JPS61243977A - Photomagnetic recording medium - Google Patents
Photomagnetic recording mediumInfo
- Publication number
- JPS61243977A JPS61243977A JP8568985A JP8568985A JPS61243977A JP S61243977 A JPS61243977 A JP S61243977A JP 8568985 A JP8568985 A JP 8568985A JP 8568985 A JP8568985 A JP 8568985A JP S61243977 A JPS61243977 A JP S61243977A
- Authority
- JP
- Japan
- Prior art keywords
- film
- recording medium
- magneto
- optical recording
- alloy film
- 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.)
- Granted
Links
Abstract
Description
【発明の詳細な説明】
技術分野
本発明はＥ−ＤＲＡＷ型光ディスクに関し、特に希土類
金属と遷移金属を主成分とするアモルファス合金からな
りかつ膜面に垂直な方向に一軸磁気異方性を有する光記
録膜を担持した光磁気記録媒体に関する。Detailed Description of the Invention Technical Field The present invention relates to an E-DRAW type optical disk, in particular an optical disc made of an amorphous alloy mainly composed of rare earth metals and transition metals and having uniaxial magnetic anisotropy in the direction perpendicular to the film surface. The present invention relates to a magneto-optical recording medium carrying a recording film.
背景技術
従来から、一定の条件下で例えば高周波スパッタリング
等の方法で作成さ、れる希土類金属と遷移金属との合金
例えばＧｄ１ｂＦｅ（ガドリニウム−テルビウム−鉄）
、ＴｂＦｅＣｏ （テルビウム−鉄−コバルト）等の合
金薄膜は、アモルファス構造をとり、膜面に垂直な一軸
磁気異方性を有することが知られている。BACKGROUND ART Conventionally, alloys of rare earth metals and transition metals, such as Gd1bFe (gadolinium-terbium-iron), are produced under certain conditions by a method such as high-frequency sputtering.
It is known that alloy thin films such as TbFeCo (terbium-iron-cobalt) have an amorphous structure and have uniaxial magnetic anisotropy perpendicular to the film surface.
この性質を光磁気記録媒体の記録膜として利用すること
が出来る。すなわち、情報の記録読取りについては次の
ように行う。先ず、−軸磁気異方性を有するアモルファ
ス合金膜上にレーザ光を焦光してその焦光部分を永久磁
石又は電磁石を用いて外部磁場を印加しながらキューリ
一温度又は補償温度付近まで局部的に加熱せしめる。こ
の時の焦光部分における熱消磁又は磁化反転の熱磁気的
効果によって、一方向に一様に磁化された合金膜面内に
反転磁区を形成して情報を記録することが出来る。次に
、形成された反転磁区に偏光レーザ光を入射し、その反
射光におけるポーラ・カー効果による偏波面の回転から
反転磁区の有無を信号として検出できる。このようにし
て、上記記録媒体において反転磁区の有無を“１″、“
０”に対応させることによって記録した情報の読取りが
可能となる。This property can be utilized as a recording film of a magneto-optical recording medium. That is, recording and reading of information is performed as follows. First, a laser beam is focused on an amorphous alloy film having -axis magnetic anisotropy, and the focused portion is locally heated to around the Curie temperature or compensation temperature while applying an external magnetic field using a permanent magnet or electromagnet. Heat it up. At this time, due to the thermomagnetic effect of thermal demagnetization or magnetization reversal in the focused portion, information can be recorded by forming reversed magnetic domains in the plane of the alloy film that is uniformly magnetized in one direction. Next, a polarized laser beam is incident on the formed inverted magnetic domain, and the presence or absence of an inverted magnetic domain can be detected as a signal from the rotation of the plane of polarization due to the Polar Kerr effect in the reflected light. In this way, the presence or absence of inverted magnetic domains in the recording medium can be determined as "1" or "1".
By making it correspond to 0'', the recorded information can be read.
従来からの希土類金属と遷移金属とのアモルファス合金
例えばＧｄＴｂＦｅ、ＴｂＦｅＣｏ等は光磁気効果及び
磁気特性、特にキューリ一点、補償温度が室温から百数
十度の範囲にあってかつ数ＫＯｅの保磁力があり光磁気
記録材料として適しているため光磁気記録媒体の記録膜
材料として注目され実用化が検討されている。Conventional amorphous alloys of rare earth metals and transition metals, such as GdTbFe and TbFeCo, have excellent magneto-optical effects and magnetic properties, especially the Curie point, compensation temperature in the range from room temperature to 100-odd degrees, and coercive force of several KOe. Since it is suitable as a magneto-optical recording material, it is attracting attention as a recording film material for magneto-optical recording media, and its practical application is being considered.
しかしながら、これら希土類金属と遷移金属とのアモル
ファス合金薄膜は酸化し易いために長期信頼性に欠けて
いる。そのために該アモルファス合金膜においては、磁
気特性や光磁気特性に経時変化が生じ易く、特に高温で
かつ高湿度の環境中ではその劣化が大きいという欠点が
あり、該アモルファス合金膜は、光磁気記録膜として使
用する場合に安定性に問題があった。However, these amorphous alloy thin films of rare earth metals and transition metals are easily oxidized and therefore lack long-term reliability. Therefore, the amorphous alloy film has the disadvantage that its magnetic properties and magneto-optical properties tend to change over time, and the deterioration is large especially in high temperature and high humidity environments. There was a problem with stability when used as a membrane.
また、かかるアモルファス合金膜は膜面に垂直な方向に
一軸磁気異方性を有する垂直磁化膜であることが必要で
あるが、従来のアモルファス合金は、その磁化容易軸が
理想的な膜面に垂直な方向からかなり傾いて分布してお
り、レーザ光で信号を読取るのに充分なカー回転角を有
しているとは言えなかった。そこで従来から、より大き
なカー回転角を得るような磁化容易軸が膜面に垂直な方
向に出来るだけ向いた垂直磁化膜としてのアモルファス
合金膜が求められている。In addition, such an amorphous alloy film must be a perpendicularly magnetized film with uniaxial magnetic anisotropy in the direction perpendicular to the film surface, but in conventional amorphous alloys, the axis of easy magnetization must be aligned with the ideal film surface. The distribution was tilted considerably from the vertical direction, and it could not be said that the Kerr rotation angle was sufficient for reading signals with laser light. Therefore, there has been a demand for an amorphous alloy film as a perpendicularly magnetized film in which the axis of easy magnetization is as perpendicular to the film surface as possible so as to obtain a larger Kerr rotation angle.
更に、アモルファス合金膜のカー回転角を高めるために
、第１図の従来の光磁気記録媒体の概略断面図にて示す
如く、Ｚｎ５（硫化亜鉛）からなるカー効果エンハンス
ｒ！Ａ２を基板１とアモルファス合金膜３との間に設は
保護膜４を積層した光磁気記録媒体も開発されている。Furthermore, in order to increase the Kerr rotation angle of the amorphous alloy film, as shown in the schematic cross-sectional view of a conventional magneto-optical recording medium in FIG. 1, a Kerr effect enhancing r! A magneto-optical recording medium in which a protective film 4 is laminated between the substrate 1 and the amorphous alloy film 3 has also been developed.
しかしながら、この従来の光磁気記録媒体おいても充分
大きなカー回転角を得るには至っていない。However, even in this conventional magneto-optical recording medium, it has not been possible to obtain a sufficiently large Kerr rotation angle.
発明の概要
本発明の目的は、経時変化の小さい長期保存性に優れ、
更に大ぎなカー回転角を有した光磁気記録媒体を提供す
ることを目的としている。Summary of the Invention The purpose of the present invention is to provide an excellent long-term storage property with little change over time;
It is an object of the present invention to provide a magneto-optical recording medium having an even larger Kerr rotation angle.
本発明の光磁気記録媒体は、基板と、該基板に担持され
かつ膜面に垂直な方向に一軸磁気異方性を有するアモル
ファス合金膜とを有する光磁気記録媒体であって、該ア
モルファス合金膜はＡＩ（アルミニウム）を添加元素と
して含む希土類金属−遷移金属系合金膜であり、かつ基
板とアモルファス合金膜との間にＺｎＳからなる第１カ
ー効果エンハンス膜及びＧｅ（ゲルマニウム）からなる
第２カー効果エンハンス膜を設けたことを特徴とする。The magneto-optical recording medium of the present invention is a magneto-optical recording medium having a substrate and an amorphous alloy film supported on the substrate and having uniaxial magnetic anisotropy in a direction perpendicular to the film surface, the amorphous alloy film is a rare earth metal-transition metal alloy film containing AI (aluminum) as an additive element, and a first Kerr effect enhancement film made of ZnS and a second Kerr effect film made of Ge (germanium) are arranged between the substrate and the amorphous alloy film. It is characterized by the provision of an effect-enhancing film.
実 施 例 以下、本発明の実施例を添附図面に基づいて説明する。Example Embodiments of the present invention will be described below with reference to the accompanying drawings.
第２図は本発明の光磁気記録媒体の拡大部分断面概略図
である。案内溝付ぎ円板状ＰＭＭＡ基板１の主面上に、
膜厚８３０人のＺｎＳ （硫化亜鉛）からなる第１カー
効果エンハンス膜２ａ１膜厚５０人のＧｅ（ゲルマニウ
ム）からなる第２カー効果エンハンス膜２ｂ、光磁気記
録材料であるアモルファス合金膜３、ＳｉＯ２からなる
保護１１１４を真空蒸着あるいはスパッタリング等の製
膜方法により順に積層し光磁気記録媒体を作成する。尚
、アモルファス合金膜３を次式の合金組成となるように
形成する。FIG. 2 is an enlarged partial cross-sectional schematic diagram of the magneto-optical recording medium of the present invention. On the main surface of the disc-shaped PMMA substrate 1 with guide grooves,
A first Kerr effect enhancement film 2a made of ZnS (zinc sulfide) with a thickness of 830 nm, a second Kerr effect enhancement film 2b made of Ge (germanium) with a film thickness of 50 nm, an amorphous alloy film 3 which is a magneto-optical recording material, SiO2 A magneto-optical recording medium is created by sequentially laminating the protection 1114 consisting of the following by a film forming method such as vacuum evaporation or sputtering. Note that the amorphous alloy film 3 is formed to have an alloy composition of the following formula.
ＣＲＴ ’） ＡＩ
Ｘ １−Ｘ １−１ ％
上式では、希土類金属Ｒは、Ｇｄ（ガドリニウム）、Ｔ
ｂ（テルビウム）及びＤｙ（ジスプロシウム）から選ば
れる１種類以上の金属であり、遷移金属Ｔは、Ｆｅ（鉄
）及びＣｏ（コバルト）から選ばれる１種類以上の金属
である。Ｘは原子比率で０．１≦Ｘ≦０．４の範囲の値
となるようにする。この範囲で垂直磁化膜が真空蒸着又
はスパッタリングによって得られることが知られている
。CRT') AI X 1-X 1-1 % In the above formula, the rare earth metal R is Gd (gadolinium), T
The transition metal T is one or more metals selected from b (terbium) and Dy (dysprosium), and the transition metal T is one or more metals selected from Fe (iron) and Co (cobalt). X is set to have a value in the range of 0.1≦X≦0.4 in terms of atomic ratio. It is known that a perpendicularly magnetized film in this range can be obtained by vacuum evaporation or sputtering.
更に本実施例では、この希土類金属−遷移金属合金へ添
加元素としてＡＩ（アルミニウム）を添加する。アモル
ファス合金における希土類金属−遷移金属合金とアルミ
ニウムとの原子比率における組成式（ＲＴ） Ａ
Ｉ は、以下に述べる理１−ｙ ｙ
由でｙが０．００５≦ｙ≦０，４の範囲の値となるよう
にして、光磁気記録媒体のアモルファス合金膜を形成す
る。Furthermore, in this example, AI (aluminum) is added as an additive element to this rare earth metal-transition metal alloy. Compositional formula (RT) in atomic ratio of rare earth metal-transition metal alloy and aluminum in amorphous alloy A
The amorphous alloy film of the magneto-optical recording medium is formed so that I has a value in the range of 0.005≦y≦0.4 based on the following principle 1-y y .
光磁気記録膜としての添加元素Ａｌを含む非晶質の希土
類金属−遷移金属合金膜における添加元素Ａｌの効果を
調べてみる。実験結果によると、Ｑ、５ａｔ、％未満の
ＡＩ＜即ちｙ＜０．００５）の希土類金属−遷移金属合
金への添加では酸化による該記録膜の経時変化を小さく
する効果がないことが確認された。また、４０ａｔ、％
を超えるのＡＩ（即ちｙ＞０．４）の希土類金属−遷移
金属合金への添加になると光磁気記録膜の磁気的及び光
磁気特性における保磁力Ｈｃやカー回転角の急激な低下
が生じ、光磁気記録媒体として使用することが不可能と
なることも確認された。The effect of the additive element Al in an amorphous rare earth metal-transition metal alloy film containing the additive element Al as a magneto-optical recording film will be investigated. According to the experimental results, it has been confirmed that the addition of an AI of less than Q, 5 at% (i.e., y < 0.005) to a rare earth metal-transition metal alloy has no effect on reducing the aging change of the recording film due to oxidation. Ta. Also, 40at,%
When an AI of more than It was also confirmed that it became impossible to use it as a magneto-optical recording medium.
第３図は、本実施例の光磁気記録媒体と従来のものとに
ついて、４５℃９０％Ｒ，Ｈ，（湿度）の状態で波長８
３０ｎｍの半導体レーザ光によって測定した場合におけ
るカー回転角θにの経時変化を調べた結果を示すグラフ
である。第３図において、縦軸にカー回転角、横軸に経
過時間を示しており、曲線Ａは（Ｔｂ （Ｆｅ
Ｃｏ ）ｘ Ｏ，８０，２
ｌ−Ｘ）１−１”Ｖ合金においてｘ＝０．１８゜ｙ＝０
．０８としてアモルファス合金膜として用いた本実施例
の光磁気記録媒体の経時変化を示し、曲線Ｂはカーエン
ハンス膜を用いることなく基板の上にＴｂＦｅＣｏ合金
膜、そして保護膜をこの順に形成した従来の光磁気記録
媒体の経時変化を示している。グラフに示す如（本実施
例の光記録媒体は従来のものよりもθｋ（カー回転角）
の劣化が小さく酸化等による経時変化少ないことが分る
。Figure 3 shows the wavelength 8 of the magneto-optical recording medium of this embodiment and the conventional one at 45°C and 90% R, H (humidity).
It is a graph showing the results of examining changes over time in the Kerr rotation angle θ when measured using a 30 nm semiconductor laser beam. In Fig. 3, the vertical axis shows the Kerr rotation angle and the horizontal axis shows the elapsed time, and the curve A is (Tb (Fe
Co)x O,80,2 l-X)1-1" In V alloy
．． 08 shows the change over time of the magneto-optical recording medium of this example used as an amorphous alloy film, and curve B shows the change over time of the magneto-optical recording medium of this example used as an amorphous alloy film. It shows the change over time of the magneto-optical recording medium. As shown in the graph (the optical recording medium of this embodiment has a lower θk (Kerr rotation angle) than the conventional one)
It can be seen that there is little deterioration and little change over time due to oxidation, etc.
更に、本実施例の光磁気記録媒体と従来のものとを４５
℃９０％Ｒ，Ｈ，（湿度）の状態である時間保持した侵
、波長８３０ｎｍの半導体レーザ光を用いてそれぞれの
光磁気記録媒体のカー回転角θｋについて調べて見る。Furthermore, the magneto-optical recording medium of this example and the conventional one were
The Kerr rotation angle θk of each magneto-optical recording medium was examined using a semiconductor laser beam with a wavelength of 830 nm while maintaining the temperature at 90% R, H (humidity).
本実施例の光磁気記録媒体のカー回転角θには１．０５
°となり、従来の光記録媒体のカー回転角θには０．５
４°となることが分った。このことは、本実施例では第
２図に示す如く膜厚８３０人のＺｎＳからなる第１カー
効果エンハンス膜２ａと膜厚５０人のＧｅからなる第２
カー効果エンハンス膜２ｂを基板１とアモルファス合金
膜３との間に積層させているので、従来からのＺｎＳの
誘電体の見掛上Ｑカー回転角の増大効果にざらにＧｅに
よる増大効果が付与されることを示している。The Kerr rotation angle θ of the magneto-optical recording medium of this example is 1.05.
The Kerr rotation angle θ of the conventional optical recording medium is 0.5°.
It was found that the angle was 4°. This means that in this example, as shown in FIG.
Since the Kerr effect enhancing film 2b is laminated between the substrate 1 and the amorphous alloy film 3, the increasing effect of Ge is roughly added to the apparent Q Kerr rotation angle increasing effect of the conventional ZnS dielectric. This indicates that the
また、ＺｎＳからなる第１カー効果エンハンス膜の膜厚
は５０人〜１５００人の範囲で変化させ、かつまた、Ｇ
ｅ（ゲルマニウム）からなる第２カー効果エンハンス膜
の膜厚は１０人〜１００Ａの範囲で変化させるなど、こ
れら両者のカー効果エンハンス膜の膜厚を適当に選択す
ることによって、４５℃９０％Ｒ，Ｈ，の状態で波長８
３０ｎｍの半導体レーザ光を用いてカー回転角Ｏｋを測
定したところ、上記同様のカー回転角の増大効果が得ら
れることが確認できた。In addition, the thickness of the first Kerr effect enhancing film made of ZnS was varied in the range of 50 to 1500, and
By appropriately selecting the thickness of both Kerr effect enhancement films, such as changing the thickness of the second Kerr effect enhancement film made of e (germanium) in the range of 10A to 100A, it is possible to ,H, and the wavelength is 8.
When the Kerr rotation angle Ok was measured using a 30 nm semiconductor laser beam, it was confirmed that the same effect of increasing the Kerr rotation angle as described above was obtained.
１艶立１１
以上の如く本発明によれば、希土類金属−遷移金属合金
に添加元素としてＡｌを添加することにより、さらにま
たＺｎＳからなる第１カー効果エンハンス膜及びＧｅか
らなる第２カー効果エンハンス膜を記録膜と基板との間
に設けることにより１、経時変化の少ない長期保存性に
優れかつカー回転角の増大した光磁気記録媒体を得るこ
とができる。1. Polishing 11. As described above, according to the present invention, by adding Al as an additive element to the rare earth metal-transition metal alloy, the first Kerr effect enhancement film made of ZnS and the second Kerr effect enhancement film made of Ge are further formed. By providing the film between the recording film and the substrate, it is possible to obtain a magneto-optical recording medium which is 1. excellent in long-term storage with little change over time and has an increased Kerr rotation angle.
第１図は従来の光磁気配記録媒体の概略断面図であや、
第２図は本発明による光磁気記録媒体の概略断面図であ
り、第３図は従来の光記録媒体と本発明にの光記録媒体
との４５℃、湿度９０％の状態におけるカー回転角θに
の経時変化を示すグラフである。
主要部分の符号の説明
１・・・・・・ＰＭＭＡ基板
２．２ａ、２ｂ・・・・・・カー効果エンハンス膜３・
・・・・・アモルファス合金膜
４・・・・・・保護膜Figure 1 is a schematic cross-sectional view of a conventional magneto-optical recording medium.
FIG. 2 is a schematic cross-sectional view of a magneto-optical recording medium according to the present invention, and FIG. 3 is a Kerr rotation angle θ of a conventional optical recording medium and an optical recording medium according to the present invention at 45° C. and 90% humidity. It is a graph showing the change over time. Explanation of symbols of main parts 1...PMMA substrate 2.2a, 2b...Kerr effect enhancement film 3.
...Amorphous alloy film 4...Protective film
Claims (3)
な方向に一軸磁気異方性を有するアモルファス合金膜と
を有する光磁気記録媒体であつて、前記アモルファス合
金膜はＡｌを添加元素として含む希土類金属−遷移金属
合金膜であり、かつ前記基板と前記アモルファス合金膜
との間にＺｎＳからなる第１カー効果エンハンス膜及び
Ｇｅからなる第２カー効果エンハンス膜を設けたことを
特徴とする光磁気記録媒体。(1) A magneto-optical recording medium comprising a transparent substrate and an amorphous alloy film supported on the transparent substrate and having uniaxial magnetic anisotropy in a direction perpendicular to the film surface, wherein the amorphous alloy film contains Al as an added element. A rare earth metal-transition metal alloy film comprising: a first Kerr effect enhancement film made of ZnS and a second Kerr effect enhancement film made of Ge are provided between the substrate and the amorphous alloy film. magneto-optical recording medium.
用いて、 （Ｒ＿ｘＴ＿１＿−＿ｘ）＿１＿−＿ｙＡｌ＿ｙで示さ
れる組成を有する多元合金の膜であり、ＲはＧｄ、Ｔｂ
、Ｄｙから選ばれる１種類以上の希土類金属であり、Ｔ
はＦｅ、Ｃｏから選ばれる１種類以上の遷移金属であり
、かつｘ及びｙは０．１≦ｘ≦０．４及び０．００５≦
ｙ≦０．４の各々の範囲にある値であることを特徴とす
る特許請求の範囲第１項記載の光磁気記録媒体。(2) The amorphous alloy film is a multi-component alloy film having a composition represented by (R_xT_1_-_x)_1_-_yAl_y, where x and y are used as atomic ratios, and R is Gd, Tb
, one or more rare earth metals selected from Dy, T
is one or more transition metals selected from Fe and Co, and x and y are 0.1≦x≦0.4 and 0.005≦
2. The magneto-optical recording medium according to claim 1, wherein the value is in the range of y≦0.4.
膜厚は５０Å〜１５００Åでありかつ前記Ｇｅからなる
第２カー効果エンハンス膜の膜厚は１０Å〜１００Åで
あることを特徴とする特許請求の範囲第２項記載の光磁
気記録媒体。(3) The first Kerr effect enhancement film made of ZnS has a thickness of 50 Å to 1500 Å, and the second Kerr effect enhancement film made of Ge has a thickness of 10 Å to 100 Å. The magneto-optical recording medium according to scope 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8568985A JPS61243977A (en) | 1985-04-22 | 1985-04-22 | Photomagnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8568985A JPS61243977A (en) | 1985-04-22 | 1985-04-22 | Photomagnetic recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61243977A true JPS61243977A (en) | 1986-10-30 |
| JPH0445898B2 JPH0445898B2 (en) | 1992-07-28 |
Family
ID=13865808
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8568985A Granted JPS61243977A (en) | 1985-04-22 | 1985-04-22 | Photomagnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61243977A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02152041A (en) * | 1988-12-05 | 1990-06-12 | Hitachi Ltd | Production of optical disk |
| US5175715A (en) * | 1990-08-03 | 1992-12-29 | Goldstar Co., Ltd. | Magneto-optical recording medium anti-reflective layers made of amorphous thin films having a specific reflective index range |
-
1985
- 1985-04-22 JP JP8568985A patent/JPS61243977A/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02152041A (en) * | 1988-12-05 | 1990-06-12 | Hitachi Ltd | Production of optical disk |
| US5175715A (en) * | 1990-08-03 | 1992-12-29 | Goldstar Co., Ltd. | Magneto-optical recording medium anti-reflective layers made of amorphous thin films having a specific reflective index range |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0445898B2 (en) | 1992-07-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5747136A (en) | High-density magneto-optic disk and method of manufacturing the same | |
| JP2561646B2 (en) | Method for manufacturing magneto-optical recording medium | |
| JPS6227459B2 (en) | ||
| US5663935A (en) | Magneto-optical recording medium having two magnetic layers of exchange-coupled at ferromagnetic phase | |
| US5639563A (en) | Magneto-optical recording medium | |
| JPS61246946A (en) | Photomagnetic recording medium | |
| US5100741A (en) | Magneto-optic recording systems | |
| JPH0550400B2 (en) | ||
| JPS61243977A (en) | Photomagnetic recording medium | |
| JPS63179435A (en) | Thin film magnetic recording medium | |
| EP0391738A2 (en) | Magneto-optic memory medium | |
| US5529854A (en) | Magneto-optic recording systems | |
| JPH0343697B2 (en) | ||
| JPH047023B2 (en) | ||
| JPH0614416B2 (en) | Magneto-optical recording / reproducing method | |
| JPS60101702A (en) | Recording method of photomagnetic recording medium | |
| JPS61208650A (en) | Photomagnetic recording medium | |
| JPS62172547A (en) | Photomagnetic recording medium | |
| JP2705066B2 (en) | Photothermal magnetic recording media | |
| KR950004494Y1 (en) | Optical recording medium | |
| KR930002168B1 (en) | Magneto-optic memory medium | |
| JPH0259603B2 (en) | ||
| JPS63148447A (en) | Thermomagneto-optical recording medium | |
| JPH08315435A (en) | Magneto-optical recording medium | |
| JPS6068607A (en) | Magnetic thin film recording medium |