JPH06290496A - Magneto-optical recording medium, reproducing method and reproducing device - Google Patents

Magneto-optical recording medium, reproducing method and reproducing device

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JPH06290496A
JPH06290496A JP7714193A JP7714193A JPH06290496A JP H06290496 A JPH06290496 A JP H06290496A JP 7714193 A JP7714193 A JP 7714193A JP 7714193 A JP7714193 A JP 7714193A JP H06290496 A JPH06290496 A JP H06290496A
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magnetic layer
temperature
magneto
magnetic
recording medium
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JP3332458B2 (en )
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Tsutomu Shiratori
力 白鳥
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Canon Inc
キヤノン株式会社
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Abstract

PURPOSE: To greatly improve a recording density and transfer speed and to miniaturize the reproducing device by enabling the reproduction of signals of periods below the diffraction threshold of light at a high speed without lowering the amplitude of the reproduced signals.
CONSTITUTION: A first magnetic layer 11, a second magnetic layer 12 and a third magnetic layer 13 are successively laminated. This first magnetic layer 11 is relatively smaller in the coercive force of magnetic walls than the third magnetic layer and is larger in the mobility of the magnetic walls. The second magnetic layer 12 is lower in Curie temp. than the first magnetic layer and the third magnetic layer. Further, a fourth magnetic layer may be formed between the first magnetic layer and the second magnetic layer. The magnetic walls 15 are moved backward by heating TS.
COPYRIGHT: (C)1994,JPO

Description

【発明の詳細な説明】 DETAILED DESCRIPTION OF THE INVENTION

【0001】 [0001]

【産業上の利用分野】本発明は、磁気光学効果を利用してレーザー光により情報の記録再生を行う光磁気記録媒体等に関し、更に詳しくは媒体の高密度記録化を可能とする光磁気記録媒体、再生方法および再生装置に関する。 The present invention relates to relates to a magneto-optical recording medium or the like for recording and reproducing information with a laser beam by utilizing the magneto-optical effect, more particularly a magneto-optical recording that allows high density recording of the medium medium, a reproducing method and reproducing apparatus.

【0002】 [0002]

【従来の技術】書き換え可能な高密度記録方式として、 2. Description of the Related Art As a rewritable high density recording method,
半導体レーザーの熱エネルギーを用いて、磁性薄膜に磁区を書き込んで情報を記録し、磁気光学効果を用いて、 Using thermal energy of a semiconductor laser, information is recorded by writing magnetic domains in a magnetic thin film, using a magneto-optical effect,
この情報を読み出す光磁気記録媒体が注目されている。 Magneto-optical recording medium to read out this information is noted.
また、近年この光磁気記録媒体の記録密度を高めて更に大容量の記録媒体とする要求が高まっている。 Further, there is a growing further request for a large capacity recording medium in recent years increasing the recording density of the magneto-optical recording medium.

【0003】光磁気記録媒体等の光ディスクの線記録密度は、再生光学系のレーザー波長および対物レンズの開口数に大きく依存する。 [0003] linear recording density of an optical disk such as a magneto-optical recording medium largely depends on the numerical aperture of the laser wavelength and objective lens of the reproducing optical system. すなわち、再生光学系のレーザー波長λと対物レンズの開口数NAが決まるとビームウェストの径が決まるため、信号再生時の空間周波数は2 That is, since the diameter of the beam waist when the numerical aperture NA of the laser wavelength λ and an objective lens of the reproducing optical system are determined are determined, the spatial frequency of the signal reproduction is 2
NA/λ程度が検出可能な限界となってしまう。 About NA / λ becomes the detectable limit.

【0004】したがって、従来の光ディスクで高密度化を実現するためには、再生光学系のレーザー波長を短くし、対物レンズの開口数NAを大きくする必要がある。 [0004] Therefore, in order to realize a high density in a conventional optical disk, a shorter laser wavelength of the reproducing optical system, it is necessary to increase the numerical aperture NA of the objective lens.
しかしながら、レーザー波長や対物レンズの開口数の改善にも限度がある。 However, there is a limit to the improvement of the numerical aperture of the laser wavelength and an objective lens. このため、記録媒体の構成や読み取り方法を工夫し、記録密度を改善する技術が開発されている。 Therefore, by devising a structure and method of reading a recording medium, to improve the recording density techniques have been developed.

【0005】例えば、特開平3−93058号においては、磁気的に結合される再生層と記録保持層とを有してなる多層膜の、記録保持層に信号記録を行うとともに、 [0005] For example, in Japanese Patent Laid-Open No. 3-93058, a multi-layer film made and a reproducing layer and a recording holding layer magnetically coupled, performs signal recorded on the recording holding layer,
再生層の磁化の向きを揃えた後、レーザー光を照射して加熱し、再生層の昇温領域に、記録保持層に記録された信号を転写しながら読み取る信号再生方法が提案されている。 After aligning the magnetization direction of the reproducing layer is heated by irradiating a laser beam, the heated region of the reproducing layer, a signal reproducing method for reading while transferring the recorded on the recording holding layer signal have been proposed.

【0006】この方法によれば、再生用のレーザーのスポット径に対して、このレーザーによって加熱されて転写温度に達し信号が検出される領域は、より小さな領域に限定できるため、再生時の符号間干渉を減少させ、光の回折限界以下の周期の信号が再生可能となる。 [0006] According to this method, with respect to the spot diameter of the laser for reproduction, the region signal reaches a transfer temperature is heated by the laser is detected, it is possible to limit to a smaller area, the sign of the time of reproduction between interference is reduced, the signal of the following cycle the diffraction limit of light becomes reproducible.

【0007】 [0007]

【発明が解決しようとしている課題】しかしながら、特開平3−93058号記載の光磁気再生方法では、再生用のレーザーのスポット径に対して、有効に使用される信号検出領域が小さくなるため、再生信号振幅が大幅に低下し、十分な再生出力が得られない欠点を有している。 An invention is, however, a magneto-optical reproducing method of JP-A 3-93058 Patent described, since the signal detection region relative to the spot diameter of the laser for reproduction, is effectively used is small, reproduction the signal amplitude is greatly reduced, and a sufficient reproduction output can not be obtained drawbacks.

【0008】また、再生層の磁化をレーザー光が照射する前に一方向に揃えなければならない。 [0008] In addition, the laser beam the magnetization of the reproducing layer must be aligned in one direction prior to irradiation. そのため、従来の装置に再生層の初期化用磁石を追加することが必要となる。 Therefore, it is necessary to add a magnet for initializing the reproducing layer in a conventional apparatus. このため前記再生方法は、光磁気記録装置が複雑化し、コストが高くなる、小型化が難しい等の問題点を有している。 The reproducing method for the magneto-optical recording apparatus is complicated, the cost is high, there is a problem such as reduction in size is difficult.

【0009】本発明は、この様な従来技術の課題を解決すべくなされたものである。 [0009] The present invention has been made to solve the problems of such prior art. すなわち本発明の目的は、 That object of the present invention,
再生信号振幅を低下させることなく光の回折限界以下の周期の信号が高速で再生可能となり、記録密度並びに転送速度を大幅に向上でき、再生装置の小型化も可能な光磁気記録媒体、再生方法および再生装置を提供することにある。 Signal of a diffraction limit or less of the period of light without decreasing the reproduction signal amplitude becomes reproducible at a high speed, the recording density and can significantly improve the transfer speed, miniaturization magneto-optical recording medium of the reproducing apparatus, reproducing method and to provide a reproducing apparatus.

【0010】 [0010]

【問題点を解決するための手段】上記目的は、以下の本発明により達成される。 Means for Solving the Problems] The above object is achieved by the following present invention.

【0011】本発明の第1の光磁気記録媒体は、少なくとも、第1、第2、第3の磁性層が順次積層されている光磁気記録媒体であって、該第1の磁性層は、周囲温度近傍の温度において該第3の磁性層に比べて相対的に磁壁抗磁力が小さく磁壁移動度大きな垂直磁化膜からなり、該第2の磁性層は、該第1の磁性層および第3の磁性層よりもキュリー温度の低い磁性層からなり、該第3 [0011] The first magneto-optical recording medium of the present invention, at least a first, second, and third magnetic layer to a magneto-optical recording medium are sequentially laminated, the magnetic layer of said first, relatively wall coercivity is from smaller domain wall mobility large perpendicular magnetization film compared to the magnetic layer of the third at a temperature of ambient temperature near, the magnetic layer of said second, said first magnetic layer and the third made from a low magnetic layer having a Curie temperature than the magnetic layer, the third
の磁性層は垂直磁化膜であることを特徴とする光磁気記録媒体である。 The magnetic layer is a magneto-optical recording medium, which is a perpendicular magnetization film.

【0012】本発明の第2の光磁気記録媒体は、少なくとも、第1、第4、第2、第3の磁性層が順次積層されている光磁気記録媒体であって、該第1の磁性層は、周囲温度近傍の温度において該第3の磁性層に比べて相対的に磁壁抗磁力が小さな垂直磁化膜からなり、該第2の磁性層は、該第1の磁性層および第3の磁性層よりもキュリー温度の低い磁性層からなり、該第3の磁性層は垂直磁化膜であり、該第4の磁性層は、該第2の磁性層よりも高く、該第1の磁性層よりも低いキュリー温度を有し、かつ少なくとも該第2の磁性層のキュリー温度以上の温度において、該第3の磁性層に比べて相対的に磁壁抗磁力が小さな垂直磁化膜からなることを特徴とする光磁気記録媒体である。 A second magneto-optical recording medium of the present invention, at least a first, fourth, second, and third magnetic layer to a magneto-optical recording medium are sequentially stacked, the first magnetic layer is relatively wall coercivity is a small perpendicular magnetic film in comparison with the magnetic layer of the third at a temperature near ambient temperature, the magnetic layer of said second, said first magnetic layer and the third made from a low magnetic layer having a Curie temperature than the magnetic layer, the magnetic layer of the third is a perpendicular magnetization film, a magnetic layer of said fourth, higher than the second magnetic layer, the first magnetic layer It has a Curie temperature lower than, and wherein at least at the Curie temperature or higher temperature of the second magnetic layer, that relatively wall coercivity than the magnetic layer of the third consists of small perpendicularly magnetized film a magneto-optical recording medium according to.

【0013】本発明の第1の再生方法は、本発明の第1 A first reproducing method of the present invention, a first aspect of the present invention
の光磁気記録媒体から記録情報を再生する方法であって、光ビームを該媒体に対して相対的に移動させながら前記第1の磁性層の側から照射し、該媒体上に該光ビームのスポットの移動方向に対して勾配を有する温度分布を形成し、該温度分布を少なくとも前記第2の磁性層のキュリー温度よりも高い温度領域を有する温度分布とすることによって該第1の磁性層に形成されていた磁壁を移動させ、該光ビームの反射光の偏光面の変化を検出して記録情報を再生することを特徴とする再生方法である。 Of a method for reproducing the recorded information from the magneto-optical recording medium, a light beam is irradiated from the side of the while moving relative to the medium first magnetic layer, of the light beam on the said medium forming a temperature distribution having a gradient relative to the moving direction of the spot, the temperature distribution magnetic layer of the first by a temperature distribution having a higher temperature region than the Curie temperature of at least the second magnetic layer moving the domain walls had been formed, a reproducing method characterized by reproducing the detected and recorded information change of the polarization plane of the reflected light of the light beam.

【0014】本発明の第2の再生方法は、本発明の第2 [0014] The second reproduction method of the present invention, the second invention
の光磁気記録媒体から記録情報を再生する方法であって、光ビームを該媒体に対して相対的に移動させながら前記第1の磁性層の側から照射し、該媒体上に該光ビームのスポットの移動方向に対して勾配を有する温度分布を形成し、該温度分布を少なくとも前記第2の磁性層のキュリー温度よりも高くし且つ前記第4の磁性層のキュリー温度近傍の温度領域を有する温度分布とすることによって、該第1及び第4の磁性層に形成されていた磁壁を移動させ、該光ビームの反射光の偏光面の変化を検出して記録情報を再生することを特徴とする再生方法である。 Of a method for reproducing the recorded information from the magneto-optical recording medium, a light beam is irradiated from the side of the while moving relative to the medium first magnetic layer, of the light beam on the said medium forming a temperature distribution having a gradient relative to the moving direction of the spot, having a temperature region near the Curie temperature of the temperature distribution higher than the Curie temperature of at least said second magnetic layer and the fourth magnetic layer by the temperature distribution, and characterized by moving a magnetic domain wall which is formed on the first and fourth magnetic layer, reproducing the recorded information by detecting a change in the polarization plane of the reflected light of the light beam which is a reproduction how to.

【0015】本発明の再生装置は、本発明の光磁気記録媒体から記録情報を再生する再生装置であって、光ビームのスポットの移動方向に対して勾配を有する温度分布を形成できる加熱手段を有することを特徴とする再生装置である。 The reproducing apparatus of the present invention is a reproducing apparatus for reproducing recorded information from the magneto-optical recording medium of the present invention, the heating means for forming a temperature distribution having a gradient relative to the moving direction of the light beam spot a reproducing apparatus, characterized in that it comprises.

【0016】 [0016]

【作用】図1は、本発明の光磁気記録媒体およびその再生方法における作用を説明するため模式図である。 [Action] Figure 1 is a schematic diagram for explaining the operation of the magneto-optical recording medium and its playback method of the present invention.

【0017】図1(a)は、本発明の光磁気記録媒体の模式的断面図である。 [0017] FIG. 1 (a) is a schematic sectional view of a magneto-optical recording medium of the present invention. この媒体の磁性層は、第1の磁性層11、第2の磁性層12、第3の磁性層13が順次積層されてなる。 The magnetic layer of this medium comprises a first magnetic layer 11, the second magnetic layer 12, the third magnetic layer 13 is formed by sequentially stacking. 各層中の矢印14は原子スピンの向きを表している。 Arrow 14 in each layer represents the atomic spins. スピンの向きが相互に逆向きの領域の境界部には磁壁15が形成されている。 Spin direction is the magnetic wall 15 is formed at the boundary portion of the reverse area to another. また、この記録層の記録信号も下側にグラフとして表わす。 The recording signal of the recording layer is also represented as a graph on the lower side.

【0018】図1(b)は、本発明の光磁気記録媒体に形成される温度分布を示すグラフである。 [0018] FIG. 1 (b) is a graph showing temperature distribution formed on the magneto-optical recording medium of the present invention. この温度分布は、再生用に照射されている光ビーム自身によって媒体上に誘起されるものでもよいが、望ましくは別の加熱手段を併用して、再生用の光ビームのスポットの手前側から温度を上昇させ、スポットの後方に温度のピークが来るような温度分布を形成する。 This temperature distribution may be one induced on the medium by a light beam itself being irradiated for reproduction, but preferably in combination with another heating means, the temperature from the front side of the light beam spot for reproduction It is raised, thereby forming a temperature distribution such that the peak temperature in the rear of the spot. ここで位置x sにおいては、媒体温度が第2の磁性層のキュリー温度近傍の温度T sになっている。 Here in the position x s, the medium temperature is in the temperature T s near the Curie temperature of the second magnetic layer.

【0019】図1(c)は、図1(b)の温度分布に対応する第1の磁性層の磁壁エネルギー密度σ 1の分布を示すグラフである。 [0019] FIG. 1 (c) is a first graph showing the distribution of magnetic wall energy density sigma 1 of the magnetic layer corresponding to the temperature distribution of FIG. 1 (b). この様にx方向に磁壁エネルギー密度σ The domain wall energy density in the x-direction in this manner σ 1の勾配があると、位置xに存在する各層の磁壁に対して下記式から求められる力F 1が作用する。 If there is a gradient of the force F 1 obtained from the following equation acts on the magnetic wall of each layer at the position x.

【0020】 [0020]

【数1】 [Number 1] この力F 1は、磁壁エネルギーの低い方に磁壁を移動させるように作用する。 The force F 1 acts to move the domain walls in the lower domain wall energy. 第1の磁性層は、磁壁抗磁力が小さく磁壁移動度が大きいので、単独では、この力F 1によって容易に磁壁が移動する。 The first magnetic layer, since the domain wall coercive force is small domain wall mobility is large, alone, readily domain wall is moved by the force F 1. しかし、位置x sより手前(図では右側)の領域では、まだ媒体温度がT sより低く、磁壁抗磁力の大きな第3の磁性層と交換結合しているために、第3の磁性層中の磁壁の位置に対応した位置に第1の磁性層中の磁壁も固定されている。 However, in the region of the front of the position x s (in the figure right), yet the medium temperature is lower than T s, in order to exchange-coupled with the large third magnetic layer of the magnetic wall coercivity, the third magnetic layer also fixed the first magnetic domain wall in the magnetic layer of a position corresponding to the position of the domain wall.

【0021】本発明においては、図1(a)に示す様に、磁壁15が媒体の位置x sにあると、媒体温度が第2の磁性層のキュリー温度近傍の温度T sまで上昇し、 In the present invention, as shown in FIG. 1 (a), the domain wall 15 is in the position x s of the medium, increased the medium temperature to a temperature T s near the Curie temperature of the second magnetic layer,
第1の磁性層と第3の磁性層との間の交換結合が切断される。 Exchange coupling between the first magnetic layer and the third magnetic layer is cut. この結果、第1の磁性層中の磁壁15は、破線矢印17で示した様に、より温度が高く磁壁エネルギー密度の小さな領域へと”瞬間的”に移動する。 As a result, the first magnetic wall 15 of the magnetic layer is, as indicated by broken line arrows 17, to move to a more temperature to high small area of ​​the magnetic wall energy density "instantaneous".

【0022】再生用の光ビームのスポット16の下を磁壁15が通過すると、スポット内の第1の磁性層の原子スピンは全て一方向に揃う。 The domain wall 15 under the light beam spot 16 for reproduction has passed, atomic spins of the first magnetic layer in the spot, all aligned in one direction. そして、媒体の移動に伴って磁壁15が位置x sに来る度に、スポットの下を磁壁15が瞬間的に移動しスポット内の原子スピンの向きが反転して全て一方向に揃う。 Each time the magnetic wall 15 with the movement of the medium comes to a position x s, and moves under the spot domain wall 15 is momentarily aligned in all one direction inverted atomic spins in the spot. この結果、図1(a)に示す様に、再生信号振幅は記録されている磁壁の間隔(即ち記録マーク長)によらず、常に一定かつ最大の振幅になり、光学的な回折限界に起因した波形干渉等の問題から完全に解放されるのである。 As a result, as shown in FIG. 1 (a), regardless of the spacing of the magnetic domain wall reproduction signal amplitude is recorded (i.e. a recording mark length), always constant and maximum amplitude, due to the optical diffraction limit were it to be fully released from the waveform interference or the like in question.

【0023】但し、磁壁の移動速度は無限大ではないから、スポットの下を磁壁が通過するのに要する時間τ [0023] However, since the movement speed of the domain wall is not infinite, the time required under the spot to the domain wall to pass through τ
が、最短記録マーク長相当の距離を媒体が移動するのに要する時間t minよりも長くならないようにする必要がある(図2参照)。 But it is necessary to distance the shortest recording mark length corresponding medium is not longer than the time t min required to move (see FIG. 2).

【0024】図3は、上述の原理作用による本発明と、 FIG. 3 is a present invention in accordance with the principles action described above,
通常の従来法とを比較する模式図である。 It is a schematic diagram comparing the normal conventional method. この図において(a1)〜(a7)、および(b1)〜(b7)は、 In this figure (a1) ~ (a7), and (b1) ~ (b7) is
記録マーク長の異なる磁区33が形成された情報トラック36上を、再生用スポット31が移動する状態を示す。 The recording mark length different domains 33 information track 36 on which is formed, showing a state where the reproducing spot 31 moves. また(a8)および(b8)は、得られる再生信号のグラフである。 The (a8) and (b8) is a graph of a reproduction signal obtained.

【0025】従来の再生方法においては、再生用スポット31自体が情報トラック36上のひとつの磁区内に完全に入った状態(b2)でないと、再生信号の最大振幅が得られない(b8)。 [0025] In the conventional reproducing method, so, if a state where the reproducing spot 31 itself enters entirely within a single magnetic domain in the information track 36 (b2), can not be obtained the maximum amplitude of the reproduced signal (b8). 一方、本発明においては、再生用スポット31と温度プロファイルを同方向32に相対移動させ、再生用スポット31の直前部分が第2の磁性層の臨界温度T sになる様にしてある。 On the other hand, in the present invention, the reproducing spot 31 and the temperature profile are relatively moved in the same direction 32, just before the portion of the reproducing spot 31 are the manner becomes critical temperature T s of the second magnetic layer. したがって、再生用スポット31が磁壁34に差掛る直前において、磁壁34の部分の温度が臨界温度Tsとなり、磁壁34が逆方向35に移動し、再生用スポット31が記録マーク内に完全に入った状態(a2)となり、瞬時に再生信号の最大振幅が得られる(a8)。 Accordingly, immediately before reaches the reproducing spot 31 is the domain wall 34, the temperature becomes critical temperature Ts of the portion of the magnetic wall 34, the domain wall 34 moves in the opposite direction 35, reproducing spot 31 enters completely into the recording mark condition (a2), and the maximum amplitude of the instantaneous reproduction signal is obtained (a8).

【0026】また、従来の再生方法においては、磁区3 [0026] In addition, in the conventional reproduction method, the magnetic domain 3
3がスポット径よりも狭い場合には、再生用スポット3 3 If narrower than the spot diameter, reproducing spot 3
1全体が磁区内に納まらず(b3〜b7)、得られる再生信号も不明瞭となる(b8)。 1 overall can not fit within the domain (b3~b7), it becomes unclear reproduction signal obtained (b8). 一方、本発明においては、再生用スポット31が記録マークの磁壁にほぼ差掛った段階で、磁壁が逆方向後方に逐次移動するので(a On the other hand, in the present invention, at the stage of reproducing spot 31 has approached almost domain wall of the recording mark, so the domain wall is successively moved in the opposite direction backward (a
3〜a7)、極めて明瞭な再生信号が得られる(a 3~a7), crystal clear reproduction signal is obtained (a
8)。 8).

【0027】以上、第1の磁性層〜第3の磁性層を有する本発明の光磁気記録媒体について説明したが、本発明においては、図4に示す様に、第4の磁性層44を第1 [0027] Having described the magneto-optical recording medium of the present invention having a first magnetic layer through the third magnetic layer, in the present invention, as shown in FIG. 4, the fourth magnetic layer 44 a 1
の磁性層41と第2の磁性層42との間に設けてもよい。 Magnetic layer 41 and may be provided between the second magnetic layer 42. この第4の磁性層44は、第2の磁性層よりも高く、該第1の磁性層よりも低いキュリー温度を有し、かつ少なくとも該第2の磁性層のキュリー温度以上の温度において、該第3の磁性層に比べて相対的に磁壁抗磁力が小さな垂直磁化膜からなるものである。 In the fourth magnetic layer 44 is higher than the second magnetic layer has a Curie temperature lower than the first magnetic layer and the Curie temperature or higher of at least said second magnetic layer, the relatively wall coercivity than the third magnetic layer is made of small perpendicular magnetic film. この第4の磁性層は、更に第1の磁性層中の磁壁を移動させるのに充分な力を誘発するためのものである。 The fourth magnetic layer is provided to induce sufficient force to further move the first magnetic domain wall in the magnetic layer.

【0028】図4(a)(b)に示す様に、この第4の磁性層を有する光磁気記録媒体においても同様に、位置x sで第2の磁性層のキュリー温度近傍の温度T sとすることによって、第4の磁性層と第3の磁性層との間の交換結合を切断し、第1及び第4の磁性層中の磁壁を移動できる。 [0028] As shown in FIG. 4 (a) (b), also in the fourth magneto-optical recording medium comprising a magnetic layer, the temperature T s near the Curie temperature of the second magnetic layer at the position x s and by the exchange coupling between the fourth magnetic layer and the third magnetic layer is cut, you can move the domain wall of the first and fourth magnetic layer.

【0029】図4(c)は、上述の温度分布に対応した第1の磁性層の磁壁エネルギー密度σ 1および第4の磁性層の磁壁エネルギー密度σ 4の分布を示すグラフである。 FIG. 4 (c) is a graph showing the distribution of magnetic wall energy density sigma 4 of the first magnetic layer wall energy density sigma 1 and the fourth magnetic layer corresponding to the temperature distribution described above. この様にx方向に磁壁エネルギー密度σ 1の勾配があると、先に説明したと同様に位置xに存在する各層の磁壁に対して力F iが作用し、この力F iは、磁壁エネルギーの低い方に磁壁を移動させるのである。 When such a there is a magnetic wall energy density sigma 1 gradient in the x direction, and a force F i with respect to the magnetic wall of each layer existing in the same manner the position x as that described above, the force F i is the domain wall energy it is to move the magnetic domain walls to the lower of.

【0030】一方、記録を高速で読み出すためには、磁壁を高速で移動させる必要がある。 On the other hand, to read the high-speed recording, it is necessary to move the magnetic wall at a high speed. そのために、磁壁に大きな力を作用させる必要がある。 Therefore, it is necessary to exert a large force on the domain wall. 一般に、磁壁エネルギー密度の温度依存性は、キュリー温度に近づく程大きくなる。 In general, the temperature dependence of the magnetic wall energy density becomes larger the closer to the Curie temperature. 従って、キュリー温度近傍の温度範囲で温度勾配を与えた方が、x方向の磁壁エネルギー密度の勾配を大きくすることができ、磁壁に大きな力を作用させることができる。 Therefore, it gave a temperature gradient in a temperature range near the Curie temperature is, it is possible to increase the gradient of the magnetic wall energy density of the x-direction, it is possible to exert a large force on the domain wall. しかし、第1の磁性層からの反射光の偏光面の変化を検出するためには、再生用の光ビームのスポットの照射領域においては、第1の磁性層のキュリー温度よりも充分に低い温度になっている必要がある。 However, in order to detect the change in the polarization plane of the reflected light from the first magnetic layer is in the irradiation region of the light beam spot for reproduction, first sufficiently lower temperature than the Curie temperature of the magnetic layer it is necessary to have become.

【0031】ここで図4に示した様に、よりキュリー温度の低い第4の磁性層44を、第1の磁性層の光ビームの入射側と反対側に隣接して設ければ、再生用の光ビームのスポットの照射領域において、第1の磁性層のキュリー温度よりは充分低く、かつ第4の磁性層のキュリー温度近傍の温度範囲で温度勾配を与えることができる。 [0031] Here as shown in FIG. 4, the fourth magnetic layer 44 lower and more Curie temperatures, be provided adjacent to the side opposite to the incident side of the light beam of the first magnetic layer, a reproduction in the light beam spot irradiation region, it is possible to provide a temperature gradient in a temperature range near the Curie temperature of the first well lower than the Curie temperature of the magnetic layer, and fourth magnetic layer.
この結果、第4の磁性層中の磁壁に大きな力が作用し、 As a result, a large force to the fourth magnetic domain wall of the magnetic layer is applied,
第1の磁性層中の磁壁にも、第4の磁性層との交換相互作用による力が付加されて、大きな力が作用するのである。 To the first magnetic domain wall of the magnetic layer, a fourth of the force due to the exchange interaction between the magnetic layer is added, a large force is acting.

【0032】また更に、第4の磁性層に、第2の磁性層に近づく程キュリー温度が低くなるような膜厚方向のキュリー温度の勾配をつければ、x方向の温度勾配に伴って、x方向に順次キュリー温度直下の第4の磁性層の構成部を形成できるので、磁壁を移動させる必要のあるx [0032] Furthermore, the fourth magnetic layer, mean gradient in the thickness direction of the Curie temperature such that the Curie temperature is lower the closer to the second magnetic layer, with the temperature gradient in the x-direction, x can be formed a structure of the fourth magnetic layer sequentially Curie temperature just below the direction, it is required to move the magnetic domain wall x
方向の範囲全般に渡って、比較的大きな力を作用させることが可能になる。 Over a range of directions in general, it is possible to exert a relatively large force.

【0033】 [0033]

【実施例】以下、本発明を適用した実施例について図面を参照しながら説明する。 EXAMPLES The following will be described with reference to the drawings embodiment applying the present invention.

【0034】図5は、本発明の光磁気記録媒体の層構成の一実施態様を示す模式的断面図である。 [0034] FIG. 5 is a schematic cross-sectional view showing one embodiment of the layer structure of the magneto-optical recording medium of the present invention. この態様においては、透明基板56上に、誘電体層55、第1の磁性層51、第2の磁性層52、第3の磁性層53、誘電体層54が順次積層されている。 In this embodiment, on the transparent substrate 56, dielectric layer 55, the first magnetic layer 51, the second magnetic layer 52, a third magnetic layer 53, a dielectric layer 54 are sequentially stacked.

【0035】透明基板56としては、例えば、ポリカーボネート、ガラス等を用いることができる。 [0035] As the transparent substrate 56, for example, it may be used polycarbonate, and glass. 誘電体層5 Dielectric layer 5
5としては、例えば、Si 34 、AlN、SiO 2 The 5, for example, Si 3 N 4, AlN, SiO 2,
SiO、ZnS、MgF 2などの透明誘電材料が使用できる。 SiO, ZnS, transparent dielectric material such as MgF 2 can be used. 最後に保護膜として再び形成される誘電体層54 Dielectric layer 54 formed again as the last protective film
も同様のものを用いることができる。 You can also use the similar. これら各層は、例えばマグネトロンスパッタ装置による連続スパッタリング、または連続蒸着等によって被着形成できる。 Each of these layers, for example, can be deposited forming a continuous sputtering by a magnetron sputtering apparatus or by continuous vapor deposition. 特に各磁性層は、真空を破ることなく連続成膜されることで、 In particular the magnetic layer, by being continuously formed without breaking vacuum,
互いに交換結合をしている。 Are the exchange-coupled to each other.

【0036】また、この構成に、更にAl、AlTa、 [0036] In addition, in this configuration, further Al, AlTa,
AlTi、AlCr、Cuなどからなる金属層を付加して、熱的な特性を調整してもよい。 AlTi, AlCr, by adding a metal layer made of Cu, may adjust the thermal properties. また、高分子樹脂からなる保護コートを付与してもよい。 In addition, it may be given a protective coating made of a polymer resin. あるいは、成膜後の基板を貼り合わせてもよい。 Alternatively, it may be bonded to the substrate after the film formation.

【0037】上記媒体において、各磁性層51〜53 [0037] In the medium, each of the magnetic layers 51 - 53
は、種々の磁性材料によって構成することが考えられるが、例えば、Pr、Nd、Sm、Gd、Tb、Dy、H It is considered to be composed of a variety of magnetic materials, for example, Pr, Nd, Sm, Gd, Tb, Dy, H
oなどの希土類金属元素の一種類あるいは二種類以上が10〜40at%と、Fe、Co、Niなどの鉄族元素の一種類あるいは二種類以上が90〜60at%とで構成される希土類−鉄族非晶質合金によって構成し得る。 o earth composed of a 10~40At% one kind or two or more kinds of rare earth metal elements such as, Fe, Co, or one kind or two kinds of iron group elements such as Ni is the 90~60at% - Iron It may be constituted by a family amorphous alloy.
また、耐食性向上などのために、これにCr、Mn、C Further, because of such improved corrosion resistance, which the Cr, Mn, C
u、Ti、Al、Si、Pt、Inなどの元素を少量添加してもよい。 u, Ti, Al, Si, Pt, may be added in small quantities element such as In.

【0038】重希土類−鉄族非晶質合金の場合、飽和磁化は、希土類元素と鉄族元素との組成比により制御することが可能である。 The heavy rare earth - the case of iron group amorphous alloy, the saturation magnetization can be controlled by the composition ratio between rare earth element and iron group element. また、キュリー温度も、組成比により制御することが可能であるが、飽和磁化と独立に制御するためには、鉄族元素として、Feの一部をCoで置き換えた材料を用い、置換量を制御する方法がより好ましく利用できる。 Further, the Curie temperature, it is possible to control the composition ratio, in order to control independently of the saturation magnetization, as an iron group element, using a material obtained by replacing a part of Fe with Co, the amount of substitution method of controlling available more preferred. 即ち、Fe 1at%をCoで置換することにより、6℃程度のキュリー温度上昇が見込めるので、この関係を用いて所望のキュリー温度となるようにCoの添加量を調整する。 That is, by replacing Fe 1 at.% In Co, since the Curie temperature increase of about 6 ° C. can be expected to adjust the addition amount of Co to a desired Curie temperature using this relationship. また、Cr、Tiなどの非磁性元素を微量添加することにより、逆にキュリー温度を低下させることも可能である。 Further, Cr, by a non-magnetic element such as Ti is added in a small amount, it is possible to lower the Curie temperature conversely. あるいはまた、二種類以上の希土類元素を用いてそれらの組成比を調整することでもキュリー温度を制御できる。 Alternatively, it is also controlled Curie temperature by adjusting their composition ratio by using two or more kinds of rare earth elements.

【0039】この他に、ガーネット、白金族−鉄族周期構造膜、もしくは白金族−鉄族合金などの材料も使用可能である。 [0039] In addition, garnet, platinum group - iron group periodic structure film or a platinum group, - material such as iron group alloys can be used.

【0040】第1の磁性層としては、例えば、GdC [0040] As the first magnetic layer, for example, GdC
o、GdFeCo、GdFe、NdGdFeCoなどの垂直磁気異方性の小さな希土類−鉄族非晶質合金や、ガーネット等のバブルメモリ用材料が望ましい。 o, GdFeCo, GdFe, a small rare earth of perpendicular magnetic anisotropy, such as NdGdFeCo - and iron group amorphous alloy, bubble memory for material such as garnet is desirable.

【0041】第3の磁性層としては、例えば、TbFe [0041] The third magnetic layer, for example, TbFe
Co、DyFeCo、TbDyFeCoなどの希土類− Co, DyFeCo, rare earth, such as TbDyFeCo -
鉄族非晶質合金や、Pt/Co、Pd/Coなどの白金族−鉄族周期構造膜など、垂直磁気異方性が大きく安定に磁化状態が保持できるものが望ましい。 And iron group amorphous alloy, platinum group such as Pt / Co, Pd / Co - iron group periodic structure film, which perpendicular magnetic anisotropy is large stable magnetization state can be maintained is desired.

【0042】本発明の光磁気記録媒体へのデータ信号の記録は、媒体を移動させながら、第3の磁性層がキュリー温度以上になるようなパワーのレーザー光を照射しながら外部磁界を変調して行うか、もしくは、一定方向の磁界を印加しながらレーザーパワーを変調して行う。 The recording of the data signal to the magneto-optical recording medium of the present invention, while moving the medium, the third magnetic layer by modulating the external magnetic field while irradiating a laser beam having a power such that above the Curie temperature or performed, or performed by modulating the laser power while applying a magnetic field in a constant direction. 後者の場合、光スポット内の所定領域のみが第3の磁性層のキュリー温度近傍になる様にレーザー光の強度を調整すれば、光スポットの径以下の記録磁区が形成でき、その結果、光の回折限界以下の周期の信号を記録できる。 In the latter case, by adjusting the intensity of the laser beam so as to only a predetermined area is the vicinity of the Curie temperature of the third magnetic layer in the light spot, the recording magnetic domain under smaller than the diameter of the light spot can be formed, as a result, light the signal in the following cycle the diffraction limit of the possible record.

【0043】更に、第4の磁性層を設けた媒体の構成を図6に示す。 [0043] Further, showing the configuration of the fourth magnetic layer provided medium in FIG. この態様においては、透明基板66上に、 In this embodiment, on the transparent substrate 66,
誘電体層65、第1の磁性層61、第4の磁性層64、 Dielectric layer 65, the first magnetic layer 61, the fourth magnetic layer 64,
第2の磁性層62、第3の磁性層63、誘電体層64が順次積層されている。 The second magnetic layer 62, a third magnetic layer 63, dielectric layer 64 are sequentially stacked. 各層の材料、製造法等に関しては、図5について述べたものと同様である。 Each layer of material, with respect to the production process or the like, are the same as those described for FIG.

【0044】以下に具体的な実施例をもって本発明を更に詳細に説明するが、本発明はその要旨を越えない限り以下の実施例に限定されるものではない。 [0044] The present invention will be described with specific examples in more detail below, but the present invention is not limited to the following Examples unless exceeding the gist thereof.

【0045】まず、図5に示した様な第1〜第3の磁性層を有する光磁気記録媒体の実施例を以下に挙げる。 [0045] First, it is given an embodiment of a magneto-optical recording medium, comprising: first, second and third magnetic layers, such as shown in FIG. 5 below.

【0046】<実施例1>直流マグネトロンスパッタリング装置に、BドープしたSi、及びGd、Dy、T [0046] <Example 1> DC magnetron sputtering apparatus, B-doped Si, and Gd, Dy, T
b、Fe、Coの各ターゲットを取り付け、トラッキング用の案内溝の形成されたポリカーボネイト基板を基板ホルダーに固定した後、1×10 -5 Pa以下の高真空になるまでチャンバー内をクライオポンプで真空排気した。 b, Fe, attaching each target of Co, vacuum polycarbonate substrate formed with the guide groove for tracking was fixed on a substrate holder, at cryopump chamber until a high vacuum of 1 × 10 -5 Pa It was evacuated. 真空排気をしたままArガスを0.3Paとなるまでチャンバー内に導入し、基板を回転させながら、干渉層であるSiN層を800オングストローム成膜した。 Ar gas while the evacuation was introduced until the chamber becomes 0.3 Pa, while rotating the substrate, a SiN layer is an interference layer was deposited 800 Å.
引き続き、第1の磁性層としてGdCo層を300オングストローム、第2の磁性層としてDyFe層を100 Subsequently, 300 angstrom GdCo layer as the first magnetic layer, a DyFe layer as the second magnetic layer 100
オングストローム、第3の磁性層としてTbFeCo層を400オングストローム順次成膜した。 Å, and the TbFeCo layer as a third magnetic layer are sequentially deposited 400 Å. 最後に、保護層としてSiN層を800オングストローム成膜した。 Finally, the SiN layer was deposited 800 angstroms as a protective layer.
SiN層成膜時にはArガスに加えてN 2ガスを導入し、直流反応性スパッタにより成膜した。 During SiN layer deposition by introducing N 2 gas in addition to Ar gas, it was formed by DC reactive sputtering. 各磁性層は、 Each of the magnetic layer,
Gd、Dy、Tb、Fe、Coの各ターゲットに直流パワーを印加して成膜した。 Gd, Dy, Tb, Fe, was formed by applying a DC power to each target of Co.

【0047】各磁性層の組成は、全て補償組成近傍になるように調整し、キュリー温度は、第1の磁性層が30 [0047] The composition of each magnetic layer was adjusted so that all become near the compensation composition, the Curie temperature, the first magnetic layer 30
0℃以上、第2の磁性層が70℃、第3の磁性層が20 0 ℃ above, the second magnetic layer is 70 ° C., the third magnetic layer 20
0℃程度となるように設定した。 It was set to be 0 ℃ about.

【0048】この媒体は、図7(a)に断面形状で示した様に、基板71上に、誘電体層72、磁性層73、誘電体層74が積層され、基板71の案内溝を深さ100 [0048] This medium, as shown in cross section in FIG. 7 (a), on a substrate 71, a dielectric layer 72, magnetic layer 73, dielectric layer 74 is laminated, the depth of the guide groove of the substrate 71 is 100
0オングストロームの矩形に形成してある。 It is formed in a rectangular angstrom. このため、 For this reason,
ランド76上に積層された磁性層72は、案内溝75の部分でほぼ分離されている。 Magnetic layer 72 stacked on the land 76 is substantially separated at the portion of the guide groove 75. なお実際には、段差部にも多少膜が堆積して磁性層が繋がってしまうが、他の部分と比較して膜厚が非常に薄くなるので、段差部での結合は無視できる。 Note In practice, the magnetic layer is deposited slightly film in the step part which leads, the film thickness compared to other portions is very thin, coupled with the stepped portion can be ignored. 本発明において、各情報トラック間で互いに磁気的に分離されるとは、この様な状態も含まれる。 In the present invention, it is to be magnetically separated from each other between the information tracks is also included such a state. このランド76上に幅いっぱいに反転磁区を形成すると、図7(b)に示す様に、ランド76上の磁区の境界部に、閉じていない磁壁77が形成される。 When forming the inverted magnetic domains on the lands 76 on the full width, as shown in FIG. 7 (b), the boundary portion of the magnetic domains on the lands 76, the magnetic domain wall 77 not closed is formed. このような磁壁77は、トラック方向に移動させても、トラック側部の磁壁77の生成・消滅を伴わないので、容易に移動させることができる。 Such magnetic walls 77 can also be moved in the track direction, since without the creation and annihilation of the magnetic wall 77 of the track side, can be easily moved.

【0049】この様にして得た光磁気記録媒体について、記録再生特性を測定した。 The magneto-optical recording medium obtained in this manner was measured recording and reproducing characteristics.

【0050】測定に用いた記録再生装置には、図8に示すように、一般的な光磁気ディスク記録再生装置の光学系に、加熱用のレーザーが付加されている。 [0050] recorded in the reproducing apparatus used for the measurement, as shown in FIG. 8, the optical system of the general magneto-optical disk recording and reproducing apparatus, a laser for heating is added. 81は、記録再生用のレーザー光源で、波長は780nmで、記録媒体に対してP偏向が入射する様に配置されている。 81, a laser light source for recording and reproduction, the wavelength is 780 nm, P deflection are arranged so as to be incident to the recording medium. 8
2は、加熱用のレーザー光源で、波長は1.3μmで、 2 is a laser light source for heating, the wavelength at 1.3 .mu.m,
同じく記録媒体に対してP偏向が入射する様に配置されている。 P deflection is arranged so that incident on same recording medium. 83は、780nm光を100%透過し、1. 83, passes through the 780nm light 100% 1.
3μm光を100%反射するように設計されたダイクロイックミラーである。 The 3μm light a dichroic mirror designed to reflect 100%. 84は、偏向ビームスプリッタで、780nm光、1.3μm光、各々のP偏向は70 84 is deflected by the beam splitter, 780 nm light, 1.3 .mu.m light, each of P deflection 70
〜80%透過し、S偏向は100%反射するよう設計されている。 Transmitted to 80%, S deflection is designed to reflect 100%. 1.3μm光の光束径は、対物レンズ85の開口径よりも小さくなるようにしてあり、全開口部を通過して集光される780nm光に比べて、NAが小さくなるようにしてある。 Beam diameter of 1.3μm light is Yes designed to be smaller than the aperture diameter of the objective lens 85, as compared with the 780nm light condensed through the whole aperture, are as NA becomes small. また、87は、1.3μm光が、 In addition, 87, is 1.3μm light,
信号検出系に漏れ込まないようにするために設けるもので、780nm光を100%透過し、1.3μm光を1 Provided in order to so leaking into the signal detection system, the 780nm light transmitted through 100%, a 1.3μm light 1
00%反射するように設計されたダイクロイックミラーである。 100% a dichroic mirror designed to reflect.

【0051】この光学系により、記録媒体86の記録面上に、図9(a)に示すように、案内溝94間のランド95上にいおいて、記録再生用のスポット91と、加熱用のスポット92とを結像させることができる。 [0051] The optical system, onto the recording surface of the recording medium 86, as shown in FIG. 9 (a), at a land 95 on Nii between the guide groove 94, the spot 91 for recording and reproduction, for heating and the spot 92 can be imaged. 加熱用のスポット92は、波長が長くNAが小さいので、記録再生用のスポット91よりも径が大きくなる。 Spot 92 for heating, since the wavelength is long NA is small, the diameter is larger than the spot 91 for recording and reproduction. これにより、移動している媒体の記録面上の記録再生用のスポット91の領域に、図9(b)に示してあるような所望の温度勾配を容易に形成することができる。 Thus, the area of ​​the recording and reproducing spot 91 on the recording surface of the medium is moving, a desired temperature gradient as are shown in FIG. 9 (b) can be easily formed. ここで温度T Here at a temperature T
sの等温線96も図示する。 s isotherms 96 is also shown. 記録再生は媒体を線速5m Recording and reproduction linear velocity of the medium 5m
/secで駆動して行なった。 / It was carried out driven by sec.

【0052】まず、記録再生用レーザーを8mWでDC [0052] First of all, the recording and reproducing laser in 8mW DC
照射しながら磁界を±150 Oeで変調することにより、第3の磁性層のキュリー温度以上に加熱した後の冷却過程で、磁界の変調に対応した上向き磁化と下向き磁化との繰り返しパターンを形成した。 By modulating the magnetic field at ± 0.99 Oe while irradiating, in the cooling process after heating above the Curie temperature of the third magnetic layer to form a repeating pattern of upward magnetization and downward magnetization corresponding to the modulation of the magnetic field . 尚、この時、加熱用のレーザーを合わせて照射して、記録再生用レーザーの記録パワーを低減させることも可能である。 At this time, by irradiating the combined laser for heating, it is possible to reduce the recording power of the recording reproducing laser.

【0053】記録磁界の変調周波数は1〜10MHzまで変化させ、2.5〜0.25μmの範囲のマーク長のパターンを記録した。 [0053] The modulation frequency of the recording magnetic field is varied from 1-10 MHz, it was recorded pattern having a mark length ranging from 2.5~0.25Myuemu.

【0054】再生時の記録再生用のレーザーのパワーは1mWとし、加熱用のレーザーを20mWのパワーで同時に照射しながら、各マーク長のパターンについてC/ [0054] Power of the laser for recording and reproduction during reproduction was set to 1 mW, while simultaneously irradiated with a laser for heating at a power of 20 mW, the pattern of each mark length C /
Nを測定した。 It was measured N. この時の媒体面上の温度分布は図9 Temperature distribution on the medium surface at this time is 9
(b)に示すとおりである。 It is as shown in (b).

【0055】この測定結果を図10のグラフ線aに示す。 [0055] The measurement results are shown in graph line a in FIG. 10. また比較のため同図中の特開平3−93058号に記載の従来の超解像再生方法による測定結果をグラフ線bとして示し、超解像現象の起こらない通常の再生方法による測定結果をグラフ線cとして示す。 Also shows the result of measurement by the conventional super-resolution reproducing method described in JP-A-3-93058 in the drawing for comparison as graph line b, graph the measurement results of normal playback method that does not happen with super-resolution phenomenon It is shown as line c.

【0056】本発明の再生方法によると、マーク長が短くなっても再生用のスポット内の全磁化の反転が検出されるので、光の回折限界以下の周期の信号が再生可能となるのみならず、C/Nのマーク長依存性がほとんどなくなる。 [0056] According to the reproducing method of the present invention, since the total magnetization inversion in the spot for reproduction even mark length is shortened is detected, if only a signal of less than the diffraction limit of the period of light becomes reproducible not, there is almost no mark length dependency of C / N.

【0057】尚、本実施例の媒体において、第1の磁性層の磁壁が、温度勾配によって移動する様子は、以下に述べるように、偏光顕微鏡による直接観察で確認された。 [0057] Incidentally, in the medium of the present embodiment, the magnetic wall of the first magnetic layer, how to move by the temperature gradient, as described below, was confirmed by direct observation with a polarizing microscope.

【0058】まず、実施例1と同様の構成で、磁性層の積層順を逆にしたサンプルを作製した。 [0058] First, the same structure as in Example 1 to prepare a sample in which the lamination order of the magnetic layer is reversed. このサンプルに実施例1と同様の記録方法により、磁区パターンを形成した。 This the same recording method as in Example 1 to the sample, thereby forming a magnetic domain pattern. これを膜面側、即ち第1の磁性層側から偏光顕微鏡で観察した。 This film surface side, i.e., was observed with a polarizing microscope from the first magnetic layer side.

【0059】次に、このサンプルに加熱用の集光レーザーを照射して、偏光顕微鏡の視野内で、実施例1とほぼ同様の温度分布を形成した。 Next, by irradiating a focused laser for heating the sample, in the field of view of the polarization microscope, it was formed almost the same temperature distribution as in Example 1.

【0060】この状態で、サンプルに500 Oe 程度の磁界を印加した。 [0060] In this state, the application of a magnetic field of about 500 Oe to sample. この結果、温度分布に対応した円形の領域のみが、外部磁界の方向に配向するのが観察された。 As a result, only the circular area corresponding to the temperature distribution, for orientation in the direction of the external magnetic field was observed. これは、この領域において、第1の磁性層と第3 This is because in this region, the first magnetic layer and the third
の磁性層との間の交換結合が切断されていることを意味している。 The exchange coupling between the magnetic layer is meant that it is disconnected.

【0061】次に、磁界の印加を停止して、トラック方向にサンプルをゆっくりと移動させた。 Next, by stopping the application of the magnetic field was moved slowly sample in the track direction. すると、トラック上に形成されている磁区の境界部が上述の円形の結合切断領域に入る度に、移動してきた磁区が円形領域の中心方向に向かって拡大するのが観察された。 Then, the boundary portion of the magnetic domains formed on the track each time entering the bond cleavage region of circular above, the magnetic domain which has moved is observed to expand toward the center of the circular area.

【0062】加熱用のレーザーの照射を停止すると、第3の磁性層に保存されていた磁区パターンが第1の磁性層に転写されるのが観察された。 [0062] Upon stopping the irradiation of the laser for heating, a third magnetic domain pattern that was stored in the magnetic layer that is transferred to the first magnetic layer was observed.

【0063】以上より、第3の磁性層との結合が切断された領域において、第1の磁性層の磁壁が、温度勾配によって高温側へ移動することが確認された。 [0063] From the above, in the area where binding is broken and the third magnetic layer, the domain wall of the first magnetic layer, it was confirmed that moves to the high temperature side by a temperature gradient.

【0064】<実施例2>実施例1と同様の成膜機、成膜方法で、同様にポリカーボネイト基板上に薄膜を成膜して光磁気記録媒体を作成した。 [0064] <Example 2> Example 1 and the same film formation apparatus, the film formation method to prepare a magneto-optical recording medium by forming a thin film in the same manner as polycarbonate substrate. 但し、本実施例においては、以下の三点を変更した。 However, in this embodiment, by changing the following three points.

【0065】第一に、成膜前の基板表面にArイオンの加速照射処理を加えたこと、第二に、干渉層であるSi [0065] First, the addition of acceleration irradiation treatment Ar ions to the substrate surface before film formation, secondary to interference layer Si
N層を成膜した後の膜表面にArイオンの加速照射処理を加えたことである。 On the film surface after forming the N layer is the addition of accelerated irradiation treatment Ar ions. これらの処理により、表面状態を平滑化した。 By these processes, the surface state was smoothed. 更に、第三に、第1の磁性層の膜厚を20 Further, the third, the thickness of the first magnetic layer 20
00オングストロームに変更したことである。 00 is that it was changed to angstroms. これらの変更点は、それぞれ独立に、第1の磁性層の磁壁移動度の向上に寄与する。 These changes are each independently contributes to the improvement of the magnetic wall displacement of the first magnetic layer.

【0066】この媒体の記録再生特性を実施例1と同様の方法で測定したところ、実施例1と同様の良好な結果が得られた。 [0066] When the recording and reproducing characteristics of the medium was measured in the same manner as in Example 1, excellent results similar to Example 1 were obtained. 更に、再生時の媒体の線速度を20m/s In addition, the linear velocity of the playback of media 20m / s
ecまで高速化して再生しても、再生特性は低下しなかった。 Be regenerated to speed up ec, reproduction characteristics did not decrease.

【0067】<実施例3>実施例1と同様の成膜機、成膜方法で、同様にポリカーボネイト基板上に薄膜を成膜して光磁気記録媒体を作製した。 [0067] <Example 3> Example 1 and the same film formation apparatus, the film formation method, to prepare a magneto-optical recording medium by forming a thin film in the same manner as polycarbonate substrate.

【0068】但し、本実施例においては、基板として、 [0068] However, in the present embodiment, as the substrate,
プレピットが形成されており、案内溝の断面形状がU型になっているものを用いた。 Prepits are formed, the cross-sectional shape of the guide groove was used that is a U shape. このため、積層した磁性層は、案内溝の部分で形状的に分断されていない。 Therefore, laminated magnetic layers are not geometrically separated at the portion of the guide groove.

【0069】この媒体の、案内溝の部分に高出力のレーザーを照射し、案内溝の部分の磁性層を全面にアニールした。 [0069] The medium, the portion of the guide grooves irradiated with a laser of high output, were annealed magnetic layer portion of the guide groove over the entire surface. この結果、案内溝の部分の磁性層が変質して面内膜になり、案内溝を介して、互いに隣接するトラックの磁性層の間の結合が分断された。 This results in plane film magnetic layer portions of the guide grooves is altered, through a guide groove, which is divided the coupling between the magnetic layers of adjacent tracks to each other. この媒体の記録再生特性を実施例1と同様の方法で測定したところ、実施例1 The recording and reproducing characteristics of the medium was measured in the same manner as in Example 1, Example 1
と同様の良好な結果が得られた。 Good results similar to was obtained.

【0070】また、上述のアニール処理を施さずに、上記の媒体の記録再生特性を実施例1と同様の方法で測定したところ、実施例1の結果に比べてノイズが上昇したが、光の回折限界以下の周期の信号の再生は、十分可能であった。 [0070] Further, without performing the annealing treatment described above, was the recording and reproduction characteristics of the medium was measured in the same manner as in Example 1, but the noise is increased in comparison with the results of Example 1, the light reproduction of the diffraction limit or less of the period of the signal was sufficiently possible. この媒体では、閉じた磁壁で囲まれた磁区が存在するので、この磁区を拡大させる方向に磁壁を移動させる時に動作が不安定になりノイズが上昇した。 In this medium, because it was surrounded by a closed magnetic wall domain is present, the operation noise become unstable is increased when moving the magnetic domain wall in a direction to expand the magnetic domain.

【0071】なお、隣接するトラックの磁性層との間の結合を分断する別の方法として、エッチング処理によるパターニングを行ってもよい。 [0071] Incidentally, as another method of dividing the bond between the magnetic layer of the adjacent tracks, it may be carried out patterning by etching.

【0072】<実施例4>実施例1の媒体を用いて、実施例1とほぼ同様の記録再生装置で記録再生特性を評価した。 [0072] using a medium <Example 4> Example 1 to evaluate recording and reproduction characteristics in substantially the same recording and reproducing apparatus as in Example 1.

【0073】但し、記録再生用のスポットと、加熱用のスポットとの位置関係を図11のように変更した。 [0073] However, the spot for recording and reproduction, the positional relationship between the spot of heating were changed as shown in Figure 11. 即ち、加熱用レーザーによって誘起される温度分布の、媒体の移動方向に対して前方の斜面に、記録再生用のスポットが配置されるようにした。 That is, the temperature distribution induced by the heating laser, in front of the inclined surface with respect to the moving direction of the medium, the spot for recording and reproduction is to be placed.

【0074】媒体が移動して、図中Sで示した位置を通過すると、第1の磁性層と第3の磁性層とが再び結合して、第1の磁性層に第3の磁性層の磁化配向状態が転写される。 [0074] medium moves, passes through the position shown in the figure S, the first magnetic layer and the third magnetic layer are bonded again, the third magnetic layer to the first magnetic layer magnetization orientation state is transferred. 第3の磁性層の磁壁がSで示した位置を通過すると、第1の磁性層のSで示した位置に磁壁が残され、 When the domain wall of the third magnetic layer passes through the position indicated by S, the domain wall is left at the position indicated by the S of the first magnetic layer,
この磁壁が瞬間的に後方に移動する。 The domain wall is moved momentarily to the rear. 記録再生用のスポットを、上述のように配置しておくと、この時の磁壁の移動が検出される。 The spot for recording and reproduction, the previously arranged as described above, the movement of the domain wall at this time is detected.

【0075】この配置にすると、Sで示した臨界温度T [0075] With this arrangement, the critical temperature T indicated by S
sの等温線の形状と、磁界変調方式で形成された磁区の磁壁の形状とがほぼ整合するので、磁壁の移動がより安定に行われるようになる。 s and the shape of the isotherms, since the magnetic field modulation system domain wall shape of the formed magnetic domain in is substantially aligned, so that the movement of the domain wall is performed more stably.

【0076】<比較例1>実施例1の媒体を用いて、加熱用のレーザーが付加されていない通常の光磁気ディスク記録再生装置によって、記録再生特性を測定した。 [0076] Using the medium of <Comparative Example 1> Example 1, by a conventional magneto-optical disc recording and reproducing apparatus laser for heating is not added, were measured recording and reproducing characteristics.

【0077】加熱用のレーザーが照射されていない他は、実施例1と同様の方法で再生特性を調べたところ、 [0077] Other laser for heating is not irradiated, were examined playback characteristics in the same manner as in Example 1,
再生パワーを3mW程度まで増大させることにより、良好なC/Nが得られた。 By increasing the reproduction power up to about 3 mW, good C / N was obtained. 但し、実施例1の結果と比較すると、各マーク長において、5dB程度C/Nが低かった。 However, when compared with the results of Example 1, in each mark length was less 5dB about C / N. これは、再生用スポットの前部においては媒体の温度が上昇しないので、再生用スポットの途中から磁壁の移動が起こり、実施例1のようには、スポット全域を有効に使用できないためである。 This is because the temperature of the medium in front of the reproducing spot does not rise, occurs movement of the domain wall from the middle of the reproducing spot, the as in Example 1, it can not be effectively used spots throughout.

【0078】次に、図6に示した様な第1〜第4の磁性層を有する光磁気記録媒体の実施例を以下に挙げる。 [0078] Next, given the example of the magneto-optical recording medium having a first through fourth magnetic layers, such as shown in FIG. 6 below.

【0079】<実施例5>直流マグネトロンスパッタリング装置に、BドープしたSi、及びGd、Tb、F [0079] in <Example 5> DC magnetron sputtering apparatus, B-doped Si, and Gd, Tb, F
e、Co、Crの各ターゲットを取り付け、トラッキング用の案内溝の形成されたポリカーボネイト基板を基板ホルダーに固定した後、1×10 -5 Pa以下の高真空になるまでチャンバー内をクライオポンプで真空排気した。 e, Co, attaching each target of Cr, vacuum polycarbonate substrate formed with the guide groove for tracking was fixed on a substrate holder, at cryopump chamber until a high vacuum of 1 × 10 -5 Pa It was evacuated.

【0080】真空排気をしたままArガスを0.3Pa [0080] 0.3Pa the Ar gas while the vacuum exhaust
となるまでチャンバー内に導入し、基板を回転させながら、干渉層であるSiN層を800オングストローム成膜した。 Introduced into the chamber until, while rotating the substrate, a SiN layer is an interference layer was deposited 800 Å. 引き続き、第1の磁性層としてGdCoCr層を300オングストローム、第4の磁性層としてGdF Subsequently, 300 angstrom GdCoCr layer as the first magnetic layer, GdF as a fourth magnetic layer
eCr層を300オングストローム、第2の磁性層としてTbFeCr層を100オングストローム、第3の磁性層としてTbFeCo層を400オングストローム順次成膜した。 eCr layer 300 Å, 100 Å TbFeCr layer as the second magnetic layer, and the TbFeCo layer as a third magnetic layer are sequentially deposited 400 Å. 最後に、保護層としてSiN層を800オングストローム成膜した。 Finally, the SiN layer was deposited 800 angstroms as a protective layer. SiN層成膜時にはArガスに加えてN 2ガスを導入し、直流反応性スパッタにより成膜した。 During SiN layer deposition by introducing N 2 gas in addition to Ar gas, it was formed by DC reactive sputtering. 各磁性層は、Gd、Tb、Fe、Co、Cr Each magnetic layer, Gd, Tb, Fe, Co, Cr
の各ターゲットに直流パワーを印加して成膜した。 It was formed by applying a DC power to each target.

【0081】各磁性層の組成は、全て補償組成近傍になるように調整し、キュリー温度は、第1の磁性層が30 [0081] The composition of each magnetic layer was adjusted so that all become near the compensation composition, the Curie temperature, the first magnetic layer 30
0℃以上、第4の磁性層が170℃、第2の磁性層が7 0 ℃ above, the fourth magnetic layer is 170 ° C., the second magnetic layer is 7
0℃、第3の磁性層が200℃程度となるように設定した。 0 ° C., was set as the third magnetic layer is about 200 ° C.. この媒体は、実施例1と同様に、図7に示した様な断面形状を有する。 The medium is as in Example 1, having a cross-sectional shape as shown in FIG.

【0082】この様にして得た光磁気記録媒体について、実施例1と同様にして記録再生特性を測定した。 [0082] The magneto-optical recording medium obtained in this manner were measured recording and reproduction characteristics in the same manner as in Example 1. ただし、記録時のDC照射レーザーパワーは10mWとし、再生時の加熱用レーザーパワーは25mWとした。 However, DC irradiation laser power for recording is set to 10 mW, the heating laser power for reproduction is set to 25 mW.
この測定結果は、実施例1と同様に、図10のグラフ線aの良好な結果が得られた。 The measurement results are as in Example 1, good results of the graph line a in FIG. 10 were obtained.

【0083】また更に、再生時の媒体の線速度を20m [0083] Furthermore, the linear velocity of the medium at the time of reproduction 20m
/secまで高速化して再生しても再生特性は低下しなかった。 / Even reproducing characteristics play to speed up sec did not decrease.

【0084】尚、第1の磁性層の磁壁が、温度勾配によって移動する様子は、実施例1と同様に偏光顕微鏡による直接観察で確認された。 [0084] Incidentally, the magnetic wall of the first magnetic layer, how to move by the temperature gradient was confirmed by direct observation by similarly polarizing microscope as in Example 1.

【0085】<実施例6>実施例5と同様の成膜機、成膜方法で、同様にポリカーボネイト基板上に薄膜を成膜して光磁気記録媒体を作成した。 [0085] <Example 6> Example 5 The same film forming apparatus, the film formation method to prepare a magneto-optical recording medium by forming a thin film in the same manner as polycarbonate substrate.

【0086】但し、本実施例においては、第4の磁性層内を、第1の磁性層の側から順に、第1、第2、及び第3の構成層で形成し、各構成層のキュリー温度を順に、 [0086] However, in this embodiment, the fourth magnetic layer, in this order from the side of the first magnetic layer, the first, is formed in the second and third component layer, the Curie of each constituent layer the temperature in turn,
180℃、160℃、140℃とし、膜厚を順に、20 180 ° C., 160 ° C., and 140 ° C., in order to film thickness, 20
0オングストローム、400オングストローム、800 0 angstroms, 400 angstroms, 800
オングストロームとして、第4の磁性層中で、膜厚方向に段階的なキュリー温度の勾配を持つようにした。 As Å, the fourth magnetic layer, and to have a gradient of stepwise Curie temperature in a thickness direction. 材料としては、GdFeCoCrを用いた。 The material was used GdFeCoCr.

【0087】また、第1の磁性層は、キュリー温度30 [0087] In addition, the first magnetic layer, the Curie temperature of 30
0℃のGdFeCoCr層を200オングストローム、 0 ℃ of GdFeCoCr layer 200 Å,
第2の磁性層は、キュリー温度120℃のTbFeCo The second magnetic layer, TbFeCo the Curie temperature 120 ° C.
Cr層を200オングストローム、第3の磁性層は、キュリー温度200℃のTbFeCoCr層を600オングストロームとした。 Cr layer 200 Å, a third magnetic layer, a TbFeCoCr layer Curie temperature 200 ° C. to 600 angstroms.

【0088】各磁性層の組成は、補償組成近傍になるように、希土類元素と鉄族元素の組成比を調整し、Co及びCrの添加量を調整して、キュリー温度を上記のように設定した。 [0088] The composition of each magnetic layer, so that the vicinity of compensation composition, and adjusting the composition ratio of the rare earth element and iron group element, by adjusting the addition amount of Co and Cr, setting the Curie temperature as described above did.

【0089】この媒体の記録再生特性を実施例5と同様の方法で測定したところ、実施例5と同様の良好な結果が得られた。 [0089] When the recording and reproducing characteristics of the medium was measured in the same manner as in Example 5, Example 5 and similar good results were obtained. 更に、再生時の媒体の線速度を30m/s Further, the linear velocity of the reproduction medium 30 m / s
ecまで高速化して再生しても、再生特性は低下しなかった。 Be regenerated to speed up ec, reproduction characteristics did not decrease.

【0090】本実施例においては、再生時に、媒体の記録面上の記録再生用のスポットの領域に、120℃から180℃程度のトラック方向の温度勾配を形成した。 [0090] In this embodiment, during reproduction, the spot of the recordable area on the recording surface of the medium, to form a temperature gradient in the track direction of about 180 ° C. from 120 ° C.. この場合、120℃から140℃の領域では、第4の磁性層の第3の構成層の磁壁に大きな力が作用し、140℃ In this case, in the region of 140 ° C. from 120 ° C., a large force to the magnetic wall of the fourth magnetic layer third constituent layers acts, 140 ° C.
から160℃の領域では、第4の磁性層の第2の構成層の磁壁に大きな力が作用し、160℃から180℃の領域では、第4の磁性層の第1の構成層の磁壁に大きな力が作用する。 From the region of 160 ° C., a large force acts on the magnetic wall of the fourth magnetic layer second constituent layer, and in the region of 180 ° C. from 160 ° C., the magnetic wall of the fourth magnetic layer first constituent layers a large force is applied. このため、記録再生用のスポットの領域全域に渡って、第1の磁性層から第4の磁性層にかけて存在している磁壁を、比較的大きな力で移動させることができ、本発明の再生動作を、より安定に、また高速に行なうことができるようになった。 Therefore, over the entire region of the spot for recording and reproduction, a magnetic domain wall being present from the first magnetic layer toward the fourth magnetic layer, it can be moved with a relatively large force, reproduction operation of the present invention a more stable and can now be performed at a high speed.

【0091】<実施例7>実施例5と同様の成膜機、成膜方法で、同様にポリカーボネイト基板上に薄膜を成膜して光磁気記録媒体を作成した。 [0091] <Example 7> Example 5 The same film forming apparatus, the film formation method to prepare a magneto-optical recording medium by forming a thin film in the same manner as polycarbonate substrate.

【0092】但し、本実施例においては、基板として、 [0092] However, in the present embodiment, as the substrate,
プレピットが形成されており、案内溝の断面形状がU型になっているものを用いた。 Prepits are formed, the cross-sectional shape of the guide groove was used that is a U shape. このため、積層した磁性層は、案内溝の部分で形状的に分断されていない。 Therefore, laminated magnetic layers are not geometrically separated at the portion of the guide groove.

【0093】磁性層その他の構成は、第4の磁性層の組成比を次に述べるように変化させた他は、実施例5と同様にした。 [0093] magnetic layers other structure, except that were varied as described below and the composition ratio of the fourth magnetic layer were the same as in Example 5.

【0094】第4の磁性層は、GdFeCrのGdの組成比を調整して、室温において鉄族元素副格子磁化優勢な組成にしたサンプル(1)と、室温において希土類元素副格子磁化優勢で、キュリー温度以下の温度に補償温度が存在する組成にしたサンプル(2)と、室温において希土類元素副格子磁化優勢で、キュリー温度以下の温度に補償温度が存在しない組成にしたサンプル(3)とを作製した。 [0094] The fourth magnetic layer, by adjusting the composition ratio of Gd GdFeCr, the sample (1) that the iron group element sublattice magnetization dominant composition at room temperature, the rare earth element sublattice magnetization dominant at room temperature, and sample the composition of the Curie temperature a temperature below the compensation temperature is present (2), the rare earth element sublattice magnetization dominant at room temperature, a sample (3) was the composition of the Curie temperature below a temperature no compensation temperature It was produced. 各サンプルのキュリー温度は、Cr添加量を調整して、全て170℃に合わせた。 Curie temperature of each sample, by adjusting the amount of Cr added and combined to all 170 ° C..

【0095】これらのサンプルの、案内溝の部分に高出力のレーザーを照射し、案内溝の部分の磁性層を全面アニールした。 [0095] These samples were irradiated with a laser of high output portion of the guide groove, and the entire surface annealed magnetic layer portion of the guide groove. この結果、案内溝の部分の磁性層が磁気的に変質し、案内溝を介して互いに隣接するトラックの磁性層の間の結合が分断された。 As a result, the magnetic layer of the portion of the guide groove is magnetically altered, the coupling between the magnetic layers of tracks adjacent to each other via a guide groove is divided.

【0096】次に、記録再生特性を実施例5と同様の方法で測定したところ、線速5m/secにおいて、各サンプルとも実施例5と同様の良好な結果が得られた。 Next, it was the recording and reproduction characteristics were measured in the same manner as in Example 5, the linear velocity 5 m / sec, good results similar to those of Example 5 in each sample was obtained.

【0097】しかし、線速を30m/secまで高速化して再生すると、サンプル(1)では、C/Nが5dB [0097] However, when played back faster linear velocity up to 30 m / sec, the sample (1), C / N is 5dB
程度低下した。 It was reduced degree. これに対し、サンプル(2)では、C/ In contrast, in the sample (2), C /
Nの低下はほとんど見られず、また、サンプル(3)では、2dB程度しか低下しなかった。 Decrease of N is hardly observed, also, in the sample (3), did not decrease only 2dB about.

【0098】これは、室温において、希土類元素副格子磁化優勢な組成のもの、中でもキュリー温度以下に補償温度を有する組成のものの方が、キュリー温度近傍における、磁壁エネルギーの温度依存性が大きく、温度勾配によって、より大きな力を磁壁に作用させることができるためであると考えられる。 [0098] This, at room temperature, that of the rare earth element sublattice magnetization dominant composition, among others who having composition having a compensation temperature below the Curie temperature, the Curie temperature near, a large temperature dependency of the magnetic wall energy, temperature the gradient is believed to be due to a greater force can be exerted on the magnetic wall.

【0099】以上挙げた実施例に本発明は限定定されるものでない。 [0099] The present invention to the embodiments mentioned above is not limited constant. 他の実施可能な例として、光ヘッドは従来のままにして、媒体上の温度分布を別の手段でつい調整する方法も考えられる。 As another possible example, the optical head is to leave the conventional, it is also considered a method of adjusting with the temperature distribution on the medium by another means. 例えば、磁界変調記録に用いる浮上ヘッドのコアを熱源として流用したり、その他適当な発熱体を媒体の再生用レーザー照射領域の近くに配置することが考えられる。 For example, to divert the core of the flying head used for magnetic field modulation recording as a heat source, be placed other suitable heating element near the reproduction laser irradiation area of ​​the medium is considered. 但し、この場合、磁壁の移動開始位置となる温度の位置と、再生用スポットとの位置関係が再生信号の周波数に近い周波数で変動することがないように注意する必要がある。 However, in this case, the position of the temperature at which the movement start position of the domain walls, it is necessary to pay attention so that the position relation between the reproducing spot is not able to vary at a frequency close to the frequency of the reproduced signal.

【0100】 [0100]

【発明の効果】以上詳細に説明したように、本発明の光磁気記録媒体、再生方法、および再生装置によれば、再生信号振幅を低下させることなく光の回折限界以下の周期の信号が高速で再生可能となり、記録密度並びに転送速度を大幅に向上でき、再生装置の小型化も可能である。 As described [Effect Invention above in detail, the magneto-optical recording medium of the present invention, playback method, and according to the reproducing apparatus, signals of less than the diffraction limit of the period of light high speed without reducing the reproduction signal amplitude in enabling playback, the recording density and the transfer rate can be greatly improved, and can also compact the reproducing apparatus.

【図面の簡単な説明】 BRIEF DESCRIPTION OF THE DRAWINGS

【図1】第1〜第3の磁性層を有する光磁気記録媒体を使用した場合の本発明の再生方法の概念を模式的に示した図である。 1 is a diagram schematically showing the concept of regeneration process of the present invention when using a magneto-optical recording medium, comprising: first, second and third magnetic layers. (a)は、再生状態における媒体の断面を示し、各磁性層のスピンの配向状態を模式的に示してある。 (A) illustrates a cross section of the medium in the reproduction state, Aru the orientation of the spin of each magnetic layer is schematically illustrated. (b)は、(a)に示されている位置における媒体上の温度分布を示している。 (B) shows the temperature distribution on the medium at the position shown in (a). (c)は、同様の位置における磁壁エネルギー密度の分布及びそれに伴って磁壁に作用する力の分布を模式的に示している。 (C) the distribution of the force acting on the magnetic wall along with distribution and that of the magnetic wall energy density at the same position is shown schematically.

【図2】スポットの下を磁壁が通過するのに要する時間τと、最短記録マーク長相当の距離を媒体が移動するのに要する時間t minとの関係を示すグラフである。 2 is a graph showing the relationship between time τ required for the domain wall to pass under a spot, and the time t min required distance of the shortest recording mark length corresponds to medium moves.

【図3】本発明の方法と通常の従来法とを比較する模式図である。 3 is a schematic view for comparing the method and the usual conventional method of the present invention.

【図4】第1〜第4の磁性層を有する光磁気記録媒体を使用した場合の本発明の再生方本発明の再生方法の概念を模式的に示した図である。 4 is a diagram schematically showing the concept of regeneration method for regenerating side of the Invention The present invention when using a magneto-optical recording medium having a first through fourth magnetic layers.

【図5】本発明の光磁気記録媒体の層構成の一実施態様を示す模式的断面図である。 5 is a schematic cross-sectional view showing one embodiment of the layer structure of the magneto-optical recording medium of the present invention.

【図6】本発明の光磁気記録媒体の層構成の一実施態様を示す模式的断面図である。 6 is a schematic cross-sectional view showing one embodiment of the layer structure of the magneto-optical recording medium of the present invention.

【図7】実施例における光磁気記録媒体の断面形状を示す図である。 7 is a diagram showing a sectional configuration of a magneto-optical recording medium of Example.

【図8】実施例において用いた記録再生装置を示す模式図である。 8 is a schematic diagram showing a recording and reproducing apparatus used in Example.

【図9】実施例における再生状態を示す模式図である。 9 is a schematic diagram showing a reproducing state in the embodiment.

【図10】実施例において得られたC/Nを示すグラフである。 10 is a graph showing the C / N obtained in Example.

【図11】実施例における再生状態を示す模式図である。 11 is a schematic diagram showing a reproducing state in the embodiment.

【符号の説明】 DESCRIPTION OF SYMBOLS

11 第1の磁性層 12 第2の磁性層 13 第3の磁性層 14 原子スピンの向き 15 磁壁 16 再生様の光ビームスポット 17 磁壁の移動方向 18 媒体の移動方向 11 the moving direction of the first magnetic layer 12 and the second magnetic layer 13 third magnetic layer 14 atomic spin direction 15 domain wall 16 play like the light beam spot 17 domain wall displacement direction 18 medium

Claims (10)

    【特許請求の範囲】 [The claims]
  1. 【請求項1】 少なくとも、第1、第2、第3の磁性層が順次積層されている光磁気記録媒体であって、該第1 1. A least first, second, and third magnetic layer to a magneto-optical recording medium are sequentially stacked, the first
    の磁性層は、周囲温度近傍の温度において該第3の磁性層に比べて相対的に磁壁抗磁力が小さく磁壁移動度大きな垂直磁化膜からなり、該第2の磁性層は、該第1の磁性層および第3の磁性層よりもキュリー温度の低い磁性層からなり、該第3の磁性層は垂直磁化膜であることを特徴とする光磁気記録媒体。 Of the magnetic layer is relatively wall coercivity is from smaller domain wall mobility large perpendicular magnetization film compared to the magnetic layer of the third at a temperature near ambient temperature, the magnetic layer of said second, said first magnetic layer and the third consists of a lower magnetic layer having a Curie temperature than the magnetic layer, the magneto-optical recording medium, wherein the magnetic layer of the third is a perpendicular magnetization film.
  2. 【請求項2】 第1の磁性層が、各情報トラック間で互いに磁気的に分離されている請求項1記載の光磁気記録媒体。 Wherein the first magnetic layer, the magneto-optical recording medium according to claim 1, wherein between each information track is magnetically isolated from each other.
  3. 【請求項3】 少なくとも、第1、第4、第2、第3の磁性層が順次積層されている光磁気記録媒体であって、 Wherein at least a first, fourth, second, and third magnetic layer to a magneto-optical recording medium are sequentially laminated,
    該第1の磁性層は、周囲温度近傍の温度において該第3 The first magnetic layer, the third at a temperature in the vicinity of ambient temperature
    の磁性層に比べて相対的に磁壁抗磁力が小さな垂直磁化膜からなり、該第2の磁性層は、該第1の磁性層および第3の磁性層よりもキュリー温度の低い磁性層からなり、該第3の磁性層は垂直磁化膜であり、該第4の磁性層は、該第2の磁性層よりも高く、該第1の磁性層よりも低いキュリー温度を有し、かつ少なくとも該第2の磁性層のキュリー温度以上の温度において、該第3の磁性層に比べて相対的に磁壁抗磁力が小さな垂直磁化膜からなることを特徴とする光磁気記録媒体。 Relatively wall coercivity than the magnetic layer is made of a small perpendicular magnetic film, the magnetic layer of the second is made lower magnetic layer having a Curie temperature than the magnetic layer and the third magnetic layer of the first , the magnetic layer of the third is a perpendicular magnetization film, a magnetic layer of said fourth, higher than the second magnetic layer has a Curie temperature lower than the first magnetic layer, and at least the in the Curie temperature or higher temperature of the second magnetic layer, the magneto-optical recording medium relatively wall coercivity is characterized in that it consists of a small perpendicular magnetic film in comparison with the magnetic layer of the third.
  4. 【請求項4】 第4の磁性層が、前記第2の磁性層に近づく程キュリー温度が低くなるように膜厚方向にキュリー温度の勾配を有する請求項3記載の光磁気記録媒体。 4. A fourth magnetic layer, the second magneto-optical recording medium according to claim 3, wherein the Curie temperature the closer to the magnetic layer has a gradient of Curie temperature in the thickness direction to be lower.
  5. 【請求項5】 第4の磁性層が、希土類−鉄族元素非晶質合金からなり、希土類元素副格子磁化優勢な組成である請求項3または4記載の光磁気記録媒体。 Wherein the fourth magnetic layer, a rare earth - of iron group element amorphous alloy, a magneto-optical recording medium according to claim 3 or 4, wherein the rare earth element is a sublattice magnetization dominant composition.
  6. 【請求項6】 第4の磁性層が、キュリー温度以下の温度に補償温度を有する請求項5記載の光磁気記録媒体。 6. A fourth magnetic layer, the magneto-optical recording medium according to claim 5, further comprising a compensation temperature higher than the Curie temperature temperatures.
  7. 【請求項7】 第1及び第4の磁性層が、各情報トラック間で互いに磁気的に分離されている請求項3〜6の何れか一つの項に記載の光磁気記録媒体。 7. A magnetic layer of the first and fourth are magneto-optical recording medium according to any one of claims 3-6 which are magnetically separated from one another among the information tracks.
  8. 【請求項8】 請求項1または2に記載の光磁気記録媒体から記録情報を再生する方法であって、光ビームを該媒体に対して相対的に移動させながら前記第1の磁性層の側から照射し、該媒体上に該光ビームのスポットの移動方向に対して勾配を有する温度分布を形成し、該温度分布を少なくとも前記第2の磁性層のキュリー温度よりも高い温度領域を有する温度分布とすることによって該第1の磁性層に形成されていた磁壁を移動させ、該光ビームの反射光の偏光面の変化を検出して記録情報を再生することを特徴とする再生方法。 8. A method for reproducing recorded information from the magneto-optical recording medium according to claim 1 or 2, the side of the while relatively moving a light beam relative to the medium first magnetic layer irradiated from the temperature with a temperature range higher than the Curie temperature of forming a temperature distribution having a gradient relative to the moving direction of the light beam spot on the said medium, the temperature distribution at least said second magnetic layer reproducing method by moving the domain walls had been formed in the magnetic layer of the first, characterized by reproducing the detected and recorded information change of the polarization plane of the reflected light of the light beam by a distribution.
  9. 【請求項9】 請求項3〜7の何れか一つの項に記載の光磁気記録媒体から記録情報を再生する方法であって、 9. A method for reproducing recorded information from the magneto-optical recording medium according to any one of claims 3-7,
    光ビームを該媒体に対して相対的に移動させながら前記第1の磁性層の側から照射し、該媒体上に該光ビームのスポットの移動方向に対して勾配を有する温度分布を形成し、該温度分布は少なくとも前記第2の磁性層のキュリー温度よりも高く且つ前記第4の磁性層のキュリー温度近傍の温度領域を有する温度分布とすることによって、該第1及び第4の磁性層に形成されていた磁壁を移動させ、該光ビームの反射光の偏光面の変化を検出して記録情報を再生することを特徴とする再生方法。 A light beam irradiated from the side of the while moving relative to the medium first magnetic layer to form a temperature distribution having a gradient relative to the moving direction of the light beam spot on the said medium, by temperature distribution of a temperature distribution having a temperature region near the Curie temperature of at least the higher than the Curie temperature of the second magnetic layer and the fourth magnetic layer, the first and the fourth magnetic layer moving the domain walls had been formed, reproduction method characterized by reproducing the recorded information by detecting a change in the polarization plane of the reflected light of the light beam.
  10. 【請求項10】 請求項1〜7の何れか一つの項に記載の光磁気記録媒体から記録情報を再生する再生装置であって、光ビームのスポットの移動方向に対して勾配を有する温度分布を形成できる加熱手段を有することを特徴とする再生装置。 10. A reproducing apparatus for reproducing recorded information from the magneto-optical recording medium according to any one of claims 1 to 7, a temperature distribution having a gradient relative to the moving direction of the light beam spot reproducing apparatus characterized by comprising a heating means capable of forming a.
JP7714193A 1993-04-02 1993-04-02 Magneto-optical recording medium Expired - Fee Related JP3332458B2 (en)

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JP7714193A JP3332458B2 (en) 1993-04-02 1993-04-02 Magneto-optical recording medium
EP20010202807 EP1158509A3 (en) 1993-04-02 1994-03-30 Magneto-optical recording method
EP20000200724 EP1020854A3 (en) 1993-04-02 1994-03-30 Magneto-optical reproducing apparatus
EP20040075214 EP1426944A3 (en) 1993-04-02 1994-03-30 Method for manufacturing a magneto-optical recording medium
DE1994630883 DE69430883T2 (en) 1993-04-02 1994-03-30 A magneto-optical recording medium on which it is possible to record information of high character density and method of reproducing the recorded information
DE1994630883 DE69430883D1 (en) 1993-04-02 1994-03-30 A magneto-optical recording medium on which it is possible to record information of high character density and method of reproducing the recorded information
EP19940302309 EP0618572B1 (en) 1993-04-02 1994-03-30 Magnetooptical recording medium on which high-density information can be recorded and method of reproducing the recorded information
US08869921 US6027825A (en) 1993-04-02 1997-06-05 Magnetooptical recording medium on which high-density information can be recorded and method of reproducing the recorded information
US09471190 US6403148B1 (en) 1993-04-02 1999-12-23 Magnetooptical recording medium on which high-density information can be recorded and method of reproducing the recorded information
US09689718 US6399174B1 (en) 1993-04-02 2000-10-13 Magnetooptical recording medium on which high-density information can be recorded and method of reproducing the recorded information

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