JPH087885B2 - Magneto-optical recording method - Google Patents
Magneto-optical recording methodInfo
- Publication number
- JPH087885B2 JPH087885B2 JP27856786A JP27856786A JPH087885B2 JP H087885 B2 JPH087885 B2 JP H087885B2 JP 27856786 A JP27856786 A JP 27856786A JP 27856786 A JP27856786 A JP 27856786A JP H087885 B2 JPH087885 B2 JP H087885B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic layer
- recording
- magnetization
- magnetic
- erasing
- 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.)
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- Recording Or Reproducing By Magnetic Means (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は磁気カー効果を利用して再生することのでき
るキュリー点書き込み方式の光磁気記録媒体記録方法に
関する。The present invention relates to a Curie point writing type magneto-optical recording medium recording method capable of reproducing by utilizing the magnetic Kerr effect.
消去可能な光メモリとして、光磁気記録媒体が知られ
ている。従来の磁気記録媒体と比べて高速・高密度記
録、非接触での記録再生などが可能であるという長所を
有する。A magneto-optical recording medium is known as an erasable optical memory. Compared with conventional magnetic recording media, it has the advantage that high-speed / high-density recording and non-contact recording / reproducing are possible.
現在は半導体レーザーを搭載したディスクドライブの
開発が行なわれているが、より高速の記録消去を行なう
には、より小さなエネルギーで記録可能な光磁気媒体が
望まれている。Currently, a disk drive equipped with a semiconductor laser is being developed, but a magneto-optical medium capable of recording with smaller energy is desired for higher-speed recording / erasing.
本発明の目的は、従来よりも高速の記録を実施するこ
とが可能な光磁気記録方法を提供することにある。An object of the present invention is to provide a magneto-optical recording method capable of recording at a higher speed than ever before.
上記目的を達成するために本発明は、 低いキュリー点（TL）と高い保磁力（HH）を有する第
１磁性層と、この磁性層に比べて相対的に高いキュリー
点（TH）と低い保磁力（HL）を有する第２磁性層とから
なり且つ下式 HH＞HL＞σW＞2Msh （ただし、Msは第２磁性層の飽和磁化、ｈは第２磁性層
の膜厚、σWは二磁性層間の磁壁エネルギーを示す。） を満たす、交換結合している二層構造の希土類−遷移
金属非晶質合金からなる垂直磁化膜を基板上に有してな
る光磁気記録媒体を使用して、情報の記録を行う記録方
法において、 前記第２磁性層のキュリー点以上まで前記媒体を昇温
させる強度のレーザー光を照射すると共にバイアス磁界
を印加し、前記第２磁性層を前記バイアス磁界の方向に
磁化させると共に前記第１磁性層の磁化を交換結合力に
より前記第２磁性層に対して安定な向きに配列させ、そ
の後磁化を反転させる力により第２磁性層の磁化のみを
反転させ消去状態を形成する消去プロセスと、 前記消去プロセスの後、前記消去状態が形成され部位
に前記第１磁性層のキュリー点以上まで前記媒体を昇温
させる強度のレーザー光を情報に応じて照射し、その照
射部位における前記第１磁性層の磁化の向きを交換結合
力により前記第２磁性層に対して安定な向きに配列させ
ることにより記録ビットを形成する記録プロセスとを備
えることを特徴とする記録方法を提案するものである。In order to achieve the above object, the present invention provides a first magnetic layer having a low Curie point (T L ) and a high coercive force (H H ), and a Curie point (T H ) relatively higher than that of this magnetic layer. And a second magnetic layer having a low coercive force (H L ), and the following formula H H > H L > σ W > 2Msh (where Ms is the saturation magnetization of the second magnetic layer and h is the second magnetic layer). The film thickness, σ W , represents the domain wall energy between the two magnetic layers.) A light having a perpendicular magnetization film made of an exchange-coupling two-layer structure rare earth-transition metal amorphous alloy on the substrate. In a recording method for recording information using a magnetic recording medium, a bias magnetic field is applied while irradiating a laser beam with an intensity that raises the temperature of the medium to a Curie point of the second magnetic layer or higher, Magnetize the magnetic layer in the direction of the bias magnetic field and exchange the magnetization of the first magnetic layer. An erasing process of arranging in a stable direction with respect to the second magnetic layer by a resultant force, and then inverting only the magnetization of the second magnetic layer by a force of inverting the magnetization to form an erased state; A portion where an erased state is formed is irradiated with laser light having an intensity that raises the temperature of the medium above the Curie point of the first magnetic layer according to information, and the magnetization direction of the first magnetic layer at the irradiated portion is exchanged. And a recording process for forming a recording bit by arranging in a stable direction with respect to the second magnetic layer by a bonding force.
以下、図面を参照して本発明を詳細に説明する。 Hereinafter, the present invention will be described in detail with reference to the drawings.
第１図（ａ），（ｂ）は各々本発明に用いる光磁気記
録媒体の一実施例を示す模式断面図である。第１図
（ａ）の光磁気記録媒体は、プリグループ（図では省
略）が設けられた透光性の基板１上に、第１の磁性層２
と第２の磁性層３が積層されたものである。第１磁性層
２は低いキュリー点（TL）と高い保磁力（HH）を有し、
第２磁性層３は、高いキュリー点（TH）と低い保磁力
（HL）を有する。ここで「高い」、「低い」とは両磁性
層を比較した場合の相対的な関係を表わす（保磁力は室
温における比較）。ただし、通常は第１磁性層２のTLは
70〜180℃、HHは、３〜10KOe、第２磁性層３のTHは150
〜400℃、HLは0.5〜2KOe程度の範囲内にするとよい。1 (a) and 1 (b) are schematic sectional views showing an embodiment of a magneto-optical recording medium used in the present invention. The magneto-optical recording medium of FIG. 1A has a first magnetic layer 2 formed on a transparent substrate 1 provided with a pregroup (not shown).
And the second magnetic layer 3 are laminated. The first magnetic layer 2 has a low Curie point (T L ) and a high coercive force (H H ),
The second magnetic layer 3 has a high Curie point (T H ) and a low coercive force (H L ). Here, “high” and “low” represent a relative relationship when the two magnetic layers are compared (coercive force at room temperature). However, normally, T L of the first magnetic layer 2 is
70 to 180 ° C., H H is 3 to 10 KOE, T H of the second magnetic layer 3 is 150
〜400 ℃, HL should be in the range of 0.5〜2KOe.
各磁性層の材料には、垂直磁気異方性を示し且つ磁気
光学効果を呈するものが利用できるが、GdCo,GdFe,TbF
e,DyFe,GdTbFe,TbDyFe,GdFeCo,TbFeCo,GdTbCo,GdTbFeCo
等の希土類元素と遷移金属元素との非晶質磁性合金が好
ましい。As a material for each magnetic layer, a material exhibiting perpendicular magnetic anisotropy and exhibiting a magneto-optical effect can be used. GdCo, GdFe, TbF
e, DyFe, GdTbFe, TbDyFe, GdFeCo, TbFeCo, GdTbCo, GdTbFeCo
Amorphous magnetic alloys of rare earth elements and transition metal elements are preferred.
両磁性層2,3は、本発明の記録以前に為される消去プ
ロセス（後に詳述する）によって形成されるビット（第
２図（ｃ）に示す磁化状態のビット）が安定に存在出来
る様に、即ち下記の関係式を満たすように、各層の膜
厚、保磁力、飽和磁化の大きさ、磁壁エネルギーなどが
適宜設定されればよい。Both magnetic layers 2 and 3 are formed so that bits (bits in a magnetized state shown in FIG. 2C) formed by an erasing process (detailed later) performed before recording of the present invention can exist stably. In other words, the film thickness, coercive force, magnitude of saturation magnetization, domain wall energy, etc. of each layer may be appropriately set so as to satisfy the following relational expression.
（ただし、Msは第２磁性層３の飽和磁化、ｈは第２磁
性層３の膜厚、σWは二磁性層間の磁壁エネルギーσWを
示す） 上式を満たせば消去プロセスにより形成されるビット
の磁化状態（第２図（ｃ））が安定になるのは次の理由
による。σW/2Mshは第２磁性層３に働く交換力の強さを
示す。つまり、この交換力がσW/2Mshの大きさの磁界に
より第２磁性層３の磁化の向きを、第１磁性層２の磁化
の向きに対して安定な方向へ（この場合は同じ方向）向
けようとする。そこで第２磁性層３の磁化がこの磁界に
抗して反転しないためには（消去プロセスにより形成さ
れるの磁化状態が安定に存在するためには）、第２磁性
層３の保磁力HLがHL＞σW/2Mshであればよい。 (However, Ms is the saturation magnetization of the second magnetic layer 3, h is the film thickness of the second magnetic layer 3, and σ W is the domain wall energy σ W between the two magnetic layers.) If the above equation is satisfied, it is formed by the erasing process. The magnetization state of the bit (FIG. 2 (c)) becomes stable for the following reason. σ W / 2Msh represents the strength of the exchange force acting on the second magnetic layer 3. That is, the direction of the magnetization of the second magnetic layer 3 is stable to the direction of the magnetization of the first magnetic layer 2 (in this case, the same direction) by the magnetic field whose exchange force is σ W / 2 Msh. I try to point. Therefore, in order that the magnetization of the second magnetic layer 3 does not reverse against this magnetic field (in order for the magnetization state formed by the erasing process to exist stably), the coercive force H L of the second magnetic layer 3 May be H L > σ W / 2 Msh.
つまり、上式を満たせば消去プロセスにより形成され
るビットが安定になり、結局このビットの安定化に起因
してその後に形成される第２図（ｄ）の記録ビットも安
定になる。That is, if the above expression is satisfied, the bit formed by the erasing process becomes stable, and eventually the recording bit of FIG. 2 (d) formed due to the stabilization of this bit also becomes stable.
第１図（ｂ）の光磁気記録媒体において、4,5は両磁
性層2,3の耐久性を向上させるためのあるいは光磁気効
果を向上させるための保護膜である。In the magneto-optical recording medium of FIG. 1 (b), reference numerals 4 and 5 are protective films for improving the durability of both magnetic layers 2 and 3 or for improving the magneto-optical effect.
６は、貼り合わせ用基板７を貼り合わすための接着層
である。貼り合わせ用基板７にも、２から６までの層を
積層し、これを接着すれば表裏で記録・再生が可能とな
る。Reference numeral 6 is an adhesive layer for bonding the bonding substrate 7. By laminating 2 to 6 layers on the bonding substrate 7 and adhering them, recording / reproducing can be performed on the front and back sides.
以下、第２図〜第４図を用いて記録・消去の一実施例
の過程を示す。第３図は上述したような光磁気ディスク
と、記録・消去に利用する装置と、を示す模式図であ
る。The process of one embodiment of recording / erasing will be described below with reference to FIGS. FIG. 3 is a schematic diagram showing the magneto-optical disk as described above and an apparatus used for recording / erasing.
記録再生ヘッド31は、消去用と記録用との２種のレー
ザーパワ値をもつレーザービームを光磁気ディスク面に
照射することができるようになっている。消去用のレー
ザーパワーは該ディスクを第２磁性層３のキュリー点以
上まで昇温できるだけのパワーであり、記録用のレーザ
ーパワーは該ディスクを第１磁性層２のキュリー点以上
まで昇温可能なパワーである。The recording / reproducing head 31 is capable of irradiating the surface of the magneto-optical disk with a laser beam having two laser power values for erasing and recording. The laser power for erasing is power that can raise the temperature of the disc to the Curie point of the second magnetic layer 3 or higher, and the laser power for recording can raise the disc to the Curie point of the first magnetic layer 2 or higher. Power.
なお、記録用レーザービームは記録信号発生部32で信
号変調され、再生用レーザービームからの信号は再生信
号発生部33で電気信号に変えられる。The recording laser beam is signal-modulated by the recording signal generator 32, and the signal from the reproducing laser beam is converted into an electric signal by the reproducing signal generator 33.
最初に消去のプロセスについて説明する。このプロセ
スの、両磁性層２と３の磁化が安定となる向きは、互い
の磁化が平行であっても反平行であってもよい。第２図
では両磁性層の磁化の安定な向きが平行な場合について
説明する。First, the erasing process will be described. In this process, the directions in which the magnetizations of both magnetic layers 2 and 3 are stable may be parallel or antiparallel to each other. FIG. 2 illustrates a case where the stable directions of magnetization of both magnetic layers are parallel.
例えば、光磁気ディスク35のある一部の磁化状態が初
め第２図（ａ）のようになっていたとする。消去に際し
て、光磁気ディスク35を、スピンドルモータにより回転
させる。こうすると第２図（ａ）で示される部分は記録
再生ヘッド31を通過する。この際、消去用のパワーのレ
ーザー光を照射して、この部分を局所的に第２磁性層３
のキュリー点以上まで昇温させる。それと同時に、第２
磁性層３の磁化を反転させるのに必要な大きさの（後述
するよう、好ましくは必要最少限の大きさの）バイアス
磁界（第２図において下向き）を加える。こうすること
により第２磁性層３の磁化の反転に続いて第１磁性層２
の磁化も交換結合力により第２磁性層３に対して安定な
向き（ここでは同じ向き）に配列する。即ち、第２図
（ａ）のどちらからも第２図（ｂ）のようなビットが形
成される。For example, assume that a part of the magnetized state of the magneto-optical disk 35 is initially as shown in FIG. At the time of erasing, the magneto-optical disk 35 is rotated by a spindle motor. As a result, the portion shown in FIG. 2A passes through the recording / reproducing head 31. At this time, laser light having an erasing power is irradiated to locally illuminate this portion of the second magnetic layer 3.
The temperature is raised to above the Curie point. At the same time, the second
A bias magnetic field (downward in FIG. 2) having a magnitude necessary for reversing the magnetization of the magnetic layer 3 (preferably the minimum magnitude necessary as described later) is applied. By doing so, the reversal of the magnetization of the second magnetic layer 3 is performed, and then the first magnetic layer 2
The magnetization is also arranged in a stable direction (here, the same direction) with respect to the second magnetic layer 3 by the exchange coupling force. That is, a bit as shown in FIG. 2 (b) is formed from both of FIG. 2 (a).
更にこの光磁気ディスク35を回転させることによりこ
の第２図（ｂ）のビットは磁界発生部34を通過する。こ
のとき、磁界発生部34の磁界の大きさを両磁性層の保磁
力HLとHHの間に設定すると（この際磁界の方向は第２図
（ｂ）のビットにおける第２磁性層３の磁化を反転させ
る方向に設定する。）、第２図（ｃ）に示すように、第
２磁性層３は磁界発生部34の磁界の方向へ磁化され、一
方第１磁性層２は第２図（ｂ）の状態のままの磁化とな
る。即ち、両磁性層の磁化状態は反平行になる。これが
最終的消去状態である。When the magneto-optical disk 35 is further rotated, the bit shown in FIG. 2 (b) passes through the magnetic field generator 34. At this time, the magnitude of the magnetic field of the magnetic field generator 34 is set between the coercive forces H L and H H of both magnetic layers (in this case, the direction of the magnetic field is the second magnetic layer 3 in the bit of FIG. 2B). 2). As shown in FIG. 2C, the second magnetic layer 3 is magnetized in the direction of the magnetic field of the magnetic field generating unit 34, while the first magnetic layer 2 is the second magnetic layer. The magnetization remains as it is in the state of FIG. That is, the magnetization states of both magnetic layers are antiparallel. This is the final erased state.
第２図（ｃ）に示された状態のビットに対して記録を
行なうには次のようにする。スピンドルモーターによ
り、光磁気ディスク35を回転させて、第２図（ｃ）のビ
ットが記録再生ヘッド31を通過するときに記録用のパワ
ーのレーザー光を照射する。こうしてその部分を第１磁
性層２のキュリー点以上まで昇温させる。このとき第２
磁性層３はこの温度でビットが安定に存在する保磁力を
有しているので、この際バイアス磁界が適切に設定され
ていると第２図（ｄ）のような状態となり記録される。Recording is performed on the bit in the state shown in FIG. 2 (c) as follows. The spindle motor rotates the magneto-optical disk 35 to irradiate a laser beam of recording power when the bit of FIG. 2 (c) passes through the recording / reproducing head 31. In this way, that portion is heated to the Curie point of the first magnetic layer 2 or higher. At this time the second
Since the magnetic layer 3 has a coercive force in which the bit stably exists at this temperature, if the bias magnetic field is properly set at this time, the state as shown in FIG. 2D is recorded.
ここで、バイアス磁界が適正に設定されているとは、
次のような意味である。Here, the fact that the bias magnetic field is properly set means that
It has the following meanings.
即ち、この記録プロセスでは、第１磁性層２は、その
磁化が第２磁性層３の磁化の向きに対して安定な向きに
（ここでは同じ方向に）配列するように、力（交換力）
を受けるので，本来バイアス磁界は特に必要でない。し
かし、前述したように消去のプロセスではバイアス磁界
を第２磁性層３の磁化反転を補助する向きに設定してお
いた。この消去プロセスでのバイアス磁界の大きさ、方
向を、その後の記録プロセスでも変えず、同じ状態に設
定しておくことが便宜上好ましい。かかる観点から、消
去プロセスにおいてバイアス磁界を消去が可能でしかも
記録プロセスを妨げない大きさ・方向（好ましくは消去
プロセスに必要最小限の大きさ・方向）に設定し、その
大きさ・方向を記録プロセスでも維持設定しておくこと
が前記の「バイアス磁界が適正に設定されている」とい
うことである。That is, in this recording process, the first magnetic layer 2 has a force (exchange force) so that its magnetization is aligned in a stable direction (here, in the same direction) with respect to the magnetization direction of the second magnetic layer 3.
Therefore, the bias magnetic field is not particularly necessary. However, as described above, in the erasing process, the bias magnetic field is set in a direction to assist the magnetization reversal of the second magnetic layer 3. It is preferable for convenience that the magnitude and direction of the bias magnetic field in this erasing process are set to the same state without changing in the subsequent recording process. From this point of view, the bias magnetic field can be erased in the erasing process, and the size and direction are set so as not to interfere with the recording process (preferably the minimum size and direction necessary for the erasing process), and the size and direction are recorded. Maintaining the setting in the process also means "the bias magnetic field is properly set".
ただし、前述したようにバイアス磁界は記録時本来必
要でないので勿論その時加えなくてよい。また、バイア
ス磁界発生手段（記録再生ヘッド31に付設）に、記録時
と消去時のそれぞれに応じて磁化方向を反転させる機能
をもたせれば、記録時と消去時にバイアス磁界を同じ方
向、大きさにする必要性はなく、各々に適するように大
きさ、方向（記録、消去に適した方向は本来は逆であ
る）を設定すれば、より高速な記録、消去が可能にな
る。However, as described above, the bias magnetic field is not necessary at the time of recording, and need not be added at that time. Further, if the bias magnetic field generating means (attached to the recording / reproducing head 31) is provided with a function of reversing the magnetization direction according to recording and erasing respectively, the bias magnetic field in the same direction and magnitude during recording and erasing can be obtained. However, if the size and direction (directions suitable for recording and erasing are essentially opposite) are set to suit each, higher speed recording and erasing becomes possible.
第２図の説明では、第１磁性層２と第２磁性層３の磁
化の向きが同じときに安定である例についての記録消去
を示したが、磁化の向きが反平行のときに安定な磁性層
についても、実質的には同じ原理での記録消去が可能で
ある。In the description of FIG. 2, recording and erasing have been shown for an example in which the magnetization directions of the first magnetic layer 2 and the second magnetic layer 3 are the same, but stable when the magnetization directions are antiparallel. Recording and erasing can be performed on the magnetic layer based on substantially the same principle.
３元のターゲット源を備えたスパッタ装置内に、プリ
グルーブ、プリフォーマット信号の刻まれたポリカーボ
ネート製のディスク状基板を、ターゲットとの間の距離
10cmの間隔にセットし、回転させた。The distance between the target and a polycarbonate disc-shaped substrate with pre-groove and pre-formatted signals is placed in a sputtering system equipped with a ternary target source.
It was set at an interval of 10 cm and rotated.
アルゴン中で、第１のターゲットより、スパッタ速度
100Å/min、スパッタ圧５×10-3TorrでZnSを保護層とし
て1000Åの厚さに設けた。次にアルゴン中で、第２のタ
ーゲットよりスパッタ速度100Å/min、スパッタ圧５×1
0-3TorrでTbFe合金をスパッタし、膜厚500Å、TL＝約14
0℃、HH＝約10KOeのTb18Fe82の第１磁性層を形成した。Sputtering speed from the first target in argon
ZnS was formed as a protective layer at a thickness of 1000 Å at 100 Å / min and a sputter pressure of 5 × 10 -3 Torr. Next, in argon, sputter rate 100 Å / min from the second target, sputter pressure 5 × 1
Sputtering TbFe alloy at 0 -3 Torr, film thickness 500Å, T L = approx. 14
A first magnetic layer of Tb 18 Fe 82 was formed at 0 ° C. and H H = about 10 KOe.
次にアルゴン中でスパッタ圧５×10-3TorrでTbFeCo合
金をスパッタし、膜厚500Å、TH＝約200℃、HL＝約1KOe
のTb23Fe63Co14の第２磁性層を形成した。Next, a TbFeCo alloy is sputtered in argon at a sputtering pressure of 5 × 10 -3 Torr, and the film thickness is 500 Å, T H = about 200 ° C., H L = about 1 KOe.
A second magnetic layer of Tb 23 Fe 63 Co 14 of was formed.
次にアルゴン中で第１のターゲットよりスパッタ速度
100Å/min、スパッタ圧５×10-3Torrで、ZnSを保護層と
して3000Åの厚さに設けた。Then sputter rate from the first target in argon
ZnS was provided as a protective layer at a thickness of 3000 Å at 100 Å / min and a sputtering pressure of 5 × 10 -3 Torr.
次に上記の膜形成を終えた基板を、ホットメルト接着
剤を用いて、ポリカーボネートの貼り合わせ用基板と貼
り合わせ光磁気ディスクを作成した。Next, the substrate on which the above film formation was completed was bonded to a polycarbonate bonding substrate using a hot melt adhesive to form a magneto-optical disk.
この光磁気ディスクを記録再生装置にセットし、約15
m/secの線速度で2.5K Oeの磁界発生部を、通過させつ
つ、約１μに集光した830nmの波長のレーザービームで
記録消去を行なった。Set this magneto-optical disk in the recording / reproducing device, and
Recording and erasing were performed with a laser beam having a wavelength of 830 nm condensed to about 1 μ while passing through a magnetic field generator of 2.5 K Oe at a linear velocity of m / sec.
記録はレーザービームを50％のデューティ、4MHzで変
調して、照射するレーザーパワーを変えながら行なっ
た。バイアス磁界は加えなかった。Recording was performed by modulating the laser beam at a duty of 50% and 4 MHz and changing the laser power to be applied. No bias field was applied.
消去はレーザーパワー6mWの連続ビームを照射しなが
ら、約150 Oeのバイアス磁界を第２磁性層の磁化を反転
させる向きに加えて行なった。Erasure was performed by applying a bias magnetic field of about 150 Oe in the direction of reversing the magnetization of the second magnetic layer while irradiating a continuous beam of laser power of 6 mW.
その後、1mWのレーザービームを照射して再生を行な
ったところ、第４図に示すように約3mWのパワーで記録
が可能であることがわかった。After that, when reproducing was performed by irradiating a laser beam of 1 mW, it was found that recording was possible with a power of about 3 mW as shown in FIG.
実施例２ 実施例１より高速の記録を行なうために、記録に際し
て、150 Oeのバイアス磁界を第１磁性層が記録時に配列
する磁化の方向に加えた。この場合はバイアス磁界の方
向が消去時と反対なので消去時に磁界の方向を反転させ
た。必要な記録パワーは約2.6mWであった。Example 2 In order to perform recording at a higher speed than in Example 1, a bias magnetic field of 150 Oe was applied to the direction of magnetization that the first magnetic layer aligns during recording during recording. In this case, the direction of the bias magnetic field was opposite to that at the time of erasing, so the direction of the magnetic field was reversed at the time of erasing. The required recording power was about 2.6 mW.
実施例３ 記録時と消去時とでバイアス磁界の方向、大きさを一
定にして記録を行なった。消去を可能とし記録を妨げな
いバイアス磁界の大きさは約200 Oeであった。Example 3 Recording was performed with the direction and magnitude of the bias magnetic field being constant during recording and erasing. The magnitude of the bias magnetic field that enables erasing and does not hinder recording was about 200 Oe.
比較例１、２ 第１磁性層と第２磁性層の間にZnSの中間層を100Åの
厚さに設けた以外は実施例と同様な方法で同構成のサン
プル−比較例１を作製した。（このサンプルは第１磁性
層と第２磁性層とが静磁結合している。） また、第１磁性層と第２磁性層とを積層する代わりに
第１磁性層だけで２層分の厚さ800Åにした以外は実施
例と同様な方法でサンプル−比較例２を作製した。Comparative Examples 1 and 2 A sample-Comparative Example 1 having the same structure was prepared in the same manner as in Example except that an intermediate layer of ZnS was provided between the first magnetic layer and the second magnetic layer to have a thickness of 100 Å. (In this sample, the first magnetic layer and the second magnetic layer are magnetostatically coupled.) Further, instead of laminating the first magnetic layer and the second magnetic layer, only the first magnetic layer is equivalent to two layers. Sample-Comparative Example 2 was prepared in the same manner as in Example except that the thickness was changed to 800Å.
比較例１、２についても実施例と同様な方法で記録消
去の実験を行なった。結果は第４図に示すように記録に
必要なパワーが約4mWであった。For Comparative Examples 1 and 2, recording and erasing experiments were conducted in the same manner as in the examples. As a result, as shown in FIG. 4, the power required for recording was about 4 mW.
消去については、実施例１、比較例１、２それぞれにお
いて、6mWのレーザーパワーで、消去されていることを
確認した。Regarding erasing, in each of Example 1 and Comparative Examples 1 and 2, it was confirmed that the laser power was 6 mW.
実施例４ 記録については実施例１と同様に行なった。Example 4 Recording was performed in the same manner as in Example 1.
消去については、上記各実施例のようにトラックごとの
消去ではなく、ディスク全面を消去する場合あるいは多
数のトラックを精度を要求されずに消去する場合に適し
た次のような消去法を実施した。即ち、第３図の記録ヘ
ッド31と磁界発生34と間に、第１磁性層の磁化の向きを
反転させることが可能な大きさであって磁界発生部34の
磁界の向きと反対方向の磁界を発生可能な別の磁界発生
部を設け、これによって消去した。こうすることにより
記録再生ヘッドを用いての消去は不要になる。Regarding erasing, the following erasing method suitable for erasing the entire surface of the disk or erasing a large number of tracks without requiring accuracy is carried out instead of erasing each track as in the above-mentioned embodiments. . That is, between the recording head 31 and the magnetic field generator 34 of FIG. 3, a magnetic field having a size capable of reversing the magnetization direction of the first magnetic layer and having a direction opposite to the magnetic field direction of the magnetic field generator 34. Another magnetic field generation unit capable of generating is generated and erased. This eliminates the need for erasing with the recording / reproducing head.
以上詳細に説明したように、前記した条件を満たす光
磁気記録媒体を使用して、消去状態を形成する消去プロ
セスにおいては２層の磁性層の磁化の向きを交換結合に
より配列する向きと逆方向とし、記録ビットを形成する
記録プロセスにおいては２層の磁性層の磁化の向きを交
換結合により配列する磁化の向きとすることによって、
小さなレーザーパワーで記録が実施できるようになっ
た。As described in detail above, in the erasing process for forming the erased state by using the magneto-optical recording medium satisfying the above-mentioned conditions, the magnetization directions of the two magnetic layers are opposite to the direction of arrangement by exchange coupling. In the recording process of forming the recording bit, the magnetization directions of the two magnetic layers are set to the magnetization directions arranged by exchange coupling,
Recording can now be performed with a small laser power.
第１図（ａ），（ｂ）は各々本発明で使用する光磁気媒
体の一例の構成を示す図、第２図は、本発明の記録法、
及び消去法を実施中の、磁性層2,3の磁化の向きを示す
図、第３図は、記録・再生装置の概念図、第４図は実施
例と比較例について、記録パワーと各記録状態でのC/N
比の関係を示す図である。 1:プリグループ付の透光性基板、2,3:磁性層、4,5:保護
層、6:接着層、7:貼り合わせ用基板、31:記録・再生用
ヘッド、32:記録信号発生部、33:再生信号発生部、34:
磁界発生部、35:光磁気ディスク、FIGS. 1 (a) and 1 (b) are views showing the structure of an example of a magneto-optical medium used in the present invention, and FIG. 2 is a recording method of the present invention.
And FIG. 3 is a diagram showing the magnetization directions of the magnetic layers 2 and 3 during the erasing and erasing method, FIG. 3 is a conceptual diagram of the recording / reproducing apparatus, and FIG. C / N in condition
It is a figure which shows the relationship of ratio. 1: translucent substrate with pre-group, 2, 3: magnetic layer, 4,5: protective layer, 6: adhesive layer, 7: bonding substrate, 31: recording / reproducing head, 32: recording signal generation Part, 33: reproduction signal generating part, 34:
Magnetic field generator, 35: Magneto-optical disk,
Claims (1)
を有する第１磁性層と、この磁性層に比べて相対的に高
いキュリー点（TH）と低い保磁力（HL）を有する第２磁
性層とからなり且つ下式 HH＞HL＞σW＞2Msh （ただし、Msは第２磁性層の飽和磁化、ｈは第２磁性層
の膜厚、σWは二磁性層間の磁壁エネルギーを示す。） を満たす、交換結合している二層構造の希土類−遷移金
属非晶質合金からなる垂直磁化膜を基板上に有してなる
光磁気記録媒体を使用して、情報の記録を行う記録方法
において、 前記第２磁性層のキュリー点以上まで前記媒体を昇温さ
せる強度のレーザー光を照射すると共にバイアス磁界を
印加し、前記第２磁性層を前記バイアス磁界の方向に磁
化させると共に前記第１磁性層の磁化を交換結合力によ
り前記第２磁性層に対して安定な向きに配列させ、その
後磁化を反転させる力により第２磁性層の磁化のみを反
転させ消去状態を形成する消去プロセスと、 前記消去プロセスの後、前記消去状態が形成され部位に
前記第１磁性層のキュリー点以上まで前記媒体を昇温さ
せる強度のレーザー光を情報に応じて照射し、その照射
部位における前記第１磁性層の磁化の向きを交換結合力
により前記第２磁性層に対して安定な向きに配列させる
ことにより記録ビットを形成する記録プロセスとを備え
ることを特徴とする記録方法。1. A low Curie point (T L ) and a high coercive force (H H ).
And a second magnetic layer having a Curie point (T H ) and a lower coercive force (H L ) which are relatively higher than those of the magnetic layer and have the following formula H H > H L >. Two exchange-coupled layers satisfying σ W > 2Msh (where Ms is the saturation magnetization of the second magnetic layer, h is the thickness of the second magnetic layer, and σ W is the domain wall energy between the two magnetic layers). In a recording method for recording information using a magneto-optical recording medium having a perpendicularly magnetized film of a rare earth-transition metal amorphous alloy having a structure, a Curie point of the second magnetic layer or higher. To the second magnetic layer in the direction of the bias magnetic field while irradiating a laser beam with an intensity that raises the temperature of the medium to the bias magnetic field, and magnetizing the first magnetic layer by the exchange coupling force. 2 Arrange the magnets in a stable direction with respect to the magnetic layer, and then reverse the magnetization. Force to invert only the magnetization of the second magnetic layer to form an erased state, and, after the erase process, raises the medium to a position where the erased state is formed up to the Curie point of the first magnetic layer or higher. A recording bit is obtained by irradiating laser light of an intensity for heating according to information, and arranging the magnetization direction of the first magnetic layer at the irradiated portion in a stable direction with respect to the second magnetic layer by an exchange coupling force. And a recording process for forming the recording method.
Priority Applications (17)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27856786A JPH087885B2 (en) | 1986-11-25 | 1986-11-25 | Magneto-optical recording method |
| CA 541367 CA1340058C (en) | 1986-07-08 | 1987-07-06 | Magnetooptical recording medium allowing overwriting with tow or more magnetic layers and recording method utilizing the same |
| AU75306/87A AU593364C (en) | 1986-07-08 | 1987-07-07 | Magnetooptical recording medium allowing overwriting with two or more magnetic layers and recording method utilizing the same |
| EP98200006A EP0838814B1 (en) | 1986-07-08 | 1987-07-08 | Magnetooptical recording medium allowing overwriting with two or more magnetic layers and recording method utilizing the same |
| DE19873752351 DE3752351T2 (en) | 1986-07-08 | 1987-07-08 | Device and system for recording on a magneto-optical recording medium |
| AT98200007T ATE216528T1 (en) | 1986-07-08 | 1987-07-08 | APPARATUS AND SYSTEM FOR RECORDING ON A MAGNETOPTICAL RECORDING MEDIUM |
| KR1019870007322A KR960003420B1 (en) | 1986-07-08 | 1987-07-08 | Magneto optical recording medium |
| DE19873752348 DE3752348T2 (en) | 1986-07-08 | 1987-07-08 | Magneto-optical recording medium with the possibility of overwriting with two or more magnetic layers and recording method using this medium |
| DE3752222T DE3752222T2 (en) | 1986-07-08 | 1987-07-08 | Magnetic optical recording medium with the possibility of overwriting with two or more magnetic layers and recording method using this medium |
| AT87306038T ATE172047T1 (en) | 1986-07-08 | 1987-07-08 | MAGNETOPTICAL RECORDING MEDIUM WITH THE POSSIBILITY OF OVERWRITING WITH TWO OR MORE MAGNETIC LAYERS AND RECORDING METHOD USING SUCH MEDIUM |
| EP87306038A EP0258978B1 (en) | 1986-07-08 | 1987-07-08 | Magnetooptical recording medium allowing overwriting with two or more magnetic layers and recording method utilizing the same |
| EP98200007A EP0838815B1 (en) | 1986-07-08 | 1987-07-08 | Apparatus and system for recording on a magnetooptical recording medium |
| US07/475,941 US5132945A (en) | 1986-07-08 | 1990-01-30 | Magnetooptical recording medium allowing overwriting with two or more magnetic layers and recording method utilizing the same |
| US08/296,163 US5525378A (en) | 1986-07-08 | 1994-08-26 | Method for producing a magnetooptical recording medium |
| US08/312,930 US5481410A (en) | 1986-07-08 | 1994-09-30 | Magnetooptical recording medium allowing overwriting with two or more magnetic layers and recording method utilizing the same |
| US08/613,431 US5783300A (en) | 1986-06-18 | 1996-02-29 | Magnetooptical recording medium allowing overwriting with two or more magnetic layers and recording method utilizing the same |
| US09/080,215 US6028824A (en) | 1986-07-08 | 1998-05-18 | Magnetooptical recording medium allowing overwriting with two or more magnetic layers |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27856786A JPH087885B2 (en) | 1986-11-25 | 1986-11-25 | Magneto-optical recording method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63133338A JPS63133338A (en) | 1988-06-06 |
| JPH087885B2 true JPH087885B2 (en) | 1996-01-29 |
Family
ID=17599065
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27856786A Expired - Fee Related JPH087885B2 (en) | 1986-06-18 | 1986-11-25 | Magneto-optical recording method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH087885B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0782673B2 (en) * | 1986-12-10 | 1995-09-06 | 株式会社ニコン | Overwritable magneto-optical recording medium |
| US5210724A (en) * | 1988-03-07 | 1993-05-11 | Canon Kabushiki Kaisha | Optomagnetic recording method and apparatus which precludes an interface magnetic wall within block magnetic wall |
| JP2001347179A (en) * | 2000-06-07 | 2001-12-18 | Matsumoto Tekkosho:Kk | Crusher |
-
1986
- 1986-11-25 JP JP27856786A patent/JPH087885B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63133338A (en) | 1988-06-06 |
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