JPH01149245A - Magneto-optical recording medium having multiple recording layers and recording method thereof - Google Patents
Magneto-optical recording medium having multiple recording layers and recording method thereofInfo
- Publication number
- JPH01149245A JPH01149245A JP30628687A JP30628687A JPH01149245A JP H01149245 A JPH01149245 A JP H01149245A JP 30628687 A JP30628687 A JP 30628687A JP 30628687 A JP30628687 A JP 30628687A JP H01149245 A JPH01149245 A JP H01149245A
- Authority
- JP
- Japan
- Prior art keywords
- recording
- layers
- magneto
- magnetic
- optical recording
- 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
- 238000000034 method Methods 0.000 title claims description 12
- 230000007423 decrease Effects 0.000 claims description 2
- 239000000758 substrate Substances 0.000 abstract description 7
- 238000010030 laminating Methods 0.000 abstract 2
- 230000003287 optical effect Effects 0.000 abstract 1
- 238000004544 sputter deposition Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 3
- 239000012528 membrane Substances 0.000 description 3
- 229910005091 Si3N Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910018979 CoPt Inorganic materials 0.000 description 1
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 101150026303 HEX1 gene Proteins 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000002223 garnet Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 238000010792 warming 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
-
- 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
Abstract
Description
【発明の詳細な説明】
〔技術分野〕
本発明は、多重記録層を有する光磁気記録媒体及びその
記録方法に関するものであり、磁気メモリ、特にコンピ
ュータ用外部メモリ、画像ファイル、音声ファイル等に
応用される。[Detailed Description of the Invention] [Technical Field] The present invention relates to a magneto-optical recording medium having multiple recording layers and a recording method thereof, and is applicable to magnetic memory, particularly external memory for computers, image files, audio files, etc. be done.
従来、キュリー温度（Ｔｃ）の低い垂直磁気異方性を示
す磁性膜を用いて、キュリー温度（Ｔｃ）を利用して記
録を行う光磁気記録方式が提案されている。Conventionally, a magneto-optical recording method has been proposed in which recording is performed using the Curie temperature (Tc) using a magnetic film exhibiting perpendicular magnetic anisotropy with a low Curie temperature (Tc).
前記方式での記録密度は平面的であり、いかに多く記録
できるかは記録ビットサイズ及びビット間隔によって決
定される。しかしながら。The recording density in the above method is flat, and how much data can be recorded is determined by the recording bit size and bit interval. however.
再生する場合には、ビーム径がビット径とほぼ同サイズ
であることが必要となるため、現在の技術からするとビ
ーム径を１μｍ以下に絞り込むのは難かしく、１μｍ以
下のビット径をもつ記録を行っても意味がなくなる。つ
まり記録ビット径の限界があるため、記録密度をより高
めることは難かしくなる欠点があった。For playback, the beam diameter must be approximately the same size as the bit diameter, so with current technology it is difficult to narrow down the beam diameter to 1 μm or less, so it is difficult to narrow down the beam diameter to 1 μm or less, so it is difficult to reproduce records with a bit diameter of 1 μm or less. There's no point in going there. In other words, there is a limit to the recording bit diameter, which makes it difficult to further increase the recording density.
本発明は従来の欠点を克服し、膜厚方向への多重記録を
行うことができる多重記録層を有する光磁気記録媒体を
提供することを目的とする。An object of the present invention is to overcome the conventional drawbacks and provide a magneto-optical recording medium having multiple recording layers capable of performing multiple recording in the film thickness direction.
本発明者等は前記目的を達成するために鋭意研究した結
果、キュリー温度（Ｔｃ）の異なる磁性膜を非磁性膜を
介して複数積層させた多重記録層を有することを特徴と
する光磁気記録媒体を提供することによって前記目的が
達成できることを見出した。As a result of intensive research to achieve the above object, the present inventors have developed a magneto-optical recording device characterized by having a multiple recording layer in which a plurality of magnetic films having different Curie temperatures (Tc) are laminated with a non-magnetic film interposed therebetween. It has been found that the above object can be achieved by providing a medium.
本発明の前記光磁気記録媒体を使用する多重光磁気記録
方法は、光を前記記録媒体の１ケ所に集中してｎ層目の
キュリー温度Ｔｎ（ｎ＝磁性暦の層数）以上まで一度昇
温した後、Ｔｎ＞Ｔｎ−ｉ＞Ｔｎ−ｉ＞”’＞Ｔａ＞Ｔ
ａ＞Ｔｉと降温してくるときに各々のキュリー温度に同
期して外部磁界の方向及び大きさを変化させて膜厚方向
に任意に記録することを特徴とする。The multiplex magneto-optical recording method using the magneto-optical recording medium of the present invention focuses light on one location of the recording medium and raises it once to the Curie temperature Tn of the nth layer (n = number of layers in the magnetic calendar). After warming, Tn>Tn-i>Tn-i>”'>Ta>T
It is characterized in that when the temperature decreases to a>Ti, the direction and magnitude of the external magnetic field are changed in synchronization with each Curie temperature to arbitrarily record in the film thickness direction.
以下、本発明を添付図面に従ってさらに具体的に説明す
る。Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.
本発明の多重記録層を有する光磁気記録媒体は第１図に
示すように基板１の上にキュリー温度Ｔｃの異なる垂直
磁気異方性を示す磁性膜２を非磁性膜３を介して複数積
層してなる多重記録層４からなる。As shown in FIG. 1, the magneto-optical recording medium of the present invention has multiple recording layers, in which a plurality of magnetic films 2 exhibiting perpendicular magnetic anisotropy with different Curie temperatures Tc are laminated on a substrate 1 via a non-magnetic film 3. It consists of a multiplex recording layer 4 made up of:
基板１はガラス、プラスチック、セラミックなどの非磁
性材を用いる。The substrate 1 is made of a non-magnetic material such as glass, plastic, or ceramic.
磁性膜２はＴｂＦｅ、ＴｂＦｅＣｏ、ＧｄＴｄＦｅ、Ｇ
ｄＣｏなどのアモルファス希土類−遷移金属系磁性膜お
よびＭｎＢ１、ＭｎＣｕＢ１．ＣｏＰｔ、Ｃ。The magnetic film 2 is made of TbFe, TbFeCo, GdTdFe, G
Amorphous rare earth-transition metal magnetic films such as dCo and MnB1, MnCuB1. CoPt,C.
フェライト、Ｂａフェライト、ガーネット等の多結晶膜
を蒸着法、スパッタ法、イオンブレーティング法等で作
製している６
非磁性膜３はＳ ｉ３ Ｎ４． Ｓ ｉｏ２等により成
り、蒸着法、スパッタ法、イオンブレーティング法等で
作製する。出来れば同一チャンバー内で磁性膜２および
非磁性膜３を順次設けられれば都合が良い。A polycrystalline film of ferrite, Ba ferrite, garnet, etc. is fabricated by a vapor deposition method, a sputtering method, an ion blasting method, etc. 6 The nonmagnetic film 3 is made of Si3N4. It is made of Sio2 or the like, and is manufactured by a vapor deposition method, a sputtering method, an ion blating method, or the like. It is convenient if the magnetic film 2 and nonmagnetic film 3 can be sequentially provided within the same chamber.
本発明の光磁気記録媒体の多重記録層は第１図のように
キュリー温度Ｔｃが高い方から順に低い方にＴｌ）’ｌ
’ｎ−１）Ｔ１−、）”’）Ｔ３）Ｔ、）Ｔ１↓こなる
ように積層されているか、その逆にＴ ｎ ＜ Ｔ ｎ
−Ｌ ＜ Ｔ ｎ−ｘ ＜ ”’ ＜ Ｔ ａ ＜ Ｔ
ｚ ＜ Ｔ ｘのようになるように積層されていても
良い。As shown in FIG. 1, the multiple recording layers of the magneto-optical recording medium of the present invention are arranged in order from the higher Curie temperature Tc to the lower Curie temperature Tc.
'n-1)T1-,)''')T3)T,)T1↓or vice versa, T n < T n
-L < T n-x <"'< Ta < T
They may be stacked so that z < T x.
磁性膜２の膜厚は１００人〜１μｍであり、好ましくは
４００人〜２０００人である。非磁性膜３の膜厚は１０
人〜５ｏｏｏ人であり、好ましくは１００人〜２０００
人である。The thickness of the magnetic film 2 is 100 to 1 μm, preferably 400 to 2000. The thickness of the non-magnetic film 3 is 10
500 people, preferably 100 to 2000 people
It's a person.
本発明の多重光磁気記録方法は第２図に示すように記録
媒体の一部にビームを固定して照射し、Ｔｎ以上の温度
まで昇温する。そのあと、ビーム照射を止めて降温して
くるときにＴｎ、Ｔｎ−い・・・、Ｔ３、Ｔ２、Ｔ工の
温度に同期して外部磁界Ｈｅｘｎ、 Ｈｅｘｎ−１、“
°°、Ｈｅｘ３、Ｈｅｘ２． ＨｅＸ１を印加して膜厚
方向に記録を行なう。外部磁界は磁界の方向及び大きさ
を変化して記録する。なお外部磁界の方向のみを変化さ
せて大きさは一定にして記録しても良い。As shown in FIG. 2, the multiplex magneto-optical recording method of the present invention irradiates a portion of a recording medium with a fixed beam and raises the temperature to a temperature higher than Tn. After that, when the beam irradiation is stopped and the temperature starts to fall, external magnetic fields Hexn, Hexn-1, "
°°, Hex3, Hex2. Recording is performed in the film thickness direction by applying HeX1. The external magnetic field is recorded by changing the direction and magnitude of the magnetic field. Note that recording may be performed by changing only the direction of the external magnetic field and keeping the magnitude constant.
記録装置の構成は第３図のように、半導体レーザ光５を
コリメータレンズ６を通して平行光にした後、集光レン
ズ７を用いて記・録層４の一部に集光させて媒体表面の
温度を上げる。外部磁界は記録媒体の近傍の外部磁界発
生用コイル８を設け、このコイルにパルス電流を流して
パルス磁界を発生させる。また、コイルだけではなくて
高透磁率材料よりなる磁心を設けても良い。As shown in FIG. 3, the configuration of the recording apparatus is such that the semiconductor laser beam 5 is made into parallel light through a collimator lens 6, and then condensed onto a part of the recording layer 4 using a condenser lens 7 to form a light beam on the surface of the medium. Raise the temperature. An external magnetic field generating coil 8 is provided near the recording medium, and a pulsed current is passed through this coil to generate a pulsed magnetic field. Furthermore, in addition to the coil, a magnetic core made of a high magnetic permeability material may be provided.
記録したあとの記録情報が上下層の磁気モーメントの影
響で消えないようにするために、磁性膜の保磁力Ｈｅを
大きくしたり、中間層の非磁性膜の厚みを厚くしたりす
る必要がある。In order to prevent the recorded information from disappearing due to the influence of the magnetic moments of the upper and lower layers, it is necessary to increase the coercive force He of the magnetic film or to increase the thickness of the non-magnetic film in the intermediate layer. .
Ｈｅについては常温で約５０００ ｅ以上は必要である
。For He, approximately 5000 e or more is required at room temperature.
キュリー温度（Ｔｃ）については低いほど感度が良く、
レーザパワーも小さくてすむが、各層毎に記録できる記
録マージンが低下するので低すぎても良くない、最適な
Ｔｃの変化範囲は、７０℃〜４００℃である。Regarding the Curie temperature (Tc), the lower the temperature, the better the sensitivity.
The laser power can also be small, but it should not be too low because the recording margin that can be recorded for each layer will be reduced.The optimum Tc variation range is 70°C to 400°C.
以下、本発明を下記の実施例に従ってさらに具体的に説
明するが、本発明はこれに限定されるものではない。EXAMPLES Hereinafter, the present invention will be explained in more detail according to the following examples, but the present invention is not limited thereto.
実施例
３元マグネトロンスパッタ装置を用いて磁性膜としての
ＴｂＦｅＣｏ膜と非磁性膜としてのＳｉ、Ｎ４膜とを基
板上に交互に積層させた。Example 3 A TbFeCo film as a magnetic film and Si and N4 films as nonmagnetic films were alternately laminated on a substrate using a magnetron sputtering apparatus.
ＴｂＦｅＣｏ膜は下記の条件でＴｂＦｅ合金ターゲット
とＣｏターゲットとを用いて２元同時スパッタにより作
成した。各々の膜はスパッタ室をあけずに同じスパッタ
室内で作成した。The TbFeCo film was created by dual simultaneous sputtering using a TbFe alloy target and a Co target under the following conditions. Each film was formed in the same sputtering chamber without opening the sputtering chamber.
−ＴｂＦｅＣｏ膜の作成条件−
残留ガス圧： １，０ＸＩＯ−”ＴｏｒｒＡｒガス圧
： ５．０Ｘ１０−３Ｔｏｒｒターゲット： Ｔｂ
Ｆｅ合金、 Ｃ。-Conditions for creating TbFeCo film- Residual gas pressure: 1,0XIO-''TorrAr gas pressure: 5.0X10-3Torr Target: Tb
Fe alloy, C.
放電型カニ １，０ＯＯＷ（ＴｂＦｅ合金）。Discharge type crab 1,00OW (TbFe alloy).
Ｏ〜２００Ｗで変化（Ｇｏ）
スパッタ時間： ３分（膜厚１０００人）基板回転数：
４０ｒｐｍ
本実施例では５層のＴｂＦｅＣｏ層を積層し、基板上の
最初の層でＣｏターゲットの放電電力を２００Ｗ、次に
Ｓｉ、Ｎ４層を介して第２の層でＣｏターゲットの放電
電力を１５０Ｗとし、順次Ｃｏターゲットの放電電力を
下記のように１００Ｗ。Changes from O to 200W (Go) Sputtering time: 3 minutes (film thickness: 1000) Substrate rotation speed:
40 rpm In this example, five TbFeCo layers were stacked, and the discharge power of the Co target was 200 W in the first layer on the substrate, and the discharge power of the Co target was 150 W in the second layer via the Si and N4 layers. The discharge power of the Co target was set to 100 W as shown below.
５０Ｗ、ＯＷと低下させて、Ｔｃの異なるＴｂＦｅＣｏ
膜を順次積層させた。TbFeCo with different Tc was lowered to 50W and OW.
The membranes were stacked sequentially.
ＴｂＦｅＣｏ膜 Ｃｏターゲット 電電力 エ劇ｌ
旦第１層 ２００Ｗ ２３０℃
第２層 １５０Ｗ ２００℃第
３層 １００Ｗ １７０℃第４
層 ５０Ｗ １４５℃第５層
ＯＷ １２０℃−８ｉ３Ｎ、
膜の作成条件−
前記ＴｂＦｅＣｏ膜と交互にＳＬ、Ｎ、膜を下記の条件
で積層させた。Ｓｉ３Ｎ、膜の作成はＴｂＦｅＣｏ膜の
作成の後、すぐに行った。TbFeCo film Co target Electric power
1st layer 200W 230℃
2nd layer 150W 200℃ 3rd layer 100W 170℃ 4th
Layer 50W 145℃ 5th layer
OW 120℃-8i3N,
Film Creation Conditions - SL, N, and films were alternately stacked with the TbFeCo film under the following conditions. The Si3N film was created immediately after the TbFeCo film was created.
Ａｒガス圧： ５．０Ｘ１０−３Ｔｏｒｒターゲット
： Ｓｉ、Ｎ。Ar gas pressure: 5.0X10-3 Torr Target: Si, N.
放電型カニ ６００Ｗ
スパッタ時間：１０分（膜厚６００人）基板回転数：
４０ｒｐｍ
このようにＴｂＦｅＣｏ膜と５１３Ｎ４膜とを交互に積
層させ、最後の第５層のＴｂＦｅＣｏ膜の上にＳｉ３Ｎ
、膜を最終的に積層させて、製膜を完了させた。Discharge type crab 600W Sputtering time: 10 minutes (film thickness 600 people) Substrate rotation speed:
40 rpm In this way, TbFeCo films and 513N4 films are alternately laminated, and Si3N is deposited on the fifth and final TbFeCo film.
, the membrane was finally laminated to complete the membrane formation.
このように作成した記録媒体に１０ｍＷの半導体レーザ
ーを用いてＴｃまで昇温し、４０００ ｅのパルス磁界
を方向を上下ランダムに変えて記録を行い、正常に記録
されていることを確認した。The temperature of the thus prepared recording medium was raised to Tc using a 10 mW semiconductor laser, and recording was performed using a 4000 e pulsed magnetic field with the direction randomly changed up and down, and it was confirmed that normal recording was performed.
以上述べたように本発明のように、膜厚方向への多重光
磁気記録を行なうことにより記録密度を上げることがで
きる。As described above, the recording density can be increased by performing multiple magneto-optical recording in the film thickness direction as in the present invention.
第１図は本発明の光磁気記録媒体の概略説明図である。 第２図は本発明の多重光磁気記録方法の説明図である。 第３図は多重光磁気記録装置の概略説明図である。 FIG. 1 is a schematic explanatory diagram of a magneto-optical recording medium of the present invention. FIG. 2 is an explanatory diagram of the multiplex magneto-optical recording method of the present invention. FIG. 3 is a schematic explanatory diagram of a multiplex magneto-optical recording device.
Claims (1)
介して複数積層させた多重記録層を有することを特徴と
する光磁気記録媒体。 ２、キュリー温度（Ｔｃ）の異なる磁性膜を非磁性膜を
介して複数積層させた多重記録層を有する光磁気記録媒
体を使用し、光を前記記録媒体の１ヶ所に集中してｎ層
目のキュリー温度Ｔｎ（ｎ＝磁性層の層数）以上まで一
度昇温した後、Ｔｎ＞Ｔｎ＿−＿１＞Ｔｎ＿−＿２＞・
・・＞Ｔ＿３＞Ｔ＿２＞Ｔ＿１と降温してくるときに各
々のキュリー温度に同期して外部磁界の方向及び大きさ
を変化させて膜厚方向に任意に記録することを特徴とす
る光磁気記録方法。[Claims] 1. A magneto-optical recording medium characterized by having multiple recording layers in which a plurality of magnetic films having different Curie temperatures (Tc) are laminated with a non-magnetic film interposed therebetween. 2. Using a magneto-optical recording medium having multiple recording layers in which a plurality of magnetic films with different Curie temperatures (Tc) are laminated with a non-magnetic film interposed therebetween, light is concentrated at one location on the recording medium to record the nth layer. After raising the temperature once to the Curie temperature Tn (n = number of magnetic layers) or higher, Tn>Tn_-_1>Tn_-_2>・
...Magneto-optical recording characterized by recording arbitrarily in the film thickness direction by changing the direction and magnitude of the external magnetic field in synchronization with each Curie temperature as the temperature decreases from >T_3>T_2>T_1. Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30628687A JPH01149245A (en) | 1987-12-03 | 1987-12-03 | Magneto-optical recording medium having multiple recording layers and recording method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30628687A JPH01149245A (en) | 1987-12-03 | 1987-12-03 | Magneto-optical recording medium having multiple recording layers and recording method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01149245A true JPH01149245A (en) | 1989-06-12 |
Family
ID=17955263
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30628687A Pending JPH01149245A (en) | 1987-12-03 | 1987-12-03 | Magneto-optical recording medium having multiple recording layers and recording method thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01149245A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1991015013A1 (en) * | 1990-03-24 | 1991-10-03 | Seiko Epson Corporation | Magnetooptic recording medium, and method of magnetooptic recording and reproduction |
| US5419999A (en) * | 1990-03-27 | 1995-05-30 | Fuji Photo Film Co., Ltd. | Optical recording medium and recording/reproducing method therefor |
| US5420728A (en) * | 1990-03-24 | 1995-05-30 | Seiko Epson Corporation | Magneto-optical recording medium including a plurality of recording layers having different curie temperatures and method of recording and reading |
| US6500598B2 (en) * | 1997-02-26 | 2002-12-31 | Kabushiki Kaisha Toshiba | Multilevel phase change optical recording medium |
| US7210155B2 (en) * | 2003-07-30 | 2007-04-24 | Canon Kabushiki Kaisha | Magneto-optical recording medium having in-plane magnetizing layer |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61107502A (en) * | 1984-10-30 | 1986-05-26 | Brother Ind Ltd | Photomagnetic recording device |
| JPS61107552A (en) * | 1984-10-30 | 1986-05-26 | Brother Ind Ltd | Optical recording medium |
-
1987
- 1987-12-03 JP JP30628687A patent/JPH01149245A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61107502A (en) * | 1984-10-30 | 1986-05-26 | Brother Ind Ltd | Photomagnetic recording device |
| JPS61107552A (en) * | 1984-10-30 | 1986-05-26 | Brother Ind Ltd | Optical recording medium |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1991015013A1 (en) * | 1990-03-24 | 1991-10-03 | Seiko Epson Corporation | Magnetooptic recording medium, and method of magnetooptic recording and reproduction |
| US5420728A (en) * | 1990-03-24 | 1995-05-30 | Seiko Epson Corporation | Magneto-optical recording medium including a plurality of recording layers having different curie temperatures and method of recording and reading |
| US5419999A (en) * | 1990-03-27 | 1995-05-30 | Fuji Photo Film Co., Ltd. | Optical recording medium and recording/reproducing method therefor |
| US6500598B2 (en) * | 1997-02-26 | 2002-12-31 | Kabushiki Kaisha Toshiba | Multilevel phase change optical recording medium |
| US7210155B2 (en) * | 2003-07-30 | 2007-04-24 | Canon Kabushiki Kaisha | Magneto-optical recording medium having in-plane magnetizing layer |
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