JPH0773529A - Magneto-optical recording system and magneto-optical recording medium - Google Patents
Magneto-optical recording system and magneto-optical recording mediumInfo
- Publication number
- JPH0773529A JPH0773529A JP21573893A JP21573893A JPH0773529A JP H0773529 A JPH0773529 A JP H0773529A JP 21573893 A JP21573893 A JP 21573893A JP 21573893 A JP21573893 A JP 21573893A JP H0773529 A JPH0773529 A JP H0773529A
- Authority
- JP
- Japan
- Prior art keywords
- magneto
- optical recording
- magnetic
- layer
- recording medium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、光磁気記録方式およ
び光磁気記録媒体に関し、さらに詳しくいえば、光磁気
記録媒体の周囲温度や移動速度などの変化に起因する、
レーザ光照射時の光磁気記録媒体の温度分布の変動を補
償するようにした光磁気記録方式および光磁気記録媒体
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording system and a magneto-optical recording medium, and more specifically, due to changes in ambient temperature and moving speed of the magneto-optical recording medium,
The present invention relates to a magneto-optical recording system and a magneto-optical recording medium that are adapted to compensate for variations in temperature distribution of the magneto-optical recording medium during laser irradiation.
【０００２】[0002]
【従来の技術】光磁気記録方式では、情報記録用の磁性
層を持つ光磁気記録媒体に高パワーのレーザ光を照射
し、それによって生じる前記磁性層の局所的温度上昇に
よりその磁性層に磁区を形成して情報を記録する。ま
た、前記光磁気記録媒体に低パワーのレーザ光を照射し
て前記磁区から記録された前記情報を光学的に再生す
る。前記光磁気記録媒体は、記録・再生時に高速で移動
し、しかも他の光磁気記録媒体と交換されることがあ
る。2. Description of the Related Art In the magneto-optical recording system, a magneto-optical recording medium having a magnetic layer for recording information is irradiated with a high-power laser beam, and the local temperature rise of the magnetic layer caused thereby causes a magnetic domain in the magnetic layer. To record information. Further, the magneto-optical recording medium is irradiated with a low power laser beam to optically reproduce the information recorded from the magnetic domain. The magneto-optical recording medium may move at high speed during recording / reproduction and may be replaced with another magneto-optical recording medium.
【０００３】前記光磁気記録媒体は通常、基板上に直接
または下地層を介して形成された情報記録用の磁性層を
有しており、その磁性層は、希土類−遷移金属合金、貴
金属−遷移金属合金などの単層膜や多層膜の単体、もし
くはそれらの膜の組成・膜厚を変えたものの積層膜から
構成される。The magneto-optical recording medium usually has a magnetic layer for recording information formed directly on a substrate or via an underlayer. The magnetic layer is a rare earth-transition metal alloy or a noble metal-transition. It is composed of a single layer film such as a metal alloy or a multi-layer film alone, or a laminated film in which the composition and film thickness of these films are changed.
【０００４】[0004]
【発明が解決しようとする課題】光磁気記録方式では前
記のようにして情報の記録・再生を行なうため、記録・
再生時に温度上昇により光磁気記録媒体の磁区の不安定
性が増加するという特性を持つ。このため、周囲（環
境）温度、光磁気記録媒体の移動速度や熱感度などの使
用環境が変化した場合、記録・再生時に光磁気記録媒体
の温度分布が変化し、それによって正常な磁区の形成や
磁区の安定的な保持など、光磁気記録媒体の特性が影響
を受けやすいという問題がある。In the magneto-optical recording method, information is recorded / reproduced as described above.
It has a characteristic that the instability of the magnetic domain of the magneto-optical recording medium increases due to the temperature rise during reproduction. Therefore, if the ambient (environmental) temperature, the moving environment of the magneto-optical recording medium, or the operating environment such as thermal sensitivity changes, the temperature distribution of the magneto-optical recording medium changes during recording / reproduction, which causes normal magnetic domain formation. There is a problem that the characteristics of the magneto-optical recording medium are easily affected, such as stable retention of magnetic domains.
【０００５】また、前記のような特性の不安定性によ
り、光磁気記録媒体に使用される磁性材料は、温度分布
の変動に対する特性の安定性が高いものに限定されると
いう問題がある。Further, due to the instability of the characteristics as described above, there is a problem that the magnetic material used for the magneto-optical recording medium is limited to the one having high stability of characteristics with respect to the fluctuation of the temperature distribution.
【０００６】そこで、この発明の目的は、光磁気記録媒
体の周囲（環境）温度や移動速度などの変動に対する記
録・再生特性の変動が小さい光磁気記録方式および光磁
気記録媒体を提供することにある。Therefore, an object of the present invention is to provide a magneto-optical recording system and a magneto-optical recording medium in which fluctuations in recording / reproducing characteristics are small with respect to fluctuations in ambient (environmental) temperature and moving speed of the magneto-optical recording medium. is there.
【０００７】この発明の他の目的は、光磁気記録媒体の
磁性層として使用する磁性材料の選択の幅が広い光磁気
記録方式および光磁気記録媒体を提供することにある。Another object of the present invention is to provide a magneto-optical recording system and a magneto-optical recording medium in which the selection range of the magnetic material used as the magnetic layer of the magneto-optical recording medium is wide.
【０００８】[0008]
（１） この発明の第１の光磁気記録方式は、記録用の
磁性層を持つ光磁気記録媒体にレーザ光を照射し、それ
によって生じる前記磁性層の局所的温度上昇によりその
磁性層に磁区を形成して情報を記録し、前記光磁気記録
媒体にレーザ光を照射して前記磁区から前記情報を再生
する光磁気記録方式において、レーザ光照射の際に生じ
る前記磁性層の温度分布の変動を検知し、その検知結果
に応じて前記光磁気記録媒体の記録特性および再生特性
の少なくとも一方の変動を補償することを特徴とする。(1) In the first magneto-optical recording method according to the present invention, a magneto-optical recording medium having a magnetic layer for recording is irradiated with a laser beam, and the local temperature rise of the magnetic layer caused thereby causes a magnetic domain in the magnetic layer. In the magneto-optical recording method in which the information is formed to record the information, and the magneto-optical recording medium is irradiated with laser light to reproduce the information from the magnetic domain, the temperature distribution of the magnetic layer fluctuates when the laser light is irradiated. Is detected, and the fluctuation of at least one of the recording characteristic and the reproducing characteristic of the magneto-optical recording medium is compensated according to the detection result.
【０００９】好ましくは、前記光磁気記録媒体の記録特
性および再生特性の少なくとも一方の変動は、前記光磁
気記録媒体に印加する磁界の強度を変えることにより補
償される。Preferably, the fluctuation of at least one of the recording characteristic and the reproducing characteristic of the magneto-optical recording medium is compensated by changing the strength of the magnetic field applied to the magneto-optical recording medium.
【００１０】好ましくは、前記磁性層の温度分布の変動
は、前記光磁気記録媒体の全体温度を介して検知する。
この場合、前記光磁気記録媒体の全体温度を、前記光磁
気記録媒体の外部に設けた温度検出手段により検知して
もよいし、前記光磁気記録媒体の内部に設けた温度検出
手段により検知してもよい。Preferably, the variation in the temperature distribution of the magnetic layer is detected via the overall temperature of the magneto-optical recording medium.
In this case, the entire temperature of the magneto-optical recording medium may be detected by a temperature detecting means provided outside the magneto-optical recording medium or by a temperature detecting means provided inside the magneto-optical recording medium. May be.
【００１１】温度検出手段としては、例えば、前記光磁
気記録媒体の保持部にその光磁気記録媒体に接するよう
に取り付けた温度センサがある。また、前記光磁気記録
媒体に近接して設けられた放射型温度計などでもよい。
放射型温度計は、無接触で温度計測が可能であるので、
前記光磁気記録媒体への接触が不要であるという利点が
ある。As the temperature detecting means, for example, there is a temperature sensor attached to the holding portion of the magneto-optical recording medium so as to be in contact with the magneto-optical recording medium. Further, a radiation type thermometer provided close to the magneto-optical recording medium may be used.
Since the radiation thermometer can measure temperature without contact,
There is an advantage that it is not necessary to contact the magneto-optical recording medium.
【００１２】前記磁性層の温度分布の変動は、前記光磁
気記録媒体の移動速度を介して検知してもよい。この移
動速度は、例えば、前記光磁気記録媒体の駆動手段から
の信号により検知することができる。Fluctuations in the temperature distribution of the magnetic layer may be detected via the moving speed of the magneto-optical recording medium. This moving speed can be detected by, for example, a signal from the driving unit of the magneto-optical recording medium.
【００１３】前記磁性層の温度分布の変動はまた、前記
光磁気記録媒体の持つ熱感度を介して検知してもよい。
この場合、前記光磁気記録媒体にその媒体の熱感度を示
す熱感度情報を付し、その熱感度情報によりその光磁気
記録媒体の熱感度を検知するのが好ましい。Variations in the temperature distribution of the magnetic layer may also be detected via the thermal sensitivity of the magneto-optical recording medium.
In this case, it is preferable that the magneto-optical recording medium is provided with thermal sensitivity information indicating the thermal sensitivity of the medium, and the thermal sensitivity information detects the thermal sensitivity of the magneto-optical recording medium.
【００１４】ここで「熱感度」とは、前記光磁気記録媒
体の磁性層の持つ磁気特性を意味し、具体的には、例え
ば磁性層の保磁力、磁化などの温度特性を意味する。The term "thermosensitivity" as used herein means the magnetic characteristics of the magnetic layer of the magneto-optical recording medium, and specifically the temperature characteristics such as coercive force and magnetization of the magnetic layer.
【００１５】前記熱感度情報は、前記光磁気記録媒体が
収容されるカートリッジに付してもよいし、前記光磁気
記録媒体自体に付してもよい。前者の場合、例えば、前
記熱感度情報をバーコード、突起列などに変換して前記
カートリッジの表面に付着し、それを記録／再生手段が
読み取るようにすることができる。The thermal sensitivity information may be attached to the cartridge in which the magneto-optical recording medium is housed, or may be attached to the magneto-optical recording medium itself. In the former case, for example, the heat sensitivity information can be converted into a bar code, a row of protrusions or the like and attached to the surface of the cartridge, and the recording / reproducing means can read the information.
【００１６】後者の場合、例えば、前記光磁気記録媒体
の内部に設けられた専用領域に前記熱感度情報を磁気的
に記録することができる。こうすれば、前記光磁気記録
媒体に記録された磁気情報（磁区）を読み出して得られ
る信号強度が規定量かどうかを判断することにより、前
記光磁気記録媒体の熱感度を容易に認識することができ
る。In the latter case, for example, the thermal sensitivity information can be magnetically recorded in a dedicated area provided inside the magneto-optical recording medium. In this way, the thermal sensitivity of the magneto-optical recording medium can be easily recognized by determining whether or not the signal intensity obtained by reading the magnetic information (magnetic domain) recorded on the magneto-optical recording medium is a specified amount. You can
【００１７】前記光磁気記録媒体の持つ熱感度は、磁性
体の組成、膜厚、膜数、基板の種類などによって異なる
ので、これらを総合したものをその光磁気記録媒体の熱
感度とし、その情報を何らかの方法でその媒体に記録す
ればよい。The thermal sensitivity of the magneto-optical recording medium varies depending on the composition of the magnetic material, the film thickness, the number of films, the type of the substrate, etc. Therefore, the total of these is taken as the thermal sensitivity of the magneto-optical recording medium. The information may be recorded on the medium in some way.
【００１８】前記光磁気記録媒体の温度分布の変動は、
前記光磁気記録媒体から得られる再生信号の強度により
検知してもよい。The fluctuation of the temperature distribution of the magneto-optical recording medium is
It may be detected by the intensity of a reproduction signal obtained from the magneto-optical recording medium.
【００１９】好ましくは、前記光磁気記録媒体の記録特
性の変動が、情報を記録する際に前記磁性層に形成され
る磁区の大きさを一定に保つように補償される。また、
前記光磁気記録媒体の再生特性の変動が、情報を再生す
る際に前記磁性層に形成された磁区の大きさを一定に保
つように補償される。Preferably, fluctuations in the recording characteristics of the magneto-optical recording medium are compensated so as to keep the size of the magnetic domains formed in the magnetic layer constant when recording information. Also,
Fluctuations in the reproduction characteristics of the magneto-optical recording medium are compensated so as to keep the size of the magnetic domains formed in the magnetic layer constant when reproducing information.
【００２０】好ましくは、情報を再生する際に前記磁性
層に形成された磁区の転写または変形が行なわれ、その
転写または変形が一定となるように前記光磁気記録媒体
の再生特性の変動が補償される。Preferably, when reproducing information, the magnetic domains formed in the magnetic layer are transferred or deformed, and fluctuations in reproduction characteristics of the magneto-optical recording medium are compensated so that the transfer or deformation is constant. To be done.
【００２１】前記光磁気記録媒体が、切断層を介して前
記記録用磁性層に隣接する再生層を有していると共に、
前記記録用磁性層の磁区が前記切断層を介して前記再生
層に転写されるようになっている場合、前記切断層の持
つ磁気的結合力の変動を補償するように磁界が印加され
るのが好ましい。The magneto-optical recording medium has a reproducing layer adjacent to the recording magnetic layer via a cutting layer, and
When the magnetic domain of the recording magnetic layer is transferred to the reproducing layer through the cutting layer, a magnetic field is applied so as to compensate for fluctuations in the magnetic coupling force of the cutting layer. Is preferred.
【００２２】（２） この発明の第２の光磁気記録方式
は、記録用の磁性層を持つ光磁気記録媒体にレーザ光を
照射し、それによって生じる前記磁性層の局所的温度上
昇によりその磁性層に磁区を形成して情報を記録し、前
記光磁気記録媒体にレーザ光を照射して前記磁区から前
記情報を再生する光磁気記録方式において、前記光磁気
記録媒体に補償用の磁性層を設け、その補償用磁性層が
発生する磁界によって、レーザ光照射の際に生じる前記
記録用磁性層の温度分布の変動を補償することを特徴と
する。(2) In the second magneto-optical recording method of the present invention, a magneto-optical recording medium having a magnetic layer for recording is irradiated with laser light, and the local temperature rise of the magnetic layer causes the magnetic property of the magnetic layer. In a magneto-optical recording system in which a magnetic domain is formed in a layer to record information, and the magneto-optical recording medium is irradiated with laser light to reproduce the information from the magnetic domain, a magnetic layer for compensation is provided on the magneto-optical recording medium. The magnetic field generated by the compensation magnetic layer is provided to compensate for variations in the temperature distribution of the recording magnetic layer that occurs during laser light irradiation.
【００２３】好ましくは、前記補償用の磁性層が発生す
る漏洩磁界および交換磁界の少なくとも一方が、前記情
報記録用の磁性層の温度分布の変動を補償するように温
度によって変動するようにする。Preferably, at least one of the leakage magnetic field and the exchange magnetic field generated by the compensating magnetic layer varies depending on the temperature so as to compensate for the variation in the temperature distribution of the information recording magnetic layer.
【００２４】前記光磁気記録媒体の温度分布の変動は、
前記光磁気記録媒体から得られる再生信号の強度により
検知してもよい。The fluctuation of the temperature distribution of the magneto-optical recording medium is
It may be detected by the intensity of a reproduction signal obtained from the magneto-optical recording medium.
【００２５】好ましくは、前記光磁気記録媒体の記録特
性の変動が、情報を記録する際に前記磁性層に形成され
る磁区の大きさを一定に保つように補償される。また、
前記光磁気記録媒体の再生特性の変動が、情報を再生す
る際に前記磁性層に形成された磁区の大きさを一定に保
つように補償される。Preferably, fluctuations in the recording characteristics of the magneto-optical recording medium are compensated so as to keep the size of the magnetic domains formed in the magnetic layer constant when recording information. Also,
Fluctuations in the reproduction characteristics of the magneto-optical recording medium are compensated so as to keep the size of the magnetic domains formed in the magnetic layer constant when reproducing information.
【００２６】好ましくは、情報を再生する際に前記磁性
層に形成された磁区の転写または変形が行なわれ、その
転写または変形が一定となるように前記光磁気記録媒体
の再生特性の変動が補償される。Preferably, when reproducing information, the magnetic domains formed in the magnetic layer are transferred or deformed, and fluctuations in reproduction characteristics of the magneto-optical recording medium are compensated so that the transfer or deformation is constant. To be done.
【００２７】前記光磁気記録媒体が、切断層を介して前
記記録用磁性層に隣接する再生層を有していると共に、
前記記録用磁性層の磁区が前記切断層を介して前記再生
層に転写されるようになっている場合、前記切断層の持
つ磁気的結合力の変動を補償するように磁界が印加され
るのが好ましい。The magneto-optical recording medium has a reproducing layer adjacent to the recording magnetic layer via a cutting layer, and
When the magnetic domain of the recording magnetic layer is transferred to the reproducing layer through the cutting layer, a magnetic field is applied so as to compensate for fluctuations in the magnetic coupling force of the cutting layer. Is preferred.
【００２８】（３） この発明の光磁気記録媒体は、基
板上に直接または下地層を介して形成された記録用の磁
性層を備えた光磁気記録媒体において、レーザ光照射の
際に生じる前記記録用磁性層の温度分布の変動を補償す
る補償用の磁性層を備えていることを特徴とする。(3) The magneto-optical recording medium according to the present invention is a magneto-optical recording medium having a recording magnetic layer formed directly on a substrate or via an underlayer, which is generated when the laser beam is irradiated. It is characterized in that it is provided with a compensating magnetic layer for compensating for variations in the temperature distribution of the recording magnetic layer.
【００２９】好ましくは、前記補償用磁性層が発生する
漏洩磁界および交換磁界の少なくとも一方が、前記記録
用磁性層の温度分布の変動を補償するように温度によっ
て変動する。Preferably, at least one of the leakage magnetic field and the exchange magnetic field generated by the compensating magnetic layer varies depending on the temperature so as to compensate for the variation in the temperature distribution of the recording magnetic layer.
【００３０】また、好ましくは、切断層を介して前記記
録用磁性層に隣接する再生層を有していると共に、前記
記録用磁性層の磁区が前記切断層を介して前記再生層に
転写されるように構成され、前記切断層の膜厚が２０ｎ
ｍ以下とされる。Further, preferably, a reproducing layer is provided adjacent to the recording magnetic layer via a cutting layer, and the magnetic domain of the recording magnetic layer is transferred to the reproducing layer via the cutting layer. And the thickness of the cutting layer is 20 n.
m or less.
【００３１】[0031]
【作用】この発明の第１の光磁気記録方式では、レーザ
光照射の際に生じる磁性層の温度分布の変動を検知し、
その検知結果に応じて光磁気記録媒体の記録特性および
再生特性の少なくとも一方の変動を補償するので、光磁
気記録媒体の周囲（環境）温度や移動速度などの変動に
対する記録・再生特性の変動を小さくし、あるいはなく
すことができる。According to the first magneto-optical recording method of the present invention, the variation in the temperature distribution of the magnetic layer caused by the laser light irradiation is detected,
Since the fluctuation of at least one of the recording characteristic and the reproducing characteristic of the magneto-optical recording medium is compensated according to the detection result, the fluctuation of the recording / reproducing characteristic with respect to the fluctuation of the ambient (environmental) temperature of the magneto-optical recording medium or the moving speed is compensated. It can be made smaller or even eliminated.
【００３２】この発明の第２の光磁気記録方式では、光
磁気記録媒体に補償用の磁性層を設け、その補償用磁性
層によって、レーザ光照射の際に生じる記録用磁性層の
温度分布の変動を補償するので、第１の光磁気記録方式
の場合と同様に、光磁気記録媒体の周囲（環境）温度や
移動速度などの変動に対する記録・再生特性の変動を小
さくし、あるいはなくすことができる。In the second magneto-optical recording method of the present invention, a magneto-optical recording medium is provided with a compensating magnetic layer, and the compensating magnetic layer is used to determine the temperature distribution of the recording magnetic layer generated upon irradiation with laser light. Since the fluctuation is compensated, it is possible to reduce or eliminate the fluctuation of the recording / reproducing characteristics with respect to the fluctuation of the ambient (environmental) temperature of the magneto-optical recording medium, the moving speed, etc., as in the case of the first magneto-optical recording method. it can.
【００３３】この発明の光磁気記録媒体は、レーザ光照
射の際に生じる記録用の磁性層の温度分布の変動を補償
する補償用の磁性層を備えているので、第１および第２
の光磁気記録方式の場合と同様に、光磁気記録媒体の周
囲（環境）温度や移動速度などの変動に対する記録・再
生特性の変動を小さくし、あるいはなくすことができ
る。Since the magneto-optical recording medium of the present invention is provided with the compensating magnetic layer for compensating for the temperature distribution variation of the recording magnetic layer caused by the irradiation of the laser beam, the first and second magneto-optical recording media are provided.
As in the case of the magneto-optical recording method, the fluctuation of the recording / reproducing characteristics with respect to the fluctuation of the ambient (environmental) temperature of the magneto-optical recording medium or the moving speed can be reduced or eliminated.
【００３４】この発明の第１および第２の光磁気記録方
式および光磁気記録媒体では、光磁気記録媒体の周囲
（環境）温度や移動速度などの変動に対する記録・再生
特性の変動が小さくなり、あるいはなくなるので、光磁
気記録媒体の磁性層として使用する磁性材料の選択の幅
が広くなる。In the first and second magneto-optical recording methods and magneto-optical recording media of the present invention, fluctuations in recording / reproducing characteristics with respect to fluctuations in ambient (environmental) temperature and moving speed of the magneto-optical recording media are reduced, Alternatively, the selection range of the magnetic material used as the magnetic layer of the magneto-optical recording medium is widened.
【００３５】[0035]
【実施例】以下、この発明の実施例について詳細に説明
する。Embodiments of the present invention will be described in detail below.
【００３６】［第１実施例］図１はこの発明の光磁気記
録方式の第１実施例を示す。◆光磁気ディスク１０はス
ピンドル３９に係止されており、所定速度で回転する。
光磁気ディスク１０はカートリッジ２０の内部に収容さ
れている。回転数検出器４０は、スピンドル３２の回転
数を検出し、その結果を電磁石駆動系３７に送る。[First Embodiment] FIG. 1 shows a first embodiment of the magneto-optical recording system of the present invention. The magneto-optical disk 10 is locked on the spindle 39 and rotates at a predetermined speed.
The magneto-optical disk 10 is housed inside a cartridge 20. The rotation speed detector 40 detects the rotation speed of the spindle 32 and sends the result to the electromagnet drive system 37.
【００３７】電磁石４１は、光磁気ディスク１０の近傍
に設けられており、電磁石駆動系３７によって駆動され
る。電磁石４１は、記録時あるいは消去時には、光磁気
ディスク１０に記録用磁界あるいは消去用磁界を印加す
る。また、再生時には後述の補償用磁界を印加する。The electromagnet 41 is provided near the magneto-optical disk 10 and is driven by the electromagnet drive system 37. The electromagnet 41 applies a recording magnetic field or an erasing magnetic field to the magneto-optical disk 10 at the time of recording or erasing. A reproducing magnetic field, which will be described later, is applied during reproduction.
【００３８】光ヘッド３０は、光源としてのレーザ３１
と、レーザ光を分割するビームスプリッタ３２と、レー
ザ光を集束して光磁気ディスク１０の表面に照射する集
束用レンズ３３と光検出器３４とを有している。The optical head 30 has a laser 31 as a light source.
A beam splitter 32 for splitting the laser light, a focusing lens 33 for focusing the laser light and irradiating it on the surface of the magneto-optical disk 10, and a photodetector 34.
【００３９】レーザ３１は、レーザ駆動系３６により駆
動され、記録および消去時には、高パワーのレーザ光を
光磁気ディスク１０の表面に照射する。再生時には、低
パワーのレーザ光を光磁気ディスク１０の表面に照射す
る。The laser 31 is driven by a laser drive system 36, and irradiates the surface of the magneto-optical disk 10 with high-power laser light during recording and erasing. During reproduction, low power laser light is applied to the surface of the magneto-optical disk 10.
【００４０】光検出器３４は、再生時に、光磁気ディス
ク１０の表面から反射されるレーザ光の強度を検出し、
その結果を信号制御系３５および電磁石駆動系３７にそ
れぞれ送る。The photodetector 34 detects the intensity of laser light reflected from the surface of the magneto-optical disk 10 during reproduction,
The results are sent to the signal control system 35 and the electromagnet drive system 37, respectively.
【００４１】ヘッド位置検出器３８は、光ヘッド３０の
位置を検出し、その結果を電磁石駆動系３７に送る。そ
れに応じて、電磁石駆動系３７は電磁石４１の位置を変
更する。The head position detector 38 detects the position of the optical head 30 and sends the result to the electromagnet drive system 37. In response to this, the electromagnet drive system 37 changes the position of the electromagnet 41.
【００４２】入力信号および出力信号を制御する信号制
御系３５は、レーザ駆動系３６を制御し、レーザ３１に
所定パワーでレーザ光を発生させる。また、光検出器３
４からの出力を受け、その結果をレーザ駆動系３６に送
る。The signal control system 35 for controlling the input signal and the output signal controls the laser drive system 36 to cause the laser 31 to generate a laser beam with a predetermined power. Also, the photodetector 3
4 and outputs the result to the laser drive system 36.
【００４３】温度検出器４２は、非接触で測定対象の温
度を測定できる放射型温度計からなり、光磁気ディスク
１０の温度を検出してその結果を電磁石駆動系３７に送
る。電磁石駆動系３７は、送られた検知結果に応じて電
磁石４１の発生する磁界の強度を制御する。The temperature detector 42 is composed of a radiation thermometer which can measure the temperature of the object to be measured without contact, detects the temperature of the magneto-optical disk 10 and sends the result to the electromagnet drive system 37. The electromagnet drive system 37 controls the strength of the magnetic field generated by the electromagnet 41 according to the sent detection result.
【００４４】この実施例で用いる光磁気ディスクの構成
を図５に示す。この光磁気ディスク１０は、表面にグル
ーブを形成したガラス基板１１上に、厚さ８０ｎｍのＳ
ｉＮ膜よりなる保護層１２と、厚さ６０ｎｍのＴｂ27Ｆ
ｅ63Ｃｏ10膜よりなる記録層１３と、厚さ８０ｎｍのＳ
ｉＮ膜よりなる保護層１４とを、スパッタ法により順に
積層したものである。The structure of the magneto-optical disk used in this embodiment is shown in FIG. This magneto-optical disk 10 comprises an S-layer having a thickness of 80 nm on a glass substrate 11 having a groove formed on its surface.
Protective layer 12 made of iN film and 60 nm thick Tb 27 F
The recording layer 13 made of an e 63 Co 10 film and an S layer having a thickness of 80 nm
The protective layer 14 made of an iN film is sequentially laminated by a sputtering method.
【００４５】この光磁気記録方式では、光磁気ディスク
１０の温度が温度検出器４２によって常に検出され、そ
の検出結果に応じて、電磁石４１の発生する磁界すなわ
ち光磁気ディスク１０に印加される磁界の強度が変化す
る。この磁界強度の変化は、記録時に、光磁気ディスク
１０の記録層１３に形成される磁区の径が一定に保たれ
るように設定されている。In this magneto-optical recording method, the temperature of the magneto-optical disk 10 is constantly detected by the temperature detector 42, and the magnetic field generated by the electromagnet 41, that is, the magnetic field applied to the magneto-optical disk 10 is detected according to the detection result. The intensity changes. The change in the magnetic field strength is set so that the diameter of the magnetic domain formed in the recording layer 13 of the magneto-optical disk 10 is kept constant during recording.
【００４６】すなわち、光磁気ディスク１０にレーザ光
が照射される時、それによって磁性層１３に形成される
磁区の大きさは、照射されるレーザ光のパワーと印加さ
れる磁界の強度により規定される。磁界強度が一定の場
合、周囲温度の上昇などによって、レーザ光照射時の光
磁気ディスク１０の温度分布が高温側に移動すると、図
１４に示すように、「昇温部」すなわち磁性層１３の温
度が磁区形成温度よりも高い部分の面積が大きくなるの
で、磁区径は増大する。逆に、レーザ光照射時の光磁気
ディスク１０の温度分布が低温側に移動すると、「昇温
部」の面積が小さくなるので、磁区径は減少する。That is, when the magneto-optical disk 10 is irradiated with the laser beam, the size of the magnetic domain formed in the magnetic layer 13 by the laser beam is defined by the power of the irradiated laser beam and the strength of the applied magnetic field. It When the magnetic field strength is constant and the temperature distribution of the magneto-optical disk 10 at the time of laser light irradiation moves to the high temperature side due to an increase in ambient temperature, as shown in FIG. Since the area where the temperature is higher than the magnetic domain formation temperature is large, the magnetic domain diameter is increased. On the contrary, when the temperature distribution of the magneto-optical disk 10 at the time of laser light irradiation moves to the low temperature side, the area of the “temperature rising portion” becomes small, and the magnetic domain diameter decreases.
【００４７】また、磁区径を一定にするのに要する磁界
強度と温度とは、一般的に図１５のような関係を持つ。
図１５から分かるように、周囲温度がＴａからＴｂへ上
昇した場合、同じ磁区径を保つには、磁区の形成を助け
る向きの磁界の強度をＨａからＨｂへ下げればよい。Further, the magnetic field strength required to keep the magnetic domain diameter constant and the temperature generally have a relationship as shown in FIG.
As can be seen from FIG. 15, when the ambient temperature rises from Ta to Tb, in order to maintain the same magnetic domain diameter, the strength of the magnetic field in the direction that assists the formation of magnetic domains may be lowered from Ha to Hb.
【００４８】そこで、光磁気ディスク１０の温度変動に
より生じる磁区径の変化を補償するように、換言すれ
ば、光磁気ディスク１０の温度変動があっても磁区径が
常に一定に保たれるように、電磁石駆動系３７における
磁界強度制御系が設定されている。Therefore, the change in the magnetic domain diameter caused by the temperature change of the magneto-optical disk 10 is compensated, in other words, the magnetic domain diameter is always kept constant even if the temperature of the magneto-optical disk 10 changes. A magnetic field strength control system in the electromagnet drive system 37 is set.
【００４９】この実施例では、回転数検出器４０によ
り、光磁気ディスク１０の回転数も常に検出され、その
結果が電磁石駆動系３７に送られる。そして、その回転
数が所定の値になっているか否かを判定し、その判定結
果によっても電磁石４１の発生する磁界の強度が調整さ
れる。これは、記録時に、光磁気ディスク１０の記録層
１３に形成される磁区の径は、光磁気ディスク１０の回
転数の変動によっても変化するため、それに起因する磁
区径の変化を補償するためである。In this embodiment, the rotation speed detector 40 constantly detects the rotation speed of the magneto-optical disk 10 and sends the result to the electromagnet drive system 37. Then, it is determined whether or not the rotation speed has reached a predetermined value, and the strength of the magnetic field generated by the electromagnet 41 is also adjusted according to the determination result. This is because the diameter of the magnetic domain formed in the recording layer 13 of the magneto-optical disk 10 at the time of recording also changes due to the fluctuation of the rotation speed of the magneto-optical disk 10, so that the change in the magnetic domain diameter caused by it is compensated. is there.
【００５０】この実施例ではさらに、光検出器３４によ
り再生信号が検出され、その結果が電磁石駆動系３７に
送られるようになっている。このため、その再生信号の
強度が所定の値になっているか否かを判定して、電磁石
４１の発生する磁界の強度が調整される。これは、光磁
気ディスク１０の温度や回転数によって再生時に磁区の
形状が変化すると、それに応じて再生信号の強度が変化
しノイズが発生する。このため、磁区の形状が常に一定
に保たれるように、再生時にも光磁気ディスク１０に磁
界を印加するのである。Further, in this embodiment, the reproduction signal is detected by the photodetector 34 and the result is sent to the electromagnet drive system 37. Therefore, the strength of the magnetic field generated by the electromagnet 41 is adjusted by determining whether or not the strength of the reproduction signal has reached a predetermined value. This is because when the shape of the magnetic domain changes during reproduction depending on the temperature and the number of rotations of the magneto-optical disk 10, the intensity of the reproduction signal changes accordingly and noise is generated. Therefore, a magnetic field is applied to the magneto-optical disk 10 during reproduction so that the shape of the magnetic domain is always kept constant.
【００５１】この実施例では、光磁気ディスク１０の温
度およびその回転数、並びに再生信号の強度を検出する
ようにしているが、再生信号の強度の検出は必ずしも必
要ではなく、また、光磁気ディスク１０の温度およびそ
の回転数のうちのいずれかを設ければ足りる。In this embodiment, the temperature of the magneto-optical disk 10 and the number of revolutions thereof, and the strength of the reproduction signal are detected, but the detection of the strength of the reproduction signal is not always necessary. It is sufficient to provide either the temperature of 10 or the number of rotations thereof.
【００５２】以上の構成を持つ光磁気記録方式で実際に
情報の記録および再生を行なったところ、次のような結
果が得られた。When information was actually recorded and reproduced by the magneto-optical recording system having the above-mentioned structure, the following results were obtained.
【００５３】まず、光磁気ディスク１０を線速度８ｍ／
ｓｅｃで回転させ、温度検出器４２によって光磁気ディ
スク１０の温度を検出したところ、１５゜Ｃであった。
電磁石４１により印加される磁界を３２ｋＡ／ｍ、レー
ザ光パワーを７ｍｗとして、４ＭＨｚの信号を光変調方
式で光磁気ディスク１０に記録した。その後、記録した
信号をパワー２ｍｗのレーザ光で再生したところ、その
信号対ノイズ比（Ｓ／Ｎ）は５４ｄＢであった。First, the magneto-optical disk 10 is moved at a linear velocity of 8 m /
When the temperature of the magneto-optical disk 10 was detected by the temperature detector 42 after rotating for sec, it was 15 ° C.
The magnetic field applied by the electromagnet 41 was 32 kA / m, the laser light power was 7 mw, and a 4 MHz signal was recorded on the magneto-optical disk 10 by the optical modulation method. Then, when the recorded signal was reproduced with a laser beam having a power of 2 mw, the signal-to-noise ratio (S / N) was 54 dB.
【００５４】次に、光磁気ディスク１０の温度を５５゜
Ｃとした以外は、同じ条件で前記と同じ信号を記録し
た。記録した信号を前記と同じ条件で再生したところ、
Ｓ／Ｎは５２ｄＢに低下した。Next, the same signal as above was recorded under the same conditions except that the temperature of the magneto-optical disk 10 was set to 55 ° C. When the recorded signal was reproduced under the same conditions as above,
The S / N dropped to 52 dB.
【００５５】そこで、光磁気ディスク１０の温度を５５
゜Ｃの時に印加磁界が２４ｋＡ／ｍとなるように調整し
たところ、再生時のＳ／Ｎは５４ｄＢとなり、温度が１
５゜Ｃの時の値に回復した。これは、光磁気ディスク１
０の温度の変動により、最適な記録条件（記録される磁
区径）が変化したが、磁界強度の変化によりこの記録条
件の変化が補償されたことを示している。Therefore, the temperature of the magneto-optical disk 10 is set to 55.
When the applied magnetic field was adjusted to be 24 kA / m at ° C, the S / N during reproduction was 54 dB and the temperature was 1
It recovered to the value at 5 ° C. This is a magneto-optical disk 1
It is shown that the optimum recording condition (the recorded magnetic domain diameter) was changed by the temperature change of 0, but the change of the recording condition was compensated by the change of the magnetic field strength.
【００５６】次に、同じ光磁気ディスク１０を用い、記
録時の光磁気ディスク１０の線速度を８ｍ／ｓｅｃから
６ｍ／ｓｅｃに変化させた。線速度以外の記録条件は上
記と同様にした。この信号を同じ条件で再生したとこ
ろ、Ｓ／Ｎは２ｄＢ低下した。そこで、記録時の印加磁
界を３２ｋＡ／ｍから２３ｋＡ／ｍに下げたところ、こ
の低下分は回復した。これは、光磁気ディスク１０の線
速度すなわち回転数の変動により、最適な記録条件（記
録される磁区径）が変化したが、磁界強度の変化により
この記録条件の変化が補償されたことを示している。Next, using the same magneto-optical disk 10, the linear velocity of the magneto-optical disk 10 during recording was changed from 8 m / sec to 6 m / sec. The recording conditions other than the linear velocity were the same as above. When this signal was reproduced under the same conditions, the S / N dropped by 2 dB. Therefore, when the applied magnetic field at the time of recording was lowered from 32 kA / m to 23 kA / m, this reduced amount was recovered. This indicates that the optimum recording condition (the diameter of the magnetic domain to be recorded) changed due to the change in the linear velocity of the magneto-optical disk 10, that is, the rotation speed, but the change in the recording condition was compensated for due to the change in the magnetic field strength. ing.
【００５７】図１では、放射型の温度検出器４２を光磁
気ディスク１０から離して設けているが、図２に示すよ
うに、光磁気ディスク１０を固定したスピンドル３９の
適当な箇所に熱電対４４を取り付けてもよい。In FIG. 1, the radiation type temperature detector 42 is provided separately from the magneto-optical disk 10, but as shown in FIG. 2, a thermocouple is provided at an appropriate position on the spindle 39 to which the magneto-optical disk 10 is fixed. 44 may be attached.
【００５８】［第２実施例］図３はこの発明の光磁気記
録方式の第２実施例を示す。図３の各構成要素は、光磁
気ディスク１０ａと熱感度情報読み取り部４３とが異な
っている以外は、図２のそれと同じである。[Second Embodiment] FIG. 3 shows a second embodiment of the magneto-optical recording system of the present invention. Each component of FIG. 3 is the same as that of FIG. 2 except that the magneto-optical disk 10a and the thermal sensitivity information reading unit 43 are different.
【００５９】光磁気ディスク１０ａは、第１実施例の光
磁気ディスク１０と同じ層構成を有しているが、磁性層
１３に熱感度を示す情報Ａが記録されている点が異な
る。熱感度情報Ａは、磁性層１３の内部に設けられた専
用領域に磁気的に記録されている。熱感度情報Ａは、光
磁気ディスク１０ａの作製時（出荷時）に個別に検査す
ることにより、容易に得ることができる。The magneto-optical disk 10a has the same layer structure as that of the magneto-optical disk 10 of the first embodiment, except that the magnetic layer 13 has information A indicating thermal sensitivity recorded therein. The thermal sensitivity information A is magnetically recorded in a dedicated area provided inside the magnetic layer 13. The thermal sensitivity information A can be easily obtained by individually inspecting the magneto-optical disk 10a at the time of manufacture (shipment).
【００６０】熱感度情報読み取り部４３は磁気ヘッドを
備えており、光磁気ディスク１０ａがスピンドル３９に
セットされた時に、その磁気ヘッドにより光磁気ディス
ク１０ａに記録されている熱感度情報Ａを読み取って電
磁石駆動系３７に送る。こうして電磁石駆動系３７は、
使用する光磁気ディスク１０ａの持つ熱感度を容易に認
識することができる。電磁石駆動系３７は、認識した熱
感度に応じて、予め設定されている熱感度に対応した磁
界強度を定めたデータに基づいて電磁石４１が発生する
磁界の強度を制御し、光磁気ディスク１０ａの記録層１
３の磁区径が一定に保たれるようにする。The thermal sensitivity information reading section 43 is equipped with a magnetic head, and when the magneto-optical disk 10a is set on the spindle 39, the thermal sensitivity information A recorded on the magneto-optical disk 10a is read by the magnetic head. It is sent to the electromagnet drive system 37. Thus, the electromagnet drive system 37
The thermal sensitivity of the magneto-optical disc 10a used can be easily recognized. The electromagnet drive system 37 controls the strength of the magnetic field generated by the electromagnet 41 on the basis of the data defining the magnetic field strength corresponding to the preset thermal sensitivity according to the recognized thermal sensitivity, and controls the magnetic field strength of the magneto-optical disk 10a. Recording layer 1
The magnetic domain diameter of 3 should be kept constant.
【００６１】この実施例の光磁気記録方式では、使用す
る光磁気ディスク１０ａの持つ熱感度が熱感度情報読み
取り部４３によって検出され、その検出結果に応じて、
電磁石４１の発生する磁界すなわち光磁気ディスク１０
ａに印加される磁界の強度が変化する。この磁界強度の
変化は、記録時に、光磁気ディスク１０ａの記録層１３
に形成される磁区の径が一定に保たれるように設定され
ている。このため、前回使用した光磁気ディスク１０ａ
と今回使用する光磁気ディスク１０ａとが持つ熱感度が
異なっていても、磁区径は常に一定になる。In the magneto-optical recording system of this embodiment, the thermal sensitivity of the magneto-optical disk 10a to be used is detected by the thermal sensitivity information reading section 43, and according to the detection result,
Magnetic field generated by electromagnet 41, that is, magneto-optical disk 10
The strength of the magnetic field applied to a changes. This change in magnetic field strength is caused by the recording layer 13 of the magneto-optical disk 10a during recording.
It is set so that the diameter of the magnetic domain formed in is kept constant. Therefore, the previously used magneto-optical disk 10a
Even if the magneto-optical disk 10a used this time has different thermal sensitivity, the magnetic domain diameter is always constant.
【００６２】以上の構成を持つ光磁気記録方式で実際に
情報の記録および再生を行なったところ、次のような結
果が得られた。◆光磁気ディスク１０ａとして、第１実
施例の光磁気ディスク１０において記録層１３の厚さの
みを６０ｎｍから８０ｎｍに変えたものを作製し、第１
実施例と同様の条件で信号の記録・再生を行なった。こ
の光磁気ディスク１０ａでは、記録層１３の厚さが大き
くなって第１実施例の光磁気ディスク１０に比べて熱感
度が低下したため、再生時のＳ／Ｎが１．５ｄＢ低下し
た。When information was actually recorded and reproduced by the magneto-optical recording system having the above structure, the following results were obtained. As the magneto-optical disk 10a, the magneto-optical disk 10 of the first embodiment in which only the thickness of the recording layer 13 was changed from 60 nm to 80 nm was prepared.
Recording and reproduction of signals were performed under the same conditions as in the example. In this magneto-optical disk 10a, the recording layer 13 was thicker and the thermal sensitivity was lower than that of the magneto-optical disk 10 of the first embodiment, so the S / N ratio during reproduction was lowered by 1.5 dB.
【００６３】そこで、記録時に印加する磁界の強度を３
２ｋＡ／ｍから４０ｋＡ／ｍに変更したところ、この低
下分は回復した。これは、光磁気ディスク１０および１
０ａ間での熱感度の変動により、最適な記録条件（記録
される磁区径）が変化したが、磁界強度の変化によりこ
の記録条件の変化が補償されたことを示している。Therefore, the strength of the magnetic field applied during recording is set to 3
When the value was changed from 2 kA / m to 40 kA / m, this decrease recovered. This is a magneto-optical disk 10 and 1
It is shown that the optimum recording condition (recorded magnetic domain diameter) was changed by the change of the thermal sensitivity between 0a, but the change of the recording condition was compensated by the change of the magnetic field strength.
【００６４】図３では、熱感度情報Ａは、磁性層１３の
内部に設けられた専用領域に磁気的に記録されている
が、図４に示すように、カートリッジ２０の表面に熱感
度情報Ｂを例えばバーコードにより記録し、そのバーコ
ードをバーコード・リーダーを持つ熱感度情報読み取り
部４３によって読み取るようにしてもよい。In FIG. 3, the thermal sensitivity information A is magnetically recorded in a dedicated area provided inside the magnetic layer 13. However, as shown in FIG. 4, the thermal sensitivity information B is recorded on the surface of the cartridge 20. May be recorded by, for example, a bar code, and the bar code may be read by the thermal sensitivity information reading unit 43 having a bar code reader.
【００６５】［第３実施例］図６はこの発明の光磁気記
録方式の第３実施例に使用する光磁気ディスクを示す。
この光磁気ディスク５０は、表面にグルーブを形成した
ガラス基板５１上に、厚さ８０ｎｍのＳｉＮ膜よりなる
保護層５２と、厚さ６０ｎｍのＴｂ27Ｆｅ63Ｃｏ10膜よ
りなる記録層５３と、厚さ３０ｎｍのＤｙ25Ｆｅ68Ｃｏ
7膜よりなる磁界発生層５４と、厚さ８０ｎｍのＳｉＮ
膜よりなる保護層５５とを、スパッタ法により順に積層
したものである。磁界発生層５４は、記録層５３に対し
て交換磁界を及ぼしている。[Third Embodiment] FIG. 6 shows a magneto-optical disk used in the third embodiment of the magneto-optical recording system of the present invention.
The magneto-optical disk 50 includes a protective layer 52 made of a SiN film having a thickness of 80 nm and a recording layer 53 made of a Tb 27 Fe 63 Co 10 film having a thickness of 60 nm on a glass substrate 51 having a groove formed on the surface thereof. 30 nm thick Dy 25 Fe 68 Co
Magnetic field generating layer 54 consisting of 7 films and SiN having a thickness of 80 nm
A protective layer 55 made of a film is sequentially laminated by a sputtering method. The magnetic field generation layer 54 exerts an exchange magnetic field on the recording layer 53.
【００６６】この実施例の光磁気記録方式の光磁気ディ
スク５０以外の構成は、図１のそれと同じである。ただ
し、後述のように、周囲温度の変動に起因する光磁気デ
ィスク５０の温度分布の変動は、磁界発生層５４によっ
て補償されるので、温度検出器４２は設けなくてもよ
い。The structure other than the magneto-optical disk 50 of the magneto-optical recording system of this embodiment is the same as that of FIG. However, as will be described later, since the fluctuation of the temperature distribution of the magneto-optical disk 50 caused by the fluctuation of the ambient temperature is compensated by the magnetic field generation layer 54, the temperature detector 42 may not be provided.
【００６７】一般的に、ある磁性層からの漏洩磁界ある
いはその磁性層と隣接する他の磁性層との間に作用する
交換磁界の強度は、その磁性層の磁化の大きさに依存す
る。このため、周囲温度の上昇によりその磁性層の磁化
が減少すると、それに伴って前記漏洩磁界あるいは交換
磁界の強度も低下する。そこで、前記漏洩磁界あるいは
交換磁界を発生する磁性層の磁界の向きを、記録用の磁
性層の磁区の形成を助ける向きに設定しておくと、その
記録用の磁区の径の変動を抑制あるいは防止することが
可能である。Generally, the strength of the leakage magnetic field from a certain magnetic layer or the exchange magnetic field acting between the magnetic layer and another adjacent magnetic layer depends on the magnitude of the magnetization of the magnetic layer. For this reason, when the magnetization of the magnetic layer decreases due to the rise in ambient temperature, the strength of the leakage magnetic field or the exchange magnetic field also decreases accordingly. Therefore, if the direction of the magnetic field of the magnetic layer that generates the leakage magnetic field or the exchange magnetic field is set to the direction that helps the formation of the magnetic domain of the recording magnetic layer, the fluctuation of the diameter of the recording magnetic domain is suppressed or It is possible to prevent.
【００６８】前記磁界発生層５４が記録層５３に及ぼす
交換磁界の温度依存性は、記録温度すなわち磁区形成温
度付近において、記録層５３の保磁力の温度依存性と等
しくなるように設定してある。このため、記録温度付近
で光磁気ディスク５０の周囲温度が変動しても、磁界発
生層５４がその変動を補償するため、記録層５３での磁
区の形成に必要な磁界の強度は一定に保たれる。The temperature dependence of the exchange magnetic field exerted on the recording layer 53 by the magnetic field generating layer 54 is set to be equal to the temperature dependence of the coercive force of the recording layer 53 near the recording temperature, that is, the magnetic domain forming temperature. . Therefore, even if the ambient temperature of the magneto-optical disk 50 fluctuates near the recording temperature, the magnetic field generation layer 54 compensates for the fluctuation, so that the strength of the magnetic field necessary for forming magnetic domains in the recording layer 53 is kept constant. Be drunk
【００６９】例えば、周囲温度が高温側へシフトした場
合、磁界発生層５４がなければ、記録用磁界により形成
される磁区径は大きくなる（図１４参照）。しかし、こ
の実施例では、周囲温度のシフトに伴なって、そのシフ
ト状況に応じて磁界発生層５４から記録層５３へ与えら
れる交換磁界が弱くなるため、形成される磁区径の拡大
が防止される。For example, when the ambient temperature shifts to the high temperature side, the magnetic domain diameter formed by the recording magnetic field becomes large without the magnetic field generating layer 54 (see FIG. 14). However, in this embodiment, as the ambient temperature shifts, the exchange magnetic field applied from the magnetic field generation layer 54 to the recording layer 53 becomes weaker according to the shift condition, so that the formed magnetic domain diameter is prevented from expanding. It
【００７０】この光磁気ディスク５０を用いて、第１実
施例に示したのと同じ条件で信号の記録および再生を行
なったところ、記録時の周囲温度を１５゜Ｃから５５゜
Ｃに上昇させても、第１実施例のようなＳ／Ｎの変化は
見られなかった。これは、光磁気ディスク５０の温度の
変動により、磁界発生層５４がなければ最適な記録条件
（記録される磁区径）は変化するはずであるが、温度変
動に応じて磁界発生層５４の交換磁界の強度が変化した
ため、前記記録条件の変化が補償されたことを示してい
る。When signals were recorded and reproduced using the magneto-optical disk 50 under the same conditions as those shown in the first embodiment, the ambient temperature during recording was raised from 15 ° C to 55 ° C. However, no change in S / N as in the first embodiment was observed. This is because the optimum recording condition (magnetic domain diameter to be recorded) should change if the magnetic field generation layer 54 does not exist due to the temperature change of the magneto-optical disk 50, but the magnetic field generation layer 54 is replaced according to the temperature change. This indicates that the change in the recording condition was compensated for because the strength of the magnetic field changed.
【００７１】［第４実施例］図７〜図１０はこの発明の
光磁気記録方式の第４実施例を示す。この実施例は「磁
気超解像再生方式」により信号を再生するものである。
この実施例の光磁気記録方式の光磁気ディスク６０以外
の構成は、図１の第１実施例のそれと同じである。[Fourth Embodiment] FIGS. 7 to 10 show a fourth embodiment of the magneto-optical recording system of the present invention. In this embodiment, a signal is reproduced by the "magnetic super resolution reproducing system".
The configuration other than the magneto-optical disk 60 of the magneto-optical recording system of this embodiment is the same as that of the first embodiment of FIG.
【００７２】光磁気ディスク６０の温度の変動により、
再生時にレーザ光照射により記録磁区が変形する可能性
がある。この記録磁区の形状の不安定性はノイズの発生
に繋がる。そこで、この実施例では、磁区を常に一定の
形として読みだすために、再生時に外部より光磁気ディ
スク６０に磁界を印加し、その磁界の強度を光磁気ディ
スク６０の温度分布の変動に応じて制御する。Due to fluctuations in the temperature of the magneto-optical disk 60,
The recording magnetic domain may be deformed by laser light irradiation during reproduction. The instability of the shape of the recording magnetic domain leads to the generation of noise. Therefore, in this embodiment, in order to always read out the magnetic domain as a constant shape, a magnetic field is applied from the outside to the magneto-optical disk 60 at the time of reproduction, and the intensity of the magnetic field is changed according to the variation of the temperature distribution of the magneto-optical disk 60. Control.
【００７３】この実施例に使用する光磁気ディスクの構
成を図７に示す。この光磁気ディスク６０は、表面にグ
ルーブを形成したガラス基板６１上に、厚さ８０ｎｍの
ＳｉＮ膜よりなる保護層６２と、厚さ５０ｎｍのＧｄ
２５Ｆｅ50Ｃｏ25膜よりなる再生層６３と、厚さ２０ｎ
ｍのＴｂ25Ｄｙ10Ｆｅ65膜よりなる切断層６４と、厚さ
２０ｎｍのＴｂ27Ｆｅ63Ｃｏ10膜よりなる記録層６５
と、厚さ８０ｎｍのＳｉＮ膜よりなる保護層６６とを、
スパッタ法により順に積層したものである。The structure of the magneto-optical disk used in this embodiment is shown in FIG. This magneto-optical disc 60 has a protective layer 62 made of a SiN film having a thickness of 80 nm and a Gd layer having a thickness of 50 nm on a glass substrate 61 having a groove formed on the surface thereof.
A reproducing layer 63 made of a 25 Fe 50 Co 25 film and having a thickness of 20 n
m of the Tb 25 Dy 10 Fe 65 film as a cutting layer 64 and a 20 nm thick Tb 27 Fe 63 Co 10 film as the recording layer 65.
And a protective layer 66 made of a SiN film having a thickness of 80 nm,
The layers are sequentially stacked by the sputtering method.
【００７４】記録層６５には、情報を記録するための磁
区が保持される。記録層６５に記録された磁区は、切断
層６４の磁気的な結合力を介して再生層６３に転写さ
れ、その再生層６３に転写された磁区から情報が再生さ
れる。切断層６４は、その磁気的な結合力により記録層
６５の記録磁区を再生層６３に転写し、その磁気的な結
合力の消滅により記録層６５と再生層６３とを切断す
る。The recording layer 65 holds magnetic domains for recording information. The magnetic domain recorded in the recording layer 65 is transferred to the reproducing layer 63 via the magnetic coupling force of the cutting layer 64, and the information is reproduced from the magnetic domain transferred to the reproducing layer 63. The cutting layer 64 transfers the recording magnetic domain of the recording layer 65 to the reproducing layer 63 by its magnetic coupling force, and cuts the recording layer 65 and the reproducing layer 63 by disappearing of the magnetic coupling force.
【００７５】磁気超解像再生方式の原理を図１０を用い
て詳細に説明すると、次の通りである。光磁気ディスク
６０に再生用のレーザ光を照射した場合、光磁気ディス
ク６０は回転移動しているので、照射されたレーザ光に
より加熱昇温される部分はレーザ光スポットの後部（光
磁気ディスク６０のトラック方向の後部）に生成され
る。The principle of the magnetic super resolution reproducing method will be described in detail with reference to FIG. When the reproducing laser light is irradiated onto the magneto-optical disk 60, the magneto-optical disk 60 is rotating and moving, so that the portion heated by the irradiated laser light is heated at the rear portion (the magneto-optical disk 60). In the track direction).
【００７６】切断層６４が与える磁気的結合力は温度に
敏感なため、図１０の低温部では結合力が強く、高温部
では結合力が弱くなる。このため、高温部では、再生層
６３の記録磁区が外部から印加される磁界によって容易
に反転し、記録層６５の記録磁区が現われない。低温部
では、再生層６３に記録層６５の記録磁区がそのまま現
われるため、再生されるのは低温部にある記録磁区のみ
となる。こうして、レーザ光スポットよりも小さな磁区
を確実に再生することが可能となる。Since the magnetic coupling force given by the cutting layer 64 is sensitive to temperature, the coupling force is strong in the low temperature portion and weak in the high temperature portion in FIG. Therefore, in the high temperature portion, the recording magnetic domain of the reproducing layer 63 is easily reversed by the magnetic field applied from the outside, and the recording magnetic domain of the recording layer 65 does not appear. In the low temperature portion, the recording magnetic domain of the recording layer 65 appears in the reproducing layer 63 as it is, so that only the recording magnetic domain in the low temperature portion is reproduced. In this way, it is possible to reliably reproduce a magnetic domain smaller than the laser light spot.
【００７７】磁気超解像再生方式では、以上のようにし
て、再生層６３によりレーザ光スポット内に視野を制限
するマスクとなる磁区が形成され、それによって再生信
号の得られる領域が縮小する結果、高分解能が確保され
るものである。しかし、再生層６３のマスクとなる磁区
は、レーザ光照射による昇温により形成されるので、周
囲温度の変動などによりその磁区の大きさが変化して超
解像再生特性が変動する恐れがある。As described above, in the magnetic super-resolution reproducing method, the reproducing layer 63 forms a magnetic domain serving as a mask for limiting the field of view in the laser beam spot, and as a result, the area where the reproduced signal can be obtained is reduced. , High resolution is ensured. However, since the magnetic domain that serves as a mask of the reproducing layer 63 is formed by the temperature rise caused by laser light irradiation, there is a possibility that the size of the magnetic domain may change due to changes in ambient temperature and the super-resolution reproducing characteristics may change. .
【００７８】この第４実施例では、第１〜第３の実施例
と同様に、図１に示す構成において、記録時に、温度検
出器４２により光磁気ディスク６０の温度を検出し、そ
の温度に応じて最適な強度の磁界を電磁石４１により印
加するようにしているが、さらに再生時においても、温
度検出器４２により光磁気ディスク６０の温度を検出
し、その温度に応じて最適な強度の磁界を電磁石４１に
より印加するようにしている。再生時に印加される磁界
の強度は、光磁気ディスク６０の温度変動により生じる
切断層６４の磁気的結合力の変化を補償するように、換
言すれば、光磁気ディスク６０の温度変動があっても磁
気的結合力が常に一定に保たれるように設定されてい
る。このため、周囲温度の変動により超解像再生特性が
変動する恐れがない。In the fourth embodiment, similarly to the first to third embodiments, in the structure shown in FIG. 1, the temperature of the magneto-optical disk 60 is detected by the temperature detector 42 at the time of recording and the temperature is detected. Accordingly, the magnetic field having the optimum strength is applied by the electromagnet 41. However, even during reproduction, the temperature of the magneto-optical disk 60 is detected by the temperature detector 42, and the magnetic field having the optimum strength is detected according to the temperature. Is applied by the electromagnet 41. The strength of the magnetic field applied during reproduction compensates for the change in the magnetic coupling force of the cutting layer 64 caused by the temperature change of the magneto-optical disk 60, in other words, even if the temperature change of the magneto-optical disk 60 occurs. It is set so that the magnetic coupling force is always kept constant. Therefore, there is no fear that the super-resolution reproduction characteristic will change due to the change in ambient temperature.
【００７９】以上の構成を持つ光磁気記録方式で実際に
情報の記録および再生を行なった。光磁気ディスク６０
を線速度１０ｍ／ｓｅｃで回転させ、レーザ光パワーを
変えて再生信号強度を測定した。再生層６３に転写され
る磁区の径は０．４μｍとした。得られた再生信号の強
度を図８に示す。超解像による再生信号の増強が得られ
ている。Information was actually recorded and reproduced by the magneto-optical recording system having the above configuration. Magneto-optical disk 60
Was rotated at a linear velocity of 10 m / sec, the laser signal power was changed, and the reproduction signal intensity was measured. The diameter of the magnetic domain transferred to the reproducing layer 63 was 0.4 μm. The intensity of the obtained reproduction signal is shown in FIG. Enhancement of the reproduced signal by super-resolution has been obtained.
【００８０】印加磁界の強度が４８ｋＡ／ｍ、レーザ光
パワーが１．５ｍＷの時に、光磁気ディスク６０の温度
を３５゜Ｃから５５゜Ｃに上げたところ、図８に示すよ
うに、再生信号強度が４ｄＢ減少した。この減少は、高
温部の面積の増大により再生層６３のマスク磁区の面積
が拡大した結果（図１４参照）、反射光量が減少したた
めである。When the intensity of the applied magnetic field was 48 kA / m and the laser light power was 1.5 mW, the temperature of the magneto-optical disk 60 was raised from 35 ° C. to 55 ° C. As shown in FIG. The strength was reduced by 4 dB. This decrease is due to the increase in the area of the mask magnetic domain of the reproducing layer 63 due to the increase in the area of the high temperature portion (see FIG. 14), resulting in a decrease in the amount of reflected light.
【００８１】次に、磁界強度を４８ｋＡ／ｍから１６ｋ
Ａ／ｍに減少したところ、再生信号強度は温度が上がる
以前のレベルに回復した。これは、磁界強度の減少によ
り、マスク磁区の面積が元に戻ったことを示している。Next, the magnetic field strength is changed from 48 kA / m to 16 k
When it was reduced to A / m, the reproduced signal strength recovered to the level before the temperature was raised. This indicates that the area of the mask magnetic domain returned to the original due to the decrease of the magnetic field strength.
【００８２】このように、この実施例では、再生時に印
加する磁界の強度を切断層６４の磁気的結合力の変化を
補償するように設定しているため、周囲温度が変動して
も超解像再生特性が一定に保たれる。As described above, in this embodiment, the strength of the magnetic field applied during reproduction is set so as to compensate for the change in the magnetic coupling force of the cutting layer 64. The image reproduction characteristic is kept constant.
【００８３】切断層６４の磁気的結合力の変化を補償す
るための磁界の強度は、その変化の温度依存性に関係す
る。磁気的結合力の変化の温度依存性を小さくすると、
印加する磁界の強度が低減され、その結果、使用する電
磁石４１が小さくて済むようになる。よって、磁気的結
合力の変化の温度依存性はできるだけ小さくすることが
望まれる。The strength of the magnetic field for compensating the change in the magnetic coupling force of the cutting layer 64 is related to the temperature dependence of the change. By reducing the temperature dependence of the change in magnetic coupling force,
The strength of the applied magnetic field is reduced, and as a result, the electromagnet 41 used can be small. Therefore, it is desirable to minimize the temperature dependence of the change in the magnetic coupling force.
【００８４】そのためには、切断層６４の膜厚を２０ｎ
ｍ以下とし、さらに、切断層６４を磁気異方性や交換結
合力の小さな材料により形成するのが好ましい。◆例え
ば、図９に示すように、磁気的結合力を５０゜Ｃの温度
差に対して３２ｋＡ／ｍ（４００エルステッド）の変化
に抑えたい場合、切断層６４の膜厚を２０ｎｍ以下にす
ることによりそれを実現できる。切断層６４の膜厚が２
０ｎｍ以下になると、隣接する記録層６５と再生層６３
の影響を受けて、切断層６４の磁化が温度上昇により消
失する温度が不明瞭となる。その結果、切断層６４の磁
化すなわち磁気的結合力の温度依存性が小さくなるから
である。For that purpose, the thickness of the cutting layer 64 is set to 20 n.
It is preferable that the thickness is not more than m and the cutting layer 64 is formed of a material having a small magnetic anisotropy or an exchange coupling force. ◆ For example, as shown in FIG. 9, when it is desired to suppress the magnetic coupling force to a change of 32 kA / m (400 oersted) with respect to a temperature difference of 50 ° C., the thickness of the cutting layer 64 should be 20 nm or less. Can achieve it. The thickness of the cutting layer 64 is 2
When it becomes 0 nm or less, the recording layer 65 and the reproducing layer 63 which are adjacent to each other are
Under the influence of, the temperature at which the magnetization of the cutting layer 64 disappears due to the temperature rise becomes unclear. As a result, the temperature dependence of the magnetization of the cutting layer 64, that is, the magnetic coupling force is reduced.
【００８５】磁気異方性や交換結合力の小さな材料を選
択するのは、磁気的結合力の大きさは磁気異方性および
交換結合力に依存するので、それらの小さい材料を選択
することにより磁気的結合力を小さくすることができる
からである。例えば、ここで用いているＴｂ25Ｄｙ10Ｆ
ｅ65膜に代えて、ＴｂまたはＤｙをＧｄに代えた材料を
用いると、磁気的結合力がいっそう小さくなる。非磁性
物質（例えば、Ｔｉ、Ｖ、Ｚｒ、Ｎｂ、Ｃｒ、Ｍｎ、Ｎ
ｉ、Ｃｕ、Ｚｎ、Ｂ、Ｃ、Ａｌ、Ｓｉ、Ｇｅ、Ｍｏ、Ｒ
ｈ、Ｐｄ、Ｃｕ、Ａｇ、Ａｕ、Ｔａ、Ｗ、Ｉｒ、Ｐｅ等
の遷移金属）を添加してもよい。A material having a small magnetic anisotropy or an exchange coupling force is selected because the magnitude of the magnetic coupling force depends on the magnetic anisotropy and the exchange coupling force. This is because the magnetic coupling force can be reduced. For example, Tb 25 Dy 10 F used here
When a material in which Tb or Dy is replaced by Gd is used instead of the e 65 film, the magnetic coupling force is further reduced. Non-magnetic material (eg Ti, V, Zr, Nb, Cr, Mn, N
i, Cu, Zn, B, C, Al, Si, Ge, Mo, R
h, Pd, Cu, Ag, Au, Ta, W, Ir, Pe and other transition metals) may be added.
【００８６】切断層６４のキュリー点は、それに隣接す
る記録層６５および再生層６３のキュリー点よりも低く
なる（切断層６４のキュリー点が最低となる）ように選
ばれる。これは超解像再生方式の原理に基づく。つま
り、レーザ光の照射時に、所定温度で磁気的結合力を失
って記録層６５と再生層６３とを磁気的に遮断でき、且
つ、その際に記録層６５および再生層６３が磁化を失わ
ないようにするためである。The Curie point of the cutting layer 64 is selected to be lower than the Curie points of the recording layer 65 and the reproducing layer 63 adjacent thereto (the Curie point of the cutting layer 64 is the lowest). This is based on the principle of the super-resolution reproduction method. That is, when the laser beam is irradiated, the recording layer 65 and the reproducing layer 63 can be magnetically shielded by losing the magnetic coupling force at a predetermined temperature, and at that time, the recording layer 65 and the reproducing layer 63 do not lose their magnetization. To do so.
【００８７】これらの点を考慮し、切断層６４の厚さを
１０ｎｍにした以外は光磁気ディスク６０と同じ構成の
光磁気ディスクを作製して、上記と同様にして再生信号
強度を測定した。その結果、補償に必要な磁界の強度を
約２０％減少することができた。Taking these points into consideration, a magneto-optical disk having the same structure as the magneto-optical disk 60 except that the thickness of the cutting layer 64 was set to 10 nm was prepared, and the reproduction signal intensity was measured in the same manner as above. As a result, the strength of the magnetic field required for compensation could be reduced by about 20%.
【００８８】さらに、切断層６４としてＤｙ30Ｆｅ70膜
を用いた以外は光磁気ディスク６０と同じ構成の光磁気
ディスクを作製し、上記と同様にして再生信号強度を測
定した。その結果、補償に必要な磁界の強度を約５０％
に削減することができた。Further, a magneto-optical disk having the same structure as the magneto-optical disk 60 except that a Dy 30 Fe 70 film was used as the cutting layer 64 was prepared, and the reproduction signal intensity was measured in the same manner as above. As a result, the strength of the magnetic field required for compensation is about 50%.
Could be reduced to
【００８９】［第５実施例］図１１はこの発明の光磁気
記録方式の第５実施例に使用する光磁気ディスクを示
す。この光磁気ディスク７０は、表面にグルーブを形成
したガラス基板７１上に、厚さ８０ｎｍのＳｉＮ膜より
なる保護層７２と、厚さ２０ｎｍのＴｂ27Ｆｅ63Ｃｏ10
膜よりなる記録層７３と、厚さ５ｎｍのＳｉＮ膜よりな
る絶縁層７４と、厚さ４０ｎｍのＴｂ25Ｆｅ53Ｃｏ22膜
よりなる磁界発生層７５と、厚さ８０ｎｍのＳｉＮ膜よ
りなる保護層７６とを、スパッタ法により順に積層した
ものである。[Fifth Embodiment] FIG. 11 shows a magneto-optical disk used in the fifth embodiment of the magneto-optical recording system of the present invention. This magneto-optical disk 70 has a protective layer 72 made of a SiN film having a thickness of 80 nm and a Tb 27 Fe 63 Co 10 film having a thickness of 20 nm on a glass substrate 71 having a groove formed on the surface thereof.
A recording layer 73 made of a film, an insulating layer 74 made of a SiN film having a thickness of 5 nm, a magnetic field generating layer 75 made of a Tb 25 Fe 53 Co 22 film having a thickness of 40 nm, and a protective layer made of a SiN film having a thickness of 80 nm. 76 and 76 are sequentially laminated by a sputtering method.
【００９０】この磁界発生層７５が発生する漏洩磁界
は、絶縁層７４を介して記録層７３に及んでいるが、こ
の漏洩磁界の温度依存性は、記録温度付近で記録層７３
の保磁力の温度依存性と等しくなるように設定してある
ので、この記録温度付近で光磁気ディスク５０の温度が
変動しても、磁区形成に必要な磁界は変動しない。The leakage magnetic field generated by the magnetic field generating layer 75 reaches the recording layer 73 through the insulating layer 74, and the temperature dependency of this leakage magnetic field is near the recording temperature.
Since the coercive force is set to be equal to the temperature dependence of the coercive force, even if the temperature of the magneto-optical disk 50 fluctuates near this recording temperature, the magnetic field required for magnetic domain formation does not fluctuate.
【００９１】この光磁気ディスク７０は、第３実施例の
光磁気ディスク５０と同様に磁界発生層を有している。
しかし、光磁気ディスク５０では、磁界発生層５４が記
録層５３に直接接しており、それら両層５３および５４
の間に作用する交換磁界を利用しているのに対し、この
第５実施例の光磁気ディスク７０では、磁界発生層７５
が絶縁層７４を介して記録層７３に接しており、それら
両層７３および７５の間に作用する漏洩磁界を利用して
いる点で、両者は異なる。The magneto-optical disk 70 has a magnetic field generating layer like the magneto-optical disk 50 of the third embodiment.
However, in the magneto-optical disk 50, the magnetic field generation layer 54 is in direct contact with the recording layer 53, and both of these layers 53 and 54.
In contrast to the use of the exchange magnetic field acting between the magnetic field generating layer 75 and the magneto-optical disk 70 of the fifth embodiment, the magnetic field generating layer 75
Are in contact with the recording layer 73 via the insulating layer 74, and the leakage magnetic field acting between the two layers 73 and 75 is utilized, so that they are different from each other.
【００９２】上記構成を持つ光磁気ディスク７０と共
に、比較用として、光磁気ディスク７０において絶縁層
７４と磁界発生層７５とを除いたものを作製し、両ディ
スクについて、３５゜Ｃおよび５５゜Ｃにおいて次のよ
うにして信号の記録を行ない、記録特性の変動を調べ
た。その際の光磁気ディスク７０の線速度は４ｍ／ｓｅ
ｃとした。For comparison, a magneto-optical disk 70 having the above-mentioned structure was prepared by removing the insulating layer 74 and the magnetic field generating layer 75 from the magneto-optical disk 70, and both disks were manufactured at 35 ° C. and 55 ° C. In the above, signals were recorded in the following manner, and fluctuations in recording characteristics were investigated. The linear velocity of the magneto-optical disk 70 at that time is 4 m / se.
c.
【００９３】まず、両ディスクに、４８ｋＡ／ｍ（６０
０エルステッド）の下向き磁界を印加しながら、パワー
１０ｍＷのレーザ光（連続光）を照射し、磁界発生層７
５の磁化の向きを下向きに揃えた。次に、３２ｋＡ／ｍ
（４００エルステッド）の上向き磁界を印加しながら、
パワー４ｍＷのレーザ光（連続光）を照射し、記録層７
３の磁化の向きのみを上向きにした。この状態で、３２
ｋＡ／ｍ（４００エルステッド）の下向きの磁界を印加
しながら、２ＭＨｚで変調されたレーザ光を両ディスク
に照射し、信号を記録した。First, 48 kA / m (60
While applying a downward magnetic field (0 Oersted), a laser beam (continuous light) having a power of 10 mW is irradiated to the magnetic field generating layer 7
The magnetization direction of No. 5 was aligned downward. Next, 32 kA / m
While applying an upward magnetic field (400 Oersted),
The recording layer 7 is irradiated with laser light (continuous light) having a power of 4 mW.
Only the direction of magnetization of No. 3 was upward. In this state, 32
While applying a downward magnetic field of kA / m (400 oersted), laser light modulated at 2 MHz was applied to both disks to record signals.
【００９４】比較用のディスクでは、この記録条件でデ
ィスクの温度を３５゜Ｃから５５゜Ｃに上げると、記録
可能となるレーザ光パワーが３．５ｍＷから３．３ｍＷ
に減少したが、図１１の光磁気ディスク７０では、記録
可能となるレーザ光パワーが３．７ｍＷで一定であっ
た。In the comparative disc, when the disc temperature was raised from 35 ° C. to 55 ° C. under this recording condition, the recordable laser light power was 3.5 mW to 3.3 mW.
However, in the magneto-optical disk 70 shown in FIG. 11, the recordable laser light power was constant at 3.7 mW.
【００９５】これは次のような理由による。比較用の光
磁気ディスクでは、温度が上昇すると、記録層に磁区が
形成されやすくなるため、記録可能となるレーザ光パワ
ーが減少した。これに対し、この実施例の光磁気ディス
ク７０では、外部から印加される補償用の磁界と磁界発
生層７５からの漏洩磁界との和が、記録する際の磁界と
なる。温度が上昇すると、記録層７３に磁区が形成され
やすくなるが、それを補償するように磁界発生層７５か
らの漏洩磁界が減少するため、記録可能となるレーザ光
パワーを一定にすることができたものである。This is for the following reason. In the magneto-optical disk for comparison, when the temperature increased, magnetic domains were easily formed in the recording layer, so that the laser light power capable of recording decreased. On the other hand, in the magneto-optical disk 70 of this embodiment, the sum of the magnetic field for compensation applied from the outside and the leakage magnetic field from the magnetic field generation layer 75 becomes the magnetic field for recording. When the temperature rises, magnetic domains tend to be formed in the recording layer 73, but the leakage magnetic field from the magnetic field generating layer 75 decreases so as to compensate for it, so that the laser light power that enables recording can be made constant. It is a thing.
【００９６】この発明の光磁気記録方式および光磁気記
録媒体は、以上述べた実施例に限定されず、磁区の形
成、転写または変形のいずれについても適用可能であ
る。ここで、磁区の「転写」とは、図１２のように、レ
ーザ光の照射により第２磁性層８２の磁区を第１磁性層
８１に転写することを言う。磁区の「変形」とは、図１
３のように、レーザ光の照射または磁界の印加により磁
性層８３の磁区の大きさを変えること、および、レーザ
光の照射または磁界の印加によりある磁性層の磁区の大
きさを変えて他の磁性層に転写することを言う。The magneto-optical recording system and the magneto-optical recording medium of the present invention are not limited to the above-mentioned embodiments, and can be applied to any of formation, transfer and deformation of magnetic domains. Here, “transfer” of the magnetic domain means that the magnetic domain of the second magnetic layer 82 is transferred to the first magnetic layer 81 by irradiation of laser light as shown in FIG. The "deformation" of a magnetic domain is shown in Fig. 1.
3, the size of the magnetic domain of the magnetic layer 83 is changed by the irradiation of the laser beam or the application of the magnetic field, and the size of the magnetic domain of a certain magnetic layer is changed by the irradiation of the laser beam or the application of the magnetic field. Transferring to the magnetic layer.
【００９７】また、レーザ光照射の際に生じる磁性層の
温度分布の変動を検知する方法は、任意であり、以上述
べた実施例に限定されるものではない。Further, the method of detecting the variation in the temperature distribution of the magnetic layer caused by the laser light irradiation is arbitrary and is not limited to the embodiments described above.
【００９８】[0098]
【発明の効果】この発明の光磁気記録方式および磁気記
録媒体では、光磁気記録媒体の周囲（環境）温度や移動
速度などの変動に対する記録・再生特性の変動が小さい
光磁気記録方式および光磁気記録媒体が得られる。According to the magneto-optical recording method and the magnetic recording medium of the present invention, the magneto-optical recording method and the magneto-optical recording method have small fluctuations in the recording / reproducing characteristics with respect to fluctuations in the ambient (environmental) temperature and moving speed of the magneto-optical recording medium. A recording medium is obtained.
【００９９】また、光磁気記録媒体の磁性層として使用
する磁性材料の選択の幅を広げることができる。Further, it is possible to widen the selection range of the magnetic material used as the magnetic layer of the magneto-optical recording medium.
【図１】この発明の光磁気記録方式の第１実施例を示す
全体構成図である。FIG. 1 is an overall configuration diagram showing a first embodiment of a magneto-optical recording system of the present invention.
【図２】この発明の光磁気記録方式の第１実施例の変形
例を示す部分図である。FIG. 2 is a partial view showing a modification of the first embodiment of the magneto-optical recording system of the present invention.
【図３】この発明の光磁気記録方式の第２実施例を示す
全体構成図である。FIG. 3 is an overall configuration diagram showing a second embodiment of the magneto-optical recording system of the present invention.
【図４】この発明の光磁気記録方式の第２実施例の変形
例を示す部分図である。FIG. 4 is a partial view showing a modification of the second embodiment of the magneto-optical recording system of the present invention.
【図５】この発明の光磁気記録方式の第１実施例に使用
する光磁気ディスクの要部断面図である。FIG. 5 is a cross-sectional view of essential parts of a magneto-optical disk used in the first embodiment of the magneto-optical recording system of the present invention.
【図６】この発明の光磁気記録方式の第３実施例に使用
する光磁気ディスクの要部断面図である。FIG. 6 is a cross-sectional view of an essential part of a magneto-optical disk used in a third embodiment of the magneto-optical recording system of the present invention.
【図７】この発明の光磁気記録方式の第４実施例に使用
する光磁気ディスクの要部断面図である。FIG. 7 is a cross-sectional view of an essential part of a magneto-optical disk used in a fourth embodiment of the magneto-optical recording system of the present invention.
【図８】この発明の光磁気記録方式の第４実施例により
得られたグラフである。FIG. 8 is a graph obtained by a fourth embodiment of the magneto-optical recording system of the present invention.
【図９】この発明の光磁気記録方式の第４実施例におい
て、磁気的結合力の変化の温度依存性を説明するための
図である。FIG. 9 is a diagram for explaining the temperature dependence of the change in the magnetic coupling force in the fourth embodiment of the magneto-optical recording system of the present invention.
【図１０】この発明の光磁気記録方式の第４実施例の動
作原理を説明するための図である。FIG. 10 is a diagram for explaining the operation principle of the fourth embodiment of the magneto-optical recording system of the present invention.
【図１１】この発明の光磁気記録方式の第５実施例に使
用する光磁気ディスクの要部断面図である。FIG. 11 is a cross-sectional view of essential parts of a magneto-optical disk used in the fifth embodiment of the magneto-optical recording system of the present invention.
【図１２】磁区の転写を説明するための図である。FIG. 12 is a diagram for explaining transfer of magnetic domains.
【図１３】磁区の変形を説明するための図である。FIG. 13 is a diagram for explaining deformation of magnetic domains.
【図１４】レーザ光照射時の磁性層内での位置と温度と
の関係を示すグラフである。FIG. 14 is a graph showing the relationship between the position in the magnetic layer and the temperature during laser light irradiation.
【図１５】レーザ光照射時の磁性層の温度と印加磁界と
の関係を示すグラフである。FIG. 15 is a graph showing the relationship between the temperature of the magnetic layer and the applied magnetic field during laser light irradiation.
１０ 光磁気ディスク １１ ガラス基板 １２ 保護層 １３ 記録層 １４ 保護層 ２０ カートリッジ ３０ 光ヘッド ３１ レーザ ３２ ビームスプリッタ ３３ 集束用レンズ ３４ 光検出器 ３５ 信号制御系 ３６ レーザ駆動系 ３７ 電磁石駆動系 ３８ 光ヘッド位置検出器 ３９ スピンドル ４０ 回転数検出器 ４１ 電磁石 ４２ 温度検出器 ４３ 熱感度読み取り部 ４４ 熱電対 Ａ，Ｂ 熱感度を示す情報 ５０ 光磁気ディスク ５１ ガラス基板 ５２ 保護層 ５３ 記録層 ５４ 磁界発生層 ５５ 保護層 ６０ 光磁気ディスク ６１ ガラス基板 ６２ 保護層 ６３ 再生層 ６４ 切断層 ６５ 記録層 ６６ 保護層 ７０ 光磁気ディスク ７１ ガラス基板 ７２ 保護層 ７３ 記録層 ７４ 絶縁層 ７５ 磁界発生層 ７６ 保護層 ８１ 第１磁性層 ８２ 第２磁性層 ８３ 磁性層 10 magneto-optical disk 11 glass substrate 12 protective layer 13 recording layer 14 protective layer 20 cartridge 30 optical head 31 laser 32 beam splitter 33 focusing lens 34 photodetector 35 signal control system 36 laser drive system 37 electromagnet drive system 38 optical head position Detector 39 Spindle 40 Rotation speed detector 41 Electromagnet 42 Temperature detector 43 Thermal sensitivity reading section 44 Thermocouple A, B Information indicating thermal sensitivity 50 Magneto-optical disk 51 Glass substrate 52 Protective layer 53 Recording layer 54 Magnetic field generating layer 55 Protection Layer 60 Magneto-optical disk 61 Glass substrate 62 Protective layer 63 Reproducing layer 64 Cutting layer 65 Recording layer 66 Protective layer 70 Magneto-optical disk 71 Glass substrate 72 Protective layer 73 Recording layer 74 Insulating layer 75 Magnetic field generating layer 76 Protective layer 81 First magnetic Layer 82 Second magnetic layer 83 Magnetic layer
───────────────────────────────────────────────────── フロントページの続き (72)発明者 新原 敏夫 東京都国分寺市東恋ケ窪１丁目280番地 株式会社日立製作所中央研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Niihara 1-280, Higashi Koikekubo, Kokubunji, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd.
Claims (21)
レーザ光を照射し、それによって生じる前記磁性層の局
所的温度上昇によりその磁性層に磁区を形成して情報を
記録し、前記光磁気記録媒体にレーザ光を照射して前記
磁区から前記情報を再生する光磁気記録方式において、 レーザ光照射の際に生じる前記磁性層の温度分布の変動
を検知し、その検知結果に応じて前記光磁気記録媒体の
記録特性および再生特性の少なくとも一方の変動を補償
することを特徴とする光磁気記録方式。1. A magneto-optical recording medium having a magnetic layer for recording is irradiated with a laser beam, and a local temperature rise of the magnetic layer caused thereby forms a magnetic domain in the magnetic layer to record information. In a magneto-optical recording method of irradiating a magneto-optical recording medium with laser light to reproduce the information from the magnetic domains, a change in temperature distribution of the magnetic layer that occurs during laser light irradiation is detected, and according to the detection result, A magneto-optical recording method which compensates for at least one variation in recording characteristics and reproducing characteristics of the magneto-optical recording medium.
生特性の少なくとも一方の変動を、前記光磁気記録媒体
に印加する磁界の強度を変えることにより補償する請求
項１に記載の光磁気記録方式。2. The magneto-optical recording method according to claim 1, wherein fluctuations in at least one of recording characteristics and reproducing characteristics of the magneto-optical recording medium are compensated by changing the strength of a magnetic field applied to the magneto-optical recording medium. .
磁気記録媒体の全体温度を介して検知する請求項１また
は２に記載の光磁気記録方式。3. The magneto-optical recording method according to claim 1, wherein the variation in the temperature distribution of the magnetic layer is detected via the overall temperature of the magneto-optical recording medium.
光磁気記録媒体の外部に設けた温度検出手段により検知
する請求項３に記載の光磁気記録方式。4. The magneto-optical recording method according to claim 3, wherein the entire temperature of the magneto-optical recording medium is detected by a temperature detecting means provided outside the magneto-optical recording medium.
光磁気記録媒体の内部に設けた温度検出手段により検知
する請求項３に記載の光磁気記録方式。5. The magneto-optical recording system according to claim 3, wherein the temperature of the entire magneto-optical recording medium is detected by a temperature detecting means provided inside the magneto-optical recording medium.
磁気記録媒体の移動速度を介して検知する請求項１また
は２に記載の光磁気記録方式。6. The magneto-optical recording method according to claim 1, wherein the variation of the temperature distribution of the magnetic layer is detected through the moving speed of the magneto-optical recording medium.
号により、前記光磁気記録媒体の移動速度の変化を検知
する請求項６に記載の光磁気記録方式。7. The magneto-optical recording method according to claim 6, wherein a change in the moving speed of the magneto-optical recording medium is detected by a signal from the driving means of the magneto-optical recording medium.
磁気記録媒体の持つ熱感度を介して検知する請求項１ま
たは２に記載の光磁気記録方式。8. The magneto-optical recording method according to claim 1, wherein the variation of the temperature distribution of the magnetic layer is detected through the thermal sensitivity of the magneto-optical recording medium.
を示す熱感度情報を付し、その熱感度情報によりその光
磁気記録媒体の熱感度を検知する請求項８に記載の光磁
気記録方式。9. The magneto-optical recording according to claim 8, wherein the magneto-optical recording medium is provided with thermal sensitivity information indicating the thermal sensitivity of the medium, and the thermal sensitivity of the magneto-optical recording medium is detected by the thermal sensitivity information. method.
収容されており、前記熱感度情報がそのカートリッジに
付されている請求項９に記載の光磁気記録方式。10. The magneto-optical recording method according to claim 9, wherein the magneto-optical recording medium is housed in a cartridge, and the thermal sensitivity information is attached to the cartridge.
体自体に付されている請求項９に記載の光磁気記録方
式。11. The magneto-optical recording method according to claim 9, wherein the thermal sensitivity information is attached to the magneto-optical recording medium itself.
にレーザ光を照射し、それによって生じる前記磁性層の
局所的温度上昇によりその磁性層に磁区を形成して情報
を記録し、前記光磁気記録媒体にレーザ光を照射して前
記磁区から前記情報を再生する光磁気記録方式におい
て、 前記光磁気記録媒体に補償用の磁性層を設け、その補償
用磁性層が発生する磁界によって、レーザ光照射の際に
生じる前記記録用磁性層の温度分布の変動を補償するこ
とを特徴とする光磁気記録方式。12. A magneto-optical recording medium having a magnetic layer for recording is irradiated with laser light, and a local temperature rise of the magnetic layer caused thereby forms a magnetic domain in the magnetic layer to record information. In a magneto-optical recording method of irradiating a magneto-optical recording medium with laser light to reproduce the information from the magnetic domains, a magneto-optical recording medium is provided with a compensating magnetic layer, and a magnetic field generated by the compensating magnetic layer, A magneto-optical recording method, which compensates for fluctuations in the temperature distribution of the recording magnetic layer that occur during laser light irradiation.
および交換磁界の少なくとも一方が、前記記録用磁性層
の温度分布の変動を補償するように温度によって変動す
る請求項１２に記載の光磁気記録方式。13. The magneto-optical device according to claim 12, wherein at least one of a leakage magnetic field and an exchange magnetic field generated by the compensating magnetic layer varies with temperature so as to compensate for a variation in temperature distribution of the recording magnetic layer. Recording method.
を、前記光磁気記録媒体から得られる再生信号の強度を
介して検知する請求項１〜１３のいずれかに記載の光磁
気記録方式。14. The magneto-optical recording method according to claim 1, wherein a variation in temperature distribution of the magneto-optical recording medium is detected based on the intensity of a reproduction signal obtained from the magneto-optical recording medium.
が、情報を記録する際に前記磁性層に形成される磁区の
大きさを一定に保つように補償される請求項１〜１４の
いずれかに記載の光磁気記録方式。15. The method according to claim 1, wherein fluctuations in recording characteristics of the magneto-optical recording medium are compensated so as to keep the size of magnetic domains formed in the magnetic layer constant when recording information. A magneto-optical recording method described in.
が、情報を再生する際に前記磁性層に形成された磁区の
大きさを一定に保つように補償される請求項１〜１４の
いずれかに記載の光磁気記録方式。16. The method according to claim 1, wherein fluctuations in reproduction characteristics of the magneto-optical recording medium are compensated so as to keep the size of magnetic domains formed in the magnetic layer constant when reproducing information. A magneto-optical recording method described in.
された磁区の転写または変形が行なわれ、その転写また
は変形が一定となるように前記光磁気記録媒体の再生特
性の変動が補償される請求項１〜１４のいずれかに記載
の光磁気記録方式。17. When reproducing information, the magnetic domain formed in the magnetic layer is transferred or deformed, and the fluctuation of the reproducing characteristic of the magneto-optical recording medium is compensated so that the transfer or deformation is constant. The magneto-optical recording method according to any one of claims 1 to 14.
て前記記録用磁性層に隣接する再生層を有していると共
に、前記記録用磁性層の磁区が前記切断層を介して前記
再生層に転写されるようになっており、前記切断層の持
つ磁気的結合力の変動を補償するように磁界が印加され
る請求項１７に記載の光磁気記録方式。18. The magneto-optical recording medium has a reproducing layer adjacent to the recording magnetic layer via a cutting layer, and the magnetic domain of the recording magnetic layer reproduces via the cutting layer. 18. The magneto-optical recording method according to claim 17, wherein the magneto-optical recording system is adapted to be transferred to a layer, and a magnetic field is applied so as to compensate for fluctuations in the magnetic coupling force of the cutting layer.
成された記録用の磁性層を備えた光磁気記録媒体におい
て、 レーザ光照射の際に生じる前記記録用磁性層の温度分布
の変動を補償する補償用の磁性層を備えていることを特
徴とする光磁気記録媒体。19. A magneto-optical recording medium comprising a recording magnetic layer formed directly on a substrate or via an underlayer, wherein fluctuations in temperature distribution of the recording magnetic layer caused by laser light irradiation are recorded. A magneto-optical recording medium comprising a magnetic layer for compensation.
および交換磁界の少なくとも一方が、前記記録用磁性層
の温度分布の変動を補償するように温度によって変動す
る請求項１９に記載の光磁気記録媒体。20. The magneto-optical device according to claim 19, wherein at least one of a leakage magnetic field and an exchange magnetic field generated by the compensating magnetic layer varies with temperature so as to compensate for a variation in temperature distribution of the recording magnetic layer. recoding media.
接する再生層を有していると共に、前記記録用磁性層の
磁区が前記切断層を介して前記再生層に転写されるよう
になっており、前記切断層の膜厚が２０ｎｍ以下である
請求項１９に記載の光磁気記録方式。21. A reproducing layer is provided adjacent to the recording magnetic layer via a cutting layer, and magnetic domains of the recording magnetic layer are transferred to the reproducing layer via the cutting layer. 20. The magneto-optical recording method according to claim 19, wherein the thickness of the cutting layer is 20 nm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21573893A JPH0773529A (en) | 1993-08-31 | 1993-08-31 | Magneto-optical recording system and magneto-optical recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21573893A JPH0773529A (en) | 1993-08-31 | 1993-08-31 | Magneto-optical recording system and magneto-optical recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0773529A true JPH0773529A (en) | 1995-03-17 |
Family
ID=16677383
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21573893A Pending JPH0773529A (en) | 1993-08-31 | 1993-08-31 | Magneto-optical recording system and magneto-optical recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0773529A (en) |
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