JPH01100753A - Magneto-optical recording medium - Google Patents
Magneto-optical recording mediumInfo
- Publication number
- JPH01100753A JPH01100753A JP25902287A JP25902287A JPH01100753A JP H01100753 A JPH01100753 A JP H01100753A JP 25902287 A JP25902287 A JP 25902287A JP 25902287 A JP25902287 A JP 25902287A JP H01100753 A JPH01100753 A JP H01100753A
- Authority
- JP
- Japan
- Prior art keywords
- layer
- temperature
- magneto
- write
- magnetic field
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002902 ferrimagnetic material Substances 0.000 claims description 2
- 230000005291 magnetic effect Effects 0.000 abstract description 38
- 239000000758 substrate Substances 0.000 abstract description 7
- 230000001681 protective effect Effects 0.000 abstract description 4
- 230000003068 static effect Effects 0.000 abstract description 3
- 239000010410 layer Substances 0.000 description 92
- 230000005415 magnetization Effects 0.000 description 28
- 239000010408 film Substances 0.000 description 19
- 238000000034 method Methods 0.000 description 19
- 238000010586 diagram Methods 0.000 description 7
- 239000004417 polycarbonate Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B11/00—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
- G11B11/10—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
- G11B11/105—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing
- G11B11/10582—Record carriers characterised by the selection of the material or by the structure or form
- G11B11/10586—Record carriers characterised by the selection of the material or by the structure or form characterised by the selection of the material
Abstract
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、光磁気記録媒体の媒体構成に係わる。[Detailed description of the invention] (Industrial application field) The present invention relates to the structure of a magneto-optical recording medium.
（従来の技術）
近年、レーザーを用いた高密度記録法として、レーザー
光を照射して記録媒体を局部加熱することによりビット
を書き込み、磁気光学効果を利用して読みだすという光
磁気記録が研究開発されている。その記録媒体としては
、希土類−遷移金属合金からなる非晶質磁性薄膜が注目
されている。光磁気記録方式では、従来単一記録層、単
一ビームにより光変調方式で行われていたため、重ね書
き（オーバーライド）記録が不可能であった。そこで、
重ね書き記録を可能にする方法として、磁界変調方式、
マルチビームによる疑似重ね書き記録方式、２層膜によ
る方式等が考えられている。(Prior technology) In recent years, research has been conducted on magneto-optical recording as a high-density recording method using lasers, in which bits are written by locally heating the recording medium by irradiating laser light and read out using the magneto-optic effect. being developed. As such a recording medium, an amorphous magnetic thin film made of a rare earth-transition metal alloy is attracting attention. Conventionally, magneto-optical recording has been performed using an optical modulation method using a single recording layer and a single beam, making override recording impossible. Therefore,
As a method to enable overwriting recording, magnetic field modulation method,
A pseudo-overwriting recording method using multi-beams, a method using a two-layer film, etc. are being considered.
（発明が解決しようとする問題点）
磁界変調方式では、高周波で高磁場を発生する事が困難
であり、ハードディスク等に使われているスライダーを
用いた方法は、光磁気記録の特徴である非接触性を犠牲
にする等の欠点を有している。また、マルチビームによ
る疑似オーバーライド方式は、装置が複雑になる欠点を
有している。(Problems to be solved by the invention) With the magnetic field modulation method, it is difficult to generate a high magnetic field at high frequencies, and the method using a slider used in hard disks, etc. It has drawbacks such as sacrificing contact properties. Furthermore, the pseudo override method using multiple beams has the disadvantage that the device becomes complicated.
また、従来の２層膜を利用したオーバーライド方式（第
３４回応用物理学関係連合講演会予稿集、 ２８ｐ−Ｚ
Ｌ−３，Ｐ７２１．１９８７）は次のような方法がとら
れる。まず記録に先立ち予め外部磁場により補助層の磁
化を一方向にそろえる。次にメモリー層のキュリー温度
ＴＣＲ１また記録時に先行外部磁場の方向と逆向きに印
加されている外部磁場の大きさと補助層の保磁力とが等
しくなる温度をＴＢとしたときに、媒体の温度ＴをＴｅ
Ｒ＜ Ｔ ＜ ＴＢなる温度まで昇温させ、その後冷却
すると、予め一方向にそろえられた補助層の磁化方向が
記録層に転写される。また媒体をＴＢ以上に昇温した後
に冷却すると、記録時に印加されている磁場方向に記録
層の磁化が向く。このために、記録に先立ち補助層を予
め消去するための外部磁場と記録時に印加する二つの外
部磁場が必要となり、装置が複雑になる。In addition, an override method using a conventional two-layer film (Proceedings of the 34th Applied Physics Association Conference, 28p-Z
L-3, P721.1987), the following method is used. First, prior to recording, the magnetization of the auxiliary layer is aligned in one direction using an external magnetic field. Next, the Curie temperature TCR1 of the memory layer, and when TB is the temperature at which the coercive force of the auxiliary layer is equal to the magnitude of the external magnetic field applied in the opposite direction to the direction of the preceding external magnetic field during recording, the temperature of the medium T Te
When the temperature is raised to a temperature such that R<T<TB and then cooled, the magnetization direction of the auxiliary layer, which has been aligned in one direction in advance, is transferred to the recording layer. Furthermore, when the medium is cooled after being heated to a temperature higher than TB, the magnetization of the recording layer is oriented in the direction of the magnetic field applied during recording. For this reason, two external magnetic fields are required, one for erasing the auxiliary layer prior to recording and the other for applying during recording, which complicates the apparatus.
本発明の目的は、単一ビーム、単一磁場によりオーバー
ライドが可能となる光磁気記録媒体を提供することにあ
る。An object of the present invention is to provide a magneto-optical recording medium that can be overridden by a single beam and a single magnetic field.
（発明が解決しようとする手段）
本発明は光磁気記録媒体の記録層として垂直磁化膜から
なる読み出し層と垂直磁化膜であるフェリ磁性体からな
る書き込み層とが積層された２層膜を有し、室温をＴｒ
、読み出し層、書き込み層の室温での保磁力をそれぞれ
ＨｃＲ９Ｈｃｗ、読み出し層のキュリー温度をＴｃｕ、
書き込み層のキュリー温度をＴｃＷ、書き込み層の補償
温度をＴｃｏｍｐ、Ｗとしたときに、Ｈｃｗ＜ＨｃＲＳ
Ｔｒ＜ＴｃＲ＜Ｔｃｏｍｐ９ｗ＜Ｔｃｗなる関係を満足
する光磁気記録媒体である。(Means to be Solved by the Invention) The present invention has a two-layer film as a recording layer of a magneto-optical recording medium in which a reading layer made of a perpendicularly magnetized film and a writing layer made of a ferrimagnetic material which is a perpendicularly magnetized film are laminated. and set the room temperature to Tr
, the coercive force of the reading layer and the writing layer at room temperature are HcR9Hcw, respectively, and the Curie temperature of the reading layer is Tcu,
When the Curie temperature of the writing layer is TcW and the compensation temperature of the writing layer is Tcomp, W, Hcw<HcRS
This is a magneto-optical recording medium that satisfies the relationship Tr<TcR<Tcomp9w<Tcw.
（作用）
本発明では、光磁気記録媒体の記録層として、室温以上
に補償組成を有する垂直磁化膜である書き込み層と、該
書き込み層の磁化方向を転写する垂直磁化膜である読み
出し層とからなる。第１図（ａ）。(Function) In the present invention, the recording layer of the magneto-optical recording medium is composed of a writing layer which is a perpendicular magnetization film having a compensation composition above room temperature, and a readout layer which is a perpendicular magnetization film that transfers the magnetization direction of the writing layer. Become. Figure 1(a).
（ｂ）には、書き込み層、読み出し層に要求さ゛れる保
磁力の温度特性を示す。第１図（ａ）、 （ｂ）におい
て、１゜１′は読み出し層の保磁力の温度特性であり、
２は書き込み層の保磁力の温度特性であり、３は外部磁
場のレベルである。第１図（ａ）は読み出し層の補償温
度が室温とキュリー温度の間に存在しない場合であり、
第１図（ｂ）は存在する場合である。本発明では書き込
み層の補償温度が室温より高い温度にある記録媒体を用
いるが、読み出し層の場合には、必ずしも補償温度が室
温以上にある必要はない。読み出し層、書き込み層に要
求される磁気特性は、室温をＴｒ、読み出し層のキュリ
ー温度ＴｃＲ１書き込み層のキュリー温度ＴｃＷ、書き
込み層の補償温度Ｔｃｏｍｐ、ｗ、室温における書き込
み層、読み出し層の保磁力をそれぞれＨｃｗｌＨｃＲｌ
とするとＴｒ＜ＴｃＲ＜Ｔｃｏｍｐｏｗ＜ＴｃｗＳＨｃ
ｗ＜ＨｃＲの関係を満足しなければならない。(b) shows the temperature characteristics of the coercive force required for the writing layer and the reading layer. In Figures 1(a) and (b), 1°1' is the temperature characteristic of the coercive force of the readout layer,
2 is the temperature characteristic of the coercive force of the writing layer, and 3 is the level of the external magnetic field. FIG. 1(a) shows the case where the compensation temperature of the readout layer does not exist between room temperature and the Curie temperature,
FIG. 1(b) shows the case where it exists. In the present invention, a recording medium in which the compensation temperature of the writing layer is higher than room temperature is used, but in the case of the reading layer, the compensation temperature does not necessarily need to be higher than room temperature. The magnetic properties required for the read layer and write layer are as follows: room temperature is Tr, read layer Curie temperature TcR1, write layer Curie temperature TcW, write layer compensation temperature Tcomp, w, and coercive force of the write layer and read layer at room temperature. HcwlHcRl respectively
Then, Tr<TcR<Tcompow<TcwSHc
The relationship w<HcR must be satisfied.
第２図は本発明を実施するための典型的な膜構造図であ
る。第２図では、グループ付き基板４上に誘電体層５、
読み出し層６、書き込み層７、保護膜層８といった膜構
造になっている。FIG. 2 is a diagram of a typical membrane structure for implementing the present invention. In FIG. 2, a dielectric layer 5,
It has a film structure including a read layer 6, a write layer 7, and a protective film layer 8.
次に、本発明による光磁気記録媒体を用いた記録方法を
説明する。記録時には、第１図に示すように室温におけ
る読み出し層の保磁力Ｈｃｕよりも小さいが書き込み層
の保磁力Ｈｅｗよりも大きい外部磁場３を印加する。こ
のために、室温では書き込み層の磁化は外部磁場方向を
常に向くことになる。第１図において、読み出し層の保
磁力と外部磁場の大きさが等しくなる温度をＴＡ、書き
込み層の保償温度より高温側で、書き込み層の保磁力と
外部磁場の大きさとが等しくなる温度をＴＢとする。外
部磁場を印加した状態で、レーザー照射により媒体の温
度Ｔを第１図中のＴｃＲ＜Ｔ＜ＴＢなる領域Ａまで昇温
しそののちに冷却させるとすると、読み出し層のキュリ
ー温度ＴｃＲでは、書き込み層の磁化は外部磁場と同一
方向に向いていることになり、さらに媒体が冷却されて
いくと書き込み層の磁化方向が読み出し層に転写される
ことになる。転写に際し、読み出し層の磁化が書き込み
層の磁化と同一方向に転写される場合には、室温での読
み出し層の磁化は、第１図（ａ）の場合には外部磁場方
向に向くことになり、第１図（ｂ）では、キュリー温度
ＴＣＲ付近で書き込み層と同一方向に転写された読み出
し層の磁化は、媒体の温度が下がり読み出し層の補償温
度以下に媒体温度が下がると磁化方向が反転するために
、室温での読み出し層の磁化は外部磁場と逆向きに向く
ことになる。次に、前記外部磁場中で、レーザー照射に
より、磁性媒体の温度Ｔを第１図中のＴＢ＜Ｔなる領域
Ｂまで昇温しそののちに冷却する場合を考える。この場
合には、媒体の温度が書き込み層の補償温度以上では、
書き込み層の磁化は外部磁場方向を向くことになるが、
媒体の温度が補償温度以下に下がると、書き込み層の磁
化は外部磁場とは逆向きに向くことになる。したがって
、この場合には媒体の温度がＴＣＲ付近まで下がった時
、読み出し層に転写される書き込み層の磁化方向は、先
はどの場合と逆向きになる。よって、外部磁場中で第３
図に示すように、媒体温度が領域Ａになるレーザー照射
パワーレベル１０と媒体温度が領域Ｂになるレーザー照
射パワーレベル１１とを所望の記録パターンに応じて印
加することにより、単一ビーム、単一静磁場による光磁
気記録の重ね書きが可能となる。以上は、書き込み層の
磁化方向が読み出し層に転写される際に、同一方向に転
写される場合を説明したが、逆向きに転写される場合に
も、同様にして記録することができる。Next, a recording method using the magneto-optical recording medium according to the present invention will be explained. During recording, as shown in FIG. 1, an external magnetic field 3 is applied which is smaller than the coercive force Hcu of the reading layer but larger than the coercive force Hew of the writing layer at room temperature. Therefore, at room temperature, the magnetization of the writing layer always points in the direction of the external magnetic field. In Figure 1, TA is the temperature at which the coercive force of the readout layer and the magnitude of the external magnetic field are equal, and TA is the temperature at which the coercive force of the write layer and the magnitude of the external magnetic field are equal, which is higher than the guaranteed temperature of the write layer. Let's call it TB. If the temperature T of the medium is increased by laser irradiation to region A where TcR<T<TB in FIG. The magnetization of the layer will be oriented in the same direction as the external magnetic field, and as the medium is further cooled, the magnetization direction of the write layer will be transferred to the read layer. During transfer, if the magnetization of the read layer is transferred in the same direction as the magnetization of the write layer, the magnetization of the read layer at room temperature will be oriented in the direction of the external magnetic field in the case of Figure 1 (a). , in Fig. 1(b), the magnetization of the read layer, which was transferred in the same direction as the write layer near the Curie temperature TCR, reverses when the medium temperature decreases to below the compensation temperature of the read layer. Therefore, the magnetization of the readout layer at room temperature is oriented in the opposite direction to the external magnetic field. Next, consider a case where the temperature T of the magnetic medium is raised to a region B where TB<T in FIG. 1 by laser irradiation in the external magnetic field, and then cooled. In this case, if the temperature of the medium is above the compensation temperature of the writing layer,
The magnetization of the writing layer will be oriented in the direction of the external magnetic field,
When the temperature of the medium falls below the compensation temperature, the magnetization of the writing layer will point in the opposite direction to the external magnetic field. Therefore, in this case, when the temperature of the medium drops to near the TCR, the magnetization direction of the write layer transferred to the read layer will be opposite to that in any other case. Therefore, the third
As shown in the figure, by applying a laser irradiation power level 10 at which the medium temperature becomes region A and a laser irradiation power level 11 at which the medium temperature becomes region B in accordance with a desired recording pattern, a single beam is produced. It becomes possible to overwrite magneto-optical recording using a single static magnetic field. Although the case where the magnetization direction of the writing layer is transferred to the reading layer in the same direction has been described above, recording can be performed in the same manner even when the magnetization direction is transferred in the opposite direction.
また、書き込み層の磁化が読み出し層に転写される際、
各層の磁化方向が同一方向になる場合には、レーザ照射
により媒体を第１図におけるＴＡ ＜ Ｔ ＜ ＴｃＲ
となる温度領域Ａ′まで昇温し冷却した場合と、５Ｔｃ
ｒｔ＜Ｔ ＜ＴＢとなる温度領域Ａまで昇温し冷却した
場合とは、室温での読み出し層の磁化方向は同一方向と
なるが、書き込み層の磁化が読み出し層に転写される際
、各層の磁化方向が逆方向になる場合には、温度領域Ａ
′まで昇温し冷却した場合と、温度領域Ａまで昇温し冷
却した場合とで、室温での読み出し層の磁化方向が逆方
向になる。同様に、転写の際に、各層の磁化が逆方向に
なる場合には、温度領域Ａ′とＢにより磁化方向が逆方
向になる。このように、外部磁場中で、第３図に示すよ
うに媒体温度が領域Ａ′になるレーザー照射パワー１０
と、媒体温度が領域ＡまたはＢになるレーザー照射パワ
ー１１とを所望の記録パターンに応じて印加することに
より、単一ビーム、単一磁場による光磁気記録の重ね書
きが可能となる。Also, when the magnetization of the writing layer is transferred to the reading layer,
When the magnetization direction of each layer is the same, the medium is irradiated with a laser so that TA < T < TcR in FIG.
5Tc
When the temperature is raised to a temperature range A where rt<T<TB and then cooled, the magnetization direction of the readout layer at room temperature is the same, but when the magnetization of the write layer is transferred to the readout layer, the magnetization of each layer is If the magnetization direction is opposite, temperature range A
The direction of magnetization of the readout layer at room temperature is opposite between the case where the temperature is raised to temperature range A and then cooled. Similarly, when the magnetization of each layer becomes opposite during transfer, the magnetization directions become opposite depending on the temperature regions A' and B. In this way, in an external magnetic field, the laser irradiation power is set to 10 so that the medium temperature becomes the region A' as shown in FIG.
By applying a laser irradiation power 11 that brings the medium temperature into region A or B according to a desired recording pattern, it becomes possible to overwrite magneto-optical recording using a single beam and a single magnetic field.
再生方法は、無磁場中で媒体温度ＴがＴ＜ＴＣＲとなる
第３図の読み出しレベル９のレーザー照射により従来と
同一方法により行うことができる。再生時には外部磁場
を必要としないが、再生時のレーザー照射により読み出
し層の温度が上がり、ＴＡ以上にならなければ外部磁場
を印加したままで再生することができる。The reproducing method can be carried out in the same manner as in the conventional method by laser irradiation at read level 9 in FIG. 3, where the medium temperature T is T<TCR in the absence of a magnetic field. Although an external magnetic field is not required during reproduction, the temperature of the readout layer increases due to laser irradiation during reproduction, and as long as the temperature does not exceed TA, reproduction can be performed with the external magnetic field applied.
この方法では、従来の単一ビーム、単一磁場の光磁気記
録装置をそのまま利用することができ、従来の２層膜を
利用した重ね書き方法で必要とした先行外部磁場を必要
としないことを特徴としている。With this method, a conventional single beam, single magnetic field magneto-optical recording device can be used as is, and there is no need for a preceding external magnetic field, which is required in the conventional overwriting method using a two-layer film. It is a feature.
（実施例）
本発明を実施するために、第２図と同一の膜構造の光磁
気記録媒体を作製した。第２図の基板４としてグループ
付きのポリカーボネイト基板（ｐｃ）を用いた。ＰＣ基
板の外径、内径はそれぞれ１３０ｍｍの、１５ｍｍので
ある。この基板上に誘電体層５、読み出し層６、書き込
み層７、保護膜層８をスパッター法により真空中で連続
成膜を行った。誘電体層５、保護膜膜８として膜厚８０
０人のＳｉ３Ｎ４を用いた。読み出し層６、書き込み層
７としてそれぞれ膜厚５００人のＤｙ０．２１ＦｅＯ，
７９膜、 （Ｇｄ０．５Ｔｂ０．５）０．２７（Ｆｅ□
、ｇ５Ｃｏ□、５）０．７３膜を用しゝた。第４図に、
読み出し層の保磁力の温度特性１２と書き込み層の保磁
力の温度特性１３とを示す。読み出し層６、書き込み層
７のキュリー温度はそれぞれ２１０°Ｃ１１２０°Ｃで
あり、書き込み層の補償温度は、１８０’Ｃとなってい
る。(Example) In order to carry out the present invention, a magneto-optical recording medium having the same film structure as that shown in FIG. 2 was manufactured. A polycarbonate substrate (PC) with groups was used as the substrate 4 in FIG. The outer diameter and inner diameter of the PC board are 130 mm and 15 mm, respectively. A dielectric layer 5, a reading layer 6, a writing layer 7, and a protective film layer 8 were successively formed on this substrate in a vacuum by sputtering. The dielectric layer 5 and the protective film 8 have a film thickness of 80 mm.
0 Si3N4 was used. The reading layer 6 and the writing layer 7 are each made of Dy0.21FeO with a film thickness of 500 mm.
79 film, (Gd0.5Tb0.5)0.27(Fe□
, g5Co□, 5) 0.73 membrane was used. In Figure 4,
The temperature characteristics 12 of the coercive force of the reading layer and the temperature characteristics 13 of the coercive force of the writing layer are shown. The Curie temperature of the reading layer 6 and the writing layer 7 is 210°C and 1120°C, respectively, and the compensation temperature of the writing layer is 180'C.
この記録媒体に垂直に２ＫＯｅの外部磁場を印加し、線
速１０ｍ１ｓでオーバーライド特性の測定をおこなった
。はじめに、第３図中の書き込みパワーレベル１０が５
．２ｍＷ、書き込み時のレーザー照射レベル１１が７．
３ｍＷ、読み出し時のレーザー照射レベル９が１ｍＷの
条件で、ＩＭＨｚの信号の記録・再生を行ったところＣ
／Ｎ比４８ｄＢが得られた。さらにこの上に、同一条件
により２ＭＨｚの信号を重ね書きしたところＣ／Ｎ比４
７ｄＢが得られた。An external magnetic field of 2 KOe was applied perpendicularly to this recording medium, and the override characteristics were measured at a linear velocity of 10 m1s. First, write power level 10 in Figure 3 is 5.
．． 2mW, laser irradiation level 11 during writing is 7.
When recording and reproducing an IMHz signal under the conditions of 3 mW and a laser irradiation level 9 of 1 mW during readout, C
/N ratio of 48 dB was obtained. Furthermore, when a 2MHz signal was overwritten on top of this under the same conditions, the C/N ratio was 4.
7dB was obtained.
第２図の媒体構成図において、誘電体層５、保護層８と
して、多層膜を用いたり、保温層やヒートシンク層等を
設けてもよい。また、基板としては、ＰＭＭＡ等の樹脂
基板やガラス基板を用いてもよい。また、成膜法として
は゛、スパッター法のほかに、蒸着法等の成膜法を用い
てもよい。In the medium configuration diagram of FIG. 2, a multilayer film may be used as the dielectric layer 5 and the protective layer 8, or a heat insulating layer, a heat sink layer, etc. may be provided. Further, as the substrate, a resin substrate such as PMMA or a glass substrate may be used. Further, as a film forming method, in addition to the sputtering method, a film forming method such as a vapor deposition method may be used.
このように、本発明の光磁気記録媒体を利用することに
より、単一ビーム、単一磁場の従来の光磁気記録装置を
用いて良好なオーバーライド特性を得ることができた。As described above, by using the magneto-optical recording medium of the present invention, it was possible to obtain good override characteristics using a conventional magneto-optical recording device using a single beam and a single magnetic field.
（発明の効果）
本発明によれば、従来の単一ビーム、単一静磁場の光磁
気記録装置によりレーザー照射強度の変調のみにより光
磁気記録媒体への重ね書きが可能となる。(Effects of the Invention) According to the present invention, it is possible to overwrite a magneto-optical recording medium by only modulating the laser irradiation intensity using a conventional single beam, single static magnetic field magneto-optical recording device.
第１図（ａ）、（ｂ）は、本発明の光磁気記録媒体に要
求される保磁力の温度特性を示す図、第２図は、本発明
を実施するための媒体の一例を示す媒体構成図、第３図
は本発明の媒体を用い重ね書き記録を行うためのレーザ
ーパワー変調法の説明図、第４図は、実施例に用いた読
み出し層、書き込み層の保磁力の温度特性を示す図FIGS. 1(a) and (b) are diagrams showing the temperature characteristics of coercive force required for the magneto-optical recording medium of the present invention, and FIG. 2 is a diagram showing an example of the medium for implementing the present invention. 3 is an explanatory diagram of the laser power modulation method for overwriting recording using the medium of the present invention, and FIG. 4 is a diagram showing the temperature characteristics of the coercive force of the reading layer and writing layer used in the example. Diagram shown
Claims (1)
出し層と垂直磁化膜であるフェリ磁性体からなる書き込
み層とが積層された２層膜を有し、室温をＴｒ、読み出
し層、書き込み層の室温での保磁力をそれぞれＨｃ＿Ｒ
、Ｈｃ＿Ｗ、読み出し層のキュリー温度をＴｃ＿Ｒ、書
き込み層のキュリー温度をＴｃ＿Ｗ、書き込み層の補償
温度をＴｃｏｍｐ．＿Ｗとしたときに、Ｈｃ＿Ｗ＜Ｈｃ
＿Ｒ、Ｔｒ＜Ｔｃ＿Ｒ＜Ｔｃｏｍｐ．＿Ｗ＜Ｔｃ＿Ｗな
る関係を満足することを特徴とする光磁気記録媒体。The recording layer of the magneto-optical recording medium has a two-layer film in which a reading layer made of a perpendicularly magnetized film and a writing layer made of a ferrimagnetic material, which is a perpendicularly magnetized film, are laminated. The coercive force at room temperature is Hc_R, respectively.
, Hc_W, the Curie temperature of the read layer is Tc_R, the Curie temperature of the write layer is Tc_W, and the compensation temperature of the write layer is Tcomp. When _W, Hc_W<Hc
_R, Tr<Tc_R<Tcomp. A magneto-optical recording medium characterized by satisfying the relationship _W<Tc_W.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25902287A JPH01100753A (en) | 1987-10-13 | 1987-10-13 | Magneto-optical recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25902287A JPH01100753A (en) | 1987-10-13 | 1987-10-13 | Magneto-optical recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01100753A true JPH01100753A (en) | 1989-04-19 |
Family
ID=17328261
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25902287A Pending JPH01100753A (en) | 1987-10-13 | 1987-10-13 | Magneto-optical recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01100753A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62175948A (en) * | 1985-06-11 | 1987-08-01 | Nippon Kogaku Kk <Nikon> | Overwritable photomagnetic recording method and photomagnetic recording device and medium therefor |
| JPS63148446A (en) * | 1986-12-10 | 1988-06-21 | Nikon Corp | Magneto-optical recording medium capable of over-write |
| JPS63155449A (en) * | 1986-12-19 | 1988-06-28 | Canon Inc | Magneto-optical recording method |
-
1987
- 1987-10-13 JP JP25902287A patent/JPH01100753A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62175948A (en) * | 1985-06-11 | 1987-08-01 | Nippon Kogaku Kk <Nikon> | Overwritable photomagnetic recording method and photomagnetic recording device and medium therefor |
| JPS63148446A (en) * | 1986-12-10 | 1988-06-21 | Nikon Corp | Magneto-optical recording medium capable of over-write |
| JPS63155449A (en) * | 1986-12-19 | 1988-06-28 | Canon Inc | Magneto-optical recording method |
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