JPH04311008A - Magneto-optical recording medium - Google Patents
Magneto-optical recording mediumInfo
- Publication number
- JPH04311008A JPH04311008A JP7609591A JP7609591A JPH04311008A JP H04311008 A JPH04311008 A JP H04311008A JP 7609591 A JP7609591 A JP 7609591A JP 7609591 A JP7609591 A JP 7609591A JP H04311008 A JPH04311008 A JP H04311008A
- Authority
- JP
- Japan
- Prior art keywords
- magneto
- film
- optical recording
- recording
- magnetic anisotropy
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000000203 mixture Substances 0.000 claims abstract description 13
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 6
- 230000005415 magnetization Effects 0.000 claims description 4
- 229910052771 Terbium Inorganic materials 0.000 claims description 3
- 238000010586 diagram Methods 0.000 abstract description 6
- 229910045601 alloy Inorganic materials 0.000 abstract description 5
- 239000000956 alloy Substances 0.000 abstract description 5
- 239000000463 material Substances 0.000 abstract description 5
- 238000000137 annealing Methods 0.000 abstract description 4
- 150000002910 rare earth metals Chemical class 0.000 abstract description 2
- 230000006866 deterioration Effects 0.000 abstract 2
- 230000007704 transition Effects 0.000 abstract 1
- 230000007423 decrease Effects 0.000 description 18
- 230000000694 effects Effects 0.000 description 11
- 239000000654 additive Substances 0.000 description 7
- 230000000996 additive effect Effects 0.000 description 7
- 229910052723 transition metal Inorganic materials 0.000 description 7
- 238000002425 crystallisation Methods 0.000 description 3
- 230000008025 crystallization Effects 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 150000003624 transition metals Chemical class 0.000 description 3
- 229910052692 Dysprosium Inorganic materials 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- -1 rare earth transition metal Chemical class 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 230000005374 Kerr effect Effects 0.000 description 1
- 229910004205 SiNX Inorganic materials 0.000 description 1
- 229910000808 amorphous metal alloy Inorganic materials 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Landscapes
- Thin Magnetic Films (AREA)
Abstract
Description
【0001】0001
【産業上の利用分野】本発明は、レーザ光などのエネル
ギービームを用いて情報の記録,再生,消去を行う光磁
気記録にかかわる。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to magneto-optical recording in which information is recorded, reproduced and erased using an energy beam such as a laser beam.
【0002】0002
【従来の技術】光磁気記録材料として、膜面に垂直方向
に磁化容易軸を有する非晶質希土類遷移金属合金が、一
般に用いられている。この合金は、室温で大きな保磁力
を持ち、記録された情報を安定して保持すること、媒体
ノイズが少ないこと、などの点で、他の材料系に優って
いる。2. Description of the Related Art Amorphous rare earth transition metal alloys having an axis of easy magnetization perpendicular to the film surface are generally used as magneto-optical recording materials. This alloy has a large coercive force at room temperature, is superior to other material systems in terms of stable retention of recorded information, and low media noise.
【0003】0003
【発明が解決しようとする課題】光磁気記録において、
読み出し耐性の向上,パワーマージン向上,媒体環境温
度の変動に対する許容度の向上のためには、記録膜のキ
ュリー温度を上げて、高い温度で記録消去を行うことが
望ましい。特に、近年、半導体レーザの出力が大きくな
るのにともない、高い温度で記録を行うことが記録装置
面からは、可能となりつつある。しかるに、光磁気記録
膜として通常用いられる非晶質希土類−遷移金属合金は
、高温にさらされると熱構造緩和を起こし、多数回の繰
り返し記録消去後に再生信号が低下することが知られて
いる。この原因は、レーザ光による加熱により、非晶質
記録膜の構造緩和により垂直磁気異方性が減少し、記録
膜中で最も高温に達するトラック中心位置において、磁
化容易軸が膜面内方向に倒れるからであることが、わか
っている(ジャパン ジャーナル オブ アプラ
イドフィジクス Japan J.Appl.Phy
s.)vol.28,Suppl.28−3,pp61
)。本発明の目的は、上記の欠点をのぞき、レーザ光照
射により高温にさらされた後にも比較的構造緩和がゆる
やかで、垂直磁気異方性の低下が少ない光磁気記録媒体
を提供することにある。[Problem to be solved by the invention] In magneto-optical recording,
In order to improve read durability, power margin, and tolerance to fluctuations in medium environmental temperature, it is desirable to increase the Curie temperature of the recording film and perform recording and erasing at a high temperature. In particular, in recent years, as the output of semiconductor lasers has increased, it has become possible for recording devices to perform recording at high temperatures. However, it is known that the amorphous rare earth-transition metal alloy commonly used as a magneto-optical recording film undergoes thermal structural relaxation when exposed to high temperatures, resulting in a decrease in the reproduced signal after repeated recording and erasing many times. The reason for this is that the perpendicular magnetic anisotropy decreases due to structural relaxation of the amorphous recording film due to heating by laser light, and the axis of easy magnetization shifts in the in-plane direction at the track center position, which reaches the highest temperature in the recording film. It is known that this is because the person collapses (Japan Journal of Applied Physics Japan J.Appl.Phy
s. ) vol. 28, Suppl. 28-3, pp61
). An object of the present invention is to eliminate the above-mentioned drawbacks and provide a magneto-optical recording medium that exhibits relatively slow structural relaxation and less decrease in perpendicular magnetic anisotropy even after being exposed to high temperatures by laser beam irradiation. .
【0004】0004
【課題を解決するための手段】上記目的は、光磁気記録
媒体として、その組成が
{Ra(FebCo1−b)1−a}1−xAx但し、
RはTb,Dyの少なくとも1種を含む希土類元素、A
はB,C,Pのうち少なくとも1種を含む元素、0.1
5<a<0.35,b<0.8,0.2<x<0.4で
あらわせる磁性膜を使用することにより達成される。[Means for Solving the Problems] The above object is to provide a magneto-optical recording medium whose composition is {Ra(FebCo1-b)1-a}1-xAx, but
R is a rare earth element containing at least one of Tb and Dy; A
is an element containing at least one of B, C, and P, 0.1
This is achieved by using a magnetic film that satisfies the following relationships: 5<a<0.35, b<0.8, 0.2<x<0.4.
【0005】[0005]
【作用】加熱により、垂直磁気異方性が低下する機構と
しては、非晶質膜中で構造緩和が起こり、原子配置がよ
り安定な非晶質状態に移行しようとし、その際に、製膜
時に形成された垂直磁気異方性が失われるからと考えら
れる。[Effect] The mechanism by which perpendicular magnetic anisotropy decreases due to heating is that structural relaxation occurs in the amorphous film, and the atomic arrangement attempts to shift to a more stable amorphous state. This is thought to be because the perpendicular magnetic anisotropy that was formed at the time is lost.
【0006】この構造緩和は、添加元素により、抑制す
ることが考えられる。添加する元素としては、遷移金属
との間で、非晶質合金を作る、B,C,P,Si,Ge
などが有望である。これらの元素は、遷移金属元素と合
金化したときに、非晶質状態を安定にし、結晶化を妨げ
る効果があることが知られている。しかし、結晶化と、
非晶質状態の中でより安定な状態に緩和する現象は、必
ずしも1対1に対応しない。すなわち、結晶化を妨げる
ことに効果がある添加元素が、必ずしも、構造緩和を抑
制する効果があるとは、限らない。[0006] It is thought that this structural relaxation can be suppressed by adding elements. Elements to be added include B, C, P, Si, and Ge, which form an amorphous alloy with transition metals.
etc. are promising. These elements are known to have the effect of stabilizing the amorphous state and preventing crystallization when alloyed with transition metal elements. However, crystallization and
The phenomenon of relaxation to a more stable state within an amorphous state does not necessarily correspond one-to-one. That is, an additive element that is effective in inhibiting crystallization does not necessarily have an effect in suppressing structural relaxation.
【0007】種々の添加元素に関して、検討した結果、
B,C,P添加が、構造緩和抑制に効果があることが明
らかになった。これらの元素に共通することは、遷移金
属よりも原子半径が小さいことである。すなわち、Fe
,Coの原子半径が1.25Åであるのに対し、Bの原
子半径は0.98Å,Cは0.91Å,Pは1.10Å
である。そこで、これらの添加元素が非晶質構造中の隙
間を埋めて、原子の移動を起こりにくくしており、これ
が構造緩和抑制に寄与しているものと考えられる。[0007] As a result of studying various additive elements,
It has become clear that the addition of B, C, and P is effective in suppressing structural relaxation. What these elements have in common is that they have smaller atomic radii than transition metals. That is, Fe
, the atomic radius of Co is 1.25 Å, whereas the atomic radius of B is 0.98 Å, C is 0.91 Å, and P is 1.10 Å.
It is. Therefore, these additive elements fill the gaps in the amorphous structure and make it difficult for atoms to move, which is thought to contribute to suppressing structural relaxation.
【0008】添加元素としてのB,C,Pの3元素を互
いに比較すると、価格に関しては、C,P,Bの順に高
価になる。構造緩和の抑止効果は、大きいほうから、B
,C,Pの順である。磁気光学効果に関しては、B,C
,Pの順でしだいに、添加によるカー効果の低下の程度
が大きくなる。これらを総合すると、性能的には、B添
加が最も優れており、経済性に関しては、C添加が最も
好ましい。Comparing the three elements B, C, and P as additive elements, C, P, and B are more expensive in this order. The deterrent effect of structural relaxation is ranked in descending order of magnitude: B
, C, P in that order. Regarding the magneto-optic effect, B, C
, P, the degree of decrease in the Kerr effect due to addition increases gradually. Taking all these into account, addition of B is the most excellent in terms of performance, and addition of C is the most preferable in terms of economy.
【0009】つぎに、上記組成範囲について、説明する
。磁化を安定して、膜面に対して垂直方向に向かせるた
めには、希土類RはTb,Dyの少なくとも1種を含み
、かつRと遷移金属との比は、0.15<a<0.35
である必要が有ることが知られている(例えば特公平1
−23927号)。Next, the above composition range will be explained. In order to stably direct the magnetization in the direction perpendicular to the film surface, the rare earth R contains at least one of Tb and Dy, and the ratio of R to the transition metal is 0.15<a<0. .35
It is known that there is a need for
-23927).
【0010】B,C,P添加量に関しては、次のような
制約が有る。x>0.4 の場合には、室温でのカー回
転角が0.15° 以下となり、光磁気記録信号の再生
が困難となり、光磁気記録材料として適さない。x<0
.2 の場合には、添加元素による構造緩和抑制効果が
、不十分である。Fe対Co比はキュリー点を決定し、
bが大きいほどキュリー点は降下するが、本発明の場合
、B,C,P添加により既にキュリー点が降下している
ので、b≧0.8 の組成では、キュリー点が100℃
以下となってしまい、読みだし光の照射によって記録が
破壊される可能性が有り、このために、b<0.8 で
あることが必要である。[0010] Regarding the amounts of B, C, and P added, there are the following restrictions. If x>0.4, the Kerr rotation angle at room temperature will be 0.15° or less, making it difficult to reproduce magneto-optical recording signals and making it unsuitable as a magneto-optical recording material. x<0
.. In the case of 2, the effect of suppressing structural relaxation by the additive element is insufficient. The Fe to Co ratio determines the Curie point;
The larger b is, the lower the Curie point is, but in the case of the present invention, the Curie point has already been lowered by the addition of B, C, and P, so in a composition where b≧0.8, the Curie point is 100°C.
If b<0.8, there is a possibility that the recording will be destroyed by irradiation with the read light.
【0011】[0011]
【実施例】以下実施例によって、本発明を詳細に説明す
る。組成{Tb0.22(Fe0.5Co0.5)0.
78}1−xAx,(A=B,C,P)で表わされる一
連の膜を作り、焼鈍後の垂直磁気異方性の変化を調べた
。図1に、これらの膜において、250℃での焼鈍によ
り、垂直磁気異方性が、製膜初期値の50%に降下する
時間τを、B,C,P添加量xに対してプロットした。
B,C,Pの添加量x<0.2の場合は、τは、無添加
の場合の3倍程度にしか伸びない。しかし、0.2<x
の場合には、緩和抑制効果は、顕著になる。添加元素
間の比較では、Bが最も効果が大きく、ついでCであり
、P添加の効果は、Bの場合の約半分である。EXAMPLES The present invention will be explained in detail with reference to Examples below. Composition {Tb0.22(Fe0.5Co0.5)0.
A series of films represented by 78}1-xAx, (A=B, C, P) were prepared, and changes in perpendicular magnetic anisotropy after annealing were investigated. In Figure 1, the time τ for the perpendicular magnetic anisotropy to drop to 50% of the initial value of the film after annealing at 250°C is plotted against the amount x of B, C, and P added in these films. . When the amount of B, C, and P added is x<0.2, τ increases only about three times as much as when no additive is added. However, 0.2<x
In the case of , the relaxation suppressing effect becomes significant. In comparing the additive elements, B has the greatest effect, followed by C, and the effect of P addition is about half that of B.
【0012】次に、上記の膜の磁気光学効果を検討した
。図2に{Tb0.22(Fe0.5Co0.5)0.
78}1−xAx膜(A=B,C,P)の、室温におけ
るカー回転角θK の、組成依存性を示す。添加元素量
を増やすとカー回転角は単調に減少する。xが小さい間
は、減少率は小さいがxが0.3 を越えると急激に減
少し、xが0.4と0.5との間で、キュリー点が室温
以下になる。カー回転角の減少の程度は、B,C,Pの
順にしだいに大きくなる。光磁気記録に用いるためには
、カー回転角が0.15 度以上ないと再生が困難にな
るために、添加量xは0.4以下である必要がある。Next, the magneto-optical effect of the above film was investigated. In FIG. 2, {Tb0.22(Fe0.5Co0.5)0.
78} The composition dependence of the Kerr rotation angle θK at room temperature of the 1-xAx film (A=B, C, P) is shown. As the amount of added elements increases, the Kerr rotation angle decreases monotonically. While x is small, the rate of decrease is small, but when x exceeds 0.3, it decreases rapidly, and when x is between 0.4 and 0.5, the Curie point becomes below room temperature. The degree of decrease in the Kerr rotation angle gradually increases in the order of B, C, and P. In order to use it for magneto-optical recording, the amount x added needs to be 0.4 or less, since reproduction becomes difficult unless the Kerr rotation angle is 0.15 degrees or more.
【0013】次に、Fe対Coの比を変えた一連の膜を
作製し、そのキュリー温度の変化を調べた。図3に、{
(Tb0.5Dy0.5)0.22(FebCo1−b
)0.0.78}0.4A0.6膜(A=B,C,P)
の、キュリー温度の、組成依存性を示す。Feの比率が
大きくなるにつれて、キュリー温度は降下する。キュリ
ー温度が、100℃以下となると、レーザ光による読み
出し時に光磁気記録磁区が破壊されてしまい、記録媒体
として適さない。そこで、この図よりb<0.7である
ことが必要であることがわかる。[0013] Next, a series of films with different ratios of Fe to Co were prepared, and changes in their Curie temperatures were investigated. In Figure 3, {
(Tb0.5Dy0.5)0.22(FebCo1-b
)0.0.78}0.4A0.6 membrane (A=B,C,P)
shows the composition dependence of the Curie temperature. As the proportion of Fe increases, the Curie temperature decreases. If the Curie temperature is 100° C. or lower, the magneto-optical recording domain will be destroyed during reading by laser light, making it unsuitable as a recording medium. Therefore, it can be seen from this figure that b<0.7 is required.
【0014】以上の検討結果をもとに、B,C添加記録
膜を用いた光磁気ディスクを作成し、繰り返し記録消去
特性を測定した。記録媒体は、ガラス2P基板上に、S
iNx下部保護膜/記録膜/SiNx 上部保護膜を、
この順に積層して作成した。記録膜厚は、100nmと
した。記録消去は、媒体線速10m/sec で行い、
消去レーザパワーは膜面で8mWとした。この時、媒体
の最高到達温度は、約300℃と推定される。Based on the above study results, a magneto-optical disk using a recording film doped with B and C was prepared, and its repeated recording and erasing characteristics were measured. The recording medium is S on a glass 2P substrate.
iNx lower protective film/recording film/SiNx upper protective film,
It was created by laminating layers in this order. The recording film thickness was 100 nm. Record erasure is performed at a linear velocity of 10 m/sec.
The erasing laser power was 8 mW at the film surface. At this time, the maximum temperature reached by the medium is estimated to be about 300°C.
【0015】図4に、{Tb0.22(FebCo1−
b)0.78}1−xBxの組成の記録膜を用い、上記
の条件のもとで、繰り返し記録消去後の再生信号の低下
ΔCを示す。B添加によるキュリー点の低下を補正して
、記録感度を統一するために、x=0,0.1,0.2
,0.3に対して、それぞれ、b=0.5,0.45,
0.4,0.35とした。Bを添加しない場合には、1
05回で信号の低下が見えはじめ、107回書き替え後
には、信号低下は4dBとなった。B添加量xを増加す
ると信号低下は小さくなり、x=0.3では、107回
書き替え後も、再生信号の低下は全く見られなかった。
光磁気ディスク製品には106から107回の書き替え
が要求されることを考慮すると、xは0.2 以上でな
ければならない。FIG. 4 shows {Tb0.22(FebCo1−
b) Using a recording film with a composition of 0.78}1-xBx, the decrease ΔC in the reproduced signal after repeated recording and erasing is shown under the above conditions. In order to correct the decrease in Curie point due to the addition of B and unify the recording sensitivity, x = 0, 0.1, 0.2.
, 0.3, b=0.5, 0.45, respectively.
0.4, 0.35. If B is not added, 1
The signal began to deteriorate after 05 times, and after 107 rewrites, the signal decreased by 4 dB. As the B addition amount x increases, the signal drop becomes smaller, and when x=0.3, no drop in the reproduced signal was observed even after 107 rewrites. Considering that magneto-optical disk products are required to be rewritten 106 to 107 times, x must be 0.2 or more.
【0016】上記と同様の評価を、C添加系記録膜にお
いても行った。図4に、{Tb0.22(FebCo1
−b)0.78}1−xCxの組成の記録膜を用い、上
記の条件のもとで、繰り返し記録消去後の再生信号の低
下ΔCを示す。
C添加によるキュリー点の低下を補正して、記録感度を
統一するために、x=0,0.1,0.2,0.3 に
対して、それぞれ、b=0.5,0.44,0.38,
0.32とした。B添加の場合と同様に、C添加量xを
増加すると再生信号低下は小さくなり、x=0.3では
、107回書き替え後も、再生信号の低下は全く見られ
なかった。
C添加に関しても、106から107回の書き替え可能
回数を確保するためには、xが0.2 以上でなければ
ならない。Evaluations similar to those described above were also conducted for C-added recording films. In FIG. 4, {Tb0.22(FebCo1
-b) Using a recording film having a composition of 0.78}1-xCx and under the above conditions, the decrease ΔC in the reproduced signal after repeated recording and erasure is shown. In order to correct the decrease in the Curie point due to C addition and unify the recording sensitivity, b = 0.5, 0.44 for x = 0, 0.1, 0.2, 0.3, respectively. ,0.38,
It was set to 0.32. As in the case of B addition, as the C addition amount x is increased, the reproduction signal decrease becomes smaller, and when x=0.3, no decrease in the reproduction signal was observed even after 107 rewrites. Regarding the addition of C, x must be 0.2 or more in order to ensure a rewritable number of 106 to 107 times.
【0017】上記のように、B,Cを適正量添加した記
録膜を用いることにより、光磁気ディスクの書き替え可
能回数を106以上に増大することができた。As described above, by using a recording film containing appropriate amounts of B and C, it was possible to increase the rewritable number of times of the magneto-optical disk to 106 or more.
【0018】[0018]
【発明の効果】本発明によれば、希土類遷移金属合金非
晶質膜からなる光磁気記録材料に、B,C,Pのいずれ
かを添加することによって、熱構造緩和を抑制すること
が可能とる。これを利用して、記録消去時のレーザ光加
熱に伴う、垂直磁気異方性の低下を抑制した光磁気ディ
スクを作成し、その書き替え回数を106 以上に増大
することが可能となった。[Effects of the Invention] According to the present invention, thermal structural relaxation can be suppressed by adding B, C, or P to a magneto-optical recording material made of an amorphous film of a rare earth transition metal alloy. Take. Utilizing this, it has become possible to create a magneto-optical disk that suppresses the decline in perpendicular magnetic anisotropy due to laser beam heating during recording and erasing, and to increase the number of rewrites to 106 or more.
【図1】250℃焼鈍により、{Tb0.22(Fe0
.5Co0.5)0.78}1−xAx膜(A=B,C
,P)の、垂直磁気異方性が、初期値の50%になる時
間τの、組成依存性を示す図。[Figure 1] By annealing at 250°C, {Tb0.22(Fe0
.. 5Co0.5)0.78}1-xAx film (A=B,C
, P) is a diagram showing the composition dependence of the time τ at which the perpendicular magnetic anisotropy becomes 50% of the initial value.
【図2】{Tb0.22(Fe0.5Co0.5)0.
78}1−xAx膜(A=B,C,P)の、室温におけ
るカー回転角θKの、組成依存性を示す図。FIG. 2 {Tb0.22(Fe0.5Co0.5)0.
78} A diagram showing the composition dependence of the Kerr rotation angle θK of a 1-xAx film (A=B, C, P) at room temperature.
【図3】{(Tb0.5Dy0.5)0.22(Feb
Co1−b)0.78}0.4A0.6膜(A=B,C
,P)の、キュリー温度の、組成依存性を示す図。[Figure 3] {(Tb0.5Dy0.5)0.22(Feb
Co1-b)0.78}0.4A0.6 film (A=B,C
, P) is a diagram showing the composition dependence of the Curie temperature.
【図4】{Tb0.22(FebCo1−b)0.78
}1−xBx膜を用いた光磁気ディスクの繰り返し記録
消去後の再生信号低下ΔCを示す図。FIG. 4 {Tb0.22(FebCo1-b)0.78
} A diagram showing a reproduction signal drop ΔC after repeated recording and erasing of a magneto-optical disk using a 1-xBx film.
【図5】{Tb0.22(FebCo1−b)0.78
}1−xCx膜を用いた光磁気ディスクの繰り返し記録
消去後の再生信号低下ΔCを示す図。FIG. 5 {Tb0.22(FebCo1-b)0.78
} A diagram showing a reproduction signal decrease ΔC after repeated recording and erasing of a magneto-optical disk using a 1-xCx film.
Claims (1)
晶質磁性膜を有し、その組成が{Ra(FebCo1−
b)1−a}1−xAx,但し、RはTb,Dyの少な
くとも1種を含む希土類元素、AはB,C,Pのうち少
なくとも1種を含む元素、0.15<a<0.35,b
<0.8,0.2<x<0.4、であらわせることを特
徴とする光磁気記録媒体。Claim 1: An amorphous magnetic film having an axis of easy magnetization in a direction perpendicular to the film surface, the composition of which is {Ra(FebCo1-
b) 1-a}1-xAx, where R is a rare earth element containing at least one of Tb and Dy, A is an element containing at least one of B, C, and P, and 0.15<a<0. 35,b
A magneto-optical recording medium characterized by being expressed by <0.8, 0.2<x<0.4.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7609591A JPH04311008A (en) | 1991-04-09 | 1991-04-09 | Magneto-optical recording medium |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7609591A JPH04311008A (en) | 1991-04-09 | 1991-04-09 | Magneto-optical recording medium |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH04311008A true JPH04311008A (en) | 1992-11-02 |
Family
ID=13595295
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP7609591A Pending JPH04311008A (en) | 1991-04-09 | 1991-04-09 | Magneto-optical recording medium |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH04311008A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6324127B1 (en) | 1996-01-18 | 2001-11-27 | Samsung Electronics Co., Ltd. | Magneto-optical recording layer having double-layer structure and magneto-optical disk adopting the same |
-
1991
- 1991-04-09 JP JP7609591A patent/JPH04311008A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6324127B1 (en) | 1996-01-18 | 2001-11-27 | Samsung Electronics Co., Ltd. | Magneto-optical recording layer having double-layer structure and magneto-optical disk adopting the same |
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