JPH04153934A - Magneto-optical recording and reproducing method and magneto-optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To realize a direct over-write with laser light intensity in a wide allowable range and with excellent reproduction signal quality to practical use by executing in order at least a reverse magnetic field process and an initialization process by the time when a reproducing action or a next recording action is started after the completion of the recording action. CONSTITUTION:For ensuring that the extinguishing of a magnetic domain 13 left un-extinguished due to the application of the reverse magnetic field can be compatible with the direct over-write, it is required to apply in order at least the reverse magnetic field and the initialization magnetic field to a recording area by the time just before executing the next recording or reproduction after the irradiation of recording laser light. Assuming that the sizes of two different inversed magnetic fields of a auxiliary layer 12 are H1 and H2, the reverse magnetic field HINV having a direction reversal to the initialization magnetic field in the range of 0<HINV<H1 and the initialization magnetic field larger than the H1 are applied in order after irradiating th laser light on a medium. Thus, in the magneto-optical recording system capable of over-write by means of a switched connection magnetic thin film, the direct over-write with the laser light intensity in the wide allowable range and with excellent reproduction signal quality can be realize to practical use.

Description

【発明の詳細な説明】 ［産業上の利用分野］ 本発明は光磁気記録に関するもので、特に直接重ね書き
が可能な光磁気記録再生方法ならびにそれに用いる光磁
気記録再生装置に関するもので、特に交換結合多層膜を
用いた光変調オーバライド方式の改良に関するものであ
る。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to magneto-optical recording, and in particular to a magneto-optical recording and reproducing method that allows direct overwriting and a magneto-optical recording and reproducing device used therein. This paper relates to improvements in optical modulation override methods using coupled multilayer films.

［従来の技術１ 近年、書換え可能な光記録方式の一つとして垂直磁化膜
を記録層に用いた光磁気記録方式の研究が盛んに行われ
、第１世代の記録再生装置と記録媒体が商品化されるに
至っている。しかしながらこの第１世代の記録再生装置
では情報の書換えを行うためには、既に書かれている情
報を消去する過程と、新たな情報を書き込む過程の２段
階を経る必要があるために、消去動作を必要としない直
接重ね書き（ダイレクトオーバライド）は不可能であり
、情報の実質的な転送速度は、固定磁気ディスク装置な
どと比較して劣ると考えられている。[Conventional technology 1] In recent years, research has been actively conducted on magneto-optical recording, which uses a perpendicularly magnetized film as a recording layer, as one of the rewritable optical recording methods, and first-generation recording/reproducing devices and recording media have become commercially available. It has come to be However, in order to rewrite information in this first generation recording/playback device, it is necessary to go through two steps: erasing the information that has already been written, and writing new information. Direct override is not possible, and the actual transfer speed of information is considered to be inferior to fixed magnetic disk devices.

そこでダイレクトオーバライドを実現するために技術確
立が盛んに行われているが、その中に特開昭６２−１７
５９４８等に開示されているような交換結合多層膜を記
録媒体として用いる、いわゆる光変調オーバライド方式
が提案されている。Therefore, many efforts are being made to establish technology to realize direct override, and one of them is JP-A-62-17
A so-called optical modulation override method has been proposed in which an exchange-coupled multilayer film as disclosed in No. 5948 and the like is used as a recording medium.

このダイレクトオーバライド方式では、記録層と呼ぶ第
１の磁性層と補助層と呼ぶ第２の磁性層を基板上に順次
積層したものが記録媒体として用いられる。適切な大き
さの初期化磁界を印加することによって記録層の磁化の
方向は既に記録されている２値情報に応じた状態にした
ままで、補助層の磁化の方向を一方向に揃えたのち、適
切な大きさの書き込み磁界を印加すると同時に、相対的
に低い媒体温度を与えるレーザ光を照射するが（以下り
記録という）、または相対的に高い媒体温度を与えるレ
ーザ光を照射するか（以下Ｈ記録という）によって記録
を行う。Ｌ記録では補助層の磁化の向きは変化せず、記
録層の磁化は、補助層の磁化に対して交換結合エネルギ
ーが低くなるようになる。Ｈ記録では高い媒体温度が実
現されるため書き込み磁界により補助層の磁化の向きが
反転し、次いで記録層の磁化は補助層の磁化に対して交
換結合エネルギーが低くなるような状態になる。In this direct override method, a recording medium in which a first magnetic layer called a recording layer and a second magnetic layer called an auxiliary layer are sequentially laminated on a substrate is used. By applying an initialization magnetic field of an appropriate magnitude, the direction of magnetization of the auxiliary layer is aligned in one direction while the direction of magnetization of the recording layer remains in a state corresponding to the already recorded binary information. At the same time, a writing magnetic field of an appropriate magnitude is applied, and at the same time a laser beam is applied that gives a relatively low medium temperature (hereinafter referred to as recording), or a laser beam that gives a relatively high medium temperature is applied ( Recording is performed using H recording (hereinafter referred to as H recording). In L recording, the direction of magnetization of the auxiliary layer does not change, and the exchange coupling energy of the magnetization of the recording layer becomes lower than that of the auxiliary layer. In H recording, since a high medium temperature is achieved, the direction of magnetization of the auxiliary layer is reversed by the write magnetic field, and then the magnetization of the recording layer becomes in a state where the exchange coupling energy is lower than that of the auxiliary layer.

再び初期化磁界を印加することにより記録後の状態は補
助層が一方向に揃えられ、記録層の磁化の向きは書き込
み後の向きと一致している状態へ移行する。By applying the initialization magnetic field again, the auxiliary layer is aligned in one direction after recording, and the direction of magnetization of the recording layer shifts to a state in which it matches the direction after writing.

［発明が解決しようとする課題］ ダイレクトオーバライドでは、新たな情報を確実に記録
するためには、前の情報の消し残りを無くさなくてなな
らない。従来技術のダイレクトオーバライド方式を深く
検討した結果、Ｌ記録における消し残りが問題になるこ
とが判った。第３図にこのような光磁気記録媒体を用い
たときのＬ記録を行った領域の各層の見かけの磁化の状
態を矢印で図示し、説明を行う。なお、この説明の磁性
層は、記録層３１は室温において遷移金属磁気モーメン
トリッチの希土類遷移金属合金フェリ磁性膜と、補助層
３２には室温とキュリー温度の間に補償温度のある希土
類金属磁気モーメントリッチの希土類遷移金属合金フェ
リ磁性膜の組合せである。[Problems to be Solved by the Invention] In direct override, in order to reliably record new information, it is necessary to eliminate any unerased information from the previous one. As a result of a deep study of the conventional direct override method, it was found that unerased data in L recording poses a problem. In FIG. 3, the apparent magnetization state of each layer in the area where L recording is performed when such a magneto-optical recording medium is used is illustrated by arrows, and will be explained. The magnetic layer in this explanation is that the recording layer 31 is a rare earth transition metal alloy ferrimagnetic film rich in transition metal magnetic moments at room temperature, and the auxiliary layer 32 is a rare earth metal magnetic moment film with a compensation temperature between room temperature and the Curie temperature. It is a combination of rich rare earth transition metal alloy ferrimagnetic film.

Ｌ記録において記録が完全に行われたならば、第３図（
ａ）に示す様に、記録層の磁化は補助層に対して界面磁
壁がない方向を向くが、実際には第３図（ｂ）または第
３図（ｃ）に示すように記録層に反転磁区領域３３がし
ばしば観測される。これが消し残りとしてふるまってい
ることが判明した。If the recording is completed completely in the L recording, Fig. 3 (
As shown in Figure 3 (a), the magnetization of the recording layer is oriented in a direction where there is no interfacial domain wall with respect to the auxiliary layer, but in reality it is reversed in the recording layer as shown in Figure 3 (b) or Figure 3 (c). Magnetic domain regions 33 are often observed. It turned out that this was acting as an eraser.

記録媒体の磁気特性のゆらぎやフォーカスサーボの残差
等により、ある一部分では補助層の磁化による転写が行
われず微小磁区を形成したり、あるいは初期化過程にお
いて補助層に未反転領域が残留することがこの消し残り
の原因である。従来の技術ではこの消し残りをなくすた
めに、Ｌ記録のレーザ光強度を大きくしたり、初期化磁
界を大きくすることが行われている。これらの方法によ
ればある程度の改善は認められるものの、前者ではＬ記
録に適切なレーザ光強度の許容範囲が狭くなるという欠
点がある。また、後者の方法では光磁気記録装置の設計
上、大きな初期化磁界を発生させることが困難なため、
実用的な方法ではない。Due to fluctuations in the magnetic properties of the recording medium, focus servo residuals, etc., transfer due to the magnetization of the auxiliary layer may not take place in a certain part, forming a minute magnetic domain, or an uninverted region may remain in the auxiliary layer during the initialization process. is the cause of this unerased image. In conventional techniques, in order to eliminate this unerased area, the intensity of the laser beam for L recording is increased or the initialization magnetic field is increased. Although these methods provide a certain degree of improvement, the former has the disadvantage that the permissible range of laser light intensity suitable for L recording becomes narrow. In addition, in the latter method, it is difficult to generate a large initializing magnetic field due to the design of the magneto-optical recording device.
It's not a practical method.

さらに、再生信号品質を向上させるために記録層に高い
キュリー温度の磁性膜を用いる要求があるが、これによ
りＬ記録に必要なレーザパワーが高くなってしまうとい
う問題点があった。Furthermore, there is a demand for the use of a magnetic film with a high Curie temperature in the recording layer in order to improve the reproduction signal quality, but this poses a problem in that the laser power required for L recording increases.

そこで本発明はこのような課題を解決するためになされ
たもので、その目的とするところは、広い許容範囲のレ
ーザ光強度で、かつ良好な再生信号品質のダイレクトオ
ーバライドを実現する光磁気記録再生方法ならびに光磁
気記録再生装置を提供することにある。The present invention has been made to solve these problems, and its purpose is to provide magneto-optical recording and reproducing that achieves direct override with a wide permissible range of laser light intensity and good reproduction signal quality. An object of the present invention is to provide a method and a magneto-optical recording/reproducing device.

［課題を解決するための手段］ 上記の目的は以下の本発明によって達成できる。[Means to solve the problem] The above objects can be achieved by the following invention.

すなわち本発明の光磁気記録再生方法は、室温において
互いに交換結合した、室温で相対的に大きな保磁力と低
いキュリー点を有する第１の磁性層と、室温で相対的に
小さな保磁力と高いキュリー点を有する第２の磁性層の
積層膜を光磁気記録層とし、前記第２の磁性層の磁化曲
線におけるマイナーループの二つの反転磁界の絶対値が
各々Ｈ。That is, the magneto-optical recording and reproducing method of the present invention comprises a first magnetic layer having a relatively large coercive force and a low Curie point at room temperature, which are exchange-coupled with each other at room temperature, and a first magnetic layer having a relatively small coercive force and a high Curie point at room temperature. A laminated film of a second magnetic layer having a dot is used as a magneto-optical recording layer, and the absolute values of the two reversal magnetic fields of the minor loop in the magnetization curve of the second magnetic layer are H.

Ｈ，（Ｈ，＞Ｈ２）であり、膜面に垂直方向にＨｌより
大きな初期化磁界を印加することにより、第２の磁性層
の磁化の向きのみを一方向にそろえた円盤状の光磁気記
録媒体を用い、 （ａ）該光磁気記録媒体の膜面に垂直な記録磁界を印加
すると同時にレーザ光を照射し第１の加熱状態を実現す
ることにより、第２の磁性層に磁化反転を起こさないで
、第１の磁性層の加熱領域のみを第２の磁性層に対して
安定な向きに磁化する第１の記録か、記録磁界を印加す
ると同時にレーザ光を照射し第２の加熱状態を実現する
ことにより、まず第２の磁性層の加熱領域が磁化反転し
、次いで第１の磁性層が第２の磁性層に対して安定な向
きに磁化する第２の記録かを記録情報に応じて行なう記
録動作 （ｂ）前記記録動作を行った領域にレーザ光を照射し、
第１の磁性層に形成されている磁化の方向を検出して情
報の再生を行う再生動作 からなる光磁気記録再生方法において、（ｃ）前記記録
動作を行った領域に前記初期化磁界を印加する初期化過
程 （ｄ）前記記録動作を行った領域に前記初期化磁界と逆
向きでＨｌより小さい静磁界を印加する逆磁界過程 を定義するとき、記録動作終了の後、前記再生動作、ま
たは次の記録動作に入る直前までに、少なくとも逆磁界
過程、初期化過程を順に行うことを特徴としている。こ
こで、逆磁界過程の前に初期化過程を加えるとことによ
り、より効果を増す場合がある。H, (H,>H2), and by applying an initialization magnetic field larger than Hl in the direction perpendicular to the film surface, a disk-shaped magneto-optical structure is created in which only the direction of magnetization of the second magnetic layer is aligned in one direction. Using a recording medium, (a) applying a recording magnetic field perpendicular to the film surface of the magneto-optical recording medium and simultaneously irradiating a laser beam to achieve a first heating state, thereby causing magnetization reversal in a second magnetic layer; Either a first recording state in which only the heated region of the first magnetic layer is magnetized in a stable direction with respect to the second magnetic layer without causing the magnetization to occur, or a second heating state in which a laser beam is irradiated at the same time as the recording magnetic field is applied. By realizing this, first the magnetization of the heated region of the second magnetic layer is reversed, and then the first magnetic layer is magnetized in a stable direction relative to the second magnetic layer. Recording operation performed accordingly (b) Irradiating the area where the recording operation was performed with a laser beam,
In a magneto-optical recording and reproducing method comprising a reproducing operation of detecting the direction of magnetization formed in a first magnetic layer and reproducing information, (c) applying the initializing magnetic field to the area where the recording operation has been performed; (d) When defining a reverse magnetic field process in which a static magnetic field smaller than Hl is applied in the opposite direction to the initialization magnetic field to the area where the recording operation has been performed, after the recording operation is completed, the reproducing operation, or It is characterized in that at least a reverse magnetic field process and an initialization process are performed in order immediately before starting the next recording operation. Here, the effect may be further enhanced by adding an initialization process before the reverse magnetic field process.

さらに本発明の光磁気記録再生方法は、光磁気記録媒体
を回転させる手段と、光ヘッドと、該光ヘッドと異なる
位置で前記初期化磁界を発生させる手段と、光磁気記録
媒体の磁性層上に記録情報に応じて前記第１ならびに第
２の加熱状態を実現するレーザ変調手段と、情報の記録
時に前記光磁気記録媒体に前記記録磁界を印加する手段
をそなえてなる従来の光変調オーバライド方式に用いら
れる光磁気記録再生装置に、前記静磁界の発生手段を付
加することにより具体的に実現することができる。Furthermore, the magneto-optical recording and reproducing method of the present invention includes a means for rotating a magneto-optical recording medium, an optical head, a means for generating the initializing magnetic field at a position different from the optical head, and a magnetic layer on a magnetic layer of the magneto-optical recording medium. A conventional optical modulation override system comprising: laser modulation means for realizing the first and second heating states according to recording information; and means for applying the recording magnetic field to the magneto-optical recording medium when recording information. This can be concretely realized by adding the above-mentioned static magnetic field generating means to a magneto-optical recording/reproducing device used for.

［作用］ 本発明の光磁気記録再生方法では、室温において相対的
に大きな保磁力と低いキュリー点を有する記録層と、室
温において相対的に小さな保磁力と高いキュリー点を持
つ補助層からなり、室温における磁気特性は、両層の間
の界面磁壁エネルギー密度をσい補助層の飽和磁化をＭ
、、補助層の膜厚をｈ２、記録層の保磁力をＨｃｌ、補
助層の保磁力をＨｃ２としたとき、特開昭６２−１７５
９４８や特開昭６３−１５３７５２に開示されているも
のと同様に、を満たす光磁気記録媒体を用いる。[Function] The magneto-optical recording and reproducing method of the present invention comprises a recording layer having a relatively large coercive force and a low Curie point at room temperature, and an auxiliary layer having a relatively small coercive force and a high Curie point at room temperature, The magnetic properties at room temperature are as follows: σ is the interfacial domain wall energy density between both layers, and M is the saturation magnetization of the auxiliary layer.
,, When the thickness of the auxiliary layer is h2, the coercive force of the recording layer is Hcl, and the coercive force of the auxiliary layer is Hc2, JP-A-62-175
A magneto-optical recording medium that satisfies the requirements is used, similar to those disclosed in No. 948 and Japanese Patent Application Laid-Open No. 63-153752.

発明の解決しようとする課題でも示したように、Ｌ記録
における消し残りは、第３図（ｂ）または第３図（ｃ）
のような状態になっている。As shown in the problem to be solved by the invention, the unerased area in the L recording is as shown in FIG. 3(b) or FIG. 3(c).
It is in a state like this.

まず第１図（ａ）に示すように記録層１１にできた第３
図（ｂ）のタイプの消し残り１３に、初期化磁界とは逆
向きの静磁界Ｈ１０，（以降ではこの磁界を逆磁界と称
する）を印加する場合について考察する。いま記録層の
円筒磁壁の磁壁エネルギー密度をσ８、記録層の飽和磁
化をＭ５１、記録層の膜厚をり、、消し残り磁区の半径
をＲとすると、０　＜　Ｈｌ−＜　Ｈ１＋□　・　・（
１）２Ｍ、ｈ。First, as shown in FIG. 1(a), a third
A case will be considered in which a static magnetic field H10, which is in the opposite direction to the initialization magnetic field (hereinafter, this magnetic field will be referred to as a reverse magnetic field), is applied to the eraser residue 13 of the type shown in FIG. 2B. Now, if the domain wall energy density of the cylindrical domain wall of the recording layer is σ8, the saturation magnetization of the recording layer is M51, the film thickness of the recording layer is R, and the radius of the unerasable magnetic domain is R, then 0 <Hl-< H1+□ ・ ・ (
1) 2M, h.

のときは、真円を仮定した円筒磁区に関する反磁界の項
を無視したバブル磁区理論による簡単な考察により、 を満たすとき消し残り磁区は消滅して、第１図（ｂ）の
ような正常な消去状態に落ち着くことがわかる。また、 ０＜Ｈ，、＋−＜Ｈ，、＜Ｈ，＋−−（３）２Ｍ、ｈ、
　　　　　　２Ｍ、、ｈ。When , a simple consideration based on the bubble domain theory that ignores the demagnetizing field term for a cylindrical domain assuming a perfect circle shows that when , the residual domain disappears and a normal state as shown in Figure 1 (b) is obtained. It can be seen that the image settles into an erased state. Also, 0<H,,+-<H,,<H,+--(3)2M,h,
2M,,h.

のときも、 を満たすときには、補助層２２が一様に磁化された第１
図（ｃ）の状態を経て、第１図（ｄ）に示す磁化状態に
なった後、初期化磁界ＨＺａｉを印加することにより第
１図（ｂ）の正常な消去状態に落ち着くことがわかる。Also when satisfying the following, the auxiliary layer 22 is uniformly magnetized.
It can be seen that after passing through the state shown in FIG. 1(c) and reaching the magnetization state shown in FIG. 1(d), the application of the initialization magnetic field HZai settles into the normal erased state shown in FIG. 1(b).

一方、第３図（ｃ）のタイプの消し残りの場合、Ｈ１４
，が（１）式を満たすときは、逆磁界を通過しただけで
は直ちに消し残り磁区は消滅しないが、−旦初期化磁界
を通過すると補助層が一様に磁化され第３図（ｂ）の状
態になるため、光磁気記録媒体の回転にともなう２度目
の逆磁界の印加により、上述したケースと同じ経路をた
どり消し残りは（２）式にしたがって消滅する。また、
Ｈｌ、、ｖが（３）式を満たすときは、先に考察した第
３図（ｂ）と同じ経路をたどって、消し残りは（４）式
にしたがって消滅する。On the other hand, in the case of the type of unerased material shown in Figure 3(c), H14
, satisfies equation (1), the unerasable magnetic domain does not immediately disappear simply by passing through the reverse magnetic field, but once it passes through the initializing magnetic field, the auxiliary layer becomes uniformly magnetized, as shown in Figure 3(b). Therefore, by applying a second reverse magnetic field as the magneto-optical recording medium rotates, it follows the same path as in the above case and the remaining part disappears according to equation (2). Also,
When Hl, , v satisfy equation (3), the unerased portion disappears according to equation (4) following the same path as in FIG. 3(b) considered earlier.

なお、Ｈ記録により形成された反転磁区の初期化磁界を
通過する直後および直前の状態は、各々第３図（ｂ）、
第３図（ｃ）の消し残り磁区とは磁区径を除いて相似形
の形態を取る。したがって、この記録磁区も上述の磁区
理論にしたがってふるまうので、記録磁区径が太きく（
２）式および（４）式を満たさない場合には、消し残り
磁区の消滅は起こらない。したがって、（２）式および
（４）式において消し残り磁区は消滅し、記録磁区は消
滅させないような適当な大きさの逆磁界Ｈ１，，を印加
することにより、記録情報に対応する大きな磁区を破壊
することなく、消し残り磁区だけを消すことができる。The states of the inverted magnetic domain formed by H recording immediately after and immediately before passing through the initialization magnetic field are shown in FIG. 3(b) and FIG. 3(b), respectively.
The remaining magnetic domain shown in FIG. 3(c) has a similar shape except for the magnetic domain diameter. Therefore, this recording magnetic domain also behaves according to the above-mentioned magnetic domain theory, so the diameter of the recording magnetic domain is large (
If the equations 2) and (4) are not satisfied, the remaining magnetic domains will not disappear. Therefore, in equations (2) and (4), by applying a reverse magnetic field H1 of an appropriate magnitude so that the unerasable magnetic domain disappears and the recorded magnetic domain does not disappear, a large magnetic domain corresponding to the recorded information is created. It is possible to erase only the remaining magnetic domains without destroying them.

ところで、逆磁界による消し残り磁区の消滅は、逆磁界
Ｈ１，，，の大きさが（１）式の範囲にあるときと（３
）式の範囲にあるとき同じように起こるが、（２）式と
（４）式かられかるように消し残りの消滅は、（１）式
を満たす場合の方がはるかに小さな逆磁界で実現するこ
とができる。したがって、実用的には（１）式を満たす
場合の方が好ましいことが分かる。By the way, the annihilation of unerasable magnetic domains by a reverse magnetic field occurs when the magnitude of the reverse magnetic field H1,... is within the range of equation (1) and (3
), but as can be seen from equations (2) and (4), the annihilation of the remaining parts is achieved with a much smaller reverse magnetic field when equation (1) is satisfied. can do. Therefore, it can be seen that it is practically preferable to satisfy formula (1).

さて、この交換結合多層膜を用いた光変調オーバライド
方式において重要な点は、記録用のレーザ光の照射に先
だち補助層は一様に磁化しておく必要があることである
。したがって次の記録動作にはいる直前には少なくとも
初期化磁界印加直後の状態を実現する必要がある。すな
わち上述した（１）式を満たす逆磁界印加による消し残
り磁区の消滅とダイレクトオーバライドを両立するため
には、記録用レーザ光の照射後人の記録または再生を行
う直前までに、記録領域に少なくとも逆磁界、初期化磁
界を順に印加する必要がある。Now, an important point in the optical modulation override method using this exchange-coupled multilayer film is that the auxiliary layer must be uniformly magnetized prior to irradiation with the recording laser beam. Therefore, immediately before starting the next recording operation, it is necessary to achieve at least the state immediately after application of the initializing magnetic field. In other words, in order to achieve both annihilation of unerasable magnetic domains and direct override by applying a reverse magnetic field that satisfies the above-mentioned formula (1), it is necessary to at least add at least It is necessary to apply a reverse magnetic field and an initializing magnetic field in this order.

以上に述べたように、交換結合多層膜を用いた光変調オ
ーバライドが可能な光磁気記録媒体において、補助層の
異なる二つの反転磁界の大きさをＨｌ、Ｈ２を第２図の
ように定義すると、記録レーザ光を媒体に照射した後、
Ｏ＜Ｈｌ、、＜Ｈｌの範囲で初期化磁界とは逆向きの逆
磁界Ｈ１７，とＨｌより大きい初期化磁界を順次印加す
ることにより、消し残りを抑制した良好なダイレクトオ
ーバライドを実現することができる。また消し残りの種
類によっては、逆磁界の前にも初期化磁界を印加すれば
より効果がある。なお実用的な効果を得るための逆磁界
強度の下限は用いる光磁気記録媒体によって異なるが、
−数的には５００〜１００００ｅ程度である。As mentioned above, in a magneto-optical recording medium that uses an exchange-coupled multilayer film and is capable of optical modulation override, the magnitudes of two switching magnetic fields of different auxiliary layers, Hl and H2, are defined as shown in Figure 2. , after irradiating the medium with recording laser light,
By sequentially applying a reverse magnetic field H17, which is in the opposite direction to the initializing magnetic field, and an initializing magnetic field larger than Hl in the range O<Hl, , <Hl, it is possible to realize a good direct override that suppresses unerasing. can. Furthermore, depending on the type of unerased material, it may be more effective to apply an initializing magnetic field before applying the reverse magnetic field. Note that the lower limit of the reverse magnetic field strength to obtain a practical effect varies depending on the magneto-optical recording medium used, but
- In terms of number, it is about 500 to 10,000e.

このような光磁気記録再生方法は、円盤状の光磁気記録
媒体を用いるとき、記録情報に応じたレーザ光の強度変
調が可能な光ヘッドと、記録光照射位置に記録磁界を発
生する機構と、これと異なる位置に初期化磁界を発生さ
せる機構と、初期化磁界とは逆向きの逆磁界を発生する
機構と、基板を回転させる機構とを適宜配置した光磁気
記録再生装置で実現することができる。すなわち、同−
半径上に記録磁界発生機構、逆磁界発生機構、初期化磁
界発生機構を順に光磁気記録媒体の回転方向に配置する
場合には、記録レーザ光を照射した後最低１回転、場合
によっては２回転する間に全ての記録に要する動作は完
了し、同−半径上に記録磁界発生機構、初期化磁界発生
機構、逆磁界発生機構、初期化磁界発生機構を順に光磁
気記録媒体の回転方向に配置する場合には、記録レーザ
光を照射した後１回転する間に全ての記録に要する動作
は完了する。This type of magneto-optical recording and reproducing method uses an optical head that can modulate the intensity of laser light according to recorded information and a mechanism that generates a recording magnetic field at the recording light irradiation position when using a disc-shaped magneto-optical recording medium. , to be realized by a magneto-optical recording/reproducing device in which a mechanism for generating an initializing magnetic field at a different position, a mechanism for generating a reverse magnetic field in the opposite direction to the initializing magnetic field, and a mechanism for rotating the substrate are appropriately arranged. I can do it. That is, the same
When a recording magnetic field generation mechanism, a reverse magnetic field generation mechanism, and an initialization magnetic field generation mechanism are arranged on a radius in order in the rotational direction of the magneto-optical recording medium, at least one rotation after irradiation with the recording laser beam, and in some cases two rotations. During this time, all the operations required for recording are completed, and the recording magnetic field generating mechanism, initializing magnetic field generating mechanism, reverse magnetic field generating mechanism, and initializing magnetic field generating mechanism are arranged in order in the rotation direction of the magneto-optical recording medium on the same radius. In this case, all operations required for recording are completed during one rotation after irradiation with the recording laser beam.

なお説明で用いた光磁気記録媒体は、記録層は室温にお
いて遷移金属磁気モーメントリッチの希土類遷移金属合
金フェリ磁性膜と、補助層には室温とキュリー温度の間
に補償温度のある希土類金属磁気モーメントリッチの希
土類遷移金属合金フ工り磁性膜の２つの磁性層からなる
交換結合膜であったが、そのほかのタイプの交換結合膜
や、２層間の磁壁エネルギーを抑制するのに有効な中間
層を導入した光磁気記録媒体を用いても、同様に説明で
きる。In the magneto-optical recording medium used in the explanation, the recording layer is a rare earth transition metal alloy ferrimagnetic film rich in transition metal magnetic moment at room temperature, and the auxiliary layer is a rare earth metal magnetic moment film with a compensation temperature between room temperature and the Curie temperature. Although the exchange-coupled film consists of two magnetic layers of a rich rare-earth transition metal alloy fabricated magnetic film, other types of exchange-coupled films and intermediate layers that are effective in suppressing the domain wall energy between the two layers have been developed. The same explanation can be given using the introduced magneto-optical recording medium.

［実施例］ 以下実施例にもとづいて本発明の詳細な説明する。[Example] The present invention will be described in detail below based on Examples.

実施例１： 第４図は本発明による光磁気記録再生装置の構成図であ
る。モーター４２によって矢印の方向に回転するディス
ク状の光磁気記録媒体４１の周上に逆磁界発生装置４６
、初期化磁界発生装置４４、レーザ変調手段を伴う光ヘ
ッド４３を順次配置する。また記録磁界発生装置４５は
、光磁気記録媒体をはさんで光ヘッドと対向させる。こ
のような構成をとることにより媒体上の信号記録領域は
、ディスクの回転にともなって逆磁界発生装置、初期化
磁界発生装置、光ヘッド（記録磁界発生装置）の順に繰
り返し通過することになる。なお記録再生のレーザ光波
長は７８０ｎｍで、レーザ光は光磁気記録媒体の基板側
から入射する。Embodiment 1: FIG. 4 is a block diagram of a magneto-optical recording/reproducing apparatus according to the present invention. A reverse magnetic field generator 46 is installed on the circumference of a disk-shaped magneto-optical recording medium 41 that is rotated in the direction of the arrow by a motor 42.
, an initialization magnetic field generator 44, and an optical head 43 with laser modulation means are arranged in this order. Further, the recording magnetic field generating device 45 is arranged to face the optical head with the magneto-optical recording medium in between. With this configuration, the signal recording area on the medium repeatedly passes through the reverse magnetic field generating device, the initializing magnetic field generating device, and the optical head (recording magnetic field generating device) in this order as the disk rotates. Note that the laser light wavelength for recording and reproduction is 780 nm, and the laser light is incident from the substrate side of the magneto-optical recording medium.

次に本実施例で用いた光磁気記録媒体について説明する
。すなわち第５図で示すように樹脂基板５１に保護層５
２を８０ｎｍ、記録層５３を５０ｎｍ、補助層５４を１
１００ｎ、保護層５５を８０ｎｍの順に積層して光磁気
記録媒体を構成した。ここで記録層には室温で遷移金属
の副格子磁化が優勢（７Ｍリッチ）なＮｄＤｙＴｂＦｅ
Ｃｏを、補助層には希土類金属の副格子磁化が優勢（Ｒ
Ｅリッチ）なりｙＦｅＣｏを、保護層にはＡｌ５ｉＮを
用い、磁気特性の異なる２水準の試料（試料１、試料２
）を用意した。これらの試料の記録層、補助層の見かけ
の保磁カー、Ｈｌを第１表に示す。ここで見かけの保磁
力とは、記録層と補助層が交換結合した結果、単層膜で
の保磁力からシフトした後の量をさす。ただし補助層に
ついては、磁化曲線のマイナーループの反転磁界におい
て、絶対値の大きい方（すなわち第２図におけるＨｌ）
の値である。Next, the magneto-optical recording medium used in this example will be explained. That is, as shown in FIG. 5, a protective layer 5 is formed on a resin substrate 51.
2 is 80 nm, the recording layer 53 is 50 nm, and the auxiliary layer 54 is 1
A magneto-optical recording medium was constructed by laminating a protective layer 55 with a thickness of 100 nm and a protective layer 55 with a thickness of 80 nm in this order. Here, the recording layer is made of NdDyTbFe in which transition metal sublattice magnetization is dominant (7M rich) at room temperature.
In Co, sublattice magnetization of rare earth metal is dominant in the auxiliary layer (R
Two levels of samples (Sample 1, Sample 2) with different magnetic properties were used.
) was prepared. Table 1 shows the apparent coercive force and Hl of the recording layer and auxiliary layer of these samples. The apparent coercive force here refers to the amount shifted from the coercive force of a single layer film as a result of exchange coupling between the recording layer and the auxiliary layer. However, for the auxiliary layer, in the reversal magnetic field of the minor loop of the magnetization curve, the one with the larger absolute value (i.e. Hl in Figure 2)
is the value of

第１表 本実施例で用いたこれらの試料は上述したように、記録
層が７Ｍリッチ、補助層がＲＥリッチな組成からなる。Table 1 As described above, these samples used in this example had a recording layer having a composition rich in 7M and an auxiliary layer having a composition rich in RE.

第４図の光磁気記録再生装置において初期化磁界は記録
磁界と同一の方向に印加し、逆磁界は記録磁界とは逆方
向に印加することになる。In the magneto-optical recording/reproducing apparatus shown in FIG. 4, the initializing magnetic field is applied in the same direction as the recording magnetic field, and the reverse magnetic field is applied in the opposite direction to the recording magnetic field.

Ｌ記録レーザパワーの許容範囲、すなわちパワーマージ
ンの評価は、７ＭＨｚの信号を記録した光磁気記録媒体
の領域に２ＭＨｚの信号をオーバーライドしたとき、オ
ーバーライド前の信号の消し残り強度をスペクトラムア
ナライザーで測定するすることによりおこなった。記録
再生時の記録媒体の相対移動速度は１５ｍ／ｓｅｃとし
Ｈ記録のレーザパワーは１５　ｍ　Ｗである。To evaluate the permissible range of the L recording laser power, that is, the power margin, when a 2 MHz signal is overridden in the area of a magneto-optical recording medium where a 7 MHz signal has been recorded, the unerased intensity of the signal before override is measured using a spectrum analyzer. This was done by doing. The relative moving speed of the recording medium during recording and reproduction was 15 m/sec, and the laser power for H recording was 15 mW.

第６図（ａ）、（ｂ）は各々試料１と試料２のオーバラ
イド後の消し残りの信号強度レベルを、Ｌ記録のレーザ
パワーに対してプロットしたもので、消し残りの信号が
消えるパワーをＰＬとする。ここで初期化磁界は４．０
ｋＯｅ、逆磁界は２．０ｋＯｅと４．０ｋＯｅの２水準
で、比較のために逆磁界を印加しない従来の光磁気記録
再生方法によるものもあわせて図示した。第６図（ａ）
と（ｂ）より逆磁界を印加することによりＰＬを低下で
きることがわかる。Figures 6(a) and (b) are plots of the signal intensity levels of unerased signals after override for Sample 1 and Sample 2, respectively, against the laser power of L recording, and the power at which the unerased signals disappear is calculated. PL. Here, the initialization magnetic field is 4.0
There are two levels of kOe and reverse magnetic field, 2.0 kOe and 4.0 kOe, and for comparison, a conventional magneto-optical recording and reproducing method in which no reverse magnetic field is applied is also shown. Figure 6(a)
It can be seen from (b) that PL can be lowered by applying a reverse magnetic field.

すなわちＬ記録のパワーマージンが拡大することがわか
る。特に試料１．２ともに逆磁界強度が２．０ｋＯｅの
ときにはＰＬは約１．５ｍＷ低下し、Ｌ記録のパワーマ
ージンの拡大に有効であることが明らかである。In other words, it can be seen that the power margin for L recording is expanded. In particular, when the reverse magnetic field strength is 2.0 kOe for both samples 1 and 2, the PL decreases by about 1.5 mW, which is clearly effective in expanding the power margin of L recording.

次に試料１と試料２について逆磁界を０．ＯＯｅから７
．０ｋＯｅまで０．５ｋＯｅ毎に変えたときのＰ、の変
化を各々第７図（ａ）、（ｂ）に示す。ここで初期化磁
界は４．０ｋＯｅである。第７図と第１表から明らかな
ようにＰ、は、逆磁界０．００ｅの値Ｐ、。から補助層
のみかけの保磁力（Ｈｌ）直下まで低下を続け、Ｈｌを
越えるとＰＬはふたたびＰＬ０付近まで不連続に変化し
、そこから緩やかに減少する。したがって逆磁界は、特
にＨ１以下の領域でＰＬの低下すなわちＬ記録のパワー
マージンの拡大に大きく寄与することがわかる。Next, for sample 1 and sample 2, the reverse magnetic field was set to 0. 7 from OOe
．． Figures 7(a) and 7(b) show the changes in P when changing it every 0.5 kOe up to 0 kOe. Here, the initialization magnetic field is 4.0 kOe. As is clear from FIG. 7 and Table 1, P is the value P when the reverse magnetic field is 0.00e. PL continues to decrease from to just below the apparent coercive force (Hl) of the auxiliary layer, and when Hl is exceeded, PL changes discontinuously again to around PL0, and then gradually decreases from there. Therefore, it can be seen that the reverse magnetic field greatly contributes to a decrease in PL, that is, an increase in the power margin of L recording, especially in the region below H1.

実施例２： 第８図は本発明による光磁気記録再生装置の構成図であ
る。モーター８２によって矢印の方向に回転するディス
ク状の光磁気記録媒体８１の周上に、初期化磁界発生装
置８４、逆磁界発生装置８６もう一つの初期化磁界発生
装置８４゛、レーザ変調手段を伴う光ヘッド８３を順次
配置する。また記録磁界発生装置８５は、光磁気記録媒
体をはさんで光ヘッドと対向させる。このような構成を
とることにより媒体上の信号記録領域は、ディスクの回
転にともなって初期化磁界発生装置８４、逆磁界発生装
置、初期化磁界発生装置８４′、光ヘッド（記録磁界発
生装置）の順に繰り返し通過することになる（以下初期
化磁界発生装置８４°による磁界を第１初期化磁界、初
期化磁界発生装置８４による磁界を第２初期化磁界とよ
ぶ）。なお記録再生のレーザ光波長は７８０ｎｍで、レ
ーザ光は光磁気記録媒体の基板側から入射する。Embodiment 2: FIG. 8 is a block diagram of a magneto-optical recording and reproducing apparatus according to the present invention. On the circumference of a disk-shaped magneto-optical recording medium 81 rotated in the direction of the arrow by a motor 82, there are an initializing magnetic field generator 84, a reverse magnetic field generator 86, another initializing magnetic field generator 84', and a laser modulation means. The optical heads 83 are arranged one after another. Further, the recording magnetic field generating device 85 is arranged to face the optical head across the magneto-optical recording medium. By adopting such a configuration, the signal recording area on the medium is divided into the initializing magnetic field generating device 84, reverse magnetic field generating device, initializing magnetic field generating device 84', and optical head (recording magnetic field generating device) as the disk rotates. (Hereinafter, the magnetic field generated by the initialization magnetic field generator 84° will be referred to as the first initialization magnetic field, and the magnetic field generated by the initialization magnetic field generator 84 will be referred to as the second initialization magnetic field.) Note that the laser light wavelength for recording and reproduction is 780 nm, and the laser light is incident from the substrate side of the magneto-optical recording medium.

次に本実施例で用いた光磁気記録媒体について説明する
。第５図において記録層５３としてＮｄＤｙＴｂＦｅＣ
ｏを５Ｏｎｍｓ補助層５４としてＤｙＦｅＣ。Next, the magneto-optical recording medium used in this example will be explained. In FIG. 5, the recording layer 53 is made of NdDyTbFeC.
DyFeC with o as 5 Onms auxiliary layer 54.

を１００ｎｍ　％保護層５２．５５としてＡｌ５ｉＮを
各々８０ｎｍ用いて磁気特性の異なる２水準の試料（試
料３．４）を用意した。これらの試料の記録層と補助層
の実施例１で定義した見かけの保磁力Ｈ，，、Ｈｌを第
２表に示す。Two levels of samples (sample 3.4) with different magnetic properties were prepared using Al5iN with a thickness of 80 nm and a protective layer of 52.55% with a thickness of 100 nm. Table 2 shows the apparent coercive forces H, . . . Hl defined in Example 1 of the recording layer and auxiliary layer of these samples.

第２表 いずれの試料も記録層は７Ｍリッチ、補助層はＲＥリッ
チである。したがって、第８図の光磁気記録再生装置に
おいて二つの初期化磁界は記録磁界と同一の方向に印加
し、逆磁界は記録磁界とは逆方向に印加することになる
。In all the samples in Table 2, the recording layer is 7M rich and the auxiliary layer is RE rich. Therefore, in the magneto-optical recording/reproducing apparatus shown in FIG. 8, the two initializing magnetic fields are applied in the same direction as the recording magnetic field, and the reverse magnetic field is applied in the opposite direction to the recording magnetic field.

第９図（ａ）、（ｂ）は各々試料３、試料４について記
録再生の線速１７ｍ／ｓｅｃ、　Ｈ記録のレーザパワー
１５ｍＷで７ＭＨｚの信号上に２ＭＨｚの信号をオーバ
ーライドしたときの消し残りの信号強度レベルを、Ｌ記
録のレーザパワーに対してプロットしたものである。こ
こで第１初期化磁界、第２初期化磁界はともに４．０ｋ
Ｏｅ、逆磁界は２．０ｋＯｅで、比較のために逆磁界を
印加しない従来の光磁気記録再生方法によるものも図示
した。第９図（ａ）、（ｂ）によれば逆磁界を印加する
ことによりＰ、を１．５ｍＷ以上低減できることがわか
る。Figures 9(a) and 9(b) show the remaining data when a 2 MHz signal is overridden on a 7 MHz signal at a recording/reproducing linear velocity of 17 m/sec and an H recording laser power of 15 mW for Samples 3 and 4, respectively. The signal intensity level is plotted against the laser power for L recording. Here, both the first initialization magnetic field and the second initialization magnetic field are 4.0k.
Oe, and the reverse magnetic field was 2.0 kOe. For comparison, a conventional magneto-optical recording and reproducing method in which no reverse magnetic field was applied is also shown. According to FIGS. 9(a) and 9(b), it can be seen that by applying a reverse magnetic field, P can be reduced by 1.5 mW or more.

ところでこの評価では記録動作が完了後直ちに１トラツ
クジヤンプをおこない、記録動作から再生動作に移る間
に、第２初期化磁界、逆磁界、第１初期化磁界を順に１
回だけ記録領域に印加したあとで再生をおこなった。し
たがって、本願の作用の項で述べたように、第３図（ｃ
）のタイプの消し残りに対しても消し残りを解消する効
果が上述した結果に含まれていることが期待できる。こ
れを確認するために、第８図の光磁気記録再生装置にお
いて第２初期化磁界のない場合（ａ）ならびに、第２初
期化磁界と逆磁界のない場合（ｂ）の両方について試料
３を用いて消し残り信号のＬ記録レーザパワー依存性の
測定をおこなったところ、第１０図に示す結果を得た。By the way, in this evaluation, one track jump is performed immediately after the recording operation is completed, and during the transition from the recording operation to the reproduction operation, the second initialization magnetic field, reverse magnetic field, and first initialization magnetic field are sequentially changed to 1.
Reproduction was performed after applying the voltage to the recording area only once. Therefore, as described in the operation section of the present application, as shown in FIG.
) type of unerased areas as well, it can be expected that the above-mentioned results include the effect of eliminating unerased areas. In order to confirm this, sample 3 was prepared in the magneto-optical recording/reproducing apparatus shown in Fig. 8 for both the case (a) without the second initializing magnetic field and the case (b) without the second initializing magnetic field and reverse magnetic field. When the dependence of the unerased signal on the L recording laser power was measured using this method, the results shown in FIG. 10 were obtained.

なお第１０図には、第２初期化磁界及び逆磁界がある場
合（ｃ）の結果も合わせて示しである。これによれば、
（ｂ）に比べて（ａ）は本願の明細書実施例１に示した
ものと同様に、消し残りが最小になるし記録パワーが低
下しＬ記録のパワーマージンが拡大することがわかる。Note that FIG. 10 also shows the results for the case (c) when there is a second initialization magnetic field and a reverse magnetic field. According to this,
It can be seen that in comparison with (b), in (a), the unerased area is minimized, the recording power is lowered, and the power margin for L recording is expanded, similar to that shown in Example 1 of the specification of the present application.

ところが（ａ）を（ｃ）と比較したとき、消し残りが最
小となるＬ記録パワーには差が認められないが、消し残
りのキャリアレベルに約５ｄＢの差があることがわかる
。すなわち、この実施例で用いた光磁気記録媒体は、本
発明の一つの形態である（ａ）の光磁気記録再生方法で
は解消しきれない第３図（ｃ）のタイプの消し残り磁区
が存在するが、逆磁界と第２初期化磁界を導入すること
により、このようなタイプの消し残りをも解消すること
ができる。However, when comparing (a) with (c), it is found that although there is no difference in the L recording power at which the unerased area is minimized, there is a difference of approximately 5 dB in the carrier level of the unerased area. That is, in the magneto-optical recording medium used in this example, there is a residual magnetic domain of the type shown in FIG. However, by introducing a reverse magnetic field and a second initialization magnetic field, it is possible to eliminate this type of unerased data.

実施例３： この実施例では、本発明がＬ記録のパワーマージンなら
びにＬ記録感度を悪化させることなく、記録層のキュリ
ー温度を上げて媒体のカー回転角を上げることができる
ことを明らかにする。ここで用いた光磁気記録再生装置
は本願明細書の実施例１で第４図として示したものと同
一のものである。また本実施例で用いた光磁気記録媒体
は、第５図において記録層５３としてＮｄＤｙＴｂＦｅ
Ｃｏを５０ｎｍ、補助層５４としてＤｙＦｅＣｏを１１
００ｎ、保護層５２．５５としてＡｌ５ｉＮを各々８０
ｎｍ用いて構成され、磁気特性の異なる２水準の試料（
試料５、試料６）を用意した。いずれの試料も記録層は
ＴＭリッチであり、補助層はＲＥリッチである。また補
助層は試料５．６で共通とする。これらの試料の記録層
のキュリー温度Ｔｃおよび記録層と補助層の実施例１で
定義した見かけの保磁力Ｈ，ｎ、　Ｈ。Example 3: This example demonstrates that the present invention can increase the Curie temperature of the recording layer and increase the Kerr rotation angle of the medium without deteriorating the power margin of L recording and the L recording sensitivity. The magneto-optical recording and reproducing apparatus used here is the same as that shown in FIG. 4 in Example 1 of the present specification. Further, in the magneto-optical recording medium used in this example, the recording layer 53 is made of NdDyTbFe in FIG.
50 nm of Co, 11 nm of DyFeCo as the auxiliary layer 54
00n, Al5iN as protective layer 52.55, respectively 80
Two levels of samples with different magnetic properties (
Samples 5 and 6) were prepared. In each sample, the recording layer is TM-rich, and the auxiliary layer is RE-rich. Further, the auxiliary layer is the same for samples 5 and 6. The Curie temperature Tc of the recording layer of these samples and the apparent coercivity H, n, H of the recording layer and auxiliary layer defined in Example 1.

を第３表に示す。are shown in Table 3.

第３表 試料５、試料６は共に記録層がＴＭリッチ、補助層がＲ
Ｅリッチな組成からなるので、第４図でみるように初期
化磁界は記録磁界と同一の方向に印加し、また逆磁界は
記録磁界と逆方向に印加する。記録再生時の記録媒体面
の相対移動速度は１７ｍ／ｓｅｃとし、７ＭＨｚの信号
上に２ＭＨｚの信号をオーバーライドする。Ｈ記録のレ
ーザパワーは１５ｍＷに固定し、初期化磁界は４．０ｋ
Ｏｅとした。Table 3 Samples 5 and 6 both have a recording layer that is TM rich and an auxiliary layer that is R.
Since it has an E-rich composition, the initializing magnetic field is applied in the same direction as the recording magnetic field, and the reverse magnetic field is applied in the opposite direction to the recording magnetic field, as shown in FIG. The relative moving speed of the recording medium surface during recording and reproduction is 17 m/sec, and a 2 MHz signal is overridden on a 7 MHz signal. The laser power for H recording was fixed at 15mW, and the initialization magnetic field was 4.0k.
Oe.

逆磁界強度は２．０ｋＯｅで、比較のために従来の光磁
気記録再生方法に対応する逆磁界０．０ｋＯｅについて
も調べた。The reverse magnetic field strength was 2.0 kOe, and for comparison, a reverse magnetic field of 0.0 kOe, which corresponds to the conventional magneto-optical recording and reproducing method, was also investigated.

第４表には、試料２水準と逆磁界２水準の組み合わせに
ついて、上述の方法で測定した消し残り信号が消滅する
し記録のレーザパワーＰＬとオ−パーライトした信号の
搬送波対雑音比（ｃ／Ｎ比）を示す。Table 4 shows that the unerased signal measured by the above method disappears, the recording laser power PL and the carrier-to-noise ratio (c/ N ratio).

第４表 まず第４表から、記録層のキュリー温度が高い媒体（試
料６）の方がＣ／Ｎ比が高いことがわかる。Table 4 First, from Table 4, it can be seen that the medium (Sample 6) whose recording layer has a higher Curie temperature has a higher C/N ratio.

一方、記録層のキュリー温度が高い媒体の方が高いＰＬ
を必要とすることがわかる。ところが、キュリー温度が
高い試料６であっても本発明の逆磁界を導入した場合、
試料５を逆磁界がない従来の光磁気記録再生方法によっ
て記録した場合に相当するまでＰ、を下げることが可能
になり、Ｌ記録のレーザパワーに対して高感度化がはか
れることがわかる。このことは翻って、本発明による逆
磁界を用いることにより、Ｌ記録に対するパワーマージ
ンならびに記録感度を悪化させることなく、記録層のキ
ュリー温度を上げることによりカー回転角を増大させ、
媒体のＣ／Ｎ比を上げることが可能であることを示して
いる。On the other hand, the medium with a higher Curie temperature of the recording layer has a higher PL.
It turns out that it is necessary. However, even in sample 6, which has a high Curie temperature, when the inverse magnetic field of the present invention is introduced,
It can be seen that it is possible to lower P to a level equivalent to that when the sample 5 is recorded by the conventional magneto-optical recording and reproducing method without a reverse magnetic field, and that high sensitivity can be achieved with respect to the laser power of L recording. On the other hand, by using the reverse magnetic field according to the present invention, the Kerr rotation angle can be increased by increasing the Curie temperature of the recording layer without deteriorating the power margin for L recording and the recording sensitivity.
This shows that it is possible to increase the C/N ratio of the medium.

なおこれらの実施例において、各磁性層がＴｂＦｅＣｏ
、　ＴｂＦｅＣｏＣｒ、　ＤｙＴｂＦｅＣｏ、　ＮｄＤ
ｙＦｅＣ。Note that in these examples, each magnetic layer is made of TbFeCo.
, TbFeCoCr, DyTbFeCo, NdD
yFeC.

、ＳｍＤｙＦｅＣｏ、　ＰｒＤｙＦｅＣｏ等の成分から
なるものであっても、上述したものと同様の傾向の結果
が得られた。, SmDyFeCo, PrDyFeCo, etc., results similar to those described above were obtained.

［発明の効果］ 本発明によれば、交換結合磁性薄膜を用いたオーバーラ
イド可能な光磁気記録方式において、広い許容範囲のレ
ーザ光強度で、かつ良好な再生信号品質のグイレフトオ
ーバライトを実現する光磁気記録再生方法、ならびに光
磁気記録再生装置を提供することができる。さらに、従
来の方法では解消することができなかった不完全な初期
化に因を発する消し残りをも効果的に解消することがで
きる。[Effects of the Invention] According to the present invention, in an overridable magneto-optical recording method using an exchange-coupled magnetic thin film, it is possible to realize gray left overwriting with a wide permissible range of laser light intensity and good reproduction signal quality. A magneto-optical recording and reproducing method and a magneto-optical recording and reproducing apparatus can be provided. Furthermore, it is also possible to effectively eliminate unerased areas caused by incomplete initialization, which could not be eliminated using conventional methods.

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

第１図（ａ）　　　（ｂ）　　　（ｃ）　　　（ｄ）は
、本発明を説明するために用いた図で、記録媒体の磁化
の状態を示す図。 １１：記録層 １２：補助層 １３：消し残り磁区 第２図は、補助層の磁化曲線のマイナーループを示す図
。 第３図（ａ）はＬ記録が完全に行われた場合の、第３図
（ｂ）、（ｃ）はＬ記録領域の消し残りがある場合の記
録層、補助層のみかけの磁化状態を矢印で示す図。 ３１：記録層 ３２：補助層 ３３：消し残り磁区 第４図は本発明にかかる実施例１における光磁気記録再
生装置の構成図。 ４１：光磁気記録媒体 ４２：モーター ４３：光ヘッド ４４：初期化磁界発生装置 ４５：記録磁界発生装置 ４６：逆磁界発生装置 第５図は本実施例で用いた記録媒体の側面断面図。 ５１：樹脂基板 ５２：保護層 ５３：記録層 ５４：補助層 ５５：保護層 第６図（ａ）、（ｂ）は実施例１において、各々試料１
と試料２のＬ記録レーザパワーと消し残りレベルの関係
を示す図。 第７図（ａ）、（ｂ）は実施例１において、各々試料１
と試料２の逆磁界とＰＬの関係を示す図。 第８図は実施例２における記録再生装置の、各磁界発生
装置の位置関係を示す図。 ８１：光磁気記録媒体 ８２：モーター ８３：光ヘッド ８４．８４゛：初期化磁界発生装置 ８５：記録磁界発生装置 ８６：逆磁界発生装置 第９図（ａ）、（ｂ）は実施例２において、各々試料３
と試料４の、本発明の光磁気記録再生方法ならびに光磁
気記録再生装置によるし記録レーザパワーと消し残りレ
ベルの関係を示す図。 第１０図は実施例２において、試料３の記録レーザパワ
ーと消し残りレベルの関係を示す図。 以上 出願人　セイコーエプソン株式会社 代理人弁理士　鈴木喜三部（他１名） （ａ） 第１図 （ｃ） 第３図 第５図 ４．０　　　　　５．０　　　　　６．ＯＬ記録レーザ
パワー（ｍＷ） （ａ） ４．０　　　　　５．０　　　　　６．ＯＬ記録レーザ
パワー（ｍＷ） （ｂ） 第６図 逆磁界（ｋｏｅ） （ａ） 逆磁界（ｋｏｅ） （ｂ） 第７図 ４．０　　　　５．０　　　　６．Ｏ Ｌ記録レーザパワー（ｍＷ） （ａ） ７．０ ４．０　　　　５．０　　　　６．Ｏ Ｌ記録レーザパワー（ｍＷ） （ｂ） 第９図 ７．０FIGS. 1(a), (b), (c), and (d) are diagrams used to explain the present invention, showing the state of magnetization of a recording medium. 11: Recording layer 12: Auxiliary layer 13: Remaining magnetic domain FIG. 2 is a diagram showing a minor loop of the magnetization curve of the auxiliary layer. Figure 3 (a) shows the apparent magnetization state of the recording layer and auxiliary layer when L recording is completed, and Figures 3 (b) and (c) show the apparent magnetization state of the recording layer and auxiliary layer when there is some unerased area in the L recording area. Diagram indicated by arrow. 31: Recording layer 32: Auxiliary layer 33: Remaining magnetic domain FIG. 4 is a block diagram of a magneto-optical recording and reproducing apparatus in Example 1 according to the present invention. 41: Magneto-optical recording medium 42: Motor 43: Optical head 44: Initialization magnetic field generator 45: Recording magnetic field generator 46: Reverse magnetic field generator FIG. 5 is a side sectional view of the recording medium used in this example. 51: Resin substrate 52: Protective layer 53: Recording layer 54: Auxiliary layer 55: Protective layer
FIG. 4 is a diagram showing the relationship between the L recording laser power and the unerased level for sample 2. FIGS. 7(a) and 7(b) show sample 1 in Example 1, respectively.
A diagram showing the relationship between the reverse magnetic field and PL of sample 2. FIG. 8 is a diagram showing the positional relationship of each magnetic field generating device in the recording/reproducing apparatus in Example 2. 81: Magneto-optical recording medium 82: Motor 83: Optical head 84.84゛: Initialization magnetic field generator 85: Recording magnetic field generator 86: Reverse magnetic field generator , each sample 3
3 is a diagram showing the relationship between the recording laser power and the unerased level using the magneto-optical recording and reproducing method and the magneto-optical recording and reproducing apparatus of the present invention for Sample 4 and Sample 4. FIG. FIG. 10 is a diagram showing the relationship between recording laser power and unerased level of sample 3 in Example 2. Applicant Seiko Epson Corporation Representative Patent Attorney Kizobe Suzuki (1 other person) (a) Figure 1 (c) Figure 3 Figure 5 4.0 5.0 6. OL recording laser power (mW) (a) 4.0 5.0 6. OL recording laser power (mW) (b) Fig. 6 Reverse magnetic field (koe) (a) Reverse magnetic field (koe) (b) Fig. 7 4.0 5.0 6. OL recording laser power (mW) (a) 7.0 4.0 5.0 6. OL recording laser power (mW) (b) Figure 9 7.0

Claims (3)

【特許請求の範囲】[Claims] （１）室温において互いに交換結合した、室温で相対的
に大きな保磁力と低いキュリー点を有する第１の磁性層
と、室温で相対的に小さな保磁力と高いキュリー点を有
する第２の磁性層の積層膜を光磁気記録層とし、前記第
２の磁性層の磁化曲線におけるマイナーループの二つの
反転磁界の絶対値が各々Ｈ＿１、Ｈ＿２（Ｈ＿１＞Ｈ＿
２）であり、膜面に垂直方向にＨ＿１より大きな初期化
磁界を印加することにより、第２の磁性層の磁化の向き
のみを一方向にそろえた円盤状の光磁気記録媒体を用い
、（ａ）該光磁気記録媒体の膜面に垂直な記録磁界を印
加すると同時にレーザ光を照射し第１の加熱状態を実現
することにより、第２の磁性層に磁化反転を起こさない
で、第１の磁性層の加熱領域のみを第２の磁性層に対し
て安定な向きに磁化する第１の記録か、記録磁界を印加
すると同時にレーザ光を照射し第２の加熱状態を実現す
ることにより、まず第２の磁性層の加熱領域が磁化反転
し、次いで第１の磁性層が第２の磁性層に対して安定な
向きに磁化する第２の記録かを記録情報に応じて行なう
記録動作 （ｂ）前記記録動作を行った領域にレーザ光を照射し、
第１の磁性層に形成されている磁化の方向を検出して情
報の再生を行う再生動作 からなる光磁気記録再生方法において、 （ｃ）前記記録動作を行つた領域に前記初期化磁界を印
加する初期化過程 （ｄ）前記記録動作を行った領域に前記初期化磁界と逆
向きでＨ＿１より小さい静磁界を印加する逆磁界過程 を定義するとき、記録動作終了の後、前記再生動作、ま
たは次の記録動作に入る直前までに、少なくとも逆磁界
過程、初期化過程を順に行うことを特徴とする光磁気記
録再生方法。(1) A first magnetic layer having a relatively large coercive force and a low Curie point at room temperature and a second magnetic layer having a relatively small coercive force and a high Curie point at room temperature, which are exchange coupled to each other at room temperature. The laminated film of is used as a magneto-optical recording layer, and the absolute values of the two reversal magnetic fields of the minor loop in the magnetization curve of the second magnetic layer are H_1 and H_2 (H_1>H_
2), using a disk-shaped magneto-optical recording medium in which only the direction of magnetization of the second magnetic layer is aligned in one direction by applying an initializing magnetic field larger than H_1 in the direction perpendicular to the film surface. a) By applying a recording magnetic field perpendicular to the film surface of the magneto-optical recording medium and simultaneously irradiating laser light to achieve the first heating state, the first heating state is achieved without causing magnetization reversal in the second magnetic layer. Either the first recording is performed by magnetizing only the heated region of the magnetic layer in a stable direction relative to the second magnetic layer, or the second heating state is achieved by applying a recording magnetic field and irradiating laser light at the same time. First, the magnetization of the heated region of the second magnetic layer is reversed, and then the first magnetic layer is magnetized in a stable direction with respect to the second magnetic layer. b) irradiating the area where the recording operation has been performed with a laser beam;
In a magneto-optical recording and reproducing method comprising a reproducing operation of detecting the direction of magnetization formed in a first magnetic layer and reproducing information, (c) applying the initializing magnetic field to the area where the recording operation has been performed; (d) When defining a reverse magnetic field process in which a static magnetic field smaller than H_1 is applied to the area where the recording operation has been performed in the opposite direction to the initialization magnetic field, after the recording operation is completed, the reproducing operation, or A magneto-optical recording and reproducing method characterized in that at least a reverse magnetic field process and an initialization process are sequentially performed immediately before starting the next recording operation. （２）前記逆磁界過程以前に初期化過程を行うことを特
徴とする請求項１記載の光磁気記録再生方法。(2) The magneto-optical recording and reproducing method according to claim 1, characterized in that an initialization process is performed before the reverse magnetic field process. （３）光磁気記録媒体を回転させる手段と、光ヘッドと
、該光ヘッドと異なる位置で前記初期化磁界を発生させ
る手段と、光磁気記録媒体の磁性層上に記録情報に応じ
て前記第１ならびに第２の加熱状態を実現するレーザ変
調手段と、情報の記録時に前記光磁気記録媒体に前記記
録磁界を印加する手段をそなえてなる光磁気記録再生装
置において、前記静磁界の発生手段を具備することを特
徴とする光磁気記録再生装置。(3) means for rotating the magneto-optical recording medium; an optical head; means for generating the initializing magnetic field at a position different from the optical head; In a magneto-optical recording and reproducing apparatus, the magneto-optical recording and reproducing apparatus includes a laser modulation means for realizing the first and second heating states, and a means for applying the recording magnetic field to the magneto-optical recording medium during recording of information, the magneto-optical recording and reproducing apparatus comprising: A magneto-optical recording and reproducing device comprising: