-based random copolymers [A] and [B], the cyclic olefin component is represented by the formula [n-a] shown below. a].

... [■-al However, in the above [n-a], n is O or 1, m is 0 or a positive integer, and R1 to RIB each independently represent a hydrogen atom, a halogen atom, and Represents an atom or group selected from the group consisting of hydrocarbon groups.

R15 to RI8 may be bonded to each other to form a monocyclic or polycyclic group, and the monocyclic or polycyclic group may have a double bond.

Furthermore, RIB and R18 or R17 and R18 may form an alkylidene group.

The cyclic olefin that is a component of the above-mentioned cyclic olefin random copolymer is at least one type of cyclic olefin selected from the group consisting of unsaturated monomers represented by -Sakuburu.

- The cyclic olefin represented by [I] can be easily produced by condensing cyclopentadiene and the corresponding olefin in a Diels-Alder reaction.

- Cyclic olefin represented by [2] 17- - Specifically, compounds listed in Table 1 or 1.
4.5.8-dimethano-1,2,3,4,4a, 5.
8.8a-In addition to octahydronaphthalene, 2-methyl-1,4,5,8-dimethano-1,2,3,4,4a
, 5.8.8a-octahydronaphthalene, 2-ethyl-1,4,5,8-dimethano-1,2,3,4゜4a
, 5.8.8a-octahydronaphthalene, 2-propyl-1,4,5,8-dimethano-1,2,3,4,4
a, 5.8.8a-octahydronaphthalene, 2-hexyl-1,4,5,8-dimethano-1,2,3,4,
4a, 5.8.8a-octahydronaphthalene, 2.
3-dimethyl-1,4,5,8-dimethano-1,2,3
,4,4a, 5°8.8a-octahydronaphthalene, 2-methyl-3-ethyl-1,4,5,8-dimethano-1,2,3,4,4a, 5.8.8a-octa Hydronaphthalene, 2-chloro-1,4,5,8-dimethano-1,2,3,4,4a, 5.8.8a-octahydronaphthalene, 2-bromo-1,4,5,8-dimethano -1,2,3,4,4a, 5゜8.8a-octahydronaphthalene, 2-fluoro-1゜4,5,8-dimethano-1,2,3,4,4a, 5.8.8a -octahydronaphthalene, 2,3-dichloro-1,4,5,8-
Dimethano-1,2,3,4,4a, 5.8.8a-octahydronaphthalene, 2-cyclohexyl-1,4,
5,8-dimethano-1,2,3,4°-) 4a, 5.8.8a-octahydronaphthalene, 2-
n-butyl 1,4.5.8-dime, tano 1.2.3.
4.4a, 5.8.8a-octahydronaphthalene,
2-inbutyl-1,4,5,8-dimethano-1,2,
Examples include octahydronaphthalenes such as 3,4,4a, and 5.8.8a-octahydronaphthalene.

Furthermore, examples of the cyclic olefin [2] represented by the formula include the compounds described below.

Namely, as the cyclic olefin represented by the above formula [■] used in the present invention, specifically, bicyclo[2,2,1]hept-2-ene-derived tetracyclo[4,4,0, 12, 5, i? 1” ]-]3
-dodecene-induced hexacyph O[6,6,1,13,a, l+s, +3
．． Q2. y, Qe, + Lee 4-heptadensen induction book t 'y tashi'y 'cl [8, 8, 0, 12・9
．． 1' 7.111-18.113 ・I 'Q31.
Q12.17]-5-tococene derivative, pentacyclo[
6,6,1,13・6,02・7, Q9, I
A ]-] 4-hexadecene derivative Vermilion cyclo-5-icosene derivative, heptacyclo 5-heneicosene derivative, tricyclo[4,3,0,12・5]-3-decene derivative, tricyclo[4,3,0,12・5-co 3-undecene induced tree pentacyclo [6,5,1,13,8,02・7.09・
13]-4-hentadecene derivative pentacyclopentadecadiene derivative pentacyclo[4,7,O,I2・S, Q8,
l 3 , 19 , 12 ] ] 3-pentadecene derivative book)) 0 [7, 8, Q, 13.6. Q2. ?
, 11 [I, +7. QIl, l19.112・+6]
4-eicosene derivative book and nonasif O [9,10,1,1,4,7,038,02
,1",012211+3.2[I,Q14.+9,1
15.18] Mention may be made of 5-hentacocene derivatives.

Specific examples of such compounds are shown below.

Bicyclo[2,2,1] such as hept − conductor; 屹shi CH.

enticement CH.

4 tons 5.10-dimethyltetra 9-isobutyl-11,12 5,8,9,10-tetramethy8-methyltetrasif 8-ethyltetrasif 19-3-dodecene C,,H,7 + 9 ]-] 3-dodecene 5.17 III-3-dodecene 19-3-dodecene-3-dodecene 1 [I]-]3-dodecene 12 5.17 IQ]-3-dodecene 19]-3-dodecene 8-methyl-9 -ethylte 3 dodecene 8-promotitrasif-3-dodecene + 9]-3-dodecene 11-3-dodecene 4 tons 8-ethylidene-9-iso-dodecene, 12 5.17 1θ]-3-dodecene 5.17 Illco 3 -Dodecene 8-n-propylidene-9 -Dodecene 8-n-propylidene-9 8-Impropylidene [4,4,0,12 5,17 Iff code 3 -dodecene-dodecene [4,4,0,12 7 +11],, -3-dodecene I e ] -3 dodecene 8-n-propylidene-9 [4,4,0,12 5,17 fi! ]-3 H8 [4,4,0,12 5,17 fi! ]-3 Tetracyclo[4,4,0,125,17 11!1. -3-Dodecene derivative; (blank space below) -4-hebutadecene 13, Q2, 7, Q9, +4]-]
4-heptadecene Which hexacyclo[6,6,1,136,119 13, Q2, 7, Q9 decene.I4]-4-hebutadecene derivative; decentcosene 18.113.16. Q3 8.01 +7]-5-tococene+7]-5-tococene and other octacyclo[8,8,0,129,14 7,1st+9. II Heptacyclo-5-icosene derivatives such as heptacyclo [8,7,0 cosene or heptacyclo-5-heneicosene derivatives; Hs Sen, etc. Pentacyclo[6,6,1,13,'l,02.
T, 0914-4 hexadecene derivatives) 1,3-dimethyl-penta and other tricyclo[4,3,0,125-5-3-decene derivatives 10-methyl-tricif 14,15-dimethylpene and other tricyclo[ 4,4,0,12 5] Pentacyclo[6,5,1,13・6. O2・7
．． 0913 ] -4- body; Pentadecene derivative; Diene compounds such as 21.113.2 [I, Ql4. lla, 115.1]
Pentacyclo[4,7,0,12・6,Ql
l, j3, lQ, +2']-3-pentadecene derivative; Cosene 3.211. Q11119. lls, l]-5-hentacocene and other nonacyclo[9,10,1,1'・7.03・8
, Q2 , I Q , Ql 221, 113.
28. Ql4. IQ, llS, I11] -5-hentacocene derivatives: (blank below) 2.16] -4-eicosene and other hebutacyclo[7,8,0,18・6.02・?
, lle, I7. Q11.16. lI2. IB], -
4-eicosene derivative; circle) In this cyclic olefin random copolymer, as mentioned above, the force f which has ethylene and the cyclic olefin as essential components, and the object of the present invention in addition to the two essential components. If necessary, other copolymerizable unsaturated monomer components may be contained within a range that does not impair the composition. Specifically, the unsaturated monomer which may be optionally copolymerized includes, for example, propylene, 1-butene, 4-methyl in an amount less than equimolar to the ethylene component unit in the random copolymer to be produced. -1-pentene, 1-hexene, 1-octene, 1
Examples include α-olefins having 3 to 20 carbon atoms, such as -decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.

In the above-mentioned cyclic olefin random copolymer, the repeating unit (a) derived from ethylene is 40 to
The repeating unit (b) derived from the cyclic olefin is present in an amount of 85 mol%, preferably 50 to 75 mol%, and 15 to 60 mol%, preferably 25 to 5 mol%.
The repeating units (a) derived from ethylene and the repeating units (b) derived from the cyclic olefin are present in a range of 0 mol %, and are arranged substantially linearly at random. The ethylene composition and cyclic olefin composition are +3 (measured by NMR). This cyclic olefin random copolymer is substantially linear,
The copolymer does not have a gel-like crosslinked structure.
This can be confirmed by complete dissolution in decalin at 35°C.

135 of such a cyclic olefin random copolymer
The intrinsic viscosity [η] measured in decalin at ℃ is 0.0
5-10dl/g, preferably 0.08-5dl/
in the range of g.

In addition, the softening temperature (TMA) of the cyclic olefin random copolymer was measured using a thermal mechanical analyzer.
is preferably 70°C or higher, particularly preferably 90 to 25°C.
The temperature is preferably 0°C, more preferably 100 to 200°C. The softening temperature (TMA) is determined by DuPont's Therm.
A quartz needle was placed on the sheet, a load of 49 g was applied, and the temperature was raised at a rate of 5°C/min until the needle reached 0.05°C.
The glass transition temperature (T
g) is usually 50 to 230t, preferably 7o to 210t
It is desirable to be in the range of ℃.

The degree of crystallinity of this cyclic olefin random copolymer measured by X-ray diffraction is in the range of 0 to 10%, preferably 0 to 7%, particularly preferably 0 to 5%.

The above-mentioned cyclic olefin copolymer constituting the substrate in the present invention is disclosed in JP-A-60-168708, JP-A-61.
-120816 Public/Private JP 61-115912 Public/Private JP 61-115916 Public/Private Patent Application 1982-9
No. 5905 Public Kaede Japanese Patent Application No. 1983-95906, Japanese Patent Application No. 1982-271308 Public/Private Japanese Patent Application No. 1982-27221
It can be manufactured by appropriately selecting conditions according to the method proposed by the applicant in Publication No. 6 and the like.

In addition, as the resin forming the substrate, in addition to the above-mentioned cyclic olefin random copolymer, the above-mentioned formula [
A polymer or copolymer containing a repeating unit represented by the following formula [[I] formed by ring-opening polymerization of a cyclic olefin represented by A polymer or copolymer containing a repeating unit represented by the following formula [■] formed by hydrogenating the repeating unit represented by [m] may be included.

Beto...[■] However, in the above formulas [m] and [■], n and R1-R12 have the same meanings as n and R1-R1 in the cyclic olefin represented by the above formula [I].

In addition, the above cyclic olefin copolymer may include, if necessary,
Heat-resistant stabilizers, weather-resistant stabilizers, antistatic agents, slip agents, anti-blocking agents, anti-fog agents, lubricants, dyes, pigments, natural sources, synthetic methods, waxes, etc. can be blended, and the blending ratio is appropriate. . Specifically, as a stabilizer that may be added as an optional ingredient, tetrakis [
Methylene-3(3,5-di-t-butyl-4-hydroxyphenyl)propionate comethane, β-(3,5-
di-t-butyl-4-hydroxyphenyl) propionic acid alkyl ester (alkyl esters having 18 or less carbon atoms are particularly preferred), 2,2'-oxamidobis[ethyl-3(3,5-di-t-butyl-4 - phenolic antioxidants such as hydroxyphenyl) propionate,
Fatty acid metal salts such as zinc stearate, calcium stearate, calcium 12-hydroxystearate, glycerin monostearate, glycerin monolaurate, glycerin distearate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, etc. Examples include polyhydric alcohol fatty acid esters. These may be blended alone or in combination, such as tetrakis [methylene-3 (3,5-di-t-butyl-4-hydroxyphenyl) propionate comethane, zinc stearate and glycerin]. The following are examples of combinations with monostearate.

In the present invention, it is particularly preferable to use a combination of a phenolic antioxidant and a fatty acid ester of a polyhydric alcohol. Polyhydric alcohol fatty acid esters are preferred.

Such fatty acid esters of polyhydric alcohols include:
Specifically, glycerin fatty acid esters such as glycerin monostearate, glycerin monolaurate, glycerin monomyristate, glycerin monopalmitate, glycerin distearate, and glycerin dilaurate;
Fatty acid esters of pentaerythritol such as pentaerythritol monostearate, pentaerythritol monolaurate, pentaerythritol distearate, pentaerythritol dilaurate, and pentaerythritol tristearate are used.

Such a phenolic antioxidant is used in an amount of 0.01 to 10 parts by weight, preferably 0.05 to 10 parts by weight, based on 100 parts by weight of the cyclic olefin random copolymer composition.
3 parts by weight, more preferably 0. The fatty acid ester of the polyhydric alcohol is used in an amount of 0.01 to 10 parts by weight, preferably 0.05 to 3 parts by weight, based on 100 parts by weight of the composition.

In the present invention, the above-mentioned cyclic olefin random copolymer is used as the substrate 2, and this cyclic olefin random copolymer is made of polycarbonate, poly(meth)acrylate, etc. that have been conventionally used as the substrate 2. Since the water absorption rate is higher than that of the substrate, the magneto-optical recording film laminated on the substrate is less likely to be oxidized by moisture.

Further, the substrate made of the cyclic olefin random copolymer and the magneto-optical recording film have excellent adhesion, and from this point as well, oxidation of the magneto-optical recording film laminated on the substrate is effectively prevented. Therefore, a magneto-optical recording medium formed by laminating a magneto-optical recording film on a substrate made of this cyclic olefin random copolymer is convenient in terms of durability and has excellent long-term stability.

(Furthermore, the substrate made of the cyclic olefin random copolymer described above has low birefringence, and therefore has high sensitivity when reading the magneto-optical recording film, and it is also possible to use a non-differential drive device when reading. can.

In the present invention, on the substrate 2 as described above, there is provided a film that is easily magnetized perpendicular to the film surface and includes at least (i) at least one element selected from 3D transition metals and (iii) at least one element selected from rare earths. In the present invention, in such a magneto-optical recording film 3, (i) at least one selected from 3D transition metals; It is preferable to use a magneto-optical recording film comprising (ii) a corrosion-resistant metal and (iii) at least one element selected from rare earths.

First, this preferred magneto-optical recording film 3 will be explained below.

(i) 3d transition metals include Fe, Co, and Ti.

V, CrSMn, Ni, Cu, Zn, etc. are used, and among these, Fe, CO, or both are preferable.

This 3d transition metal is preferably contained in the magneto-optical recording film 3.
It is present in an amount of o to 90 atom %, more preferably 30 to 85 atom %, particularly preferably 35 to 80 atom %.

(ii) By including the corrosion-resistant metal in the magneto-optical recording film 3, the oxidation resistance of the magneto-optical recording film can be improved. Such corrosion-resistant metals include Pt,
Pd, Ti, Zr, Ta, Mo.

The force used is Nb, etc. & among these, Pt, Pd.

Ti is preferred, especially pt or Pd or both.

This corrosion-resistant metal is present in the magneto-optical recording film 3 in an amount of 5 to 30 at%, preferably 5 to 25 at%, particularly 10 to 25 at%, and more preferably 10 to 2 at%. There is.

If the content of this corrosion-resistant metal is less than 5 at %, the oxidation resistance of the resulting magneto-optical recording film will not be sufficiently improved;
Over time, the coercive force HC changes significantly or the Kerr rotation angle θk decreases.

Furthermore, if it is present in an amount exceeding 30 atomic %, the Curie point of the obtained amorphous alloy thin film tends to be lower than room temperature, which is not preferable. (i) The magneto-optical recording film 3 is configured to contain, in addition to the above (ii) and (iii), at least one rare earth element selected from the following group.

Gd, Tb, Dy, Ho, Er,
Tm, Yb.

Lu, La, Ce, Pr, Nd,
Pm, Sm.

u Among these, Gd, Tb, Dy, Ho, N
d, Sm.

Pr is preferably used.

At least one rare earth element selected from the above group is preferably contained in the magneto-optical recording film 3 in an amount of 5 to 50 atomic %.
More preferably 8 to 45 at%, particularly preferably 10
It is present in an amount of ~4o atom %.

In the present invention, it is particularly preferable that the magneto-optical recording film 3 has a composition as described below.

i 3d transition - The magneto-optical recording film according to the present invention preferably contains Fe or CO or both as (i) 3d transition element, and Fe and/or CO are 40
Preferably 1-< is present in an amount of at least 40 atom % and less than 75 atom %, more preferably at least 40 atom % and less than 59 atom %.

Furthermore, Fe and/or CO may be Co/(F
e +Co) ratio [atomic ratio] is 0 or more and 0. It is desirable that it be present in the magneto-optical recording film in an amount of 3 or less, preferably 0 or more and 0.2 or less, more preferably 0 or more and 0.2 or less.

When the amount of Fe and/or CO is in the range of 40 atomic % or more and 80 atomic % or less, a magneto-optical recording film with excellent oxidation resistance and an axis of easy magnetization in the direction perpendicular to the film surface can be obtained. It has the advantage of

By the way, when Co is added to the magneto-optical recording film, (a)
It has been observed that the Curie point of the magneto-optical recording film increases and the Kerr rotation angle (θk) increases.As a result, it is possible to adjust the recording sensitivity of the magneto-optical recording film by adjusting the amount of Co added. (1) Moreover, the carrier level of the reproduced signal can be increased by adding CO. In the magneto-optical recording film used in the present invention, from the viewpoint of noise level and CZN ratio, Co /
The (Fe + Co 2 ) ratio [atomic ratio] is 0 or more and 0.3 or less, preferably 0 or more and 0.3 or less. 2 or less, more preferably 0.01
More than 0. It is desirable that it is 2 or less.

Figure 5 shows that PtTb is applied to the cyclic olefin copolymer substrate.
Figure 6 shows the relationship between the Co/(Co + Fe) ratio [atomic ratio ko] and the noise level (dBm) in a magneto-optical recording medium laminated with a Pd Tb Fe Co-based magneto-optical recording film. Co/(Co+Fe) ratio [atomic ratio] in magneto-optical recording medium with laminated recording films
and the noise level (dBm).

Specifically, Pt13 T b 2 B Fe 6
A magneto-optical recording film (C
o/(Fe+Co) ratio [atomic ratio]: 0.15) is stacked on the substrate, the noise level is 156 dBm, whereas the magneto-optical recording film having the composition shown as P t 13Tb 2sFe 38CO23 ( Co/(Fe
+Co) ratio [atomic ratio]: 0.39), the noise level is 150 dBm, and the noise level tends to increase. Also P d 14Tb 27F
e Magneto-optical recording film having a composition represented by 62Co7 (
Co/(Fe +Co) ratio [atomic ratio]: 0.12
), the noise level was 156 dBm, while Pd 14Tb 27Fe 41 Co
A magneto-optical recording film (Co/(F
When using the e+CO) ratio [atomic ratio CO 0.31),
The noise level is 151 dBm, and the noise level tends to increase.

Figure 7 shows Pt, Tb Fe Co or Pd.
Co/(
The relationship between the Fe + Co ) ratio [atomic ratio] and erasure degradation (ΔCZN ratio (dB)) is shown.

Specifically) P t +3Tb 2sFe 5eco
Magneto-optical recording film (Co/(Fe
When erasing information recorded on a magneto-optical recording medium in which +Co) ratio [atomic ratio]: 0.155) is laminated on a multilayer substrate, the film does not change even if the energy irradiated to the film is increased. No deterioration occurs at all, and new information can be recorded with the same C/N ratio value as before erasing.

Furthermore, this preferable magneto-optical recording film used in the present invention does not undergo film deterioration even after repeated recording and erasing. For example, Pt+aTb2sFed(, Cog
Even after repeated recording and erasing of 100,000 times, no decrease in the C/N ratio was observed.

(ii) Preferable magneto-optical recording films used in the present invention include (ii)
The corrosion-resistant metal preferably contains Pt and/or Pd, and pt and/or Pd is contained in the magneto-optical recording film in an amount of 5 to 30 at%, preferably more than 10 at% to 30 at%. The amount of pt and/or Pd in the magneto-optical recording film is preferably present in an amount of more than 10 atom % and less than 20 atom %, most preferably 11 atom % to 19 atom %. When present in an amount of 5 atomic % or more, especially more than 10 atomic %, it improves the oxidation resistance of the magneto-optical recording film. have Also Ti
S Mo, Zr, Ta.

A similar effect was also observed for Nb and the like.

Figure 8 shows Pt and/or P in the magneto-optical recording film.
d content and the magneto-optical recording film at 85% relative humidity and 80°C.
The relationship between the ΔC/N ratio and the ΔC/N ratio when maintained for 1000 hours under the following environment is shown.

From FIG. 8, it can be seen that when the amount of Pt and/or Pd in the magneto-optical recording film is 5 atomic % or more, especially more than 10 atomic %, the oxidation resistance of the magneto-optical recording film is improved and it lasts for a long time. It can be seen that pitting corrosion does not occur even when used, and the C/N ratio does not deteriorate.

For example, Pt +3Tb 2eFe 511Co @
Alternatively, when a magneto-optical recording film having the composition shown as Pd+2Tb2sFes3Co7 is used, even if it is kept in an environment of 85% relative humidity and 80°C for 1000 hours, C
/() The N ratio does not change at all. On the other hand, when a magneto-optical recording film having the composition shown by Tb25Fe68C07 containing no pt or Pd is used, the relative humidity is 85%, 80%
When kept in an environment at ℃ for 1000 hours, the C/N ratio decreases significantly.

In addition, Pt, Pd, Ti,
Zr.

By adding at least one of NbS Ta and Mo in an amount within the above range, a sufficiently high C/N ratio can be achieved with a small bias magnetic field when recording information on a magneto-optical recording film or reading information. is obtained. If a sufficiently high C/N ratio can be obtained with a small bias magnetic field, the magnet for generating the bias magnetic field can be made smaller, and heat generation from the magnet can also be suppressed, making it possible to drive optical disks with a magneto-optical recording film. The device can be simplified. Moreover, a small bias magnetic field can provide a sufficiently large C.
/N ratio, it becomes easy to design a magnet for overridable magnetic field modulation recording.

In Figure 9, P t +3Tb 28Fe 5eco o
A magneto-optical recording film having a composition shown by and Tb 26
Bias magnetic field dependence and C/N when using a magneto-optical recording film having the composition shown by FeQ8Co7
The relationship with the ratio (dB) is shown.

From FIG. 9, when using the magneto-optical recording film shown by Tb25Feaeco 7, the C/N ratio does not saturate unless a bias magnetic field of 2500e or more is applied, whereas the C/N ratio shown by Pt13Tb2aFe5ecoe It can be seen that in the magneto-optical recording film, sufficient recording is possible even with a small bias magnetic field, and the C/N ratio is saturated at 1200e or more. In the examples, the value of the minimum bias magnetic field Hsat required for saturating the C/N ratio for each magneto-optical recording film is shown in the table. The smaller this value Hsat is, the more the C/N ratio is saturated with a smaller bias magnetic field.

Furthermore, FIG. 10 shows the relationship between the content of pt and/or Pd in the Pt Tb Fe Co-based magneto-optical recording film and the Pd Tb Fe Co-based magneto-optical recording film and the minimum bias magnetic field (Hsat, (Oe)). show.

From this Fig. 10, when the 57- content of Pt and/or Pd exceeds 10 at%, the minimum bias magnetic field Hs
It can be seen that at becomes sufficiently small.

(iii Earth-RE) The magneto-optical recording film according to the present invention contains a rare earth element (RE).
These rare earth elements include Nd,
Sm, Pr, CeS Eu,
Gd, Tb.

Dy or Ho is used.

Among these, NdSPr, Gd, and TbDy are preferably used, and Tb is particularly preferred.

Further, two or more kinds of rare earth elements may be used in combination, and in this case, it is preferable that Tb is contained in an amount of 50 at % or more of the rare earth elements.

This rare earth element has the advantage of providing magnetism with an axis of easy magnetization perpendicular to the film surface, so that RE/(RE+Fe +
Co) ratio [atomic ratio] is expressed as X, 0.15≦
X≦0.45, preferably 0, 20≦X≦0. It is desirable that the magneto-optical recording film be present in an amount of 4.

In the present invention, small amounts of various elements may be added to the magneto-optical recording film to improve the Curie temperature, compensation temperature, coercive force Hc, Kerr rotation angle θ, or to reduce costs. These elements can be used in a proportion of, for example, 10 atomic % of the total number of atoms constituting the recording film.

Examples of other elements that can be used in combination include the following elements.

(1) 3d transition elements other than Fe and Co Specifically, Sc, Ti, V, Cr SMnNi
, Cu, and Zn are used.

Among these, Ti, NiS Cu, Zn, etc. are preferably used.

(m) 4d transition elements other than Pd, specifically Y, Zr, Nb, Mo, TcRu,
Rh, AgS Cd are used.

Among these, Zr and Nb are preferably used.

(m) 5d transition elements other than Pt Specifically, Hf, Ta, W, Re, 0sIr,
Au and Hg are used.

Among these, Ta is preferably used.

(rv) mB group elements (Specifically, B, AI, Ga, In, and Tl are used.

Among these, B, Al, and Ga are preferably used.

(v) ■ Group B element Specifically, C, Si, Ge, Sn, and Pb are used.

Among these, Si, Ge, Sn, and Pb are preferably used.

(vr) vB group element Specifically, N, PS As, Sb, and Bi are used.

Among these, sb is preferably used.

(■) VIB group elements Specifically, SS Ss, Te, and Po are used.

Among these, Te is preferably used.

Further, in the present invention, as the iL magneto-optical recording film 3, a magneto-optical recording film comprising (i) at least one element selected from 3d transition metals and (iii) at least one element selected from rare earths as described above is also used. Can be used. As such a magneto-optical recording film, a Tb Fe Co-based magneto-optical recording film is preferable, in which Tb is contained in an amount of 10 to 40 atom%, Fe is contained in an amount of 30 to 90 atom%, and CO is contained in an amount of 0 to 30 atom%. Preferably, it is present in an amount of %. Further, in the present invention, (i) a 3d transition metal and (iii) a rare earth element, such as Tb-Fa.

In addition to the T b-Fe-Co system, for example, the above (1)
It may also contain other elements such as the elements indicated by ~(■).

The magneto-optical recording film 3 having the above composition is an amorphous thin film capable of perpendicular magnetic and magneto-optical recording, which has an axis of easy magnetization perpendicular to the film surface and often exhibits a rectangular loop with good Kerr hysteresis. This can be confirmed by wide-angle X-ray diffraction.

In this specification, a square loop with good Kerr hysteresis means that the saturated Kerr rotation angle (+ in θ) is the Kerr rotation angle at the maximum external magnetic field, and the residual Kerr rotation angle is the Kerr rotation angle at zero external magnetic field. This means that the ratio of θ to 2/θ to 1 with the rotation angle (θ to 2) is 0.8 or more.

(5) The film thickness of such a magneto-optical recording film 2 is 100 to 5000.
The angstrom is preferably about 100 to 3,000 angstroms, more preferably about 150 to 2,000 angstroms.

In the magneto-optical recording medium 1 according to the present invention, a reflective film 4 may be provided on the magneto-optical recording film 3 as described above.

The reflective film 4 is desirably made of a metal or alloy having a thermal conductivity of 2 J/cm-8 ec.K or less, preferably IJ/clII-8 ec- or less.

More preferably, the reflective film 4 has a reflectance of 50% or more, preferably 70% or more, and a thermal conductivity of 2J/12
- Preferably IJ/, less than 5ec-.

・Constructed from a metal or alloy that is less than or equal to 5ec-.

Specifically, the reflective film 4 has a thermal conductivity of 0.71 J/.
Pt whose thermal conductivity is 0, 76
J/an-sec- of Pd, thermal conductivity ÷ 0. 22 J/cm -5ee- or a thermal conductivity of 0. Co at 99 J/cm·sec.

Z whose thermal conductivity is 0.23J/cI+1・5ec-
It is preferable that it is made of R or an alloy thereof.

Such a reflective film 4 has a reflectance of 50% or more, preferably 70% or more, and a thermal conductivity of 2 J/cm-5e.
It is also preferable to use a nickel-based alloy having an I J/cm −5ec − or less, preferably I J/cm −5ec − or less.

The nickel-based alloy that constitutes such a reflective film is mainly composed of nickel, silicon, molybdenum, iron,
At least one selected from the group consisting of chromium and copper
Preferably, it contains seeds. In such a nickel-based alloy, nickel is contained in an amount of 30 to 99 at%, preferably 5
It is present in an amount of 0 to 90 atom %.

The nickel alloy that makes up the above reflective film is as follows:
Specifically, the following alloys can be used.

Ni-Cr alloy (for example, 30 to 99 atomic % Ni, 1 to 70 atomic % Cr, particularly preferably 70
~95 at.% Ni, 5-30 at.% Cr) Ni-3i
system alloy (e.g. 85 atomic%Ni1o atomic%Si, 3
atomic% Cu, 2 atomic% At) Ni-Cu alloy (
For example, 63 atomic% Ni, 29-30 atomic% Cu, 0.9
~2 atomic % Fe.

0.1-4 at% Si, O-2.75 at% Al)N
i-Mo-Fe alloy (e.g. 60-65 atomic%
Ni, 25-35 atom% Mo, 5 atom% Fe) Ni-
Mo-Fe-Cr alloy (e.g. 55-60 atomic% Ni 15-2o atomic% Mo 6 atomic% Fe
12 to 16 atom% Cr 5 atom% W) Ni-
Mo-Fe-Cr-Cu alloy (e.g. 60 atomic% Ni, 5 atomic% MO18 atomic% Fe, 21 atomic% Cr
, 3 atomic % Cu, 1 atomic % Si, 1 atomic % Mn, 1 atomic % W1, or 44 to 47 atomic % Ni, 5.
5-7. 5 at.% Mo, 21 to 23 at.% Cr, 0.
15 atomic% Cu, I atomic% Si, 1 to 2 atomic% Mn,
2. 5 atom% Co, 1 atom% W, 1.7 to 2.5
Atomic %Nb, balance Fe)Ni-Cr-Cu-M
o-based alloys (e.g. 56-57 atomic% Ni 23-
24 atom% Cr, 8 atom% Cu, 4 atom% MO12
atomic% W, 1 atomic% Si or Mn) Ni-Cr-Fe alloy (e.g. 79.5 atomic% Ni
13 atomic% Cu6.5 atomic%FeO, 2 atomic%C
u, or 30 to 34 atom% Ni, 19 to 22 atom% Cr, 0. 5 atom% Cu.

1 atomic % Si, 1. 5 atomic% Mn, balance Fe
) A magneto-optical recording medium having such a reflective film 4 has an excellent C/N ratio compared to a magneto-optical recording medium having a reflective film made of aluminum, ore, or the like.

In other words, if a reflective film such as aluminum with high thermal conductivity is used, when a laser beam is irradiated to form pits in the magneto-optical recording film, the thermal energy given to the magneto-optical recording film by the laser beam will be reflected from the film. Because it diffuses through the film, it requires a large recording laser power. Furthermore, the shape of the bits formed on the magneto-optical recording film becomes large (7) and becomes irregular. The dependence of the recording power on the film thickness of the reflective film becomes too large.

Further, the reflective film 4 as described above has the effect of improving the oxidation resistance of the magneto-optical recording film, so that a magneto-optical recording medium with excellent long-term reliability can be obtained.

The reflective film 4 has a thermal conductivity of 2J/cIll-8ec.
- A reflective film made of a nickel-based alloy with a K or less, preferably I J 7cm -5ec - or less is preferable, particularly a Ni-Cr alloy (for example, 30 to 99 atomic % Ni).

1 to 70 atom% Cr) is preferable, and further Ni70 to 9
A reflective film made of a Ni-Cr alloy containing 5 at. % and 5 to 3 o at. % of Cr is preferable because a high C/N ratio can be obtained.

On the other hand, by providing a reflective film 4 made of a metal, particularly a nickel-based alloy, that has low thermal conductivity and high reflectance,
Even if the thickness of the magneto-optical recording film is reduced, a high Kerr rotation angle and reflectance can be obtained.

The film thickness of such a reflective film 4 is 100 to 4000 angstroms, preferably 200 to 2000 angstroms.
It is about 1 Angstrom.

The total thickness of the magneto-optical recording film 3 and the reflective film is 300 to 4
The thickness is approximately 600 angstroms, preferably 350 to 2,400 angstroms.

In the magneto-optical recording medium 1 according to the present invention, an enhancement film 5 may be provided between the substrate 2 and the magneto-optical recording film 3 as described above. An enhancement film 5 may be provided in between. This enhancement film 5 functions to increase the sensitivity of the magneto-optical recording medium 1 according to the present invention, and also functions as a protective film for the magneto-optical recording film 3. Such an enhancement film 5 can be any transparent film having a refractive index greater than that of the substrate.

As such an enhancement film, Z
n S, Zn Se Cd S.

Si3N4, SiNx (0<x<4/3), Si.

AIN etc. can be used. The thickness of this enhance (cis film) is 100~1000, preferably 300~
It is about 850. Among these, from the viewpoint of crack resistance, it is particularly preferable to use Si3N and SiNx (0<x<4/3) as the enhancement film.

Next, a method for manufacturing a magneto-optical recording medium according to the present invention will be explained.

The substrate temperature is maintained at about room temperature, and a composite target in which chips made of each element constituting an amorphous alloy thin film are arranged in a predetermined ratio, or an alloy target with a predetermined composition ratio is used, and the sputtering method or electron beam evaporation method is used. An amorphous alloy thin film of a predetermined composition is deposited on this substrate (the substrate may be fixed or rotating) using conventionally known film-forming conditions, and then The magneto-optical recording medium according to the present invention can be manufactured by depositing a reflective film on the substrate in the same manner as described above.

As described above, the magneto-optical recording medium according to the present invention does not require pretreatment such as heat treatment or plasma treatment and can be formed at room temperature, and can be annealed after film formation in order to have an axis of easy magnetization perpendicular to the film surface. There is no need for heat treatment such as treatment.

Note that, if necessary, the amorphous alloy thin film can be formed on the substrate while heating the substrate temperature to 50 to 100°C or cooling it to -50°C.

Further, during sputtering, the substrate can be biased to a negative potential. In this way, ions of an inert gas such as argon accelerated by an electric field will hit not only the target material but also the perpendicularly magnetized film that is being formed, resulting in a perpendicularly magnetized film with excellent properties. Sometimes.

Effects of the Invention The magneto-optical recording medium according to the present invention has a structure in which a magneto-optical recording film made of a specific amorphous alloy thin film is laminated on a cyclic olefin random copolymer substrate made of ethylene and a cyclic olefin. Therefore, it is convenient for the adhesion between the substrate and the magneto-optical recording film, and is also excellent in oxidation resistance, magneto-optical recording characteristics, and long-term stability of magneto-optical recording (γ J) characteristics.

The present invention will be described below with reference to Examples.8 The present invention is not limited to these Examples.

In addition, the physical properties of the magneto-optical recording medium in the following examples were investigated by the following method.

(1) Composition of magneto-optical recording film: Determined by ICP analysis. (2) Kerr rotation angle was determined by measuring the residual Kerr rotation angle with zero external magnetic field measured from the substrate side using an oblique incidence method (λ = 780 nm). A specific measurement method and apparatus for the oblique incidence method are described in "Measuring Techniques for Magnetic Materials" (published by Trikebbs Co., Ltd., December 25, 1985), edited by Aibe Yamakawa, pages 261 to 263.

(3) Recording and reproduction: The magneto-optical disk has a diameter of φ130m.
m, and this magneto-optical disk is recorded at a recording frequency of IMHz using a drive device (Nakamichi 0MS-1000).
(Duty ratio 50%), linear speed 11.1 m/s,
Bias magnetic field 2000e during writing, read laser power 1. Recording and playback were performed under the condition of 0 mW. (4) Table 6 shows the signal-to-noise ratio (C /N ratio) and noise level are also shown.

(5) Then, convert this information to 3.0 from the optimum recording power.
The data was erased with a high power of mW, and new information was recorded. Perform this operation 10 times and check the C/N before and after erasing.
The difference in ratio was expressed as ΔC/N ratio.

(6) Regarding the bias magnetic field dependence, Hsat was determined from the change in the C/N ratio when the bias magnetic field was varied from 50 to 5000 e under the above conditions.

"Flame twisting" Fe as target, Co target on P
Ethylene and 1,4,5,8-dimethano-1,
2,3,4,4a, 5.8.8a-octahydronaphthalene non-quality copolymer (as determined by C-NMR analysis) Ethylene content 59 mol%, DMON content 41 mol%,
Intrinsic viscosity measured in decalin at 135°C [η burnt 0.
42 di/g, softening temperature (TMA) 154°C)
and tetrakis[methylene-3(3,5-di-t-butyl-4-hydroxyphenyl)propionate comethane, zinc stearate, and glycerin monostearate] as stabilizers at 0% each. 5%, 0.05%, 0. 5%
A disk substrate (130 mL Iφ) made of the blended composition
) (hereinafter referred to as a PC board) on this board without drying it.
The temperature was 0 to 50°C, and the vacuum attainment level was 1.5% in an Ar atmosphere using C magnetron sputtering. OX 10-7
A magneto-optical recording film of Pt, 2Tb3eFe4°Co9 having a film thickness of 1000 angstroms was formed under conditions of less than Torr. The resultant magneto-optical recording film was measured by wide-angle X-ray diffraction and was found to be amorphous. The composition was determined by ICP emission spectrometry.

The physical properties of the obtained magneto-optical recording film (medium) are shown in Table 6. Furthermore, the state of the film formation was good when observed under a microscope.

Actual JH principle: T on the Fe Co target as a target.
Using a composite target in which the chips of b were arranged at a predetermined ratio, Tb25 with a film thickness of 10oO angstroms was deposited on the same PO substrate as that used in Example 1 under the same conditions as Example 1.
A magneto-optical recording film of Fe68C○7 was formed. The obtained magneto-optical recording film was amorphous. Table 6 shows the physical properties of this magneto-optical recording film (medium). Further, the film formation was good when observed under a microscope.

P on the Fe Co target as Jing J Chen'1 Yu target
A polycarbonate resin substrate (PC board) was dried at 80°C for 6 hours in a sputtering device using a composite target in which chips of t and Tb were arranged at a predetermined ratio. Then, a magneto-optical recording film of Pt12Tb, Fe, and Co9 with a film thickness of 1000 angstroms was formed using the C magnetron sputtering method in an Ar atmosphere under conditions of a vacuum attainment of 1.0 x 10 Torr or less. The magneto-optical recording film was measured using wide-angle X-ray diffraction and was found to be amorphous.The composition was determined using ICP analysis.
Tb 2s Feeac with a film thickness of 1000 angstroms was deposited on a polycarbonate resin substrate in the same manner as in Comparative Example 1 using a composite target in which the chips of b were arranged at a predetermined ratio.
The magneto-optical recording film obtained by forming the magneto-optical recording film of o7 was measured by wide-angle X-ray diffraction and was found to be amorphous.

[Evaluation of Adhesion between Substrate and Magneto-Optical Recording Film] The adhesion between the substrate and magneto-optical recording film of the magneto-optical recording media of Examples 1 and 2 and Comparative Examples 1 and 2 was evaluated by the following method.

The results are shown in Table 1.

Substrate test (JIS K5400) Using a cutter knife, draw 11 orthogonal parallel lines at 1 mm intervals on the recording film of the sample. Make incisions in the shape of a base so that 100 squares are formed in each square.

Peeling was evaluated using cellophane tape (manufactured by Chiban).

Pressure--1 Immediately after film formation 080'C/85%FK 100 hours later A magneto-optical recording film having the composition shown was formed.

The characteristics of the obtained magneto-optical recording medium are shown in Table 1.

7-qshi 7/- point] 1" field 1 Ethylene/DMON copolymer (ethylene content 60 mol%
, DMON content 40 mol%, softening temperature (TMA) 155
°C, [η]=0. 700 di/g (in decalin at 135° C., crystallinity 0 [X-ray analysis method]) as an enhancement layer by sputtering on a disk substrate with a crystallinity of 0.
of Si Nx (0(x<4/3, refractive index n=2.
3, k (extinction coefficient) = 0.014), 300 angstrom P t +aTb 34F as magneto-optical recording layer.
'e 3eco +s and 700 angstroms of Ni 5ecr 2[I were sequentially laminated as a reflective layer to produce a magneto-optical disk.

The recording and playback characteristics of this disc are as follows:
(Duty ratio 50%), linear speed 5. Evaluation was made at 4 m/s.

As a result, the optimal recording laser power was 3.5 mW,
C/N is 50dB (reproduction laser power is 1, OmW
)Met.

Examples 22 to 27 In the same manner as in Example 21, magneto-optical disks having a magneto-optical recording layer and a reflective layer having the composition and structure shown in Table 3 were prepared and evaluated in the same manner as in Example 21.

The results are shown in Table 3.

→１ −81=

[Brief explanation of drawings]

FIGS. 1 and 2A. FIGS. 3 and 4 are cross-sectional views of magneto-optical recording media according to the present invention. Figure 5 shows Co in a magneto-optical recording film containing pt.
/ (Fe + Co) ratio [atomic ratio] and noise level (
dBm). FIG. 6 is a diagram showing the relationship between Co/(Fe +Co) ratio [atomic ratio Co] and noise level (dBm) in a magneto-optical recording film containing 13Pd. Figure 7 shows Co/(Fe
+Co) ratio [atomic ratio] and erasure degradation (△C/N ratio (d
B)) FIG. FIG. 8 shows pt and/or P, d in the magneto-optical recording film.
FIG. 2 is a diagram showing the relationship between the content (atomic %) and oxidation resistance (ΔC/N ratio). FIG. 9 is a diagram showing the relationship between the bias magnetic field (Oe) of the magneto-optical recording film and the C/N ratio. 1st
Figure 0 shows Pt and/or l; l P in the magneto-optical recording film.
The content of d (atomic %) and the bias magnetic field (Hs
It is a figure which shows the relationship with at, (Oe)). The magneto-optical disks shown in Figs. 4 to 9 all have the structure shown in Fig. 1, and the substrate is an ethylene/DMON copolymer, and recording films of 1000 angstroms are sequentially laminated on this substrate. be.

Claims (1)

[Claims] 1) A magneto-optical recording medium in which a magneto-optical recording film is laminated on a substrate, wherein the substrate is made of a copolymer of ethylene and a cyclic olefin represented by the following general formula [I]. The magneto-optical recording film is formed from a cyclic olefin random copolymer of (
i) at least one selected from 3d transition metals, and (i
ii) Magneto-optical recording medium characterized by being an amorphous alloy thin film containing at least one element selected from rare earths and having an axis of easy magnetization perpendicular to the film surface: ▲Mathematical formula, chemical formula, table, etc. There is▼...[I] (In formula [I], n is 0 or a positive integer,
R^1 to R^1^2 each represent a hydrogen atom, a halogen atom, or a hydrocarbon group, and R^9 to R^1^2 are
They may be combined with each other to form a monocyclic or polycyclic group, and the monocyclic or polycyclic group may have a double bond, and R^9 and R^1^0 and, or R^1^1 and R^
1^2 may form an alkylidene group). 2) The magneto-optical recording film is made of (i) at least one element selected from 3D transition metals, (ii) a corrosion-resistant metal, and (i) at least one element selected from rare earths, and 2. The magneto-optical recording medium according to claim 1, wherein the magneto-optical recording medium is an amorphous alloy thin film having an easy axis of magnetization perpendicular to the film surface and containing 5 to 30 at % of a magnetic metal. 3) (i) 3d transition metal contained in the magneto-optical recording film is F
3. The magneto-optical recording medium according to claim 1 or 2, characterized in that it is made of E, Co, or both. 4) The (ii) corrosion-resistant metal contained in the magneto-optical recording film is T
3. The magneto-optical recording medium according to claim 1, wherein the magneto-optical recording medium is at least one selected from i, Zr, Nb, Ta, Mo, Pt, and Pd. 5) (ii) Corrosion-resistant metal contained in the magneto-optical recording film,
The magneto-optical recording medium according to claim 1 or 2, characterized in that it is made of Pt or Pd or both. 6) The rare earth (iii) contained in the magneto-optical recording film is Nd,
Sm, Pr, Ce, Eu, Gd, Tb, Dy or Ho
The magneto-optical recording medium according to claim 1 or 2, characterized in that: 7) The amount of (i) 3d transition metal contained in the magneto-optical recording film is 40 atomic % or more and 80 atomic % or less, and (ii) the amount of corrosion-resistant metal is more than 10 atomic % and 30 atomic % or less. The magneto-optical recording medium according to claim 1, characterized in that: 8) The magneto-optical recording film is an amorphous film having an easy axis of magnetization perpendicular to the film surface and consisting of (i) at least one element selected from 3D transition metals and (iii) at least one element selected from rare earths. 2. The magneto-optical recording medium according to claim 1, which is a thin alloy film. 9) (i) 3d transition metal contained in the magneto-optical recording film is F
9. The magneto-optical recording medium according to claim 8, characterized in that it is made of E, Co, or both. 10) The (iii) rare earth contained in the magneto-optical recording film is Nd.
, Sm, Pr, Ce, Eu, Gd, Tb, Dy or H
9. The magneto-optical recording medium according to claim 8, wherein the magneto-optical recording medium is o. 11) The magneto-optical recording medium according to claim 1 or 8, wherein a reflective film is laminated on the magneto-optical recording film.