JPH06150413A

JPH06150413A - Magneto-optical recording medium

Info

Publication number: JPH06150413A
Application number: JP29692192A
Authority: JP
Inventors: Koyata Takahashi; 小弥太高橋; Toshio Inao; 俊雄稲生; Akio Kondo; 昭夫近藤
Original assignee: Tosoh Corp
Current assignee: Tosoh Corp
Priority date: 1992-11-06
Filing date: 1992-11-06
Publication date: 1994-05-31
Anticipated expiration: 2016-10-15
Also published as: JP3218735B2

Abstract

PURPOSE:To provide excellent corrosion resistance by setting the Curie temps. of first, second and third magnetic films, respectively designated as Tc1, Tc2, Tc3, at Tc3 Tc1>Tc2>room temp. and forming the first and third magnetic films of perpendicularly magnetized films and the second magnetic film of an inter-surface magnetized film. CONSTITUTION:This recording medium has the first magnetic film 2, the second magnetic film 3 and the third magnetic film 4 on a transparent substrate 1 and the Curie temps. of the films 2, 3, 4 are respectively designated as Tc1, Tc2, Tc3. The film 2 is preferably the perpendicularly magnetized film having large coercive force at room temp. and the small coercive force at Tc2. The film 4 is preferably the perpendicularly magnetized film consisting of TbFeCo, etc., and having the sufficiently large coercive force at room temp. to Tc2. The film 3 is preferably the intra-surface film satisfying Tc3, Tc1>Tc2>room temp. and is preferably a thin film constituted at least one kind of elements among Fe, Co and Ni and at least one kind of elements among Al, Si, Ge, Ti, V, Cr, Mn, Zr, Nb and Mo. As a result, the films do not contain rare earth metals and, therefore, the excellent corrosion resistance is obtd. at the time of film formation. The handling is thus facilitated.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は書き換えが可能な光磁気
記録媒体のなかで、再生層の磁化状態を変化させながら
記録信号を読み取る光磁気記録媒体に係わる。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rewritable magneto-optical recording medium for reading a recording signal while changing the magnetization state of a reproducing layer.

【０００２】[0002]

【従来の技術】光磁気記録媒体は書き換え可能な光記録
媒体であり、相変化型光記録媒体などと比較して繰り返
し消去／書き込み耐久性や消去比率に優れ、可搬型大容
量の記録媒体として注目されている。2. Description of the Related Art A magneto-optical recording medium is a rewritable optical recording medium, and is excellent in repeated erasing / writing durability and erasing ratio as compared with a phase change type optical recording medium and is a portable large capacity recording medium. Attention has been paid.

【０００３】光磁気記録媒体は、レ−ザ−光照射による
局所加熱によって記録ビットを形成し、これをカ−効果
により読み出す記録再生方法が取られる。記録ビットの
間隔はレ−ザ−光照射パワ−、記録磁界の強度などの調
整でレ−ザ−スポット径よりもかなり小さくすることが
可能であるが、読みだしは再生時のレ−ザ波長、レンズ
の開口率などによって制約を受ける。The magneto-optical recording medium employs a recording / reproducing method in which a recording bit is formed by local heating by laser light irradiation, and the recording bit is read by the curling effect. The recording bit interval can be made considerably smaller than the laser spot diameter by adjusting the laser light irradiation power, the recording magnetic field strength, etc., but the reading is the laser wavelength during reproduction. , It is limited by the aperture ratio of the lens.

【０００４】このような再生時の制約から決まる記録密
度を越えて、読み出すための改善の試みが、例えば、特
開平３−９３０５８号公報に開示され、再生前に初期化
磁石で再生層の磁化の向きを揃えた後、記録保持層の記
録ビットを再生層に転写しながら再生することにより再
生分解能を向上する技術が記述されている。An attempt to improve the reading beyond the recording density determined by such a restriction on reproduction is disclosed in, for example, Japanese Patent Laid-Open No. 3-93058, and the magnetization of the reproducing layer is initialized by an initializing magnet before reproducing. A technique for improving reproduction resolution by reproducing the recording bits of the recording holding layer while transferring the recording bits to the reproducing layer after aligning the directions is described.

【０００５】この方式は、再生光照射による温度上昇を
利用し、ビ−ムスポット内の高温領域にのみ再生時に記
録保持層の記録ビットを再生層に転写しながら再生する
ことによりビ−ムスポット内の他の領域には記録磁区が
現れないようにしたもので、再生時の符号間干渉を減少
させ、光の回折限界以下の周期の信号を再生可能とする
ものである。This system utilizes the temperature rise due to the irradiation of the reproducing light and reproduces the recording bit of the recording holding layer while transferring it to the reproducing layer during reproduction only in the high temperature region of the beam spot. The recording magnetic domain does not appear in the other area inside, so that the inter-symbol interference at the time of reproduction is reduced and a signal having a period less than the diffraction limit of light can be reproduced.

【０００６】特開平３−９３０５８号公報に開示された
技術は、浮き出し型ＭＳＲ（Ｍａｇｎｅｔｉｃａｌｌｙ
ｉｎｄｕｃｅｄＳｕｐｅｒＲｅｓｏｌｕｔｉｏ
ｎ）あるいはＲＡＤ（ＲｅａｒＡｐｅｒｔｕｒｅＤ
ｅｔｅｃｔｉｏｎ）と呼ばれるが、さらに特開平４−２
５５９４６号公報やジャパニーズジャーナルオブア
プライドフィジクス（ＪａｐａｎｅｓｅＪｏｕｒｎ
ａｌｏｆＡｐｐｌｉｅｄＰｈｙｓｉｃｓ）Ｓｅ
ｒｉｅｓ６，Ｐｒｏｃ．Ｉｎｔ．Ｓｙｍｐ．ｏ
ｎＯｐｔｉｃａｌＭｅｍｏｒｙ，１９９１，ｐｐ．
２０３−２１０には、少なくとも再生層（第１磁性
層）、中間層（第２磁性層）、記録層（第３磁性層）の
３層の構造の再生方式が提案されている。この方式は、
ダブルマスクＲＡＤと呼ばれ、再生前に初期化磁石で再
生層の磁化の向きを揃えた後、中間層あるいは再生層と
中間層の間に設けられた再生補助層のキュリ−温度を越
える再生をすることにより、磁化が第３磁性層の方向を
むいた領域が、磁化が初期化磁界の方向を向いた領域
（マスク１）と磁化が読みだしバイアス磁界の方向を向
いた領域（マスク２）に挟まれ、マスク１とマスク２の
からの信号は時間変化のないＤＣ成分となることから、
磁化が第３磁性層の方向をむいた領域からのみの信号が
検出されることにより、光の回折限界以下の周期の信号
を再生可能とするものである。磁化が第３磁性層の方向
をむいた領域が、ＲＡＤよりダブルマスクＲＡＤの方が
狭くなるので解像度はさらに上がっている。The technique disclosed in Japanese Patent Laid-Open No. 3-93058 is a raised MSR (Magnetically) type.
Induced Super Resolutio
n) or RAD (Rear Aperture D)
However, it is further referred to in Japanese Patent Laid-Open No. 4-2.
No. 55946 and Japanese Journal of Applied Physics (Japanese Journal)
al of Applied Physics) Se
ries 6, Proc. Int. Symp. o
n Optical Memory, 1991, pp.
No. 203-210 proposes a reproducing system having a three-layer structure including at least a reproducing layer (first magnetic layer), an intermediate layer (second magnetic layer), and a recording layer (third magnetic layer). This method
This is called a double mask RAD, and after the magnetization direction of the reproducing layer is aligned by an initializing magnet before reproducing, reproduction is performed that exceeds the Curie temperature of the intermediate layer or the reproducing auxiliary layer provided between the reproducing layers. By doing so, the region in which the magnetization is oriented in the direction of the third magnetic layer is a region in which the magnetization is oriented in the direction of the initializing magnetic field (mask 1) and the region in which the magnetization is oriented in the direction of the read-out bias magnetic field (mask 2). Since the signals from mask 1 and mask 2 are sandwiched between
By detecting a signal only from a region whose magnetization is oriented in the direction of the third magnetic layer, it is possible to reproduce a signal having a period equal to or shorter than the diffraction limit of light. The area where the magnetization is oriented toward the third magnetic layer is narrower in the double mask RAD than in the RAD, so the resolution is further improved.

【０００７】[0007]

【発明が解決しようとする課題】特開平３−９３０５８
号公報と特開平４−２５５９４６号公報の実施例では、
希土類遷移金属を主成分とした膜で全ての層が構成され
ている。４層構造が最も典型的な構造で再生層がＧｄＦ
ｅＣｏ、再生補助層がＴｂＦｅＣｏＡｌ、中間層がＧｄ
ＦｅＣｏ、記録層がＴｂＦｅＣｏである。[Patent Document 1] Japanese Patent Application Laid-Open No. 3-93058
In the examples of Japanese Patent Laid-Open No. 4-255946 and Japanese Patent Laid-Open No. 4-255946,
All layers are composed of a film containing a rare earth transition metal as a main component. The four-layer structure is the most typical structure and the reproduction layer is GdF
eCo, reproduction assisting layer is TbFeCoAl, intermediate layer is Gd
FeCo and the recording layer are TbFeCo.

【０００８】複雑な組成の磁性膜を積層していくとき、
各々の層に対して合金タ−ゲットを用いてスパッタする
と装置が簡単になり望ましいが、希土類遷移金属系の材
料では希土類遷移金属合金タ−ゲットの組成と膜の組成
が一致しなかったり、合金タ−ゲットの製法に特別な工
夫をする必要があったりと難しい。本発明が解決しよう
とする課題は、ＲＡＤあるいはダブルマスクＲＡＤに使
える積層膜のうち希土類遷移金属のものを減らすことで
ある。When laminating magnetic films having complicated compositions,
Sputtering with an alloy target for each layer is desirable because it simplifies the device, but rare earth transition metal alloy materials do not match the composition of the rare earth transition metal alloy target or the composition of the film, or It is difficult to do so because of the special manufacturing method of the target. The problem to be solved by the present invention is to reduce the number of rare earth transition metal layers in the laminated film that can be used for RAD or double mask RAD.

【０００９】[0009]

【課題を解決するための手段】本発明は、図１に示すよ
うに、透明基板上に互いに磁気的に結合した第１の磁性
膜と、第２の磁性膜と、第３の磁性膜とを有し、上記第
１、第２、第３の磁性膜のキュリ−温度をそれぞれＴｃ
１、Ｔｃ２、Ｔｃ３とするとき、Ｔｃ３、Ｔｃ１＞Ｔｃ
２＞室温であり、第１の磁性膜および第３の磁性膜は垂
直磁化膜で、第２の磁性膜は、Ｆｅ、Ｃｏ、Ｎｉの少な
くとも１元素と、Ａｌ、Ｓｉ、Ｇｅ、Ｔｉ、Ｖ、Ｃｒ、
Ｍｎ、Ｚｒ、Ｎｂ、Ｍｏ、Ｈｆ、Ｔａ、Ｗ、Ｃｕ、Ｐ
ｄ、Ａｇ、Ｐｔ、Ａｕのすくなくとも１元素で構成され
る面内磁化膜であり、第１磁性層の磁区を変形させなが
ら再生することが可能な光磁気記録媒体である。According to the present invention, as shown in FIG. 1, a first magnetic film, a second magnetic film, and a third magnetic film magnetically coupled to each other are formed on a transparent substrate. And the Curie temperatures of the first, second and third magnetic films are respectively set to Tc.
When 1, Tc2, Tc3, Tc3, Tc1> Tc
2> room temperature, the first magnetic film and the third magnetic film are perpendicular magnetization films, and the second magnetic film is at least one element of Fe, Co, and Ni, and Al, Si, Ge, Ti, V , Cr,
Mn, Zr, Nb, Mo, Hf, Ta, W, Cu, P
It is an in-plane magnetized film composed of at least one element of d, Ag, Pt, and Au, and is a magneto-optical recording medium capable of reproducing while deforming the magnetic domain of the first magnetic layer.

【００１０】第１の磁性膜は、室温で保磁力が大きく、
Ｔｃ２で保磁力が小さい垂直磁化膜であればよく、例え
ば補償組成付近のＧｄＦｅＣｏ、ＧｄＴｂＦｅＣｏ、Ｇ
ｄＤｙＦｅＣｏなどがあげられる。また、再生層と再生
補助層の２層構造、例えばＧｄＦｅＣｏ／ＴｂＦｅなど
の２層構造でもよい。２層構造では保磁力の変化を再生
補助層のキュリ−温度で制御することができるので、組
成のばらつきによる第１の磁性膜の保磁力のばらつきを
減らすことができる。The first magnetic film has a large coercive force at room temperature,
Any perpendicular magnetic film having a coercive force of Tc2 and a small coercive force may be used. For example, GdFeCo, GdTbFeCo, and G near the compensation composition may be used.
Examples thereof include dDyFeCo. Further, it may have a two-layer structure of a reproduction layer and a reproduction auxiliary layer, for example, a two-layer structure of GdFeCo / TbFe. In the two-layer structure, the change in coercive force can be controlled by the Curie temperature of the auxiliary reproduction layer, so that the variation in coercive force of the first magnetic film due to the variation in composition can be reduced.

【００１１】第３の磁性膜はＴｂＦｅＣｏ、ＤｙＦｅＣ
ｏ、ＮｄＤｙＦｅＣｏなど室温からＴｃ２まで保磁力が
十分大きい垂直磁化膜であれば何でも良い。The third magnetic film is TbFeCo, DyFeC.
Any perpendicular magnetic film having a sufficiently large coercive force from room temperature to Tc2, such as o and NdDyFeCo, may be used.

【００１２】第２の磁性膜は、第１の磁性膜に対する第
３の磁性膜の交換結合による有効磁界を制御して、初期
化を行うための外部磁界Ｈｉｎｉによる第１の磁性膜の
初期化状態を安定化させ、また、Ｈｒ（再生を行うため
の外部磁界）を印加した状態で、転写が始まる温度Ｔｐ
から第１磁性層が一様にＨｒの方向を向き始める温度Ｔ
ｒの範囲で、第３の磁性膜から第１の磁性膜へ磁化状態
の転写がおこるようにスイッチする働きも兼ねている。The second magnetic film controls the effective magnetic field by the exchange coupling of the third magnetic film with the first magnetic film to initialize the first magnetic film by the external magnetic field Hini for initialization. The temperature Tp at which the transfer is started while the state is stabilized and Hr (external magnetic field for reproducing) is applied.
From the temperature T at which the first magnetic layer begins to uniformly orient in the direction of Hr
In the range of r, it also has a function of switching so that the magnetization state is transferred from the third magnetic film to the first magnetic film.

【００１３】このような働きをする第２の磁性膜として
は、Ｔｃ３，Ｔｃ１＞Ｔｃ２＞室温を満たす面内磁性膜
で、Ｆｅ、Ｃｏ、Ｎｉの少なくとも１元素とＡｌ、Ｓ
ｉ、Ｇｅ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｚｒ、Ｎｂ、Ｍｏ、
Ｈｆ、Ｔａ、Ｗ、Ｃｕ、Ｐｄ、Ａｇ、Ｐｔ、Ａｕのすく
なくとも１元素で構成される薄膜が好ましい。Ａｌ、Ｓ
ｉ、Ｇｅ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｚｒ、Ｎｂ、Ｍｏ、
Ｈｆ、Ｔａ、Ｗ、Ｃｕ、Ｐｄ、Ａｇ、Ｐｔ、Ａｕはキュ
リ−温度、飽和磁化を制御するために含まれている。こ
のような組成では希土類金属を含まないので、スパッタ
リング法で成膜する時、タ−ゲットと薄膜の組成の対応
がよく、耐蝕性にも優れるので扱いやすいという特徴が
ある。The second magnetic film having such a function is an in-plane magnetic film satisfying Tc3, Tc1>Tc2> room temperature, at least one element of Fe, Co and Ni and Al and S.
i, Ge, Ti, V, Cr, Mn, Zr, Nb, Mo,
A thin film composed of at least one element of Hf, Ta, W, Cu, Pd, Ag, Pt, and Au is preferable. Al, S
i, Ge, Ti, V, Cr, Mn, Zr, Nb, Mo,
Hf, Ta, W, Cu, Pd, Ag, Pt and Au are contained for controlling the Curie temperature and the saturation magnetization. Since such a composition does not contain a rare earth metal, when the film is formed by the sputtering method, the composition of the target and the thin film has a good correspondence and the corrosion resistance is excellent, so that it is easy to handle.

【００１４】本発明の光磁気記録媒体の再生方法の一例
を図２に示す。光磁気記録媒体を回転させながら、ヘッ
ドから離れた位置において、初期化のための外部磁界Ｈ
ｉｎｉを印加し、第１の磁性膜の磁化を一定の方向へそ
ろえる。その後、Ｈｉｎｉと反対方向の、再生を行うた
めの外部磁界Ｈｒを印加しながら、Ｔｐ以上の温度範囲
に磁性層がなるようなパワ−でレ−ザ−ビ−ムを照射す
ることにより、第１の磁性膜に第３の磁性膜の記録状態
が転写され再生される。レ−ザ−スポットのなかで転写
された領域以外は、第１の磁性膜の磁化は一定方向へそ
ろっている（第１のマスク）ので、転写された領域のみ
の信号が検出され、符号間干渉を減少させ、光の回折限
界以下の周期の信号を再生できる。また、第１の磁性膜
の温度がＴｒ以上の領域にあるところでは、第１の磁性
膜の方向がＨｒの方向に向き（第２のマスク２）、第１
の磁性膜に第３の磁性膜の記録状態が転写された領域が
拡がりすぎて符号間干渉を起こすことを防ぐ。このよう
にして、第１磁性層の磁区を変形させながら、光磁気記
録媒体の情報を再生する。An example of the reproducing method of the magneto-optical recording medium of the present invention is shown in FIG. While rotating the magneto-optical recording medium, an external magnetic field H for initialization is set at a position away from the head.
By applying ini, the magnetization of the first magnetic film is aligned in a fixed direction. After that, while applying an external magnetic field Hr for reproducing in the direction opposite to Hini, the laser beam is irradiated with a power such that the magnetic layer is formed in a temperature range of Tp or higher. The recording state of the third magnetic film is transferred to and reproduced from the first magnetic film. Except for the areas transferred in the laser spot, the magnetization of the first magnetic film is aligned in a fixed direction (first mask), so signals in only the transferred areas are detected, It is possible to reduce interference and reproduce a signal having a period below the diffraction limit of light. Further, in a region where the temperature of the first magnetic film is equal to or higher than Tr, the direction of the first magnetic film faces the direction of Hr (second mask 2).
It is prevented that the area where the recording state of the third magnetic film is transferred to the magnetic film of FIG. In this way, the information on the magneto-optical recording medium is reproduced while deforming the magnetic domain of the first magnetic layer.

【００１５】なお、初期化を行うための外部磁界Ｈｉｎ
ｉ（室温）は、第１の磁性膜の保磁力をＨｃ１、上記第
３の磁性膜の保磁力をＨｃ３、上記第１の磁性膜に対し
て上記第２の磁性膜を介して上記第３の磁性膜からの交
換結合による有効磁界をＨｗ１、上記第３の磁性膜に対
して上記第２の磁性膜を介して上記第１の磁性膜からの
交換結合による有効磁界をＨｗ３とすると、Ｈｃ１＋Ｈｗ１＜Ｈｉｎｉ＜Ｈｃ３−Ｈｗ３なる関係を有する。An external magnetic field Hin for initialization is used.
i (room temperature) is the coercive force of the first magnetic film Hc1, the coercive force of the third magnetic film Hc3, and the coercive force of the third magnetic film to the third magnetic film via the second magnetic film. When the effective magnetic field due to the exchange coupling from the magnetic film is Hw1, and the effective magnetic field due to the exchange coupling from the first magnetic film through the second magnetic film to the third magnetic film is Hw3, then Hc1 + Hw1 <Hini <Hc3-Hw3.

【００１６】また、再生を行うための外部磁界ＨｒはＴ
ｐ〜Ｔｒの温度範囲で、Ｈｃ１−Ｈｗ１＜Ｈｒ＜Ｈｃ１＋Ｈｗ１なる関係を有し、更にＨｃ３は、Ｈｒよりも十分大き
い。The external magnetic field Hr for reproducing is T
In the temperature range from p to Tr, there is a relationship of Hc1-Hw1 <Hr <Hc1 + Hw1, and Hc3 is sufficiently larger than Hr.

【００１７】本発明の光磁気記録媒体の構造は、上述の
透明基板上に互いに磁気的に結合した第１の磁性膜と、
第２の磁性膜と、第３の磁性膜で構成されれば特に限定
されず、透明基板と磁性膜の間に誘電体膜をはさんだ
り、磁性膜の上に保護膜や反射膜を積層していても良
い。透明基板は、使用するレ−ザ−の波長領域において
十分透明であり、機械特性などの媒体基板としての特性
が満たされれば、ガラス、ポリカ−ボネ−ト、アモルフ
ァスポリオレフィンなど特に限定されない。The structure of the magneto-optical recording medium of the present invention comprises: a first magnetic film magnetically coupled to each other on the above-mentioned transparent substrate;
There is no particular limitation as long as it is composed of the second magnetic film and the third magnetic film, and a dielectric film is sandwiched between the transparent substrate and the magnetic film, or a protective film or a reflective film is laminated on the magnetic film. You can do it. The transparent substrate is not particularly limited to glass, polycarbonate, amorphous polyolefin, etc., as long as it is sufficiently transparent in the wavelength range of the laser used and the properties such as mechanical properties as a medium substrate are satisfied.

【００１８】本発明の光磁気記録媒体の磁性膜の膜厚は
第１の磁性膜はレ−ザ−光の大部分が第１の磁性膜で吸
収される膜厚で、１５０オングストローム以上８００オ
ングストローム以下が好ましく、第２の磁性膜はＴｃ２
以上で第１の磁性膜と第３の磁性膜の交換結合力を断ち
切れる膜厚で、２０オングストローム以上３００オング
ストローム以下が好ましく、第３の磁性膜は、記録が保
持されるのに十分な膜厚で、２００オングストローム以
上１０００オングストローム以下が好ましい。The film thickness of the magnetic film of the magneto-optical recording medium of the present invention is such that most of the laser light is absorbed by the first magnetic film in the first magnetic film, which is 150 angstroms or more and 800 angstroms or more. The following is preferable, and the second magnetic film is Tc2
As described above, the film thickness at which the exchange coupling force between the first magnetic film and the third magnetic film is cut off is preferably 20 angstroms or more and 300 angstroms or less, and the third magnetic film is a film sufficient for holding recording. The thickness is preferably 200 angstroms or more and 1000 angstroms or less.

【００１９】[0019]

【実施例】【Example】

実施例１図３に示すような光磁気媒体を作成した。ポリカ−ボネ
−ト基板１上に、窒化ケイ素からなる誘電体層２（膜
厚：８００オングストローム）、ＧｄＤｙＦｅＣｏから
なる第１の磁性膜３（膜厚：３００オングストローム、
Ｈｃ１：２ｋＯｅ（室温）、Ｈｃ１：０．２ｋＯｅ（１
５０℃）、Ｔｃ１：３３０℃）、（Ｆｅ₉₂Ｃｏ₈）₅₇Ｓ
ｉ₄₃からなる第２の磁性膜４（膜厚：８０オングストロ
ーム、Ｔｃ２：１５０℃）、ＴｂＦｅＣｏからなる第３
の磁性膜５（膜厚：５００オングストローム、Ｈｃ３：
＞１２ｋＯｅ、Ｔｃ３：２６０℃）、さらに保護層とし
て窒化ケイ素層６（膜厚：８００オングストローム）を
形成した。Example 1 A magneto-optical medium as shown in FIG. 3 was prepared. On a polycarbonate substrate 1, a dielectric layer 2 made of silicon nitride (film thickness: 800 angstrom), a first magnetic film 3 made of GdDyFeCo (film thickness: 300 angstrom,
Hc1: 2 kOe (room temperature), Hc1: 0.2 kOe (1
50 ° C), Tc1: 330 ° C), (Fe ₉₂ Co ₈ ) ₅₇ S
The second magnetic film 4 made of i ₄₃ (film thickness: 80 Å, Tc 2: 150 ° C.), the third made of TbFeCo
Magnetic film 5 (film thickness: 500 Å, Hc3:
> 12 kOe, Tc3: 260 ° C.) and a silicon nitride layer 6 (thickness: 800 Å) was formed as a protective layer.

【００２０】次に、この光磁気媒体を記録再生装置にセ
ットして、３ｋＯｅの初期化磁界（Ｈｉｎｉ）発生部
を、線速度７．３ｍ／ｓｅｃで通過させながら７８０ｎ
ｍの波長のレ−ザ−ビ−ムを３３％のデュ−ティ−で９
ＭＨｚで変調させながら８ｍＷのレ−ザ−パワ−で記録
を行なった。記録時のバイアス磁界は３００Ｏｅで初期
化磁界（Ｈｉｎｉ）と反対方向にかけた。Next, this magneto-optical medium was set in a recording / reproducing apparatus, and 780 n was passed while passing an initializing magnetic field (Hini) generating portion of 3 kOe at a linear velocity of 7.3 m / sec.
Laser beam of m wavelength is 9% with 33% duty.
Recording was performed with a laser power of 8 mW while modulating at MHz. The bias magnetic field during recording was 300 Oe and was applied in the direction opposite to the initialization magnetic field (Hini).

【００２１】バイアス磁界（Ｈｒ）を３００Ｏｅとして
レ−ザ−パワ−をあげて２．０ｍＷで再生するとＣ／Ｎ
の値は４２ｄＢ、さらに３ｍＷで再生すると４６ｄＢと
なった。When the bias magnetic field (Hr) is set to 300 Oe and the laser power is raised to reproduce at 2.0 mW, C / N is obtained.
The value of was 42 dB, and when it was reproduced at 3 mW, it was 46 dB.

【００２２】また、第２の磁性膜４をＴｃが１５０℃付
近になるようにＮｉ₉₅Ｃｒ₅、Ｃｏ₁₂Ｐｔ₈₈、Ｆｅ₅₇Ａ
ｌ₄₃などと換えてもほとんど同様の効果がえられた。Further, the second magnetic film 4 is made of Ni ₉₅ Cr ₅ , Co ₁₂ Pt ₈₈ , and Fe ₅₇ A so that Tc is around 150 ° C.
Almost the same effect was obtained even if it was replaced with l ₄₃ or the like.

【００２３】比較例１実施例１において（Ｆｅ₉₂Ｃｏ₈）₅₇Ｓｉ₄₃からなる第
２の磁性膜４を除いた他は、すべて同様にして得られた
光磁気記録媒体を、２．０ｍＷで再生するとＣ／Ｎの値
は２３ｄＢであった。Comparative Example 1 A magneto-optical recording medium obtained in the same manner as in Example 1 except that the second magnetic film 4 made of (Fe ₉₂ Co ₈ ) ₅₇ Si ₄₃ was used, was 2.0 mW. When reproduced, the C / N value was 23 dB.

【００２４】比較例２実施例１において第２の磁性膜を（Ｆｅ₉₂Ｃｏ₈）₇₂Ｓ
ｉ₂₈（Ｔｃ２：５００℃）としたところ、２．０ｍＷで
再生するとＣ／Ｎの値は３３ｄＢ、３．０ｍＷで再生す
ると３５ｄＢとなり、良好なＣ／Ｎが得られなかった。
これは、第３の磁性膜から第１の磁性膜への転写が良好
に行われなかったためと考えられる。Comparative Example 2 In Example 1, the second magnetic film was made of (Fe ₉₂ Co ₈ ) ₇₂ S.
When i ₂₈ (Tc2: 500 ° C.) was used, the C / N value was 33 dB when reproduced at 2.0 mW and 35 dB when reproduced at 3.0 mW, and a good C / N was not obtained.
It is considered that this is because the transfer from the third magnetic film to the first magnetic film was not performed well.

【００２５】実施例２ポリカ−ボネ−ト基板上に窒化ケイ素からなる誘電体層
（膜厚：８００オングストローム）、ＧｄＦｅＣｏから
なる第１の磁性膜（膜厚：３００オングストローム、Ｈ
ｃ１：０．３ｋＯｅ（室温）、Ｈｃ１：０．１ｋＯｅ
（１５０℃）、Ｔｃ１：３３０℃）、ＴｂＦｅＣｏＳｉ
からなる再生補助層（膜厚：１００オングストローム、
Ｈｃｓ：４．０ｋＯｅ（室温）、Ｔｃｓ：１４０℃）、
（Ｆｅ₉₂Ｃｏ₈）₅₉Ｓｉ₄₁からなる第２の磁性膜４（膜
厚：８０オングストローム、Ｔｃ２：１９０℃）、Ｔｂ
ＦｅＣｏからなる第３の磁性膜５（膜厚：５００オング
ストローム、Ｈｃ３：＞１２ｋＯｅ、Ｔｃ３：２６０
℃）、さらに保護層として窒化ケイ素層６（膜厚：８０
０オングストローム）を形成した。Example 2 A dielectric layer made of silicon nitride (film thickness: 800 Å) and a first magnetic film made of GdFeCo (film thickness: 300 Å, H on a polycarbonate substrate).
c1: 0.3 kOe (room temperature), Hc1: 0.1 kOe
(150 ° C), Tc1: 330 ° C), TbFeCoSi
Regeneration assisting layer (film thickness: 100 angstrom,
Hcs: 4.0 kOe (room temperature), Tcs: 140 ° C.),
Second magnetic film 4 (film thickness: 80 Å, Tc2: 190 ° C.) made of (Fe ₉₂ Co ₈ ) ₅₉ Si ₄₁ , Tb
Third magnetic film 5 made of FeCo (film thickness: 500 Å, Hc3:> 12 kOe, Tc3: 260)
C.) and a silicon nitride layer 6 (film thickness: 80 as a protective layer.
0 angstrom).

【００２６】実施例１と同様の条件で記録を行い、バイ
アス磁界を３００Ｏｅとしてレ−ザ−パワ−をあげて
２．０ｍＷで再生すると、Ｃ／Ｎの値は４３ｄＢ、さら
に３ｍＷで再生すると４７ｄＢとなった。Recording was carried out under the same conditions as in Example 1, and when the bias magnetic field was 300 Oe and the laser power was raised to reproduce at 2.0 mW, the C / N value was 43 dB, and when reproduced at 3 mW, 47 dB. Became.

【００２７】[0027]

【発明の効果】本発明の光磁気記録媒体では、光磁気記
録媒体の再生分解能の向上をはかることができる。第２
磁性層に希土類を含まない材料が使用されるので、スパ
ッタリング法で成膜する時タ−ゲットと薄膜の組成の対
応が良く、耐蝕性にも優れる。According to the magneto-optical recording medium of the present invention, the reproduction resolution of the magneto-optical recording medium can be improved. Second
Since a material containing no rare earth is used for the magnetic layer, the composition of the target and the thin film is well matched when the film is formed by the sputtering method, and the corrosion resistance is also excellent.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明の光磁気記録媒体の構造の一例を示す
断面図である。FIG. 1 is a sectional view showing an example of a structure of a magneto-optical recording medium of the present invention.

【図２】本発明の光磁気記録媒体の再生方法を示す図
である。FIG. 2 is a diagram showing a reproducing method of the magneto-optical recording medium of the present invention.

【図３】本発明の光磁気記録媒体の構造の一例を示す
断面図である。FIG. 3 is a sectional view showing an example of the structure of a magneto-optical recording medium of the present invention.

Claims

【特許請求の範囲】[Claims]

【請求項１】透明基板上に互いに磁気的に結合した第
１の磁性膜と、第２の磁性膜と、第３の磁性膜とを有
し、上記第１、第２、第３の磁性膜のキュリ−温度をそ
れぞれＴｃ１、Ｔｃ２、Ｔｃ３とするとき、Ｔｃ３、Ｔ
ｃ１＞Ｔｃ２＞室温であり、第１の磁性膜および第３の
磁性膜は垂直磁化膜で、第２の磁性膜はＦｅ、Ｃｏ、Ｎ
ｉのすくなくとも１元素とＡｌ、Ｓｉ、Ｇｅ、Ｔｉ、
Ｖ、Ｃｒ、Ｍｎ、Ｚｒ、Ｎｂ、Ｍｏ、Ｈｆ、Ｔａ、Ｗ、
Ｃｕ、Ｐｄ、Ａｇ、Ｐｔ、Ａｕのすくなくとも１元素で
構成される面内磁化膜であり、第１磁性層の磁区を変形
させながら再生することが可能な光磁気記録媒体。1. A transparent substrate having a first magnetic film magnetically coupled to each other, a second magnetic film, and a third magnetic film, wherein the first, second, and third magnetic films are provided. When the Curie temperatures of the film are Tc1, Tc2, and Tc3, respectively, Tc3 and Tc
c1>Tc2> room temperature, the first magnetic film and the third magnetic film are perpendicular magnetization films, and the second magnetic film is Fe, Co, N.
At least one element of i and Al, Si, Ge, Ti,
V, Cr, Mn, Zr, Nb, Mo, Hf, Ta, W,
A magneto-optical recording medium which is an in-plane magnetized film composed of at least one element of Cu, Pd, Ag, Pt, and Au and which can be reproduced while deforming the magnetic domain of the first magnetic layer.