JPH087884B2 - Magneto-optical recording method - Google Patents
Magneto-optical recording methodInfo
- Publication number
- JPH087884B2 JPH087884B2 JP27856686A JP27856686A JPH087884B2 JP H087884 B2 JPH087884 B2 JP H087884B2 JP 27856686 A JP27856686 A JP 27856686A JP 27856686 A JP27856686 A JP 27856686A JP H087884 B2 JPH087884 B2 JP H087884B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic layer
- recording
- magnetization
- erasing
- magnetic
- 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方法に関す
る。The present invention relates to a Curie point writing type magneto-optical 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.
特に現在は記録過程に比べて消去過程を高速で行なう
ことがむずかしく、通常記録時の1.5〜２倍程度（５〜1
0mW）のレーザーパワーを与え、消去のためのバイアス
磁界も記録時に比べて大きな値（約5000e）に設定しな
ければならない。本発明の目的は、記録ビットを記録時
と同じ程度のエネルギーで消去でき、加えて従来よりも
高速の記録消去を実施することも可能な光磁気記録方法
を提供することにある。At present, it is difficult to perform the erasing process at a higher speed than the recording process, and it is about 1.5 to 2 times that of normal recording (5 to 1
(0 mW) laser power, and the bias magnetic field for erasing must be set to a larger value (about 5000 e) than when recording. An object of the present invention is to provide a magneto-optical recording method capable of erasing a recording bit with the same level of energy as at the time of recording, and also capable of erasing recording faster than in the past.
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、その照射部位における前記第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そ
の照射部位における第２磁性層の磁化のみを反転させる
ことにより記録ビットを形成する記録プロセスと、 前記記録プロセスにて形成された記録ビットを消去す
る場合には、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の消去を行う消去プロセスとを備
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 laser beam having an intensity that raises the temperature of the medium to a Curie point of the second magnetic layer or higher is irradiated, and a bias magnetic field is applied to the irradiation site. Magnetizing the second magnetic layer in the direction of the bias magnetic field and The magnetization of the magnetic layer is arranged in a stable direction with respect to the second magnetic layer by the exchange coupling force, and then only the magnetization of the second magnetic layer at the irradiation site is inverted by the force of reversing the magnetization, thereby recording bits. The recording process to be formed, and in the case of erasing the recording bit formed in the recording process, laser light having an intensity that raises the temperature of the medium to the Curie point of the first magnetic layer or higher is irradiated, and the irradiation site And an erasing process for erasing a recording bit by arranging the magnetization direction of the first magnetic layer in the stable magnetic field with respect to the second magnetic layer by an exchange coupling force. It is a proposal.
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、プリグルーブ（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 on a transparent substrate 1 provided with a pre-groove (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、後に詳述する本発明の記録方法によ
り形成されるビット（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 a bit formed by the recording method of the present invention, which will be described later in detail (a bit in a magnetized state shown in FIG. 2C), can exist stably, that is, the following relational expression: To satisfy, the thickness of each layer, the coercive force, the magnitude of saturation magnetization,
The domain wall energy and the like may be set appropriately.
（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） 上式を満たせば記録ビットの磁化状態（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の大きさの磁界でもって第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（記録ビット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。結局上式を満たせば記録されたビットが安定と
なる。 (However, Ms is the saturation magnetization of the second magnetic layer 3, h is the 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 expression is satisfied, the magnetization state of the recording bit ( The reason why FIG. 2 (c)) becomes stable is as follows. σ W / 2Msh represents the strength of the exchange force acting on the second magnetic layer 3. That is, this exchange force is applied to the second magnetic layer 3 by a magnetic field having a magnitude of σ W / 2Msh.
Of the first magnetic layer 2 toward the stable direction (the same direction in this case). Therefore, in order to prevent the magnetization of the second magnetic layer 3 from reversing against this magnetic field (in order for the magnetization state of the recording bit to exist stably), the coercive force H L of the second magnetic layer 3 is H L >. It may be σ W / 2 Msh. Eventually, if the above equation is satisfied, the recorded bits will be 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、記録用と消去用の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。記録用のレーザ
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、消去用のレーザー
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 can irradiate a magneto-optical disk surface with a laser beam having two laser power values for recording and erasing. The laser power for recording is a 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 erasing 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用
信号発生部33で電気信号に戻される。The recording laser beam is signal-modulated by the recording signal generator 32, and the signal from the reproducing laser beam is converted back to an electric signal by the reproducing signal generator 33.
最初に記録のプロセスについて説明する。記録前、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 recording process will be described. Before recording, 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。記録に際し
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、記録用のパワーのレ
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 recording, 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, a laser beam having a recording 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
が最終的記録状態である。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, if 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
The magnetization of the second magnetic layer 3 in the bit of FIG. 6B is set to be reversed. ), As shown in FIG. 2 (c),
The second magnetic layer 3 is magnetized in the direction of the magnetic field of the magnetic field generator 34,
On the other hand, the first magnetic layer 2 is magnetized as it is in the state of FIG. That is, the magnetization states of both magnetic layers are antiparallel. This is the final recording state.
第２図（ｃ）に示された記録ビットを消去するには次
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、記録ビットが記録再生ヘッド31を
通過するときに消去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
ような状態となり消去される。To erase the recorded bits shown in FIG. 2 (c), the following is done. The spindle motor rotates the magneto-optical disk 35 to irradiate a laser beam having an erasing power when the recording bit 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 magnetic layer 3 has a coercive force that allows the bit to exist stably at this temperature. Therefore, if the bias magnetic field is properly set at this time, the state shown in FIG. To be done.
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、この消去プロセスでは、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、前述したように記録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。この記録プロセスでのバイアス磁界の大きさ、方
向を、その後の消去プロセスでも変えず、同じ状態に設
定しておくことが適宜上好ましい。かかる観点から、記
録プロセスにおいてバイアス磁界を記録が可能でしかも
消去プロセスを妨げない大きさ・方向（好ましくは記録
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・方向を消去プロセツ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 erasing 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 recording process, the bias magnetic field is set in the direction that assists the magnetization reversal of the second magnetic layer 3. It is preferable from the above point of view that the magnitude and direction of the bias magnetic field in this recording process are set to the same state without changing in the subsequent erasing process. From this point of view, the bias magnetic field can be recorded in the recording process, and the size and direction (preferably the minimum size and direction required for the recording process) that can record the erase process can be set, and the size and direction can be erased. It is said that the bias magnetic field is properly set even in the process.
ただし、前述したようにバイアス磁界は消去時本来必
要でないので勿論その時加えなくてよい。また、記録・
再生ヘッドでのバイアス磁界に、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 erasing, and needless to say not added at that time. Also, record
If the bias magnetic field in the reproducing head has a function of reversing the magnetization direction according to each of recording and erasing,
It is not necessary to set the bias magnetic field in the same direction and size at the time of recording and erasing, but by setting the size and direction to suit each direction (the directions suitable for recording and erasing are essentially the opposite), High-speed recording / erasing is 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それら磁化が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
それら磁化が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 stable when the magnetization directions are the same, but when the magnetization directions are antiparallel. In addition, even for those magnetic layers having stable magnetization, recording and erasing can be performed by 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180℃、HL＝約1KOe
のTb23Fe73Co4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 500Å, T H = about 180 ° C., H L = about 1 KOe.
A second magnetic layer of Tb 23 Fe 73 Co 4 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。記録はレーザーパワー5mWのビー
ムを、50％デューティ、4MHzで変調し、照射した。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. For recording, a beam with a laser power of 5 mW was modulated at 50% duty and 4 MHz for irradiation.
加えたバイアス磁界は第２磁性層の磁化を反転させる
方向に約150 Oeの大きさで加えた。（バイアス磁界の大
きさ方向は記録時消去時共に同じに設定した。） 次にレーザービームを、そのパワーを変化させながら
連続的に照射することによって、消去を行なった。The applied bias magnetic field was applied in a direction of reversing the magnetization of the second magnetic layer with a magnitude of about 150 Oe. (The magnitude direction of the bias magnetic field was set to be the same during recording and erasing.) Next, erasing was performed by continuously irradiating the laser beam while changing its power.
その後、1mWのレザーパワーを照射して再生を行なっ
た。その結果、第４図に示すように消去用のレーザーパ
ワーが増やされ5mW以上のパワーで消去されたときに
は、この再生の時、記録ビットの消去残り信号は10dB以
下であり、飽和していた（ほぼ、完全に消去されてい
た。）。After that, reproduction was performed by irradiating 1 mW of leather power. As a result, as shown in FIG. 4, when the erasing laser power was increased and the erasing was performed with a power of 5 mW or more, the erasure residual signal of the recording bit was 10 dB or less and saturated during this reproduction ( Almost completely erased.).
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1000Å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 set to 1000Å.
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図に示すように消去に
必要なパワーが約7mW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 erasing was about 7 mW.
記録については、実施例、比較例１、２それぞれにお
いて、5mWのレーザーパワーで、C/N比45〜50dBの信号が
記録されていることを確認した。Regarding recording, it was confirmed that a signal having a C / N ratio of 45 to 50 dB was recorded at a laser power of 5 mW in each of the examples and comparative examples 1 and 2.
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、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
により配列する向きと逆方向とし、記録ビットを消去す
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磁化の向きとすることによっ
て、従来は消去時には記録時に比べて大きなレーザーパ
ワーが必要であったものが、記録時、消去時共に同じ小
さなレーザーパワーで実施できるようになった。As described in detail above, in the recording process of forming a recording bit 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 erasing process of erasing the recording bit, the magnetization directions of the two magnetic layers are set to the magnetization directions arranged by exchange coupling, so that a large laser power is conventionally required at the time of erasing as compared with the time of recording. However, the same small laser power can be used for recording and erasing.
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、消去パワーと各消去状態での消去
残りの信号成分の関係を示す図である。 1:プリグルーブ付の透光性基板、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 process, FIG. 3 is a conceptual diagram of a recording / reproducing apparatus, and FIG. It is a figure which shows the relationship of the signal component of the deletion remainder in a state. 1: translucent substrate with pre-groove, 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、その照射部位における前記第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その
照射部位における第２磁性層の磁化のみを反転させるこ
とにより記録ビットを形成する記録プロセスと、 前記記録プロセスにて形成された記録ビットを消去する
場合には、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の消去を行う消去プロセスとを備え
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. The intensity of the laser beam that heats the medium is applied and a bias magnetic field is applied to magnetize the second magnetic layer in the irradiation site in the direction of the bias magnetic field and exchange coupling the magnetization of the first magnetic layer. Aligned in a stable direction with respect to the second magnetic layer by force Then, a recording process for forming a recording bit by reversing only the magnetization of the second magnetic layer at the irradiation site by a force for reversing the magnetization, and in the case of erasing the recording bit formed in the recording process, Irradiation with laser light having an intensity that raises the temperature of the medium to the Curie point of the first magnetic layer or higher, and the direction of magnetization of the first magnetic layer at the irradiation site is stabilized with respect to the second magnetic layer by the exchange coupling force. And a erasing process for erasing recorded bits by arranging them in different directions.
Priority Applications (17)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27856686A JPH087884B2 (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 |
|---|---|---|---|
| JP27856686A JPH087884B2 (en) | 1986-11-25 | 1986-11-25 | Magneto-optical recording method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63133337A JPS63133337A (en) | 1988-06-06 |
| JPH087884B2 true JPH087884B2 (en) | 1996-01-29 |
Family
ID=17599049
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27856686A Expired - Fee Related JPH087884B2 (en) | 1986-06-18 | 1986-11-25 | Magneto-optical recording method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH087884B2 (en) |
Families Citing this family (1)
| 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 |
-
1986
- 1986-11-25 JP JP27856686A patent/JPH087884B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63133337A (en) | 1988-06-06 |
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