JPH01211343A - Magneto-optical recording medium - Google Patents
Magneto-optical recording mediumInfo
- Publication number
- JPH01211343A JPH01211343A JP3510588A JP3510588A JPH01211343A JP H01211343 A JPH01211343 A JP H01211343A JP 3510588 A JP3510588 A JP 3510588A JP 3510588 A JP3510588 A JP 3510588A JP H01211343 A JPH01211343 A JP H01211343A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- magnetic layer
- wall energy
- domain wall
- layer
- 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.)
- Granted
Links
- 229910052742 iron Inorganic materials 0.000 claims description 5
- 239000000758 substrate Substances 0.000 claims description 3
- 229910017061 Fe Co Inorganic materials 0.000 claims 1
- 239000010410 layer Substances 0.000 description 57
- 239000010408 film Substances 0.000 description 26
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 12
- 230000008878 coupling Effects 0.000 description 12
- 238000010168 coupling process Methods 0.000 description 12
- 238000005859 coupling reaction Methods 0.000 description 12
- 230000005415 magnetization Effects 0.000 description 11
- 229910052761 rare earth metal Inorganic materials 0.000 description 11
- 238000000034 method Methods 0.000 description 8
- 239000000203 mixture Substances 0.000 description 4
- 229910052581 Si3N4 Inorganic materials 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000000151 deposition Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000001755 magnetron sputter deposition Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 150000002910 rare earth metals Chemical class 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 230000005374 Kerr effect Effects 0.000 description 1
- 229910000808 amorphous metal alloy Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000005300 metallic glass Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000002356 single layer Substances 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、磁気カー効果を利用して読み出しすることが
できるキュリー点記録タイプの磁性層を使用した、重ね
書き可能な光磁気記録媒体に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an overwritable magneto-optical recording medium using a Curie point recording type magnetic layer that can be read using the magnetic Kerr effect. .
消去可能な光デイスクメモリとして光磁気ディスクが知
られている。光磁気ディスクは、従来の磁気ヘッドを使
った磁気記録媒体と比べて高密度記録、非接触での記録
再生などが可能であるという長所がある反面、記録前に
一度記録部分を消去しなければならない（一方向に着磁
しなければならない）という欠点があった。この欠点を
補う為に、記録再生用ヘッドと消去用ヘッドを別々に設
ける方式、あるいは、レーザーの連続ビームを照射しつ
つ、同時に印加する磁場を変調しながら記録する方式な
どが提案されている。A magneto-optical disk is known as an erasable optical disk memory. Magneto-optical disks have advantages over magnetic recording media using conventional magnetic heads, such as high-density recording and non-contact recording and playback, but on the other hand, the recorded area must be erased before recording. It had the disadvantage that it cannot be magnetized in one direction (it must be magnetized in one direction). In order to compensate for this drawback, proposals have been made such as a method in which a recording/reproducing head and an erasing head are provided separately, or a method in which recording is performed while irradiating a continuous laser beam and simultaneously modulating the applied magnetic field.
しかし、これらの方法は、装置が大がかりとなり、コス
ト高になる欠点あるいは高速の変調ができないなどの欠
点を有する。However, these methods have drawbacks such as a large-scale apparatus, high cost, and the inability to perform high-speed modulation.
そこで、最近、従来の装置構成に簡易な磁界発生手段を
付設するだけで、磁気記録媒体と同様な重ね書き（オー
バーライド）を可能にした光磁気記録方法が提案されて
いる（本願出願人の特願昭６２−２０３８４号等）。Therefore, recently, a magneto-optical recording method has been proposed that enables overwriting similar to that of a magnetic recording medium by simply adding a simple magnetic field generating means to the conventional device configuration (a special feature of the applicant). (Gan No. 62-20384, etc.).
この方法では、低いキュリー温度で高い保磁力を有する
第１磁性層と、この磁性層に比べて相対的に高いキュリ
ー温度と低い保磁力を有する第２磁性層とから成る、交
換結合した二層構造の垂直磁化膜が記録媒体として用い
られている。In this method, an exchange-coupled bilayer consisting of a first magnetic layer with a low Curie temperature and high coercive force and a second magnetic layer with a relatively high Curie temperature and low coercive force compared to this magnetic layer is used. A perpendicularly magnetized film with this structure is used as a recording medium.
この媒体の設計に際しては、第１磁性層と第２磁性層の
飽和磁化、保磁力および膜厚、そして、二層間の交換結
合の強さを考えなけばならない。When designing this medium, consideration must be given to the saturation magnetization, coercive force, and film thickness of the first and second magnetic layers, as well as the strength of exchange coupling between the two layers.
例えば、磁性層に希土類−鉄族非晶質合金薄膜を用いた
場合、その飽和磁化は希土類と鉄族の組成比を変えるこ
とによって制御することが可能であるし、その保磁力も
希土類元素の種類を選ぶことによって、あるいは２種類
以上の希土類元素を用いてその組成比を変えることによ
って、制御することが可能である。また、膜厚も自由に
制御可能である。すなわち、飽和磁化、保磁力および膜
厚はそれぞれかなり独立に制御することが可能である。For example, when a rare earth-iron group amorphous alloy thin film is used for the magnetic layer, its saturation magnetization can be controlled by changing the composition ratio of the rare earth element and the iron group, and its coercive force can also be controlled by changing the composition ratio of the rare earth element and the iron group. It can be controlled by selecting the type of rare earth element or by using two or more types of rare earth elements and changing their composition ratio. Furthermore, the film thickness can also be freely controlled. That is, saturation magnetization, coercive force, and film thickness can be controlled fairly independently.
ところが、二層間の交換結合の強さは、希土類と鉄族元
素の組成比や膜厚によっては変わらないものの、希土類
元素の種類によって影響を受けるので、交換結合の強さ
と保磁力とを独立に制御することが困難である。また、
第１、第２磁性層において、交換結合の強さの制御は、
希土類元素の種類を変える以外の有効な方法はない。However, although the strength of the exchange coupling between the two layers does not change depending on the composition ratio of rare earth and iron group elements or the film thickness, it is affected by the type of rare earth element, so the strength of exchange coupling and coercive force cannot be determined independently. Difficult to control. Also,
In the first and second magnetic layers, the strength of exchange coupling can be controlled by
There is no effective method other than changing the type of rare earth element.
したが７て、媒体の作製に関してはかなりの制約が存在
し、容易に作製することが困難であった。However, there are considerable restrictions regarding the production of media, making it difficult to produce them easily.
本発明の目的は、交換結合の強さと保磁力も独立に制御
可能であって、作製上の制約が少ない光磁気記録媒体を
提供することにある。An object of the present invention is to provide a magneto-optical recording medium in which the strength of exchange coupling and coercive force can be independently controlled, and there are fewer restrictions on manufacturing.
本発明は、いままでの第１磁性層と第２磁性層との間に
、特定要件を満たす第３の磁性層を付設することによっ
て、界面磁壁エネルギーの強さを制御し、上記目的を達
成しようとするものである。即ち、本発明は、低いキュ
リー温度と高い保磁力を有する第１磁性層と、この磁性
層に比べて相対的に高いキュリー温度と低い保磁力を有
する第２磁性層とからなる、交換結合した二層構造の垂
直磁化膜を基板上に有して成る、レーザーパワーの変調
による重ね書き可能な光磁気記録媒体において、前記第
１磁性層と前記第２磁性層の間に、これらの磁性層に比
べて相対的に小さな磁壁エネルギーを有する垂直磁化膜
である第３磁性層を設けることを特徴とする光磁気記録
媒体である。特に第３磁性層をＧｄ−Ｆｅ、 Ｇｄ−Ｆ
ｅ−ＧｏまたはＧｄ−Ｇｏとすると上記目的達成により
効果的である。The present invention achieves the above object by controlling the strength of the interfacial domain wall energy by adding a third magnetic layer that satisfies specific requirements between the conventional first magnetic layer and second magnetic layer. This is what I am trying to do. That is, the present invention provides an exchange-coupled magnetic layer comprising a first magnetic layer having a low Curie temperature and high coercive force, and a second magnetic layer having a relatively high Curie temperature and low coercive force compared to this magnetic layer. In a magneto-optical recording medium that has a two-layer perpendicular magnetization film on a substrate and is overwritable by laser power modulation, these magnetic layers are provided between the first magnetic layer and the second magnetic layer. This is a magneto-optical recording medium characterized by providing a third magnetic layer which is a perpendicularly magnetized film having a relatively small domain wall energy compared to the third magnetic layer. In particular, the third magnetic layer is made of Gd-Fe, Gd-F
Using e-Go or Gd-Go is more effective in achieving the above objective.
本発明をより詳細に説明する前に、その理解の便のため
、交換結合の強さと磁壁エネルギーとの関連について言
及する。Before explaining the present invention in more detail, for ease of understanding, the relationship between exchange coupling strength and domain wall energy will be mentioned.
交換結合二層膜では、第１層のスピンと第２層のスピン
が量子交換相互作用によって互いに平行になろうとする
（動きがある。この（動きに逆らって、外部から磁界を
加えて片方の磁化のみを反転させると、二層の界面にス
ピンがねじれた領域ができる。この領域を界面磁壁と呼
び、この磁壁のエネルギーの大きさによって交換結合の
強さを見積もることができる。この磁壁は、単層膜の磁
化反転過程中にできる通常の磁壁とは異なるが、同程度
のエネルギーを蓄えると考えられる。すなわち、通常の
磁壁エネルギーが大きなものは、界面磁壁エネルギーも
大きく、交換結合の強さも大きいことになる。In an exchange-coupled bilayer film, the spins in the first layer and the spins in the second layer try to become parallel to each other due to quantum exchange interaction. When only the magnetization is reversed, a region with twisted spins is created at the interface between the two layers.This region is called an interfacial domain wall, and the strength of exchange coupling can be estimated by the magnitude of the energy of this domain wall.This domain wall is Although it is different from the normal domain wall formed during the magnetization reversal process of a single-layer film, it is thought that it stores the same amount of energy.In other words, a domain wall with a large normal domain wall energy also has a large interfacial domain wall energy, and the exchange coupling is strong. That's going to be big too.
希土類−鉄族非晶質金属薄膜で考えると、例えば、Ｇｄ
−ＦｅやＧｄ−Ｇｏのように、希土類元素がＧｄのも
のでは、通常の磁壁エネルギーの大きさは１〜３ｅｒｇ
／ｃｍ２と報告されている。Considering rare earth-iron group amorphous metal thin films, for example, Gd
-When the rare earth element is Gd, such as Fe or Gd-Go, the normal domain wall energy is 1 to 3 erg.
/cm2.
また、Ｔｂ−ＦｅやＴｂ−Ｇｏのように、希土類元素が
Ｔｂのものでは、その垂直磁気異方性エネルギーがＧｄ
系に比べて約５倍程度大きく、磁壁エネルギーは垂直磁
気異方性エネルギーの平方根に比例するので、Ｔｂ−１
％では通常の磁壁エネルギーの大きさは約２〜７ｅｒｇ
／ｃｍ２と見積もられる。すなわち、Ｇｄ系の交換結合
二層膜では界面磁壁エネルギーも約１〜３ ｅｒｇ ／
ｃｍ２程度であり、Ｔｂ系の交換結合二層膜では界面
磁壁エネルギーも約２〜７ｅｒｇ／Ｃｌ１１２程度と見
積もられる。また、一方の層がＧｄ系、他の層がＴｂ系
の交換結合二層膜の場合には、界面磁壁エネルギーはよ
り小さい方、（この場合にはＧｄ系）の磁壁エネルギー
と同程度（約１〜３ｅｒｇ／ＣＬＩ＋２）になると考え
られる。In addition, when the rare earth element is Tb, such as Tb-Fe and Tb-Go, the perpendicular magnetic anisotropy energy is Gd
Tb-1 is about 5 times larger than the Tb-1
%, the normal domain wall energy is about 2 to 7 erg.
It is estimated that /cm2. That is, in a Gd-based exchange-coupled bilayer film, the interfacial domain wall energy is also approximately 1 to 3 erg/
The interfacial domain wall energy is estimated to be about 2 to 7 erg/Cl112 in a Tb-based exchange-coupled double-layer film. In addition, in the case of an exchange-coupled double-layer film in which one layer is Gd-based and the other layer is Tb-based, the interfacial domain wall energy is approximately the same as the domain wall energy of the smaller one (in this case, Gd-based) (approximately 1 to 3 erg/CLI+2).
実際に、報告された例では、Ｇｄ −にＯ／ Ｇｄ −
Ｇｏの二層膜で約１ ｅｒｇ ／ ｃｍ２． Ｇｄ −
Ｆｅ／ Ｔｂ −Ｆｅ二層膜で約１〜２ｅｒｇ ７ｃｍ
２． Ｔｂ−Ｆｅ−（：ｏ／Ｔｂ−Ｆｅ−Ｇ。In fact, in the reported example, Gd − has O/Gd −
Approximately 1 erg/cm2 for the Go double layer film. Gd −
Approximately 1-2erg 7cm with Fe/Tb-Fe double layer film
2. Tb-Fe-(:o/Tb-Fe-G.
二層膜で約５ ｅｒｇ ／ ｃｍ２である。It is approximately 5 erg/cm2 for a two-layer film.
次に、本発明の説明に移る。Next, the present invention will be explained.
レーザーパワーの変調による重ね書き可能な交換結合二
層膜では、外部磁界なしで第１、第２磁性層間に界面磁
壁を安定に保持しなくてはならないため、両層の保磁力
が共にある程度大きくなけてはならない。このようにす
るためには、実際上、希土類元素としてはＴｂを両層に
用いなくはならない。しかし、Ｔｂ系の交換結合二層膜
では界面磁壁エネルギーが約５ｅｒｇ／Ｃｌ１１２とか
なり大きくなってしまう。In an exchange-coupled bilayer film that can be overwritten by laser power modulation, the interfacial domain wall must be stably maintained between the first and second magnetic layers without an external magnetic field, so the coercive force of both layers must be large to some extent. Indispensable. In order to do this, it is actually necessary to use Tb as the rare earth element in both layers. However, in a Tb-based exchange-coupled bilayer film, the interfacial domain wall energy is quite large, about 5 erg/Cl112.
重ね書き可能な交換結合二層膜としては、外部磁界なし
で、界面磁壁を安定に保持し、かつ外部磁界によって、
第２磁性層の磁化を容易に反転させるため、界面磁壁エ
ネルギーは好ましくは約３ｅｒｇ／ｃｍ２以下、より好
ましくは約２ｅｒｇ ７ｃｍ２以下である。前記２つの
条件を満足させるため、従来の構成では、磁性層の膜厚
を不当に厚くしていた。あるいは、磁壁エネルギーはそ
のままで外部磁界（初期化磁界）を不当に大きくしなけ
ればならなかった。As an overwritable exchange-coupled bilayer film, it can stably hold the interfacial domain wall without an external magnetic field, and
In order to easily reverse the magnetization of the second magnetic layer, the interfacial domain wall energy is preferably about 3 erg/cm2 or less, more preferably about 2 erg/cm2 or less. In order to satisfy the above two conditions, in the conventional structure, the thickness of the magnetic layer was made unduly thick. Alternatively, the external magnetic field (initialization magnetic field) had to be unduly increased while the domain wall energy remained unchanged.
本発明では、レーザーパワーの変調による重ね書き可能
な交換結合二層膜の第ｆＭｉ性層と第２磁性層の間に、
これらの磁性層に比べて相対的に小さな磁壁エネルギー
を有する垂直磁化膜である第３磁性層を設けることによ
って、保磁力を望ましい値に保持しつつ、界面磁壁エネ
ルギー、ひいては交換結合の強さを制御する。In the present invention, between the fMi-th layer and the second magnetic layer of the exchange-coupled bilayer film, which can be overwritten by laser power modulation,
By providing the third magnetic layer, which is a perpendicularly magnetized film with a relatively small domain wall energy compared to these magnetic layers, it is possible to maintain the coercive force at a desirable value while increasing the interfacial domain wall energy and, ultimately, the strength of exchange coupling. Control.
この第三磁性層としては、Ｇｄ −Ｆｅ％Ｇｄ−Ｆｅ−
Ｇｏ、 Ｇｄ−Ｇｏなど、通常の磁壁エネルギーの小さ
なものが好ましい。第３磁性層の膜厚を変えることによ
って、第１．２磁性層の希土類の、種類を変えなくても
、界面磁壁エネルギーの大きさ、ひいては第１と第２磁
性層の間に働く交換結合の強さを制御することができる
。As this third magnetic layer, Gd-Fe%Gd-Fe-
It is preferable to use ordinary materials with small domain wall energy, such as Go and Gd-Go. By changing the thickness of the third magnetic layer, the magnitude of the interfacial domain wall energy and the exchange coupling between the first and second magnetic layers can be increased without changing the type of rare earth in the first and second magnetic layers. strength can be controlled.
第３磁性層の膜厚を第３磁性層の通常の磁壁幅以上にす
ると、界面磁壁エネルギーは小さく一定（約２ ｅｒｇ
／ ｃｍ２）であり、磁壁幅より非常に薄くすると、
界面磁壁エネルギーはほとんど変わらず大きい（約５
ｅｒｇ ／ Ｃｌ１１２ ）、その中間の膜厚では、界
面磁壁エネルギーも中間の値になる。なお、Ｇｄ−Ｆｅ
、 Ｇｄ−Ｆｅ−（：ｏ％Ｇｄ−１１：ｏの磁壁幅は約
２００〜３００人と見積もられる。When the thickness of the third magnetic layer is made larger than the normal domain wall width of the third magnetic layer, the interfacial domain wall energy is small and constant (approximately 2 erg
/ cm2), and if it is made much thinner than the domain wall width,
The interfacial domain wall energy remains large (approximately 5
erg/Cl112), and at a film thickness in between, the interfacial domain wall energy also takes an intermediate value. In addition, Gd-Fe
, Gd-Fe-(:o% The domain wall width of Gd-11:o is estimated to be about 200 to 300 people.
スライドガラス上に、酸化防止のためのＳｉ３Ｎ４を１
００人、第１磁性層としてＴｂ −Ｆｅ −Ｇｏ （Ｆ
ｅ −Ｇｏ副格子磁化優勢、５０ ｅｍｕ／ｃｍ３）を
４００人、第３磁性層としてＧｄ −Ｆｅ −Ｇｏ （
Ｆｅ −Ｇｏ副格子磁化−優勢、１００ ｅｍｕ／ｃｍ
３） 、第２磁性層としてＴｂ−Ｆｅ −Ｇｏ （Ｔｂ
副格子磁化優勢、１５０ ｅｍｕ／ｃｍ３）を４００人
、酸化防止のためのＳｉ３Ｎ４を１００人、順次真空を
破ることなく連続してマグネトロンスパッタリング装置
を用いて成膜し、試料を作製した。Ａｒガス圧は０．１
５Ｐａとし、Ｓｉ３Ｎ４の成膜速度は約４０人／ｗｉｎ
、磁性層の成膜速度は約１００人／１１ｉｎであった。1 1 of Si3N4 to prevent oxidation on the slide glass.
00 people, Tb -Fe -Go (F
e -Go sublattice magnetization dominant, 50 emu/cm3) for 400 people, and Gd -Fe -Go (
Fe-Go sublattice magnetization-dominant, 100 emu/cm
3), Tb-Fe-Go (Tb
Samples were prepared by sequentially forming films using a magnetron sputtering apparatus using a magnetron sputtering apparatus using 400 people with sublattice magnetization dominant (150 emu/cm3) and 100 people with Si3N4 for oxidation prevention without breaking the vacuum. Ar gas pressure is 0.1
5 Pa, and the deposition rate of Si3N4 is approximately 40 people/win.
The deposition rate of the magnetic layer was approximately 100 persons/11 inches.
成膜後、試料をＩ Ｘ １ ｃｍに切り出し、振動試料
型磁力計によって、磁化曲線を測定し、ヒステリシスル
ープのシフト量と飽和磁化の大きさから界面磁壁エネル
ギーを算出した。After the film was formed, the sample was cut into a size of I x 1 cm, the magnetization curve was measured using a vibrating sample magnetometer, and the interfacial domain wall energy was calculated from the shift amount of the hysteresis loop and the magnitude of saturation magnetization.
第３磁性層のＧｄ −Ｆｅ −Ｇｏの膜厚が、０〜５０
人（試料Ａ）のとき界面磁壁エネルギーは約６ ｅｒｇ
／ｃｍ２であり、１００人のとき（試料Ｂ）約５ｅｒｇ
７ｃｍ２．２００人のとき、約３ ｅｒｇ ７ｃｍ２
．２５０〜３００Å以上のとき（試料Ｃ）で約２ｅｒｇ
／ｃｔｎ２となった。The thickness of Gd-Fe-Go of the third magnetic layer is 0 to 50
For a person (sample A), the interfacial domain wall energy is approximately 6 erg
/cm2, and when there are 100 people (sample B) about 5erg
7cm2. When there are 200 people, approximately 3 erg 7cm2
．． Approximately 2 erg at 250-300 Å or more (sample C)
/ctn2.
比較用に、第３磁性層を設けない以外は同様にして試料
りを作製した。For comparison, a sample was prepared in the same manner except that the third magnetic layer was not provided.
界面磁壁エネルギーは約６ ｅｒｇ ／ ｃｒｎ２であ
った。The interfacial domain wall energy was approximately 6 erg/crn2.
上記試料と同様な方法で、１３０ｍｍφのポリカーボネ
ート基板上に、試料Ａ、Ｂ、Ｃ％Ｄと層構造、膜厚、材
料が対応する光磁気記録媒体Ａ、Ｂ、Ｃ，Ｄを、作製し
た。Magneto-optical recording media A, B, C, and D having layer structures, film thicknesses, and materials corresponding to those of samples A, B, and C%D were prepared on a polycarbonate substrate of 130 mm diameter using the same method as for the above samples.
光磁気記録媒体Ａ、Ｂ、Ｄでは、交換結合の効果の方が
第２磁性層の保磁力よりも大きく、外部磁界なしで界面
磁壁を安定に保持できなかった。In magneto-optical recording media A, B, and D, the effect of exchange coupling was greater than the coercive force of the second magnetic layer, and the interfacial domain wall could not be stably maintained without an external magnetic field.
したがって、光磁気記録媒体Ａ、Ｂ、Ｄでは重ね書き動
作ができなかった。Therefore, the overwriting operation could not be performed on the magneto-optical recording media A, B, and D.
一方、光磁気記録媒体Ｃでは、外部磁界なしで界面磁壁
を安定に保持でき、初期化磁界５にＯｅ、バイアス磁界
２００ Ｏｅ１回転数１８００ｒｐｍ、５．２ｍＷと８
．２ｍＷの二値のレーザーパワーを印加しつつ記録を行
なったところ、重ね書き動作ができることが確認できた
。On the other hand, in the magneto-optical recording medium C, the interfacial domain wall can be stably maintained without an external magnetic field, and the initialization magnetic field 5 is Oe, the bias magnetic field is 200 Oe, the rotation speed is 1800 rpm, 5.2 mW, and 8
．． When recording was performed while applying a binary laser power of 2 mW, it was confirmed that an overwriting operation was possible.
以上詳細に説明したように、レーザーパワーの変調によ
る重ね書き可能な交換結合二層膜の第１磁性層と第２磁
性層の間に、これらの磁性層と比べて相対的に小さな磁
壁エネルギーを有する垂直磁化膜である第３６ｆｉ性層
を設けることにより、界面磁壁エネルギーを制御するこ
とが可能になり、結果的に、交換結合の強さと保磁力も
独立に制御可能となり、作製上の制約が少なくなった。As explained in detail above, relatively small domain wall energy is applied between the first magnetic layer and the second magnetic layer of the exchange-coupled bilayer film that can be overwritten by laser power modulation compared to these magnetic layers. By providing the 36th fi layer, which is a perpendicularly magnetized film, it becomes possible to control the interfacial domain wall energy, and as a result, the strength of exchange coupling and coercive force can also be controlled independently, eliminating manufacturing constraints. It has become less.
出 願 人 キャノン株式会社Sender: Canon Co., Ltd.
Claims (1)
と、この磁性層に比べて相対的に高いキュリー温度と低
い保磁力を有する第２磁性層とからなる、交換結合した
二層構造の垂直磁化膜を基板上に有して成る、レーザー
パワーの変調により重ね書き可能な光磁気記録媒体にお
いて、前記第１磁性層と前記第２磁性層の間に、これら
の磁性層に比べて相対的に小さな磁壁エネルギーを有す
る垂直磁化膜である第３磁性層を設けることを特徴とす
る光磁気記録媒体。 ２）前記第３磁性層がＧｄ−Ｆｅ、Ｇｄ−Ｆｅ−Ｃｏま
たはＧｄ−Ｃｏであることを特徴とする請求項１記載の
光磁気記録媒体。[Claims] 1) An exchangeable magnetic layer consisting of a first magnetic layer having a low Curie temperature and high coercive force, and a second magnetic layer having a relatively high Curie temperature and low coercive force compared to this magnetic layer. In a magneto-optical recording medium which is overwritable by laser power modulation and has a bonded two-layer perpendicularly magnetized film on a substrate, these A magneto-optical recording medium characterized in that a third magnetic layer is provided, which is a perpendicularly magnetized film having a relatively smaller domain wall energy than the magnetic layer. 2) The magneto-optical recording medium according to claim 1, wherein the third magnetic layer is Gd-Fe, Gd-Fe-Co or Gd-Co.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3510588A JP2555127B2 (en) | 1988-02-19 | 1988-02-19 | Magneto-optical recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3510588A JP2555127B2 (en) | 1988-02-19 | 1988-02-19 | Magneto-optical recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01211343A true JPH01211343A (en) | 1989-08-24 |
| JP2555127B2 JP2555127B2 (en) | 1996-11-20 |
Family
ID=12432652
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3510588A Expired - Fee Related JP2555127B2 (en) | 1988-02-19 | 1988-02-19 | Magneto-optical recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2555127B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01273248A (en) * | 1988-04-25 | 1989-11-01 | Nikon Corp | Overwritable magneto-optical recording medium controlled in exchange bonding strength between magnetic layers |
| EP0420587A2 (en) * | 1989-09-25 | 1991-04-03 | Nikon Corporation | Over-write capable magnetooptical recording medium |
-
1988
- 1988-02-19 JP JP3510588A patent/JP2555127B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01273248A (en) * | 1988-04-25 | 1989-11-01 | Nikon Corp | Overwritable magneto-optical recording medium controlled in exchange bonding strength between magnetic layers |
| EP0420587A2 (en) * | 1989-09-25 | 1991-04-03 | Nikon Corporation | Over-write capable magnetooptical recording medium |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2555127B2 (en) | 1996-11-20 |
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