JPH04219642A - Magneto-optical recording medium and method thereof - Google Patents
Magneto-optical recording medium and method thereofInfo
- Publication number
- JPH04219642A JPH04219642A JP41223690A JP41223690A JPH04219642A JP H04219642 A JPH04219642 A JP H04219642A JP 41223690 A JP41223690 A JP 41223690A JP 41223690 A JP41223690 A JP 41223690A JP H04219642 A JPH04219642 A JP H04219642A
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- film
- magneto
- magnetic field
- 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 26
- 230000005291 magnetic effect Effects 0.000 claims abstract description 57
- 230000005294 ferromagnetic effect Effects 0.000 claims abstract description 20
- 230000007704 transition Effects 0.000 claims abstract description 13
- 230000005290 antiferromagnetic effect Effects 0.000 claims description 18
- 230000001747 exhibiting effect Effects 0.000 claims description 5
- 230000001678 irradiating effect Effects 0.000 abstract description 6
- 230000005415 magnetization Effects 0.000 description 15
- 230000001681 protective effect Effects 0.000 description 7
- 229910052742 iron Inorganic materials 0.000 description 5
- 229910017061 Fe Co Inorganic materials 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 3
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- 229910052797 bismuth Inorganic materials 0.000 description 2
- 229910052681 coesite Inorganic materials 0.000 description 2
- 229910052906 cristobalite Inorganic materials 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 229910052682 stishovite Inorganic materials 0.000 description 2
- 229910052905 tridymite Inorganic materials 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910020707 Co—Pt Inorganic materials 0.000 description 1
- 229910017112 Fe—C Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 229910005091 Si3N Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000000694 effects 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
- 238000007733 ion plating Methods 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明はオーバーライト可能な光
磁気記録媒体及び光磁気記録方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overwritable magneto-optical recording medium and a magneto-optical recording method.
【０００２】0002
【従来の技術及び発明が解決しようとする課題】近年、
書き換え可能な光記録媒体として、磁気光学効果を利用
した光磁気記録媒体が精力的に研究開発され、一部では
実用化されるに至っている。この光磁気記録媒体は大容
量高密度記録、非接触記録再生、アクセスの容易さ等の
利点に加え、オーバーライト（重ね書き）が可能という
点で文書情報ファイル、ビデオ・静止画ファイル、コン
ピュータ用メモリ等への利用が期待されている。光磁気
記録媒体を磁気ディスクと同等もしくはそれ以上の性能
を持った記録媒体とするためには、いくつかの技術的課
題があり、その中の主要なものの１つに、オーバーライ
ト技術がある。現在提案されているオーバーライト技術
は、記録の方法により磁界変調方式と光変調方式（マル
チビーム方式、２層膜方式等）に大別される。[Prior art and problems to be solved by the invention] In recent years,
As rewritable optical recording media, magneto-optical recording media that utilize the magneto-optical effect have been actively researched and developed, and some have even been put into practical use. This magneto-optical recording medium has the advantages of large-capacity, high-density recording, non-contact recording and playback, and ease of access, as well as the ability to overwrite, making it suitable for document information files, video/still image files, and computers. It is expected to be used for memory, etc. In order to make a magneto-optical recording medium a recording medium with performance equal to or better than that of a magnetic disk, there are several technical issues, and one of the major ones is overwriting technology. Currently proposed overwriting techniques are broadly classified into magnetic field modulation methods and optical modulation methods (multi-beam method, two-layer film method, etc.) depending on the recording method.
【０００３】磁界変調方式は記録情報に応じて印加磁界
の極性を反転させて記録を行う方式である。この方式で
は、磁界の反転を高速で行わなくてはならないため、浮
上タイプの磁気ヘッドを用いる必要があり、媒体交換が
困難である。The magnetic field modulation method is a method in which recording is performed by reversing the polarity of the applied magnetic field depending on the recorded information. In this method, since the magnetic field must be reversed at high speed, it is necessary to use a floating type magnetic head, making it difficult to exchange the medium.
【０００４】一方、光変調方式は記録情報に応じて照射
レーザビームをオン・オフあるいは強度変調させて記録
させて記録を行う方式である。この方式のうちマルチビ
ーム方式は、２〜３個のレーザビームを用い、磁界の方
向を１回転毎に反転させてトラック毎に記録／消去を行
う擬似オーバーライト方式であるが、装置構成が複雑化
し、コストアップを招くなどの欠点を有している。また
、２層膜方式は光磁気記録媒体の記録層を２層膜とし、
オーバーライトを達成しようとするもので、例えば特開
昭６２−１７５９４８号公報等に開示されている。
同公報に記載されている方式は、例えばＴｂＦｅからな
るメモリ層とＴｂＦｅＣｏからなる補助層との２層膜の
記録層を備えた光磁気記録媒体を用い、初期化を行った
後、外部磁界の印加とパワーの異なるレーザビームの照
射によりオーバーライトを実現しようとするものである
。すなわち、この方式では、記録に先立ち予め初期化用
磁界により補助層の磁化を一方向に揃え、高出力レーザ
ビームを照射して媒体温度ＴをＴ＞Ｔｃ２（Ｔｃ２は補
助層のキュリー温度）なる温度迄昇温させ、記録用磁界
（初期化用磁界と反対方向）を印加して補助層の磁化を
反転させ、媒体が冷却される際にその磁化をメモリ層に
転写させることにより記録を行い、また、低出力レーザ
ビームを照射して媒体温度をＴｃ１＜Ｔ＜Ｔｃ２（Ｔｃ
１はメモリ層のキュリー温度）なる温度迄昇温させ、補
助層の磁化方向をメモリ層に転写させることにより消去
を行う。そのため、この方式では、媒体設計が難しい等
の問題があった。On the other hand, the optical modulation method is a method in which recording is performed by turning on/off or modulating the intensity of the irradiated laser beam depending on the recording information. Among these methods, the multi-beam method is a pseudo-overwrite method that uses two to three laser beams and reverses the direction of the magnetic field every rotation to record/erase on a track-by-track basis, but the device configuration is complicated. It has disadvantages such as increasing the cost and increasing the cost. In addition, in the two-layer film method, the recording layer of the magneto-optical recording medium is a two-layer film,
This technique attempts to achieve overwriting, and is disclosed in, for example, Japanese Patent Laid-Open No. 175948/1983. The method described in the publication uses a magneto-optical recording medium equipped with a two-layer recording layer, for example, a memory layer made of TbFe and an auxiliary layer made of TbFeCo, and after initialization, the external magnetic field is applied. This is an attempt to achieve overwriting by irradiating laser beams with different application and powers. That is, in this method, prior to recording, the magnetization of the auxiliary layer is aligned in one direction using an initializing magnetic field, and a high-power laser beam is irradiated to raise the medium temperature T such that T>Tc2 (Tc2 is the Curie temperature of the auxiliary layer). Recording is performed by heating the medium to a certain temperature, applying a recording magnetic field (in the opposite direction to the initializing magnetic field) to reverse the magnetization of the auxiliary layer, and transferring the magnetization to the memory layer as the medium cools. , the medium temperature is adjusted to Tc1<T<Tc2 (Tc
1 is the Curie temperature of the memory layer), and erasing is performed by transferring the magnetization direction of the auxiliary layer to the memory layer. Therefore, this method has problems such as difficulty in media design.
【０００５】本発明は以上のような従来技術の欠点を解
消し、信頼性が高く、媒体構成が簡単で、しかも単一レ
ーザビーム、単一磁界でオーバーライトできる光磁気記
録媒体及び光磁気記録方法を提供することを目的とする
。The present invention solves the above-mentioned drawbacks of the prior art, and provides a magneto-optical recording medium and magneto-optical recording which are highly reliable, have a simple medium configuration, and can be overwritten with a single laser beam and a single magnetic field. The purpose is to provide a method.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するため
、本発明によれば、垂直磁気異方性を示す強磁性膜から
なるメモリ層と、室温で面内磁気異方性を示し室温より
高い該メモリ層のキュリー温度付近の温度で磁気相転移
を生じて垂直磁気異方性を示す反強磁性膜からなる補助
層とを積層した２層膜からなる記録層を有することを特
徴とする光磁気記録媒体が提供される。[Means for Solving the Problems] In order to achieve the above object, the present invention provides a memory layer made of a ferromagnetic film exhibiting perpendicular magnetic anisotropy, and a memory layer comprising a ferromagnetic film exhibiting perpendicular magnetic anisotropy; It is characterized by having a recording layer made of a two-layer film laminated with an auxiliary layer made of an antiferromagnetic film that causes a magnetic phase transition at a temperature near the high Curie temperature of the memory layer and exhibits perpendicular magnetic anisotropy. A magneto-optical recording medium is provided.
【０００７】また、本発明によれば、上記光磁気記録媒
体を用い、記録時には媒体温度が前記磁気相転移の生じ
る温度以上となる迄昇温するような高いパワーのレーザ
ビームを照射するとともに外部磁界Ｈｅｘを印加し、消
去時には媒体温度が前記磁気相転移の生じる温度より下
の温度となる迄昇温するような低いパワーのレーザビー
ムを照射するとともに記録時と同じ外部磁界Ｈｅｘを印
加することを特徴とするオーバーライト可能な光磁気記
録方法が提供される。Further, according to the present invention, the above magneto-optical recording medium is used, and during recording, a high power laser beam is irradiated to raise the temperature of the medium until the temperature exceeds the temperature at which the magnetic phase transition occurs, and an external A magnetic field Hex is applied, and during erasing, a low power laser beam is irradiated to raise the temperature of the medium until it reaches a temperature below the temperature at which the magnetic phase transition occurs, and at the same time, the same external magnetic field Hex as during recording is applied. An overwritable magneto-optical recording method is provided.
【０００８】以下本発明を図面に基づき詳述する。本発
明の光磁気記録媒体は記録層が垂直磁気異方性を示す強
磁性膜からなるメモリ層と、室温で面内磁気異方性を示
し室温より高い該メモリ層のキュリー温度付近の温度で
磁気相転移を生じて垂直磁気異方性を示す反強磁性膜と
を積層してなる。図１にこのような光磁気記録媒体の一
構成例を示す。この記録媒体は、ガラス、プラスチック
、セラミックスなどからなる透明支持体１上にＳｉ３Ｎ
４、ＳｉＯ、ＳｉＯ２などからなる保護膜２（膜厚１０
０Å〜５０００Å）を設け、その上に垂直磁気異方性を
示す強磁性膜３（膜厚１００Å〜５０００Å）を設け、
その上に室温で面内磁気異方性を示し室温より高い温度
であって強磁性膜３のキュリー温度付近の温度で磁気相
転移を生じて垂直磁気異方性を示す反強磁性膜４（膜厚
１００Å〜１００００Å）を設け、さらにその上にＳｉ
３Ｎ４、ＳｉＯ、ＳｉＯ２などからなる保護膜５（膜厚
１００Å〜５０００Å）を設けて構成される。各膜はス
パッタ法、蒸着法、イオンプレーティング法等により形
成することができる。強磁性膜３は例えばＴｂ−Ｆｅ，
Ｇｄ−Ｆｅ，Ｄｙ−Ｆｅ，Ｇｄ−Ｔｂ−Ｆｅ，Ｔｂ−Ｄ
ｙ−Ｆｅ，Ｇｄ−Ｄｙ−Ｆｅ，Ｔｂ−Ｆｅ−Ｃｏ，Ｇｄ
−Ｆｅ−Ｃｏ，Ｄｙ−Ｆｅ−Ｃｏ，Ｔｂ−Ｄｙ−Ｆｅ−
Ｃｏ，Ｇｄ−Ｔｂ−Ｆｅ−Ｃｏ、Ｇｄ−Ｄｙ−Ｆｅ−Ｃ
ｏなどの希土類−遷移金属系アモルファス膜、あるいは
Ｍｎ−Ｂｉ，Ｍｎ−Ｃｕ−Ｂｉ，Ｃｏ−Ｐｔ，Ｃｏスピ
ネルフェライト，Ｂａフェライトなどの多結晶膜により
構成することができる。反強磁性膜４はＲＣｏ（Ｒ＝Ｄ
ｙ，Ｎｄ等）系膜を用いて構成することができる。これ
ら強磁性膜３及び反強磁性膜４は図２に示す如き保磁力
の温度特性を有している必要がある。すなわち、強磁性
膜３のキュリー温度をＴｃ１、反強磁性膜４のキュリー
温度をＴｃ２、反強磁性膜４の磁気相転移温度をＴｐｃ
、強磁性膜３の保磁力Ｈｃ１とバイアス磁界Ｈｅｘとが
等しくなる温度をＴａ、反強磁性膜４の保磁力Ｈｃ２と
バイアス磁界Ｈｅｘとが等しくなる温度をＴｂとすると
、次のような関係が成立している。
Ｔｐｃ≦Ｔ＜Ｔｂのとき Ｈｃ２＞
Ｈｃ１＋Ｈｅｘ Ｔａ＜Ｔ＜Ｔｐｃのとき
Ｈｃ１＜Ｈｅｘ Ｔ≦Ｔａのとき
Ｈｃ１≧ＨｅｘThe present invention will be explained in detail below with reference to the drawings. The magneto-optical recording medium of the present invention has a memory layer in which the recording layer is made of a ferromagnetic film that exhibits perpendicular magnetic anisotropy, and a memory layer that exhibits in-plane magnetic anisotropy at room temperature and at a temperature near the Curie temperature of the memory layer that is higher than room temperature. It is formed by laminating an antiferromagnetic film that causes a magnetic phase transition and exhibits perpendicular magnetic anisotropy. FIG. 1 shows an example of the configuration of such a magneto-optical recording medium. This recording medium is made of Si3N on a transparent support 1 made of glass, plastic, ceramics, etc.
4. Protective film 2 made of SiO, SiO2, etc. (film thickness 10
0 Å to 5000 Å), and a ferromagnetic film 3 (film thickness 100 Å to 5000 Å) exhibiting perpendicular magnetic anisotropy is provided thereon.
On top of that, an antiferromagnetic film 4 ( Si
A protective film 5 (film thickness 100 Å to 5000 Å) made of 3N4, SiO, SiO2, etc. is provided. Each film can be formed by sputtering, vapor deposition, ion plating, or the like. The ferromagnetic film 3 is made of, for example, Tb-Fe,
Gd-Fe, Dy-Fe, Gd-Tb-Fe, Tb-D
y-Fe, Gd-Dy-Fe, Tb-Fe-Co, Gd
-Fe-Co, Dy-Fe-Co, Tb-Dy-Fe-
Co, Gd-Tb-Fe-Co, Gd-Dy-Fe-C
It can be composed of a rare earth-transition metal amorphous film such as O, or a polycrystalline film such as Mn-Bi, Mn-Cu-Bi, Co-Pt, Co spinel ferrite, Ba ferrite, etc. The antiferromagnetic film 4 is RCo (R=D
y, Nd, etc.) based film. These ferromagnetic film 3 and antiferromagnetic film 4 must have coercive force temperature characteristics as shown in FIG. That is, the Curie temperature of the ferromagnetic film 3 is Tc1, the Curie temperature of the antiferromagnetic film 4 is Tc2, and the magnetic phase transition temperature of the antiferromagnetic film 4 is Tpc.
, if Ta is the temperature at which the coercive force Hc1 of the ferromagnetic film 3 and the bias magnetic field Hex are equal, and Tb is the temperature at which the coercive force Hc2 of the antiferromagnetic film 4 is equal to the bias magnetic field Hex, the following relationship is established. It has been established. When Tpc≦T<Tb, Hc2>
When Hc1+Hex Ta<T<Tpc
When Hc1<Hex T≦Ta
Hc1≧Hex
【０００９】なお
、本発明の光磁気記録媒体の層構成は第１図に示すもの
に限定されるものでなく種々の変形、変更が可能であり
、例えば保護膜５の上に反射膜を設けても良いし、保護
膜２，５を適当に除いても良い。The layer structure of the magneto-optical recording medium of the present invention is not limited to that shown in FIG. 1, and various modifications and changes are possible. For example, a reflective film may be provided on the protective film 5. Alternatively, the protective films 2 and 5 may be appropriately removed.
【００１０】次に、上記光磁気記録媒体を用いた光磁気
記録方法について説明する。記録は、高いパワーのレー
ザビームを記録すべき部分に照射して媒体温度を強磁性
膜３のキュリー温度Ｔｃ１付近迄上げるとともに、外部
磁界Ｈｅｘを印加して行う。当該記録すべき部分の磁化
は通常の媒体駆動状態において強磁性膜３が上向き（ま
たは下向き）で反強磁性膜４が見かけ上ゼロであったも
のが、高いパワーのレーザビーム照射によりＴｃ１付近
迄昇温するため強磁性膜３では磁化が消失ないし殆んど
零となり、反強磁性膜４では磁気相転移が生じて（Ｔｐ
ｃで生じる）面内磁気異性から垂直磁気異方性に変化し
、しかも図中下向き（飽和磁化とは逆方向）の磁化が生
じる。この下向きの磁化は、冷却の過程で強磁性膜３の
方へ転写され、そのまま保持される。図３の（ａ）には
記録後の降温時における磁化状態が示してある。なお記
録を行うときの温度範囲はＴｐｃ≦Ｔ＜Ｔｂで、Ｔｂ以
上に温度を上げると反強磁性膜４の磁化方向がバイアス
磁界Ｈｅｘ方向（図では上方向）を向いてしまい、記録
できなくなる。Next, a magneto-optical recording method using the above magneto-optical recording medium will be explained. Recording is performed by irradiating the portion to be recorded with a high-power laser beam to raise the medium temperature to around the Curie temperature Tc1 of the ferromagnetic film 3, and by applying an external magnetic field Hex. The magnetization of the area to be recorded is such that the ferromagnetic film 3 is facing upward (or downward) and the antiferromagnetic film 4 is apparently zero under normal medium driving conditions, but it is increased to around Tc1 by high power laser beam irradiation. As the temperature rises, the magnetization in the ferromagnetic film 3 disappears or becomes almost zero, and a magnetic phase transition occurs in the antiferromagnetic film 4 (Tp
(c) changes from in-plane magnetic isomerism to perpendicular magnetic anisotropy, and moreover, magnetization occurs in the downward direction in the figure (in the opposite direction to the saturation magnetization). This downward magnetization is transferred to the ferromagnetic film 3 during the cooling process and is maintained as it is. FIG. 3(a) shows the magnetization state when the temperature is lowered after recording. The temperature range during recording is Tpc≦T<Tb, and if the temperature is raised above Tb, the magnetization direction of the antiferromagnetic film 4 will be directed toward the bias magnetic field Hex direction (upward in the figure), making it impossible to record. .
【００１１】消去は、記録時より低いパワーのレーザビ
ームを消去すべき部分に照射して媒体温度をＴａ≦Ｔ＜
Ｔｐｃの温度迄上げるとともに、外部磁界Ｈｅｘを印加
して行う（図３の（ｂ））。Erasing is performed by irradiating the area to be erased with a laser beam of lower power than during recording to lower the medium temperature such that Ta≦T<
This is performed by raising the temperature to Tpc and applying an external magnetic field Hex (FIG. 3(b)).
【００１２】このように反強磁性膜からなる補助層の磁
化は常に同一方向を向いているため、磁化の初期化とい
う操作は必要なく、単一ビーム、単一磁界でのオーバー
ライトが可能となる。また、再生は媒体温度がＴａ以下
となるパワーレベルのレーザビームを照射することによ
り行われる。[0012] Since the magnetization of the auxiliary layer made of an antiferromagnetic film always points in the same direction, there is no need to initialize the magnetization, and overwriting with a single beam and a single magnetic field is possible. Become. Further, reproduction is performed by irradiating a laser beam with a power level that makes the medium temperature less than or equal to Ta.
【００１３】〔実施例〕次に本発明を実施例により更に
詳細に説明するが、本発明はここに例示の実施例に限定
されるものではない。グルーブ付きポリカーボネート基
板（直径１３０ｍｍ）の上にｒｆ２元マグネトロンスパ
ッタ法により下記の膜を真空中で順次積層し、記録媒体
を得た。
保護膜：Ｓｉ３Ｎ４膜（１０００Å） 強磁性膜
：Ｔｂ０．２（Ｆｅ０．９８Ｃｏ０．０２）０．８膜（
６００Å） 反強磁性膜：ＤｙＣｏ５膜（１５００Å
） 保護膜：Ｓｉ３Ｎ４膜（１０００Å）[Example] Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the Examples illustrated herein. The following films were sequentially laminated in vacuum on a grooved polycarbonate substrate (diameter 130 mm) by RF binary magnetron sputtering to obtain a recording medium. Protective film: Si3N4 film (1000 Å) Ferromagnetic film: Tb0.2 (Fe0.98Co0.02) 0.8 film (
600 Å) Antiferromagnetic film: DyCo5 film (1500 Å
) Protective film: Si3N4 film (1000Å)
【００１４
】強磁性膜のキュリー温度Ｔｃ１、反強磁性膜のキュリ
ー温度Ｔｃ２及び磁気相転移温度Ｔｐｃ、強磁性膜の保
磁力Ｈｃ１とバイアス磁界Ｈｅｘとが等しくなる温度Ｔ
ａ、反強磁性膜の保磁力Ｈｃ２とバイアス磁界Ｈｅｘと
が等しくなる温度Ｔｂは次の通りであった。
Ｔｃ１＝１３０℃
Ｔｃ２＝３００℃
Ｔｐｃ＝１００℃
Ｔａ＝７０℃
Ｔｂ＝１８０℃0014
] Curie temperature Tc1 of the ferromagnetic film, Curie temperature Tc2 and magnetic phase transition temperature Tpc of the antiferromagnetic film, temperature T at which the coercive force Hc1 of the ferromagnetic film and the bias magnetic field Hex are equal.
a. The temperature Tb at which the coercive force Hc2 of the antiferromagnetic film becomes equal to the bias magnetic field Hex was as follows. Tc1=130℃ Tc2=300℃ Tpc=100℃ Ta=70℃ Tb=180℃
【００１５】以上のようにして得た記録媒体を線速１０
ｍ／秒で駆動させ、外部磁界Ｈｅｘ＝７００ Ｏｅ（記
録時と消去時ともに同一方向）を印加するとともに、記
録時、消去時及び再生時で以下のように照射レーザパワ
ーを変化させて１ＭＨｚの信号を記録再生し、記録／再
生特性の評価を行った。
記録時のレーザパワー：６ｍＷ
消去時のレーザパワー：４ｍＷ
再生時のレーザパワー：１ｍＷ
その結果、Ｃ／Ｎ比は４７ｄＢであった。さらに、同記
録媒体上に同一条件で２ＭＨｚの記録周波数でオーバー
ライトを実施したところ、Ｃ／Ｎ比４７ｄＢで良好な値
を示した。[0015] The recording medium obtained as described above was processed at a linear velocity of 10
The device was driven at a speed of 1 MHz per second, an external magnetic field Hex = 700 Oe (same direction during recording and erasing) was applied, and the irradiation laser power was changed as shown below during recording, erasing, and reproducing. Signals were recorded and reproduced, and recording/reproduction characteristics were evaluated. Laser power during recording: 6 mW Laser power during erasing: 4 mW Laser power during reproduction: 1 mW As a result, the C/N ratio was 47 dB. Furthermore, when overwriting was performed on the same recording medium under the same conditions at a recording frequency of 2 MHz, a good C/N ratio of 47 dB was obtained.
【００１６】[0016]
【発明の効果】本発明によれば、前記構成としたことに
より、単一ビーム、単一磁界でのオーバーライトが信頼
性良く行える。According to the present invention, with the above structure, overwriting can be performed with a single beam and a single magnetic field with high reliability.
【図１】本発明に係る光磁気記録媒体の層構成を示す断
面図である。FIG. 1 is a cross-sectional view showing the layer structure of a magneto-optical recording medium according to the present invention.
【図２】本発明の光磁気記録媒体の強磁性膜及び反強磁
性膜の保磁力Ｈｃの温度特性を示す図である。FIG. 2 is a diagram showing the temperature characteristics of the coercive force Hc of the ferromagnetic film and antiferromagnetic film of the magneto-optical recording medium of the present invention.
【図３】（ａ）は記録時における磁化状態を示し、（ｂ
）は消去時における磁化状態を示す図である。[Fig. 3] (a) shows the magnetization state during recording, and (b)
) is a diagram showing the magnetization state during erasing.
１ 支持体 ２，５ 保護膜 ３ 強磁性膜（メモリ層） ４ 反強磁性膜（補助層） 1 Support 2,5 Protective film 3 Ferromagnetic film (memory layer) 4 Antiferromagnetic film (auxiliary layer)
Claims (2)
るメモリ層と、室温で面内磁気異方性を示し室温より高
い該メモリ層のキュリー温度付近の温度で磁気相転移を
生じて垂直磁気異方性を示す反強磁性膜からなる補助層
とを積層した２層膜からなる記録層を有することを特徴
とする光磁気記録媒体。1. A memory layer consisting of a ferromagnetic film exhibiting perpendicular magnetic anisotropy, and a memory layer that exhibits in-plane magnetic anisotropy at room temperature and undergoes a magnetic phase transition at a temperature near the Curie temperature of the memory layer, which is higher than room temperature. 1. A magneto-optical recording medium characterized by having a recording layer made of a two-layer film laminated with an auxiliary layer made of an antiferromagnetic film exhibiting perpendicular magnetic anisotropy.
、記録時には媒体温度が前記磁気相転移の生じる温度以
上となる迄昇温するような高いパワーのレーザビームを
照射するとともに外部磁界Ｈｅｘを印加し、消去時には
媒体温度が前記磁気相転移の生じる温度より下の温度と
なる迄昇温するような低いパワーのレーザビームを照射
するとともに記録時と同じ外部磁界Ｈｅｘを印加するこ
とを特徴とするオーバーライト可能な光磁気記録方法。2. Using the magneto-optical recording medium according to claim 1, during recording, a high power laser beam is irradiated to raise the temperature of the medium until the temperature reaches the temperature at which the magnetic phase transition occurs, and an external magnetic field Hex is applied. is applied, and during erasing, a low power laser beam is irradiated to raise the temperature of the medium until it becomes below the temperature at which the magnetic phase transition occurs, and the same external magnetic field Hex as during recording is applied. A magneto-optical recording method that allows overwriting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP41223690A JPH04219642A (en) | 1990-12-19 | 1990-12-19 | Magneto-optical recording medium and method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP41223690A JPH04219642A (en) | 1990-12-19 | 1990-12-19 | Magneto-optical recording medium and method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04219642A true JPH04219642A (en) | 1992-08-10 |
Family
ID=18521100
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP41223690A Pending JPH04219642A (en) | 1990-12-19 | 1990-12-19 | Magneto-optical recording medium and method thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04219642A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997048094A1 (en) * | 1996-06-14 | 1997-12-18 | Seiko Epson Corporation | Magneto-optical recording medium |
| EP1143434A2 (en) * | 1992-08-28 | 2001-10-10 | Canon Kabushiki Kaisha | A magnetooptical recording medium and information recording and reproducing methods using the recording medium |
| USRE38501E1 (en) | 1992-08-28 | 2004-04-20 | Canon Kabushiki Kaisha | Magnetooptical recording medium and information recording and reproducing methods using the recording medium |
| USRE38922E1 (en) | 1992-08-28 | 2005-12-20 | Canon Kabushiki Kaisha | Magneto-optical recording medium and method for reproducing information from a magneto-optical recording medium having three layers |
-
1990
- 1990-12-19 JP JP41223690A patent/JPH04219642A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1143434A2 (en) * | 1992-08-28 | 2001-10-10 | Canon Kabushiki Kaisha | A magnetooptical recording medium and information recording and reproducing methods using the recording medium |
| EP1143434A3 (en) * | 1992-08-28 | 2001-12-12 | Canon Kabushiki Kaisha | A magnetooptical recording medium and information recording and reproducing methods using the recording medium |
| USRE38501E1 (en) | 1992-08-28 | 2004-04-20 | Canon Kabushiki Kaisha | Magnetooptical recording medium and information recording and reproducing methods using the recording medium |
| USRE38922E1 (en) | 1992-08-28 | 2005-12-20 | Canon Kabushiki Kaisha | Magneto-optical recording medium and method for reproducing information from a magneto-optical recording medium having three layers |
| WO1997048094A1 (en) * | 1996-06-14 | 1997-12-18 | Seiko Epson Corporation | Magneto-optical recording medium |
| US6146752A (en) * | 1996-06-14 | 2000-11-14 | Seiko Epson Corporation | Magneto-optical recording medium |
| KR100509664B1 (en) * | 1996-06-14 | 2005-10-28 | 세이코 엡슨 가부시키가이샤 | Magneto-optical recording media |
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