JPH02214047A - Magneto-optical recording medium - Google Patents
Magneto-optical recording mediumInfo
- Publication number
- JPH02214047A JPH02214047A JP3412789A JP3412789A JPH02214047A JP H02214047 A JPH02214047 A JP H02214047A JP 3412789 A JP3412789 A JP 3412789A JP 3412789 A JP3412789 A JP 3412789A JP H02214047 A JPH02214047 A JP H02214047A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic layer
- magnetic
- recording medium
- layer
- 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
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 5
- 239000000956 alloy Substances 0.000 claims abstract description 5
- 229910052723 transition metal Inorganic materials 0.000 claims abstract description 5
- 239000010410 layer Substances 0.000 abstract description 58
- 238000000034 method Methods 0.000 abstract description 16
- 230000005381 magnetic domain Effects 0.000 abstract description 14
- 239000000758 substrate Substances 0.000 abstract description 14
- 230000003287 optical effect Effects 0.000 abstract description 12
- 230000005415 magnetization Effects 0.000 abstract description 7
- 239000011241 protective layer Substances 0.000 abstract description 4
- 239000012790 adhesive layer Substances 0.000 abstract description 3
- 239000011247 coating layer Substances 0.000 abstract 1
- 230000008602 contraction Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 229920000515 polycarbonate Polymers 0.000 description 3
- 239000004417 polycarbonate Substances 0.000 description 3
- 229910002546 FeCo Inorganic materials 0.000 description 2
- 230000001678 irradiating effect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 241000167880 Hirundinidae Species 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明はレーザービーム等の収束光の熱エネルギーによ
り情報の記録を行い、磁気光学効果によって再生を行う
光磁気記録ならびに光磁気記録媒体に関わり、特に光変
調方式によるダイレクトオーバーライトが可能な光磁気
記録媒体に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to magneto-optical recording and magneto-optical recording media in which information is recorded using the thermal energy of convergent light such as a laser beam and reproduced using the magneto-optic effect. In particular, the present invention relates to a magneto-optical recording medium that allows direct overwriting using an optical modulation method.
［従来の技術］
光磁気記録方式は高密度記録・ランダムアクセス・消去
可能な記録方式として様々に研究開発されており、その
第一世代のものが既に市場に登場している。これを第一
世代と呼ぶのは、書換えが可能と言っても一旦書き込ん
だ情報を別の情報に書き換えるためには、まず記録しで
ある情報の消去を行い媒体の回転を１周待った後新たな
情報の記録を行うという２段階の手続きが必要で、いわ
ゆるダイレクトオーバーライトができないためである。[Prior Art] Various types of magneto-optical recording systems have been researched and developed as high-density recording, random access, and erasable recording systems, and the first generation of these systems has already appeared on the market. This is called the first generation because even though it is said to be rewritable, in order to rewrite the information that has been written once, you must first erase the information that has been recorded, wait for one rotation of the medium, and then write the new information. This is because a two-step procedure is required to record the relevant information, and so-called direct overwriting is not possible.
光磁気記録の用途を広げて行くためには、このダイレク
トオーバライドを実現し高速な記録が可能な第二世代の
登場が不可欠であると言われている。In order to expand the applications of magneto-optical recording, it is said that the emergence of a second generation that can realize this direct override and enable high-speed recording is essential.
これまでにいくつかのダイレクトオーバーライト方式が
提案されているが、これらのうち例えばＡｐｐｌ、 Ｐ
ｈｙｓ、 Ｌｅｔｔ、 ４９．４７３−４７４ （１９
８６）やＡｐｐｌ、Ｐｈｙｓ、 Ｌｅｔｔ、 ５２．１
５３７−ＩＦ；３９（１９８８）に開示されているよう
な光変調方式によれば、レーザービームのパルス幅なら
びにパルスの高さを情報の記録時と消去時で変えること
によって、バイアス磁界の向きならびに大きさを変える
ことなくダイレクトオーバーライトを実現することがで
きる。これらの方式における記録の消去は以下のメカニ
ズムによって行われるとされている。Several direct overwrite methods have been proposed so far, including Appl, P
hys, Lett, 49.473-474 (19
86) and Appl, Phys, Lett, 52.1
537-IF; 39 (1988), by changing the pulse width and pulse height of the laser beam when recording and erasing information, the direction of the bias magnetic field and the Direct overwriting can be achieved without changing the size. The erasure of records in these methods is said to be performed by the following mechanism.
いま広くて薄い磁性膜にバブル磁区があるとすると、そ
のブロッホ磁壁に作用する力はブロッホ磁壁の磁壁エネ
ルギーによる力と反磁界エネルギーによる力と静磁エネ
ルギーによる力の和によって与えられる。このうちブロ
ッホ磁壁エネルギーによる力は磁区の収縮に、後者の二
つの力は磁区の拡大に作用する。前述のダイレクトオー
バーライト方式においては、記録パルス照射時のブロッ
ホ磁壁エネルギーにより磁壁に働（力が比較的小さいた
め記録磁区が形成されるが、消去パルス照射時には記録
層の温度勾配が大きく、そのためブロッホ磁壁エネルギ
ーによる磁壁に働く力も大きいので、新たに形成した磁
区は記録ドメインを飲み込んで収縮して小さな残留磁区
を形成する。さらに連続して発せられた次の消去パルス
によってこの残留磁区をも吸収し消去が行われるのであ
る。Assuming that there is a bubble magnetic domain in a wide and thin magnetic film, the force acting on the Bloch domain wall is given by the sum of the force due to the domain wall energy of the Bloch domain wall, the force due to demagnetizing field energy, and the force due to magnetostatic energy. Among these forces, the force due to Bloch domain wall energy acts on the contraction of the magnetic domain, and the latter two forces act on the expansion of the magnetic domain. In the above-mentioned direct overwrite method, the Bloch domain wall energy acts on the domain wall during write pulse irradiation (the force is relatively small, so a recording magnetic domain is formed, but when the erase pulse is irradiated, the temperature gradient of the recording layer is large, so Bloch domain wall energy acts on the domain wall). Since the force acting on the domain wall due to the domain wall energy is large, the newly formed magnetic domain swallows the recording domain and contracts to form a small residual magnetic domain.Furthermore, the next erase pulse emitted in succession absorbs this residual magnetic domain as well. Erasure takes place.
この光変調法によるダイレクトオーバーライト方式は磁
界の反転動作を必要としないので他の方式と比べ高い周
波数での記録が可能で、且つバイアス磁界の発生に永久
磁石を使用できることから注目を集めている。This direct overwrite method using optical modulation is attracting attention because it does not require reversal of the magnetic field, so it can record at a higher frequency than other methods, and it can also use a permanent magnet to generate the bias magnetic field. .
［発明が解決しようとする課題］
前述したように光変調方式における消去メカニズムの基
礎は記録媒体上の温度分布で決まる記録層の磁気的性質
の分布にある。それ故、記録媒体上の温度分布が十分に
大きくないときには磁区の収縮が十分に行われず消去が
不完全になる。従って記録媒体を高速で回転させたとき
、消去に必要な温度勾配が得られないことから、完全な
ダイレクトオーバーライトが遂行できなくなるという問
題点を有している。[Problems to be Solved by the Invention] As mentioned above, the basis of the erasing mechanism in the optical modulation method lies in the distribution of magnetic properties of the recording layer, which is determined by the temperature distribution on the recording medium. Therefore, if the temperature distribution on the recording medium is not large enough, the magnetic domains will not contract sufficiently and erasing will be incomplete. Therefore, when the recording medium is rotated at high speed, a temperature gradient necessary for erasing cannot be obtained, resulting in a problem that complete direct overwriting cannot be performed.
そこで本発明は上述の問題点を解決するものでその目的
とするところは、媒体回転数が大きい場合にも光変調に
よるダイレクトオーバーライトが可能な光磁気記録媒体
を提供することを目的とする。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a magneto-optical recording medium that allows direct overwriting by optical modulation even when the number of rotations of the medium is high.
［課題 を解決するための手段］
本発明の光磁気記録媒体は、情報の記録時と消去時にバ
イアス磁界の方向ならびに大きさを変えることなくレー
ザーパルスの変調のみによるダイレクトオーバーライト
が可能な光磁気記録媒体において、少なくとも希土類−
遷移金属合金から成る第一の磁性層と該磁性層に隣接す
る希土類−遷移金属合金から成る第二の磁性層を具備す
ることを特徴とする。また前記第一の磁性層に情報を記
録したとき、該第一の磁性層の記録部と前記第二の磁性
層の界面に磁壁が存在し、且つ該第一の磁性層の非記録
部と該第二の磁性層の界面に磁壁が存在しないことを特
徴とする。[Means for Solving the Problems] The magneto-optical recording medium of the present invention is a magneto-optical recording medium that enables direct overwriting only by modulating laser pulses without changing the direction and magnitude of the bias magnetic field when recording and erasing information. In the recording medium, at least rare earth
It is characterized by comprising a first magnetic layer made of a transition metal alloy and a second magnetic layer made of a rare earth-transition metal alloy adjacent to the magnetic layer. Furthermore, when information is recorded in the first magnetic layer, a domain wall exists at the interface between the recording part of the first magnetic layer and the second magnetic layer, and a domain wall exists at the interface between the recording part of the first magnetic layer and the non-recording part of the first magnetic layer. A feature is that there is no domain wall at the interface of the second magnetic layer.
［作用］
上述したようにこの光変調法によるダイレクトオーバー
ライト方式の記録の消去は、主として記録媒体の温度分
布に基づ（磁壁エネルギー勾配にによる磁区の収縮力に
かかっている。しかしながら、温度分布が小さいときは
この収縮力が小さいために十分な消去動作が行われない
。[Function] As mentioned above, the erasure of records in the direct overwrite method using this optical modulation method is mainly based on the temperature distribution of the recording medium (depending on the contraction force of the magnetic domain due to the domain wall energy gradient. When is small, this contractile force is small and a sufficient erasing operation is not performed.
いま第一 第二の磁性層からなる交換二層膜を記録活性
層とする光磁気記録媒体において、第一の磁性層と第二
の磁性層の界面に磁壁が存在すると、界面磁壁エネルギ
ー分だけエネルギーが高い状態になる。界面磁壁エネル
ギーは界面磁壁の面積に比例する量なので、全エネルギ
ーが低くなるように磁区は収縮しようとする。即ち界面
磁壁エネルギーによりブロッホ磁壁が受ける力は収縮力
として働く。それ故、２つの磁性層のうち一方の磁性層
に磁区の有無による記録を行い、他方の磁性層は記録の
有無にかかわらず一様に磁化しておき、且つこの磁化の
方向を記録部分には界面磁壁ができるようにすれば、消
去プロセスに於ける記録磁区の収縮力が得られるという
ことになる。この収縮力は界面磁壁が存在する限り働く
ので媒体の温度分布には太き（は依存せず、従って媒体
の高速回転等によって生じる前述の不都合を解決するこ
とができるのである。First, in a magneto-optical recording medium whose recording active layer is an exchange double-layer film consisting of a second magnetic layer, if a domain wall exists at the interface between the first and second magnetic layers, the energy of the interfacial domain wall will increase. Be in a high energy state. Since the interfacial domain wall energy is proportional to the area of the interfacial domain wall, the magnetic domain tends to contract so that the total energy becomes lower. That is, the force exerted on the Bloch domain wall by the interfacial domain wall energy acts as a contraction force. Therefore, recording is performed in one of the two magnetic layers depending on the presence or absence of a magnetic domain, and the other magnetic layer is uniformly magnetized regardless of the presence or absence of recording, and the direction of this magnetization is set in the recording area. This means that if an interfacial domain wall is formed, the contraction force of the recorded magnetic domain in the erasing process can be obtained. Since this contraction force acts as long as the interfacial domain wall exists, it does not depend on the temperature distribution of the medium, and therefore the above-mentioned disadvantages caused by high-speed rotation of the medium can be solved.
［実施例コ 以下実施例に基づいて本発明の詳細な説明する。[Example code] The present invention will be described in detail below based on Examples.
実施例１：
本発明の例として第１図に示すような構成の光磁気記録
媒体を作製した。即ち基板１として直径ｔａｏｍｍ板厚
１．２ｍｍの１．６μｍピッチのプリグループ付きポリ
カーボネイトを用い、そのグループ面上に下引き層２と
して膜厚８ＱｎｍのＳｉ３Ｎ４膜を成膜し、次に第一磁
性層３として膜厚ＺＯｎｍのＴｂ２４Ｆｅ７ＱＣｏ６
（ａ ｔ％）膜、第二磁性層４として膜厚２０ｎｍの
Ｔｂ２６Ｆｅ５４Ｃｏ２０（ａｔ％）膜、保護層５とし
て膜厚３０ｎｍの５１３Ｎ４膜を積層し、さらに反射層
６として膜厚３０ｎｍのＡＩ膜を積層した。次にこれを
直径１３０ｍｍのフラットなポリカーボネイト基板８と
熱硬化性樹脂による接着層７を介して貼合わせて光磁気
記録媒体とした。なお、第一磁性層、第二磁性層はいず
れも室温に於いては希土類優勢の磁気特性を示し、キュ
リー温度は各々１３０℃と２５０℃であった。Example 1: As an example of the present invention, a magneto-optical recording medium having a configuration as shown in FIG. 1 was manufactured. That is, a polycarbonate with a pre-group of 1.6 μm pitch having a diameter of taomm and a thickness of 1.2 mm is used as the substrate 1, a Si3N4 film with a thickness of 8 Qnm is formed as an undercoat layer 2 on the group surface, and then a first magnetic layer is formed. Layer 3 is Tb24Fe7QCo6 with a film thickness of ZOnm.
(at%) film, a 20 nm thick Tb26Fe54Co20 (at%) film as the second magnetic layer 4, a 30 nm thick 513N4 film as the protective layer 5, and a 30 nm thick AI film as the reflective layer 6. Laminated. Next, this was bonded to a flat polycarbonate substrate 8 with a diameter of 130 mm via an adhesive layer 7 made of thermosetting resin to form a magneto-optical recording medium. The first magnetic layer and the second magnetic layer both exhibited rare earth-dominated magnetic properties at room temperature, and their Curie temperatures were 130°C and 250°C, respectively.
この光磁気記録媒体を用いての光変調法によるダイレク
トオーバーライトを試みた。まずこの光磁気記録媒体に
２０ｋＯｅの磁界を印加し、第一ならびに第二の磁性層
の全面の磁化の向きを一方向に揃丸で全面消去の状態に
した。次に媒体回転数３６０Ｏｒｐｍ、 バイアス磁界
２０００ｅの条件下でパルス高さ８ｍＷ、ｚｆルス幅１
３１ ｎ ｓ ｅｃｌ ３，７ＭＨｚで変調したレーザ
ー光を半径６０ｍｍの位置に基板１側から照射して信号
の記録を行った。この状態で１ｍＷ連続出射レーし−光
を用いて情報の再生を行ったところ、デユーティ比５０
％の３．７ＭＨｚの再生信号出力が得られ、その搬送波
対雑音比（ＣＮＲ）は５７．５ｄＢで良好な記録が行わ
れたことが判る。We attempted direct overwriting using the optical modulation method using this magneto-optical recording medium. First, a magnetic field of 20 kOe was applied to this magneto-optical recording medium, so that the magnetization direction of the entire surface of the first and second magnetic layers was aligned in one direction, and the entire surface was erased. Next, under the conditions of medium rotation speed 360 Orpm, bias magnetic field 2000e, pulse height 8 mW, zf pulse width 1
Signals were recorded by irradiating a laser beam modulated at 31 nsec 3.7 MHz to a position with a radius of 60 mm from the substrate 1 side. In this state, when information was reproduced using 1mW continuous emitting laser light, the duty ratio was 50.
% of the reproduced signal output was obtained, and its carrier-to-noise ratio (CNR) was 57.5 dB, indicating that good recording was performed.
引き続いて、この３．７ＭＨｚの信号が記録された媒体
に同じく媒体回転数３６０Ｏｒｐｍ、 バイアス磁界
２０００ｅの条件下で、パルス幅１００ｎｓｅｃｓ
パルス高さ８ｍＷ、５ＭＨｚの記録パルスと記録パルス
間にパルス幅２０ｎ８ｅＣｓパルス高さ９．５ｍＷ、５
０ＭＨｚの消去パルスがくるように変調したレーザー光
を半径６０ｍｍの位置に基板１＠から照射した。この記
録媒体を再生したところ、再生信号からは３．７ＭＨｚ
の信号成分は検出されず、デユーティ比５０％の５ＭＨ
ｚの再生信号成分のみが得らた。またそのＣＮＲは５４
．０ｄＢであった。さらに、この媒体にパルス幅１３１
ｎ ｓ ｅ ｃ、 パルス高さ８ｍＷ。Subsequently, the medium on which this 3.7 MHz signal was recorded was subjected to a pulse width of 100 ns under the same conditions of a medium rotation speed of 360 Orpm and a bias magnetic field of 2000 e.
Pulse height 8mW, 5MHz recording pulse, pulse width 20n8eCs between recording pulses, pulse height 9.5mW, 5
A laser beam modulated to produce an erasing pulse of 0 MHz was irradiated from the substrate 1@ to a position with a radius of 60 mm. When this recording medium was played back, the playback signal showed a frequency of 3.7MHz.
signal component is not detected, 5MH with a duty ratio of 50%
Only the z reproduced signal component was obtained. Also, its CNR is 54
．． It was 0dB. Furthermore, this medium has a pulse width of 131
n sec, pulse height 8 mW.
３、 ７ Ｍ Ｈｚ （Ｄ 記ｔａ ハルスト記録パル
ス間にパルス幅２０ ｎ ｓ ｅ ｃｌ パルス高さ
９． ５ｍＷ、 ５０Ｍ・Ｈｚの消去パルスがくるよ
うに変調したレーザー光を全面に照射し３．７ＭＨｚの
信号のダイレクトオーバーライトを行ったところ、同じ
く良好な情報の書換えが可能であった。3.7 MHz (D) The entire surface was irradiated with a laser beam modulated so that erasing pulses of 50 MHz and pulse width of 20 ns ecl, pulse height of 9.5 mW, and 50 MHz were placed between recording pulses of 3.7 MHz. When we performed direct overwrite of the signal, it was possible to rewrite the information equally well.
比較のため第１図において第二磁性層４がないことを除
いて、上記本発明の例と同様な構成、材料の光磁気記録
媒体を作製し、そのダイレクトオーバーライト特性を評
価した。その結果、媒体回転数が１８０Ｏｒｐｍの場合
には良好なダイレクトオーバーライトが行われたが、媒
体回転数を３６’ＯＯｒ ｐ ｍとしたところ、消去動
作がうまく行われずダイレクトオーバーライトは実現で
きなかった。For comparison, a magneto-optical recording medium having the same structure and material as the example of the present invention was prepared, except that the second magnetic layer 4 was not provided in FIG. 1, and its direct overwrite characteristics were evaluated. As a result, good direct overwriting was performed when the media rotation speed was 180 Orpm, but when the media rotation speed was set to 36'OOrpm, the erasing operation was not performed well and direct overwriting could not be achieved. .
実施例２：
本発明の例として、第一図に於て第一磁性層３を膜厚２
０ｎｍのＴｂ２１Ｆｅ７６Ｃｏ３ （ａｔ％）膜、第
二磁性層４を膜厚２０ｎｍのＴｂ２２Ｆｅ６０Ｃｏ１ｇ
（ａｔ％）膜としたことを除いて、本発明の実施例１と
同じ構造の光磁気記録媒体を作成した。なお、第一磁性
層、第二磁性層はいずれも室温に於いてはＦｅＣｏ優勢
の磁気特性を示し、牛エリー温度は各々１２５℃と２５
０℃であった。Example 2: As an example of the present invention, the first magnetic layer 3 in FIG.
0nm Tb21Fe76Co3 (at%) film, second magnetic layer 4 with 20nm thickness Tb22Fe60Co1g
A magneto-optical recording medium having the same structure as Example 1 of the present invention was produced, except that a (at%) film was used. Note that both the first magnetic layer and the second magnetic layer exhibit magnetic properties dominated by FeCo at room temperature, and the cow Erie temperature is 125°C and 25°C, respectively.
It was 0°C.
この光磁気記録媒体を用いての光変調法によるダイレク
トオーバーライトを試みた。まずこの光磁気記録媒体に
２０ｋＯｅの磁界を印加し、第一ならびに第二の磁性層
の全面の磁化の向きを一方向に揃えて全面消去の状態に
した。次に媒体回転数３６００ｒｐｍ、 バイアス磁
界２５００ｅの条件下でパルス高さ７．５ｍＷ、 パ
ルス幅１３１ｎｓｅｃ、３．７ＭＨｚで変調したレーザ
ー光を半径６０ｍｍの位置に基板ｌ側から照射して信号
の記録を行った。この状態で１ｍＷ連続出射レーザー光
を用いて情報の再生を行ったところ、デユーティ比５０
％の３．７ＭＨｚの再生信号出力が得られ、その搬送波
対雑音比（ＣＮＲ）は５６．３ｄＢで良好な記録が行わ
れたことが判る。We attempted direct overwriting using the optical modulation method using this magneto-optical recording medium. First, a magnetic field of 20 kOe was applied to this magneto-optical recording medium, and the magnetization direction of the entire surface of the first and second magnetic layers was aligned in one direction, so that the entire surface was erased. Next, a laser beam modulated with a pulse height of 7.5 mW, a pulse width of 131 ns, and 3.7 MHz was irradiated from the substrate L side at a radius of 60 mm under the conditions of a medium rotation speed of 3600 rpm and a bias magnetic field of 2500 e to record signals. went. In this state, when information was reproduced using a 1 mW continuous emitting laser beam, the duty ratio was 50.
% of the reproduced signal output was obtained, and its carrier-to-noise ratio (CNR) was 56.3 dB, indicating that good recording was performed.
引き続いて、この３．７ＭＨｚの信号が記録された媒体
に同じく媒体回転数３６００ｒｐｍ、バイアス磁界２５
００ｅの条件下で、パルス幅１０Ｏｒｉ ｓ ｅ ｃ、
パルス高さ７．５ｍＷ、５ＭＨｚの記録パルスと記録
パルス間にパルスＩＭＡ ２０ ｎ ｓ ｅＣ，パルス
高さ９ｍＷ、５０ＭＨｚの消去パルスがくるように変調
したレーザー光を半径６０ｍｍの位置に基板１側から照
射した。この記録媒体を再生したところ、再生信号から
は３．７ＭＨｚの信号成分は検出されず、デユーティ比
５０％の５ＭＨｚの再生信号成分のみが得らた。またそ
のＣＮＲは５３．７ｄＢであった。さらに、この媒体に
パルス幅１３１ ｎ ｓ ｅ ｃ、 パルス高さ７．
５ｍＷ、３．７ＭＨｚの記録パルスと記録パルス間にパ
ルス幅２０ ｎ ｓ ｅ ｃ、 パルス高さ９ｍＷ、
５０ＭＨｚの消去パルスがくるように変調したレーザー
光を全面に照射し３．７ＭＨｚの信号のダイレクトオー
バーライトを行ったところ、同じく良好な情報の書換え
が可能であった。Subsequently, the medium on which this 3.7 MHz signal was recorded was similarly subjected to a medium rotation speed of 3600 rpm and a bias magnetic field of 25
Under the condition of 00e, the pulse width is 10Ori s e c,
A laser beam modulated so that an erasure pulse of IMA 20 ns eC, pulse height 9 mW, and 50 MHz comes between recording pulses of 5 MHz with a pulse height of 7.5 mW is applied from the substrate 1 side to a position with a radius of 60 mm. Irradiated. When this recording medium was reproduced, no 3.7 MHz signal component was detected from the reproduced signal, and only a 5 MHz reproduced signal component with a duty ratio of 50% was obtained. Moreover, its CNR was 53.7 dB. Furthermore, this medium had a pulse width of 131 ns and a pulse height of 7.
5 mW, 3.7 MHz recording pulse, pulse width 20 nsec between recording pulses, pulse height 9 mW,
When direct overwriting of a 3.7 MHz signal was performed by irradiating the entire surface with a laser beam modulated to produce a 50 MHz erase pulse, it was possible to rewrite information similarly.
実施例３二
本発明の例として、第一図に於て第一磁性層３を膜厚２
０ｎｍのＴｂ２４Ｆｅ７ＧＣｏ６ （ａ ｔ％）膜、
第二磁性層４を膜厚２０ｎｍのＴｂ２２Ｆｅ６０Ｃｏｌ
ｅ（ａｔ％）膜としたことを除いて、本発明の実施例１
と同じ構造の光磁気記録媒体を作成した。なお、室温に
於て第一磁性層は希土類優勢の、第二磁性層はＦｅＣｏ
優勢の磁気特性を示し、＋１リ一温度は各々１３０℃と
２５０℃であった。Embodiment 3 As an example of the present invention, the first magnetic layer 3 in FIG.
0nm Tb24Fe7GCo6 (a t%) film,
The second magnetic layer 4 is made of Tb22Fe60Col with a film thickness of 20 nm.
Example 1 of the present invention, except that the e(at%) film was used.
A magneto-optical recording medium with the same structure was created. Note that at room temperature, the first magnetic layer is dominated by rare earth elements, and the second magnetic layer is made of FeCo.
They exhibited dominant magnetic properties, with +1 Li temperature of 130°C and 250°C, respectively.
この光磁気記録媒体を用いての光変調法によるダイレク
トオーバーライトを試みた。まずこの光磁気記録媒体に
２０ｋＯｅの磁界を印加し、第一ならびに第二の磁性層
の全面の磁化の向きを一方向に揃えた後、逆向きの磁界
１２ｋＯｅを印加し室温に於て両磁性層間に界面磁壁が
ない状態を作った。即ち記録媒体の全面消去を行なった
。次に媒体回転数３６０ Ｏｒ ｐ ｍ、 バイアス磁
界２５００ｅの条件下でパルス高さ８ｍＷ、 パルス幅
１３１ｎｓｅｃ、３．７ＭＨｚで変調したレーザー光を
半径６０ｍｍの位置に基板ｌ側から照射して信号の記録
を行った。この状態で１ｍＷ連続出射レーザー光を用い
て情報の再生を行ったところ、デユーティ比５０％の３
．７ＭＨｚの再生信号出力が得られ、その搬送波対雑音
比（ＣＮＲ）は５７゜ＯｄＢで良好な記録が行われたこ
とが判る。We attempted direct overwriting using the optical modulation method using this magneto-optical recording medium. First, a magnetic field of 20 kOe is applied to this magneto-optical recording medium to align the magnetization direction of the entire surface of the first and second magnetic layers in one direction, and then a magnetic field of 12 kOe in the opposite direction is applied to create bimagnetism at room temperature. A state was created in which there were no interfacial domain walls between the layers. That is, the entire recording medium was erased. Next, a laser beam modulated with a pulse height of 8 mW, a pulse width of 131 nsec, and 3.7 MHz was irradiated from the substrate L side at a radius of 60 mm under the conditions of a medium rotation speed of 360 Or p m and a bias magnetic field of 2500 e to record signals. I did it. In this state, when information was reproduced using a 1 mW continuous emitting laser beam, 3
．． It can be seen that a reproduced signal output of 7 MHz was obtained, and its carrier-to-noise ratio (CNR) was 57° OdB, indicating that good recording was performed.
引き続いて、この３．７ＭＨｚの信号が記録された媒体
に同じ（媒体回転数３６０Ｏｒｐｍ、 バイアス磁界
２５００ｅの条件下で、パルス幅１００ ｎ ｓ ｅ
ｃ、 パルス高さ８ｍＷ、５ＭＨｚの記録パルスと記
録パルス間にパルス幅２０ ｎ ｓ ｅ ｃｓパルス高
さ９．５ｍＷ、５０ＭＨｚの消去パルスがくるように変
調したレーザー光を半径６０ｍｍの位置に基板ｌ側から
照射した。この記録媒体を再生したところ、再生信号か
らは３．７ＭＨｚの信号成分は検出されず、デユーティ
比５０％の５ＭＨｚの再生信号成分のみが得らた。また
そのＣＮＲは５４．５ｄＢであった。さらに、この媒体
にパルス幅１３１ ｎ ｓ ｅ ｃ、 パルス高さ８ｍ
Ｗ。Subsequently, this 3.7 MHz signal was recorded on the same medium (medium rotation speed 360 rpm, bias magnetic field 2500 e, pulse width 100 ns e).
c. A laser beam modulated so that a 5 MHz recording pulse with a pulse height of 8 mW and a 50 MHz erasing pulse with a pulse width of 20 ns is placed between the recording pulses is placed on the substrate at a radius of 60 mm. Irradiated from the side. When this recording medium was reproduced, no 3.7 MHz signal component was detected from the reproduced signal, and only a 5 MHz reproduced signal component with a duty ratio of 50% was obtained. Moreover, its CNR was 54.5 dB. Furthermore, this medium had a pulse width of 131 nsec and a pulse height of 8 m.
W.
３．７ＭＨｚの記＆ｉ ／＜ルスと記録パルス間にパル
ス幅２０ ｎ ｓ ｅ ｃ、 パルス高さ９． ５ｍ
Ｗ、 ５０ＭＨｚの消去パルスがくるように変調した
レーザー光を全面に照射し３．７ＭＨｚの信号のダイレ
クトオーバーライトを行ったところ、同じく良好な情報
の書換えが可能であった。Note for 3.7 MHz: Pulse width: 20 nsec, pulse height: 9. 5m
When the entire surface was irradiated with a laser beam modulated to produce an erase pulse of 50 MHz and a direct overwrite of a 3.7 MHz signal was performed, it was possible to rewrite information similarly.
実施例４：
本発明の例として、第一図に於て第一磁性層３を膜厚２
０ｎｍのＴｂ２１Ｆｅ７６Ｃｏ３ （ａ ｔ％）膜、
第二磁性層４を膜厚２０ｎｍのＴｂ２６Ｆｅ５４Ｃｏｃ
ｏ（ａｔ％）膜としたことを除いて、本発明の実施例１
と同じ構造の光磁気記録媒体を作成した。なお、室温に
於て第一磁性層はＦｅＣｏ優勢の、第二磁性層は希土類
優勢の磁気特性を示し、キュリー温度は各々１２５℃と
２５０℃であった。Example 4: As an example of the present invention, the first magnetic layer 3 in FIG.
0nm Tb21Fe76Co3 (a t%) film,
The second magnetic layer 4 is made of Tb26Fe54Coc with a film thickness of 20 nm.
Example 1 of the present invention except that the film was o(at%)
A magneto-optical recording medium with the same structure was created. At room temperature, the first magnetic layer exhibited FeCo-dominated magnetic properties, and the second magnetic layer exhibited rare-earth-dominated magnetic properties, and their Curie temperatures were 125°C and 250°C, respectively.
この光磁気記録媒体を用いての光変調法によるダイレク
トオーバーライトを試みた。まずこの光磁気記録媒体に
２０ｋＯｅの磁界を印加し、第一ならびに第二の磁性層
の全面の磁化の向きを一方向に揃えた後、逆向きの磁界
１２ｋＯｅを印加し室温に於て両磁性層間に界面磁壁が
ない状態を作った。即ち記録媒体の全面消去を行なった
。次に媒体回転数３６０ Ｏｒ ｐ ｍ、 バイアス磁
界２０００ｅの条件下でパルス高さ７．５ｍＷ、 パ
ルス幅１３１ｎｓｅｃ、３．７ＭＨｚで変調したレーザ
ー光を半径６０ｍｍの位置に基板１側から照射して信号
の記録を行った。この状態で１ｍＷ連続出射レーザー光
を用いて情報の再生を行ったところ、デー−ティ比５０
％の３．７ＭＨｚの再生信号出力が得られ、その搬送波
対雑音比（ＣＮＲ）は５７．５ｄＢで良好な記録が行わ
れたことが判る。We attempted direct overwriting using the optical modulation method using this magneto-optical recording medium. First, a magnetic field of 20 kOe is applied to this magneto-optical recording medium to align the magnetization direction of the entire surface of the first and second magnetic layers in one direction, and then a magnetic field of 12 kOe in the opposite direction is applied to create bimagnetism at room temperature. A state was created in which there were no interfacial domain walls between the layers. That is, the entire recording medium was erased. Next, a laser beam modulated with a pulse height of 7.5 mW, a pulse width of 131 nsec, and 3.7 MHz was irradiated from the substrate 1 side at a position with a radius of 60 mm under the conditions of a medium rotation speed of 360 Or p m and a bias magnetic field of 2000 e to generate a signal. was recorded. When information was reproduced in this state using a 1 mW continuous emitting laser beam, the data ratio was 50.
% of the reproduced signal output was obtained, and its carrier-to-noise ratio (CNR) was 57.5 dB, indicating that good recording was performed.
引き続いて、この３．７ＭＨｚの信号が記録された媒体
に同じく媒体回転数３６０Ｏｒｐｍ、バイアス磁界２０
００ｅの条件下で、パルス幅１００ ｎ ｓ ｅ ｃｓ
パルス高さ７．５ｍＷ、５ＭＨｚの記録ハルスト記
録パルス間にパルス幅２０ ｎ ｓ ｅｃｌ パルス
高さ９ｍＷ、５０ＭＨｚの消去パルスが（るように変調
したレーザー光を半径６０ｍｍの位置に基板１側から照
射した。この記録媒体を再生したところ、再生信号から
は３．７ＭＨｚの信号成分は検出されず、デユーティ比
５０％の５ＭＨｚの再生信号成分のみが得らた。またそ
のＣＮＲは５４．２ｄＢであった。さらに、この媒体に
パルス幅１３１ ｎ ｓ ｅ ｃ、 パルス高さ７，
５ｍＷ、３．７ＭＨｚの記録パルスと記録パルス間にパ
ルス幅２０ ｎ ｓ ｅ ｃ、 パルス高さ９ｍＷ、
５０ＭＨｚの消去パルスが（るように変調したレーザー
光を全面に照射し３．７ＭＨｚの信号のダイレクトオー
バーライトを行ったところ、同じく良好な情報の書換え
が可能であった。Subsequently, the medium on which this 3.7 MHz signal was recorded was similarly subjected to a medium rotation speed of 360 Orpm and a bias magnetic field of 20
Under the condition of 00e, the pulse width is 100 ns e cs
A laser beam modulated such that a pulse width of 20 ns ecl and a 50 MHz erase pulse with a pulse height of 9 mW is applied to a position with a radius of 60 mm is irradiated from the substrate 1 side between recording pulses with a pulse height of 7.5 mW and 5 MHz. When this recording medium was reproduced, no 3.7 MHz signal component was detected from the reproduced signal, and only a 5 MHz reproduced signal component with a duty ratio of 50% was obtained.The CNR was 54.2 dB. Furthermore, this medium was given a pulse width of 131 nsec, a pulse height of 7,
5 mW, 3.7 MHz recording pulse, pulse width 20 nsec between recording pulses, pulse height 9 mW,
When the entire surface was irradiated with a laser beam modulated to produce a 50 MHz erasing pulse and direct overwriting of a 3.7 MHz signal was performed, it was possible to rewrite information similarly.
［発明の効果コ
以上に述べたように本発明によれば、媒体回転数が大き
い場合にも光変調によるダイレクトオーバーライトが可
能な光磁気記録媒体を提供することができる。なお上述
の効果は実施例に示された範囲の構成、材料、条件にお
いてのみ現れるものではなく、例えば記録層、保護層、
反射層、下引き層の組成ならびに膜厚が異なっても、あ
るいは貼合わせ構造をとるかとらないか等本発明実施例
に記載されていないものに関しても同様な効果が得られ
ることは言うまでもない。[Effects of the Invention] As described above, according to the present invention, it is possible to provide a magneto-optical recording medium that allows direct overwriting by optical modulation even when the number of rotations of the medium is high. Note that the above-mentioned effects appear not only in the configuration, materials, and conditions shown in the examples, but also in the recording layer, protective layer,
It goes without saying that the same effect can be obtained even if the composition and film thickness of the reflective layer and undercoat layer are different, or even if a laminated structure is used or not, which is not described in the embodiments of the present invention.
第１図は本発明にかかる光磁気記録媒体の構成を表す図
。FIG. 1 is a diagram showing the configuration of a magneto-optical recording medium according to the present invention.
１・・・基板 ２・・・下引き層 ３・・・第一磁性層 ４・・・第二磁性層 ５・・・保護層 ６・・・反射層 ７・・・接着層 ８・・・ポリカーボネイト基板 以上 出願人 セイコーエプソン株式会社 代理人弁理士 鈴木喜三部（他１名）1... Board 2... Undercoat layer 3...first magnetic layer 4...Second magnetic layer 5...Protective layer 6...Reflection layer 7... Adhesive layer 8... Polycarbonate substrate that's all Applicant: Seiko Epson Corporation Representative Patent Attorney Kizobe Suzuki (1 other person)
Claims (2)
びに大きさを変えることなくレーザーパルスの変調のみ
によるダイレクトオーバーライトが可能な光磁気記録媒
体において、少なくとも希土類−遷移金属合金から成る
第一の磁性層と該磁性層に隣接する希土類−遷移金属合
金から成る第二の磁性層を具備することを特徴とする光
磁気記録媒体。(1) In a magneto-optical recording medium that allows direct overwriting only by modulating laser pulses without changing the direction and magnitude of the bias magnetic field during recording and erasing information, at least 1. A magneto-optical recording medium comprising a magnetic layer and a second magnetic layer made of a rare earth-transition metal alloy adjacent to the magnetic layer.
の磁性層の記録部と前記第二の磁性層の界面に磁壁が存
在し、且つ該第一の磁性層の非記録部と該第二の磁性層
の界面に磁壁が存在しないことを特徴とする特許請求の
範囲第１項記載の光磁気記録媒体。(2) When information is recorded in the first magnetic layer, a domain wall exists at the interface between the recording part of the first magnetic layer and the second magnetic layer, and a non-recording part of the first magnetic layer exists. 2. The magneto-optical recording medium according to claim 1, wherein there is no domain wall at the interface between the magnetic layer and the second magnetic layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3412789A JPH02214047A (en) | 1989-02-14 | 1989-02-14 | Magneto-optical recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3412789A JPH02214047A (en) | 1989-02-14 | 1989-02-14 | Magneto-optical recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02214047A true JPH02214047A (en) | 1990-08-27 |
Family
ID=12405568
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3412789A Pending JPH02214047A (en) | 1989-02-14 | 1989-02-14 | Magneto-optical recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02214047A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0380447A (en) * | 1989-08-22 | 1991-04-05 | Nec Corp | Magneto-optical recording medium |
| US5187703A (en) * | 1990-02-28 | 1993-02-16 | Sharp Kabushiki Kaisha | Magneto-optical multilayer recording disk and method of reproducing the same |
-
1989
- 1989-02-14 JP JP3412789A patent/JPH02214047A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0380447A (en) * | 1989-08-22 | 1991-04-05 | Nec Corp | Magneto-optical recording medium |
| US5187703A (en) * | 1990-02-28 | 1993-02-16 | Sharp Kabushiki Kaisha | Magneto-optical multilayer recording disk and method of reproducing the same |
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