JPH0498634A - Magneto-optical recording medium - Google Patents

Abstract

PURPOSE:To increase a coercive force by laminating a 1st magnetic layer which consists of a 3rd transition metal and rare earth element and has >=180 deg.C Curie temp. and a 2nd magnetic film which has <200 deg.C Curie temp. (Tc), thereby forming magneto-optical recording films. CONSTITUTION:The magneto-optical recording films 3 consisting of the 1st magnetic film 3a and the 2nd magnetic film 3b are provided via a protective film 2 on a substrate 1 and a metallic film 4 is provided on the film 3. The film 3a consists of (i) the 3rd transition metal and (iii) the rare earth element and the Curie temp. (Tc) thereof is >=180 deg.C, more preferably 220 to 300 deg.C. Its coercive force Hc is relatively small and is specified to <5kOe, more preferably <=2kOe. The film 3b consists of (i) the 3d transition metal and (iii) the rare earth element and the Curie temp. (Tc) thereof is <200 deg.C, more preferably 100 to 160 deg.C. Its coercive force Hc is relatively large and is specified to >=5kOe, more preferably >=8kOe.

Description

[Detailed Description of the Invention] i Bean Nigen Gokya 1 Invention j4 Concerning magneto-optical recording media More specifically, magneto-optical recording that has excellent recording sensitivity, excellent oxidation resistance, and excellent repeatability of recording and erasing. Regarding the medium.

Transition metals such as iron and cobalt, terbium (Tb),
A magneto-optical recording film made of an alloy with a rare earth element such as cadrinium (Gd) has an axis of easy magnetization in a direction perpendicular to the film surface, and a film surface that is entirely magnetized in one direction is opposite to this direction of magnetization. It is known that it is possible to form magnetic domains with small orientation reversals. The presence or absence of this inverted magnetic domain is “1”, “0”
”, it becomes possible to record digital signals on the magneto-optical recording film as described above.

For example, Japanese Patent Publication No. 57-20691 discloses a Tb--Fe based magneto-optical recording film containing 15 to 30 atomic % of Tb as a magneto-optical recording film made of such a transition metal and a rare earth element. A magneto-optical recording film made of Tb-Fe added with a third metal can also be used. Further Tb
Magneto-optical recording films such as those based on -Co and Tb-Fe-C0 are also known.

In order to improve the oxidation resistance of such a Tb--Fe nail or Tb--Co magneto-optical recording film, various methods of adding a third metal have been attempted.

By the way, according to Japanese Patent Application Laid-Open No. 57-78652, the first magnetic film has a high Curie temperature but a high coercive force of /h, and a second magnetic film has a low Curie temperature but has an excellent coercive force. A magneto-optical recording film is disclosed in which a magnetic film and a second magnetic film are magnetically exchange-coupled. This magneto-optical recording film has a serious problem of poor oxidation resistance, and
The effect of improving the apparent coercive force of the first magnetic film was also not sufficient. Also, the above-mentioned magneto-optical recording film disclosed in JP-A-57-78652 Table 1: When information is recorded and erased many times, Recording sensitivity decreases, etc.
At the same time, the oxidation resistance and recording sensitivity are excellent.
It is desired to develop a magneto-optical recording medium in which the apparent coercive force of the magnetic film is increased and the recording-erasing repeatability is also excellent.

In addition, the present invention provides excellent oxidation resistance and recording sensitivity, and is the first
The object of the present invention is to provide a magneto-optical recording medium in which the apparent coercive force of a magnetic film is increased and the recording-erasing repeatability is also excellent.

The first and second magneto-optical recording media according to the present invention are magneto-optical recording media in which a protective film, a magneto-optical recording film and a metal film are laminated in this order on a substrate. The magneto-optical recording film is made of (i) a 3D transition metal and (iii) a rare earth element, has a Curie temperature (Tc) of 180°C or more, and has a coercive force Hc of less than 5 KOe. A first magnetic film, (
A metal film comprising: i) a 3D transition metal; and (iii) a second magnetic film made of a rare earth element, having a Curie temperature (Tc) of less than 200°C, and a coercive force of 5 KOe or more; It is characterized by being made of aluminum alloy.

Further, the third and fourth magneto-optical recording media according to the present invention are
In a magneto-optical recording medium in which a protective film, a magneto-optical recording film, a protective film and a metal film are laminated in this order on a substrate, the protective film is made of SiNx, the magneto-optical recording film is (i) a 3d transition metal, (iii) a first magnetic film containing a rare earth element, having a Curie temperature (Tc) of 180° C. or higher, and a coercive force Hc of less than 5 KOe;
i) a 3D transition metal; and (iii) a second magnetic film consisting of a rare earth element, having a Curie temperature (Tc) of less than 200°C, and a coercive force of 5 KOe or more, which have a metal film strength. & It is characterized by being made of aluminum alloy.

In such a magneto-optical recording medium, one or both of the first magnetic film and the second magnetic film contains (1) a 3D transition metal, (iii) a rare earth element, and (ii) P.
It may contain t and/or Pd.

The magneto-optical recording medium according to the present invention has excellent recording sensitivity and excellent recording-erasing repeatability.

EMBODIMENT OF THE INVENTION Below, the magneto-optical recording medium according to the present invention will be specifically explained.

In the first and second magneto-optical recording media 10 according to the present invention, for example, as shown in FIG.
A magneto-optical recording film 3 consisting of a first magnetic film 3a and a second magnetic film 3b is provided through the magneto-optical recording film 3.
A metal film 4 is provided thereon.

Further, third and fourth magneto-optical recording media 10 according to the present invention
For example, as shown in FIG. 2, a magneto-optical recording film 3 consisting of a first magnetic film 3a and a second magnetic film 3b is provided on a substrate 1 with a protective film 2 in between. A metal film 4 is provided on the magnetic recording film 3 with a protective film 5 interposed therebetween.

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

The magneto-optical recording film 3 of the present invention has a first magnetic film 3a and a second magnetic film 3b laminated, and the first magnetic film 3a and the second magnetic film 3b are magnetically Exchange coupled.

This first magnetic film 3a includes (i) a 3d transition metal and (i) a 3d transition metal;
ii) a rare earth element; or (i) a 3d transition metal; (ii) Pt and/or Pd;
(iii) It consists of rare earth elements and has a Curie temperature (T
c) is at least 180°C, preferably from 220 to 300°C, and the coercive force Hc is relatively small, less than 5 KOe, preferably less than 2 KOe.

(i) 3d transition metals include FeS, CoS, and Ti.

V, CrS Mn1 Ni, Cu, Zn, etc. are used, but among these, Fe and/or CO are preferable.

This 3d transition metal is preferably contained in the first magnetic film at 20 to
It is present in an amount of 90 atom %, more preferably 30 to 85 atom %, particularly preferably 35 to 80 atom %.

(ii) By including Pt and/or Pd in the first magnetic film, the oxidation resistance of the first magnetic film can be improved.

This Pt and/or Pd1L does not have to be contained in the first magnetic film, but is not more than 30 at%, preferably 3 to 30 at%, more preferably 5 to 30 at%, especially 10 to 25 at% , more particularly preferably 10
Desirably, it is present in an amount of ~20 at.%.

(iii) Examples of rare earth elements include the following elements.

Gd, Er, Tm, Yb, Lu,
La, Ce.

PrS Nd, Pm, Sm, Eu, Tb, Dy.

O Among these, Gd, Eu, Pr1 NdS Pm, and Sm are preferably used.

The content of at least one rare earth element selected from the above group is preferably 5 to 50 atomic %, more preferably 8 to 45 atomic %, particularly preferably 10 to 45 atomic %, in the first magnetic film.
It is present in an amount of 40 atom%.

The second magnetic film 3b includes (i) a 3d transition metal, and (iii)
(i) a 3d transition metal; (ii) Pt and/or Pd;
ii) a rare earth element, the Curie temperature (Tc) is less than 200°C, preferably 100 to 160°C, and the coercive force Hc is relatively large, preferably 5 KOe or more, preferably 8
KOe or higher.

(i) As the 3d transition metal, the same metal as the first magnetic film 3a is used in the same amount.

(ii) Pt and/or Pd are used in the same amount as in the first magnetic film 3a.

(iii) As the rare earth element, the same one as in the first magnetic film 3a is used.

These rare earth elements are used in the same amount as in the first magnetic film 3a.

+4 in the present invention Either one or both of the first magnetic film and the second magnetic film as described above preferably contain (11) pt and/or Pd.

Further, in the present invention, it is particularly preferable that the first magnetic film and the second magnetic film have the compositions described below.

(i) 3d transition element In the first magnetic film and the second magnetic film according to the present invention, (
i) The 3d transition element preferably contains Fe and/or CO, and Fe and/or C
otdai 40 atom% or more and 80 atom% or less, preferably 40 atom%
atomic% or more 75 atomic% Wei Feng, more preferably 40 atomic%
It is desirable that the amount of the element be present in an amount of 59 atomic % or less.

Furthermore, Fe and/or Co are Co/(Fe+Co
) ratio [atomic ratio] is 0 or more and 0.3 or less, preferably 0 or more and 0.2 or less, and more preferably 0.01 or more and 0.2 or less. It is desirable that it be present inside.

When the amount of Fe and/or CO is in the range of 40 wt % or more and 80 atomic % or less, the first magnetic film and the second magnetic film have a convenient oxidation resistance and an axis of easy magnetization in the direction perpendicular to the film surface. It has the advantage that magnetic film strength can be obtained.

By the way, when Co is added to the first magnetic film and the second magnetic film, (a) the Curie point of the magneto-optical recording film increases.
In addition, the phenomenon that the rotation angle (θk) increases is observed.

The recording sensitivity of the magneto-optical recording film can be adjusted by adjusting the amount of Co added, and the carrier level of the reproduced signal can be increased by adding Co.

In the first magnetic film and the second magnetic film according to the present invention, the Co/(Fe+Co) ratio [atomic ratio] is 0 or more and 0.3 or less, preferably 0 or more and 0.2 in terms of noise level and C/N ratio. Hereinafter, it is more preferably 0.01 or more and 0.2 or less.

In the first magnetic film and the second magnetic film used in the present invention, even if recording and erasing are repeatedly performed, film deterioration does not occur. For example, in atomic ratio P t 13T b
Magneto-optical recording film plate with composition aaF essc Os
No decrease in /N ratio was observed.

(if) Pt and/or Pd In the first magnetic film and second magnetic film used in the present invention,
(ii) It is desirable that Pt and/or Pd be included as the corrosion-resistant metal;
or Pd+4 3 in the first magnetic film and the second magnetic band
0 atom % or less, preferably 3 to 30 atom %, more preferably 5 to 30 atom %, more preferably more than 10 w, 30 atom % or less, even more preferably more than 10 t'C % to 20 atom % It is desirable that the amount of carbon dioxide is present in an amount of 11 atomic % or more and 19 atomic % or less.

pt and/or P in the first magnetic film and the second magnetic film
When the amount of d is 5 atomic % or more, especially more than 10 atomic %, these magnetic films have excellent oxidation resistance. Pitting corrosion does not occur even after long-term use, and the C/N ratio does not deteriorate. has advantages.

For example, the atomic ratio is P t , 3T b2. F e5. C
A magnetic film having a composition represented by Os or P d+2Tb2sFes3COv does not change its C/N ratio at all even if it is kept in an environment of 85% relative humidity and 80° C. for 1000 hours.

On the other hand, Tb25Fe, which does not contain Pt or Pd,
, Co, a magneto-optical recording film having a composition represented by
When kept in an environment of 85% relative humidity and 80° C. for 1000 hours, the C/N ratio decreases significantly.

Furthermore, by adding pt and/or Pd to the first magnetic film and the second magnetic film, especially in the amount within the above range, the apparent coercive force Hc of the first magnetic film due to exchange coupling increases. , improving focus stability.

(iii) Rare earth element (RE) This rare earth element is used to obtain magnetism with an axis of easy magnetization perpendicular to the film surface.
o) When the ratio [atomic ratio] is expressed as X, 0.15≦X
It is desirable that X be present in the magneto-optical recording film in an amount such that ≦0.45, preferably 0.20≦X≦0.4.

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

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

(■) 3d transition elements other than Fe and co Specifically, Sc, Ti, VS CrS Mn.

Ni, Cu, and Zn are used.

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

(n) 4d transition elements other than Pd Specifically, Yl Zr, NbS Mo, Tc.

Ru, Rh, AgS and Cd are used.

Among these, Zr and Nb are preferably used.

(m) 5d transition elements other than Pt Specifically, HfS Ta, WS Re, Os, Ir,
Au and Hg are used.

Among these, Ta is preferably used.

(!V) [[lB group elements Specifically, B, AQ, Ga, In, and Tg are used.

Among these, B and A11S Ga are preferably used.

(V) TVBVB group elements +LC, St, Ge, Sn,
Pb is used.

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

(VT) VB group elements, specifically N, P, As, Sb, B
i is used.

Among these, sb is preferably used.

(■)■ Group B elements Specifically, SX Se, Te, and Po are used.

Among these, Te is preferably used.

Magneto-optical recording films with the above-mentioned laminated structure have an axis of easy magnetization perpendicular to the film surface, and are mostly amorphous, capable of perpendicular magnetic and magneto-optical recording, which exhibit a rectangular loop with good hysteresis. It is confirmed by wide-angle X-ray diffraction that it becomes a thin film.

In this specification, the term ``showing a rectangular loop with good hysteresis'' means that the saturation at the rotation angle at the maximum external magnetic field is the rotation angle (+ for θ) and at the rotation angle at zero external magnetic field. A certain residual is the ratio θ of the rotation angle (2 to θ)
This means that 2/θ is 0.8 or more.

The thickness of this first magnetic film is 200 to 2000, preferably 4300 to 1500, preferably 5oo to 12o.
It is desirable that it be about OA.

The thickness of the second magnetic film is 200 to 2000, preferably 300 to 1500, more preferably 500 to 1.
It is desirable to have around 200 people.

The first magnetic film 3a and the second magnetic film 3b are magnetically exchange-coupled.

In the present invention, the first magnetic film 3a and the second magnetic film 3b as described above are laminated so that the first magnetic film force is provided on the side irradiated with the reproduction light. That is, when the reproduction light is irradiated from the substrate side, the first magnetic film 3a is provided on the substrate side.

Next, a substrate 1 on which the magneto-optical recording film 3 as described above is laminated.
I will explain about it.

En-1 In the present invention, the material of the substrate 1 is not particularly limited, but when the laser beam is incident from the substrate 1 side (arrow A), it is preferably a transparent substrate, and specifically, glass or aluminum is preferable. Other inorganic materials such as polymethyl methacrylate, polybonate, polymer alloy of polybonate and polystyrene, U.S. Patent No. 4.614.778
Cyclic olefin random combination as disclosed in the specification Cyclic olefin random combination as described below Poly4-methyl-1-pentene, epoxy resin, polyethersulfone, polysulfone, polyetherimide Organic materials such as can be used. Among these, polymethyl methacrylate, polybonate, copolymers such as those described in US Pat. No. 4,614,778, and the cyclic olefin random copolymers described below are preferred.

In the present invention, particularly preferred materials for the substrate are ethylene and the following formula [
2] or a cyclic olefin random copolymer consisting of a copolymer with a cyclic olefin represented by [I'].

Numerical formula [+] General formula [1゛] (wherein, n is O or 1, m is 0 or a positive integer, and R1 to RI8 each independently represent a hydrogen atom, a halogen atom, and a hydrocarbon R15 to R1e represent atoms or groups selected from the group consisting of groups, and R15 to R1e may be combined with each other to form a monocyclic or polycyclic ring, and the monocyclic or polycyclic ring has a double bond. Also, R'' and R1♂ or Re7 and R1 may form an alkylidene group).

(In the formula [I'l, p is O or an integer of 1 or more, and q
and r are 0, 1, or 2, and R1 to R1B each independently represent an atom or group from the group consisting of a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and an alkoxy group, and R4 (or Re ) and R9 (or R)) may be bonded via an alkylene group having 1 to 3 carbon atoms, or may be bonded directly without any group. However, if the above formula In [I], n is 0 or 1, preferably 0. Moreover, m is 0 or a positive integer, preferably 0-3.

In the above formula [I'], p is an integer of 0 or 1 or more, preferably an integer of 0 to 3.

and R1 to R18 (formula [I]), or R1 to R1
5 (formula [I']) each independently represents an atom or group selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group. Here, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In addition, examples of hydrocarbon groups include, each independently, an alkyl group having 1 to 6 carbon atoms, and a cycloalkyl group having 3 to 6 carbon atoms, and specific examples of alkyl groups include methyl group. Ethyl group, isopropyl group, isobutyl group, amyl group, and specific examples of cycloalkyl groups include monocyclohexyl group, cyclopropyl group, cyclobutyl group, and cyclopentyl group.

Further, in the above formula [I'], R6 (or Re) and R
9 (or R7) may be bonded via an alkylene group having 1 to 3 carbon atoms, or may be bonded directly without any group.

Furthermore, in the above formula [r], RI5 to RI@ may be bonded to each other (together) to form a monocyclic or polycyclic ring, and the monocyclic or polycyclic ring has a double bond. You can leave it there. Also, with R16 and Re6, or with R1? and R
18 may form an alkylidene group. Such an alkylidene group usually includes an alkylidene group having 2 to 4 carbon atoms, and specific examples thereof include an ethylidene group, a propylidene group, an isopropylidene group, and an isobutylidene group.

The cyclic olefin iL cyclopentadiene represented by the above formula [I] or [r'] and the corresponding olefins or cyclic olefins were mixed by Diels-Alder
It can be easily produced by condensation through reaction.

Specific examples of the cyclic olefin represented by the formula [I] or [Equation] include the following compounds.

(Left below) Bicyclo[2,2,1] Hept-2 Ene derivatives such as 7-methylbicyclo[2 510-dimethyltetra Hs Inbutyl-2,7- 11,12 Trimethyledyru 11.12- Dime9-inbutyl 11, 12 Dodecene 1m 2.1 Dimethyltetradimethyltet 27.9-Trimethylte5, 8.9.10 Tetramethy (blank below) 8-Methyltetrasif 8-ethyltetrasif 1@] 3- Dodecene 8-hexyltetracy 5.17 +9] 3-dodecene 7・I@] Dodecene-3-dodecene+1]-3-dodecene p,s,l 1@] Dodecene+I] Dodecene 8-methylethylte 8-chlorotetrasif dodecene 8-promotitrasifdodecene 8-fluorotetracy 3-dodecenee] dodecene 8-ethylidene 9-y sododecene, 12 5.17・II] 3-dodecene 5.17・I@coco-dodecene-n Propylidene-9 -dodecene n-propylidene 8-isopropylidene [4,4,0,12 5,17 I@codedodecene-dodecene 1e co3-dodecene Is] 3-dodecenepropylidene-9 8-isopropylidene [ 4,4,0,12 5,1) Dodecene - Tetracyclo such as dodecene [4,4,0,12・5,1RY1 發] 3-Dodecene derivative; (Left below) 8-Impropylidenemethyl hexacyph Q2, ? , Q9 14] Hexacyclo[6,6,1,1311@, 13.
Q2. ? , Q9 Decene 1]-4-heptadecene derivative decentcosen heptadecene e, 1st @, Q3. @, Q1 2.1 Fuco-5 Docosene 15-Ethyl octash and other octacyclo[8,8,0,12#, 14), 1+s, l+ + 6, (p 1, Q12 17] 5-tococene derivatives ; such as pentacyclo[6,6,1,1”,02?,O'
4-cohexadecene derivative.

Tricyclo[4,4,0,125]-3-undecene derivatives such as heptacyclo[8,7,0-fucene or hephtacyclo-5-icosene derivatives; tricyclo[4,4,0,12 5]-3-undecene derivatives such as ,3,0,12.1-3 decene derivatives; pentacyclo[4,7,0,12,S,O'' 13.1112]-3-pentadecene derivatives such as dimethylpentamethyl-substituted pentacidimethylben; 6,5,1,13@, Q2
, ? , Q9 1]-4 Cosenpentadecene derivatives: +S] -4-Eicosene and other diene compounds such as hebutacyclo[7,8,0,1'', 02), l11 1f, 0th, lI2 1S co-4 -eicosene derivatives; and further, nonacyclo[9,10 1,1j T, Qj, @, Q2 1 @ , Ql 2 21.113.2 @ 0z, +*4+se] -5-bentacocene derivatives and the like.

(Margin below) q can be mentioned.

(Left below) Ethylene as above and - formula [r] or [I°]
As a copolymer with a cyclic olefin represented by 13
Intrinsic viscosity measured in decalin at 5°C [η is 0.05
~10dQ/g, with a softening temperature (TMA) of 7
A cyclic olefin random copolymer (hereinafter referred to as cyclic olefin random copolymer [A]) having a temperature of 0° C. or higher is preferably used. Further, if desired, ethylene and the following formula [r
] or [I'], the intrinsic viscosity [η] measured in decalin at 135°C is in the range of 0.05 to 5 dll/H, and the softening temperature ( A cyclic olefin random copolymer (hereinafter referred to as cyclic olefin random copolymer [B]) having a TMA) of less than 70° C. may be blended and used.

The above-mentioned cyclic olefin random copolymers [A] and [B], which are copolymers of cyclic olefins and ethylene, contain ethylene and the cyclic olefin as essential components. In addition to the two components, other copolymerizable unsaturated monomer components may be contained as necessary within a range that does not impair the object of the present invention. Specifically, the unsaturated monomer which may be optionally copolymerized includes, for example, propylene, 1-butene,
-Methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, etc. α having 3 to 20 carbon atoms -Olefins can be exemplified.

Cyclic olefin random copolymer [A] as described above
Then, the repeating unit (a) derived from ethylene is 40
The repeating unit (b) derived from the cyclic olefin is present in a range of 15 to 60 mol%, preferably 25 to 50 mol%.
The repeating units (a) derived from ethylene and the repeating units (b) iL derived from the cyclic olefin are present in a range of mol % and are arranged randomly and substantially linearly. The ethylene composition and cyclic olefin composition were measured by +3C-NMR. This cyclic olefin random copolymer is substantially linear and does not have a gel-like crosslinked structure. This can be confirmed by complete dissolution in decalin.

The intrinsic viscosity [η] of such a cyclic olefin random copolymer [A] measured in decalin at 135°C is 0.
．． 05 to 10 (Ill/g, preferably 0.08 to
It's in the range of 5 to 7g.

In addition, the softening temperature (T
MA) iL '70℃ or less, preferably 90-25
The temperature is preferably 0°C, more preferably 100 to 200°C. The softening temperature (TMA) is determined by DuPont's Therm.
The thermal deformation behavior of a 1-thick sheet was measured using an omechanical analyzer. That is, a quartz needle was placed on the sheet, a load of 49 g was applied, and the temperature was 5°C/
The temperature increases in minutes, and the temperature at which the needle penetrates by 0.635W is T
In addition, the glass transition temperature (Tg) of the cyclic olefin random copolymer is usually 50 to 230°C,
The temperature is preferably in the range of 70 to 210°C.

Further, the crystallinity of this cyclic olefin random copolymer [A] measured by XllA diffraction method is 0 to 10.
%, preferably 0-7%, particularly preferably 0-5%
is within the range of

In the present invention, iL also has a softening temperature (TMA) as described above.
is 70°C or higher. A copolymer of ethylene and a cyclic olefin represented by the above formula [1] or [I°] in decalin at 135°C. The measured intrinsic viscosity [V] is 0.05-5a/H
The substrate is preferably formed from a cyclic olefin random copolymer composition containing a cyclic olefin random copolymer [B] having a softening temperature (TMA) of less than 70°C.

In the cyclic olefin random copolymer [B] having a softening point (TMA) of less than 70°C, the repeating unit (a) derived from ethylene is 60 to 98 mol%, preferably 60 to 98 mol%. The repeating unit (b) derived from the cyclic olefin is present in the range of 2 to 4%.
The repeating unit (a) derived from ethylene and the repeating unit (b) derived from the cyclic olefin are present in an amount of 0 mol%, preferably 5 to 40 mol%, and are arranged substantially linearly at random. ing. The ethylene composition and cyclic olefin composition of this cyclic olefin random copolymer [B
] is substantially linear and does not have a gel-like crosslinked structure, which can be confirmed by the complete dissolution of the copolymer in decalin at 135°C.

The intrinsic viscosity [η] of such a cyclic olefin random copolymer [B] measured in decalin at 135°C is:
0.05-5au/g, preferably 0.08-3a
/g range.

In addition, the softness (1 degree (T
MA) IL 70'C Mitaki Preferably 110-6
The temperature is preferably in the range of 0°C, more preferably 10 to 55°C. Furthermore, it is desirable that the glass transition temperature (Tg) of the cyclic olefin random copolymer [B] is usually in the range of -30 to 60°C, preferably in the range of -20 to 50°C.

Further, the crystallinity of this cyclic olefin random copolymer [B] measured by X-ray diffraction method is 0 to 10%,
The range is preferably from 0 to 7%, particularly preferably from 0 to 5%.

In the present invention, when using the cyclic olefin random copolymer [A] and [B] as the substrate, the weight ratio of the cyclic olefin random copolymer [A]/the cyclic olefin random copolymer [B] is as follows: is 10010.1 ~
100/10, preferably 10010.3 to 100/7
, particularly preferably in the range of 10010.5 to 10015. [B] Acid component within this range [A
]By combining the acid component, while maintaining the excellent transparency and surface smoothness of the substrate itself, the adhesion with the reflective film used in the present invention under severe conditions is improved compared to [A] when only the acid component is used. It has the effect of further improving [A] and [B
] If the above-mentioned cyclic olefin random copolymer composition made of a blend of have.

The above cyclic olefin copolymers [A] and [B] constituting the substrate in the present invention are disclosed in Japanese Patent Application Laid-Open No. 60-16870.
8 revolution JP-A-61-120816 revolution JP-A-6
1-115912 revolves JP-A-61-115916 revolves JP-A-62-252406 revolves JP-A-62-
It can be manufactured by appropriately selecting conditions according to the method proposed by the applicant in JP-A No. 252407, JP-A-61-271308, and JP-A-61-272216.

In such a cyclic olefin random copolymer, the structural unit (b) derived from the cyclic olefin represented by the above formula [I] or [l°] is represented by the following formula [nl or [n']. Some of the structural units (b) that are considered to form the repeating units of the structure may be bonded together by ring-opening polymerization, and hydrogenation may be performed if necessary.

[nl (In the formula [nl, m, n and R1-R18 are the formula [I
] is the same as the definition in . ) (In formula [n'], p, q, r and R+ -R+ % are the same as defined in formula [I'] above.) As the substrate of the magneto-optical recording medium according to the present invention, as described above, ,
In addition to the above-mentioned random copolymers of ethylene and cyclic olefins, cyclic olefin ring-opening polymerization machines obtained by ring-opening the same or different cyclic olefin monomers, ring-opening copolymers or hydrogenated products thereof. It can also be used. To explain such cyclic olefin ring-opening polymers, ring-opening copolymers, and hydrogenated products thereof, using the cyclic olefin represented by the formula [l] as an example, they react and open as described below. It is thought that it constitutes a ring copolymer and a hydrogenated product thereof.

↓Ring-opening↓Hydrogenation Examples of such polymers include ring-opening combinations of tetracyclododecene and norbornene and their derivatives, and hydrogenated products thereof.

In addition, in the present invention, a part of the above-mentioned ring-opening polymer, ring-opening polymer, hydrogenated product, and cyclic olefin random copolymer is modified with an unsaturated carboxylic acid such as maleic anhydride. You can. Such a modified product If can be produced by reacting a cyclic olefin resin as described above with an unsaturated carboxylic acid, an anhydride thereof, and a derivative such as an alkyl ester of an unsaturated carboxylic acid. In this case, the content of structural units derived from the modifier in the modified cyclic olefin resin is usually 50 to 10 mol%. Such a modified cyclic olefin resin can be produced by blending a modifier with a cyclic olefin resin and graft polymerizing it to a desired modification rate, or by preparing a modified product with a high modification rate in advance. It can also be produced by subsequently mixing this modified product with an unmodified cyclic olefin resin.

In the present invention, these hydrogenated products, cyclic olefin random copolymers, and modified products thereof can be used alone or in combination.

Furthermore, in the present invention, when producing the above-mentioned cyclic olefin random copolymer, the formula [I] or [1'] is expressed as long as the physical properties of the resulting polymer are not impaired. It is also possible to polymerize cyclic olefins other than the cyclic olefins mentioned above. Examples of such cyclic olefins include cyclobutene, cyclopentene, cyclohexene, 34-dimethylcyclohexene, 3-methylcyclohexene, 2-(2-methylbutyl)-1-cyclohexene, 2,
3.3a,7a-tetrahuman O-4,7-methano-I
Examples include H-indene, 3a, 5.6.7a-tetrahydro-4,7-methano-IH-indene, and the like. Such other cyclic olefins can be used alone or in combination, and are usually used in an amount of 0 to 50 mol%.

Further, the substrate of the magneto-optical recording medium according to the present invention has the above [A]
and [B] Acid component, etc. Add a rubber component to improve impact strength, heat resistance stability L, weather resistance stability L
Anti-static shelving Slip shelving Anti-blocking Qi L Anti-fog shear Sliding Dyes, pigments, natural sources, synthesis methods Wax, etc. can be blended, and the blending ratio is appropriate. Parable number! Specifically, the stabilizers that may be added as optional ingredients include tetrakis[methylene-3(3,5-di-7-butyl-4hydroxyphenyl)propionate comethane, β-(3,5-di-t-butyl) -4-hydroxyphenyl)propionic acid alkyl ester, 2,2°
- Phenolic antioxidant valve L such as oxamide bis[ethyl-3(3,5-di-t-butyl-4-hydroxyphenyl) cobropionate, fatty acid metal salts such as zinc stearate, calcium stearate, and calcium 12-hydroxystearate, glycerin Examples include fatty acid esters of polyhydric alcohols such as monostearate, chrycerin monolaurate, glycerin distearate, pentaerythritol monostearate, pentaerythritol distearate, and pentaerythritol tristearate. These may be blended alone or in combination, for example, tetrakis[methylene-3 (3°5-di-t-butyl-4
-Hydroxyphenyl)propionate comethane, zinc stearate and glycerin monostearate, etc. can be exemplified.

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

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

Such phenolic antioxidants (0 parts by weight based on 100 parts by weight of the above [A] acid component and [B] acid component total weight)
The fatty acid ester of the polyhydric alcohol is used in an amount of ~10 parts by weight, preferably 0 to 5 parts by weight, and more preferably 0 to 2 parts by weight. 0~10 weight increase, preferably 0~
It is used in an amount of 5 parts by weight.

The substrate of the magneto-optical recording medium according to the present invention may include silica, diatomaceous earth,
Alumina, titanium oxide, magnesium oxide, pumice powder, pumice balloon, aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, dolomite, calcium sulfate, potassium titanate, barium sulfate, calcium sulfite, talc, clay, mica, asbestos, glass Textile glass flakes, glass peas, calcium silicate,
Fillers such as montmorillonite, bentonite, graphite, aluminum powder, molybdenum sulfide, boron rim, silicon carbide fiber, polyethylene fiber paper, polypropylene rim, polyester woven rim, polyamide fiber, etc. may be blended.

In the present invention, when a cyclic olefin random copolymer or a cyclic olefin random copolymer composition as described above is used as a substrate, from this cyclic olefin random copolymer or a composition containing the copolymer, The substrate and the recording layer laminate have excellent adhesion, and therefore the recording film has excellent long-term stability and oxidation of the recording film is effectively prevented. Therefore, the optical recording medium iL, which has a recording film laminated on a substrate made of this cyclic olefin random copolymer, has excellent recording sensitivity and excellent durability and long-term stability. Furthermore, the optical recording medium according to the present invention does not suffer from cracks.

The thickness of such a substrate 1 is not particularly limited, but is preferably 0.5 to 5. Particularly preferred is 1 to 2 loaves.

1 win In the magneto-optical recording medium 10 according to the present invention, the magneto-optical recording film 3 is provided on the substrate 1, but the protective film 2 is lost between the substrate 1 and the magneto-optical recording film 3. There is. Further, a protective film 5 may be provided between the magneto-optical recording film 3 and a metal film 4, which will be described later.

Protective film 2 used in magneto-optical recording medium 10 according to the present invention
and 5 are S i N,, Z n S, Z
n S e.

It is formed from a film having a composition such as CdS, SiS AQN, etc. Among these, SiN is particularly preferable because of its film strength.

It is preferable that LO<x≦473 with a protective film represented by SiNx, and specifically, a silicon nitride film such as Si, N, (trisilicon tetranitride) or a protective film such that 0x<4/3. A mixed film of Si, N, and Si is particularly preferably used. For example, a protective film made of SiN, such as a target and a sheet, S tzNa
A film can be formed using a sputtering method using 11S12Na and S1'. The film can also be formed by sputtering using Si as a target in a nitrogen atmosphere.

The protective film 211 made of such SiN preferably has a refractive index of usually 1.8 or more, preferably 1.8 to 2.2, and protects the magneto-optical recording film 3, which will be described later, from oxidation etc. It functions as an enhancement film that improves the recording characteristics of the magneto-optical recording film, or both. In addition, the protection 11EG made of SiN (0x≦4/3) is particularly excellent in crack resistance.

In the present invention, the thickness of the protective film is 500 to 2000A,
The number of participants is preferably 800 to 1,500.

In the present invention, by setting the thickness of the 1k protective film within the above range, a magneto-optical recording medium having a good C/N ratio and a wide recording power margin can be obtained.

Money 1 In the magneto-optical recording medium 10 according to the present invention, an aluminum alloy film is provided as the metal film 4 on the magneto-optical recording film 3 or the protective film 5 as described above.

This aluminum alloy film 1 is composed of aluminum and at least one element other than aluminum.

1) Specific examples of such aluminum alloys include the following:

Al-Cr alloy (Cr content O11~10J11U%
), AQ-Cu alloy (Cu content 0.1-10 at%)
, AQ-Mn alloy (Mn content 0.1 to 10 at%),
AQ-Hf alloy (Hf content 0.1-10 at%), A
s-Nb alloy (Nb content 0.1-10 at%), AQ
-B alloy (B content 0.1 to 10 at%), AQ-T
i alloy (Ti content 0.1-10 at%), AQ-T
1-Nb alloy (Ti content 0.1-5 at%, Nb content 0.1-5 at%), AQ-Ti-Hf alloy (Ti content 0.1-5 at%,
Hf content 0.1-10yK%), AQ-Cr-Hf
Alloy (Cr content 0.1 to 5 at%, Hf content 0.1
~10 at%), AQ-Cr-Ti alloy (Cr content 0
．． 1 to 5 w, Ti%, Ti content 0.1 to 10 atom%]
, AQ-Cr-Zr alloy (Cr content 0.1-5 at%
, Zr content 0.1 to 10 at%), AI -T 1-
Nb alloy (Ti content 0.1 to 5 at%, Nb content 0
．． 1 to 5 atomic%), AQ-Ni alloy (Ni content 0.1 to 10 [child%]), A
Q-Mg alloy (Mg content 0.1-10%), AQ
-Mg-Ti alloy (Mg content 0.1-10ffl%
, Ti content 0.1-10%), AQ-Mg-Cr
Alloy (Mg content 0.1 to 10%), Cr content 0.1 to 10Jl [%], Al1-Mg-Hf alloy (
Mg content 0.1-1oW.

Hf content 0.1-10 atomic%), AU-S e
alloy (Se content 0.1 to 10 atomic%), AM-Zr alloy (Zr content 0.1 to 10 atomic%),
Alloy (Ta content 0.1-10jtC%), A31-
Ta-Hf alloy (Ta content 0.1-10 atoms 96.H
f content 0.1-10,000%), Al1-5g alloy (S
i content 0.1~10J] K%), AI-Ag alloy (
Ag content 0.1-10W, %), AQ-P d alloy (P d content 0.1-10%), AI-P
As an alloy (Pt content of 0.1 to 10ffl), the following are particularly preferable because they have a high reflectance and excellent corrosion resistance.

Aluminum alloy containing 0.1-10 atomic % hafnium - Aluminum alloy containing 0.1-10 atomic % titanium and 0.5-5 atomic % hafnium
The total content of titanium and hafnium is 1 to 5.5
Y! , 1,000% aluminum alloy, chromium 0.1-5
Aluminum alloy with a total content of chromium and titanium of 10 at% or less, containing 0.1 to 5 at% chromium and 0.1 to 9.5 at% titanium. atom%
and hafnium 0.1-9.5g, 1,000% Aluminum alloy with a total content of chromium, titanium, and hafnium of 10 at% or less, magnesium 0.1-10 at% and chromium 0.1-10
Contains atomic% Total content of magnesium and chromium is 1
Aluminum alloy with 5 at% or less, chromium 0.1~
Combining 5W % and 0.1 to 9.5 atomic % of hafnium Aluminum alloy with a total content of chromium and hafnium of 10 atomic % or less, 0.1 to 10 atomic % of magnesium and 0.1 to 9.5 atomic % of hafnium
10y! , 1,000% combined Aluminum alloy with a total content of magnesium and hafnium of 15% or less, containing 0.1 to 5 at% of chromium and 0.1 to 9.5 at% of zirconium Total of chromium and zirconium Content is 1
Aluminum alloy, tantalum 0.0% or less.
Aluminum alloy containing 1 to 10 mol% and 0.1 to 10 ml of hafnium, with a total content of tantalum and hafnium of 15 atomic % or less, titanium 0.5 to 5 atomic %, and niobium 0.5 atomic %. Aluminum alloy with a total content of titanium and niobium of 1 to 5.5 at%, 0.1 to 10% of magnesium and 0.1 to 10% of titanium.
The total content of magnesium and titanium is 1.
5y! Aluminum alloy, magnesium 0.1~1ON, 1,000% and titanium 0.1~10W.

Aluminum alloy in which the total content of magnesium and titanium is 15 atomic % or less, 0.1 to 10 atomic % of magnesium and 0.1 to 10 W of hafnium, and 0.1 to 1 ON of titanium , and the total content of magnesium, hafnium, and titanium is 15 atomic %.
Aluminum alloy, magnesium 0.1-1
0% and hafnium 0.1~10W, % and chromium 1
Aluminum alloy in which the combined content of magnesium, hafnium, and chromium is 15 at% or less, magnesium 0.1 to 10%, titanium 0.1 to 10%, and chromium 10i. Aluminum alloy with a total content of magnesium, titanium, and chromium of 15 atomic % or less;
~10% titanium and 0.1-10% titanium and 10% chromium
% or less, and the total content of magnesium, hafnium, titanium, and chromium is 15 atomic% or less, or an aluminum alloy film as described above. It is also possible to contain one or more types of gold R (elements) as shown below. One example of such a metal is titanium (Ti).
), chromium (Cr), silicon (Si), tantalum (Ta), copper (Cu), tungsten (W), zirconium (Zr), manganese (Mn), magnesium (Mg
), vanadium (V), etc. Such other metals are usually contained in an amount of 5 atomic % or less, preferably 2 atomic % or less. (However, among the metals (elements) exemplified above, the metals (elements) already contained in the aluminum alloy film are not added in the above amount. for example,
Due to the strength of the aluminum alloy that makes up the aluminum alloy film,
Among the above metals (elements), titanium (
Ti) is not further included in the aluminum alloy in such amounts. ) The thickness of such an aluminum alloy film is 100~50
It is desirable that the number of participants be about 000 people, preferably 500 to 3000 people, and more preferably about 700 to 2000 people.

This aluminum alloy film functions as a good thermal conductor layer, and the presence of this aluminum alloy film prevents the magneto-optical recording layer from becoming excessively hot due to the recording laser beam. It is thought that the linear velocity dependence of is reduced.

In addition, the aluminum alloy 1 [IL of the present invention] can provide a magneto-optical recording medium with excellent corrosion resistance and repeated recording-erasing characteristics, and has the characteristic that the linear velocity dependence of the recording medium is small even after long-term use. It also has an excellent protective effect on the recording layer.

Further, in the optical recording medium 10 according to the present invention, a nickel alloy film (not shown) such as a nickel-chromium alloy film may be provided on the metal film 4 as described above.

The thickness of such a nickel alloy film is 200 to 2,000 people, preferably 300 to 1,500 people, and more preferably 500 people.
~1000 people is desirable.

The magneto-optical recording medium according to the present invention having such a nickel alloy film has not only the above-mentioned excellent properties but also excellent mechanical properties such as small warpage.

Magneto-optical recording medium according to the present invention No. 10 Magneto-optical recording layer on substrate & protection trap Magneto-optical recording layer A metal film or the like is formed by a film-forming method such as vacuum evaporation, sputtering or electron beam evaporation. It can be manufactured by

Magneto-optical recording medium 6 according to the present invention It has excellent oxidation resistance, excellent recording sensitivity, and excellent repeatability of recording and erasing.

[Examples] The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

lju2 130m onto ethylene-tetracyclododecene copolymer substrate in ISO format 5ts as a protective film
A magnetic film having a composition of P t+s (Gd*4FeHcoa)@I was used as the first magnetic film with a thickness of 1100 μm, and a magnetic film with a composition of P t+s (Gd*4FeHcoa)@I was used as the second magnetic film with a thickness of 500 μm. t's (T btsF etac Os)
A magnetic film having a composition of am is formed to a thickness of 500 mm, and an aluminum alloy film having an atomic ratio of A9°, Ti, ) If is formed to a thickness of 1000 mm by magnetron sputtering. The Curie temperature (Tc) of this first magnetic film was 250°C and the coercive force was 0.5KOe.9 The Curie temperature (Tc) of the second magnetic film was 140°C. , coercive force is 10KOe
When the loop was measured from the substrate side, the coercive force of this disk was approximately 3.5 KOe.The recording and reproducing characteristics were also measured at a recording frequency of 3.7M and a duty ratio of 33.
3%, linear velocity 5, 7 m 7 seconds, recording laser power 7
．． Approximately 48 dB when measured under the conditions of 0 mW, reproduction laser power 1.0 section, and external bias magnetic field 2000 e.
Furthermore, when we measured the CNR after recording and erasing 10' times on this disk, we found that the CNH decreased by 1.5 times.
Furthermore, when the linear velocity dependence of the recording sensitivity of this disk was measured at a recording frequency of IMHz and a duty ratio of 50%, it was 5.5 mW at a linear velocity of 5.7 m and 7 seconds, and a linear velocity of 11. Let at .3m/sec, 7, 7
In Example 1, a metal film having an atomic ratio of Ni, Cr, etc. was further laminated to a thickness of 500 mm on the metal film made of an aluminum alloy.
When the recording and reproducing characteristics were measured in the same manner as in Example 1,
The CNR was 48 dB.The C/N ratio decreased by 1.5 dB after recording and erasing 106 times.Furthermore, the linear velocity dependence of the recording sensitivity of this disk was investigated in Example 1.
When measured in the same manner as above, the linear velocity was 5,7 m7
This disk was heated at 70°C and 85% relative humidity.
No mechanical warping occurred on the disc when it was left for 48 hours under the following conditions.
, with a film thickness of 1000, and G in atomic ratio as the first magnetic film.
A magnetic film having a composition of d2□Fe, Cos was
Tb23Fe in atomic ratio as the second magnetic film with a human film thickness,
A magnetic film with a composition of 2COs is made with a film thickness of 500.
A film of Si3N4 was formed as a protective film by magnetron sputtering to a thickness of 1000 mm, and then AQ*vTj in atomic ratio was formed.
A magneto-optical recording medium was fabricated by depositing a metal film having a composition of +Hf2 to a thickness of 1000 nm.The Curie temperature (Tc) of this first magnetic film was 270°C, and the coercive force was 0.5KOe. Furthermore, the Curie temperature (Tc) of the second magnetic film is 160°C, and the coercive force is 10
When the loop of this disk was measured from the substrate side, the coercive force was approximately 2.0 KOe.The recording and reproducing characteristics were also measured at recording frequencies of 3 and 7 Mk, a duty ratio of 33.3%, and a linear Speed: 5, 7 m, 7 seconds, recording laser power: 7.0 niJ, reproduction laser power: 1.0 niJ
When measured under the condition of an external bias magnetic field of 2000e, a C/N ratio of approximately 48 dB was obtained.The C/N ratio decreased by 1.5 dB after 106 recording and erasing operations. Example 1 shows the linear velocity dependence of the recording sensitivity of the disc.
When measured in the same manner as above, the linear velocity was 5,7 m7
In seconds, it was 5.0 mW, and at a linear velocity of 11.3 m/s it was 8.1 mW.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of the magneto-optical recording medium of the present invention. 1. Substrate 2. Protective film 3. Magneto-optical recording film 3a. First magnetic film b.. Second magnetic film 4.
・Metal film 0... Magneto-optical recording medium

Claims (5)

[Claims] (1) In a magneto-optical recording medium in which a protective film, a magneto-optical recording film, and a metal film are laminated in this order on a substrate, the protective film is made of SiN_x, and the magneto-optical recording film is made of (i) a 3d transition metal. and (iii) a first magnetic film comprising a rare earth element, having a Curie temperature (Tc) of 180° C. or higher and a coercive force Hc of less than 5 KOe;
It consists of a 3d transition metal and (iii) a rare earth element, has a Curie temperature (Tc) of less than 200°C, and has a coercive force of 5.
1. A magneto-optical recording medium comprising: a second magnetic film having a KOe or higher; and a metal film comprising an aluminum alloy. (2) In a magneto-optical recording medium in which a protective film, a magneto-optical recording film, and a metal film are laminated in this order on a substrate, the protective film is made of SiN_x, and the magneto-optical recording film is made of (i) a 3d transition metal. and (iii) a first magnetic film comprising a rare earth element, having a Curie temperature (Tc) of 180° C. or higher and a coercive force Hc of less than 5 KOe;
A second magnetic film made of a 3d transition metal and (iii) a rare earth element, having a Curie temperature (Tc) of less than 200° C., and a coercive force of 5 KOe or more are laminated, and the first magnetic film A magneto-optical recording medium characterized in that either one or both of the film and the second magnetic film contains (ii) Pt and/or Pd, and is made of a metal film or an aluminum alloy. (3) In a magneto-optical recording medium in which a protective film, a magneto-optical recording film, a protective film and a metal film are laminated in this order on a substrate, the protective film is made of SiN_x, and the magneto-optical recording film is (i) a first magnetic film comprising a 3d transition metal and (iii) a rare earth element, having a Curie temperature (Tc) of 180° C. or higher and a coercive force Hc of less than 5 KOe;
It consists of a 3d transition metal and (iii) a rare earth element, has a Curie temperature (Tc) of less than 200°C, and has a coercive force of 5.
1. A magneto-optical recording medium comprising: a second magnetic film having a KOe or higher; and a metal film comprising an aluminum alloy. (4) In a magneto-optical recording medium in which a protective film, a magneto-optical recording film, a protective film and a metal film are laminated in this order on a substrate, the protective film is made of SiN_x, and the magneto-optical recording film is (i) a first magnetic film comprising a 3d transition metal and (iii) a rare earth element, having a Curie temperature (Tc) of 180° C. or higher and a coercive force Hc of less than 5 KOe;
A second magnetic film made of a 3d transition metal and (iii) a rare earth element, having a Curie temperature (Tc) of less than 200° C., and a coercive force of 5 KOe or more are laminated, and the first magnetic film A magneto-optical recording medium, wherein either or both of the film and the second magnetic film contain (ii) Pt and/or Pd, and the metal film is made of an aluminum alloy. (5) The magneto-optical recording film according to any one of claims 1 to 4, further comprising a nickel alloy film provided on the metal film.