JPH0350343B2 - - Google Patents
Info
- Publication number
- JPH0350343B2 JPH0350343B2 JP14227884A JP14227884A JPH0350343B2 JP H0350343 B2 JPH0350343 B2 JP H0350343B2 JP 14227884 A JP14227884 A JP 14227884A JP 14227884 A JP14227884 A JP 14227884A JP H0350343 B2 JPH0350343 B2 JP H0350343B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic layer
- magneto
- recording medium
- magnetic
- 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.)
- Expired - Lifetime
Links
- 239000000758 substrate Substances 0.000 claims description 16
- 239000010409 thin film Substances 0.000 claims description 14
- 239000010408 film Substances 0.000 claims description 13
- 229910052723 transition metal Inorganic materials 0.000 claims description 9
- 239000003989 dielectric material Substances 0.000 claims description 7
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 7
- 239000010410 layer Substances 0.000 description 79
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 16
- 238000000034 method Methods 0.000 description 11
- 239000000463 material Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 229910052751 metal Inorganic materials 0.000 description 8
- 230000005415 magnetization Effects 0.000 description 7
- 238000003860 storage Methods 0.000 description 7
- 239000011241 protective layer Substances 0.000 description 5
- 230000005374 Kerr effect Effects 0.000 description 4
- 229910052771 Terbium Inorganic materials 0.000 description 4
- 238000005566 electron beam evaporation Methods 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 230000031700 light absorption Effects 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 150000002910 rare earth metals Chemical class 0.000 description 4
- 150000003624 transition metals Chemical class 0.000 description 4
- 229910052692 Dysprosium Inorganic materials 0.000 description 3
- 229910052688 Gadolinium Inorganic materials 0.000 description 3
- 229910016629 MnBi Inorganic materials 0.000 description 3
- 229910004298 SiO 2 Inorganic materials 0.000 description 3
- 238000007733 ion plating Methods 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 230000001681 protective effect Effects 0.000 description 3
- 238000004544 sputter deposition Methods 0.000 description 3
- 238000007740 vapor deposition Methods 0.000 description 3
- 229910010413 TiO 2 Inorganic materials 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 239000012790 adhesive layer Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910001152 Bi alloy Inorganic materials 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- WAIPAZQMEIHHTJ-UHFFFAOYSA-N [Cr].[Co] Chemical class [Cr].[Co] WAIPAZQMEIHHTJ-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- KYAZRUPZRJALEP-UHFFFAOYSA-N bismuth manganese Chemical compound [Mn].[Bi] KYAZRUPZRJALEP-UHFFFAOYSA-N 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000002223 garnet Substances 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- AJCDFVKYMIUXCR-UHFFFAOYSA-N oxobarium;oxo(oxoferriooxy)iron Chemical compound [Ba]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O AJCDFVKYMIUXCR-UHFFFAOYSA-N 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000013112 stability test Methods 0.000 description 1
- 238000002834 transmittance 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
Description
【発明の詳細な説明】
〔技術分野〕
本発明は、レーザー光を用いて情報の記録・再
生・消去を行なう磁気光学記録媒体に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a magneto-optical recording medium that records, reproduces, and erases information using laser light.
従来、光磁気記録に用いられる磁気光学記録媒
体の材料としてMnBi系、ガーネツト系、希土類
−遷移金属アモルフアス系などが知られている。
MnBi系は、キユリー温度が高いため、記録の際
に出力の大きなレーザーを必要とし、また粒界ノ
イズが多いため、Ｓ／Ｎ比の高い再生が実施でき
ないという欠点があり、ガーネツト系でも光の透
過率が大きいため、記録の際に出力の大きなレー
ザーが必要となる欠点があつた。その中で、希土
類−遷移金属アモルフアス系は、両者の欠点を補
うものとして期待されている。
Conventionally, MnBi-based materials, garnet-based materials, rare earth-transition metal amorphous materials, and the like have been known as materials for magneto-optical recording media used in magneto-optical recording.
The MnBi system has the disadvantage that it requires a high-output laser for recording due to its high Curie temperature, and also has the disadvantage that reproduction with a high S/N ratio cannot be achieved due to the large amount of grain boundary noise. Because of its high transmittance, it had the disadvantage of requiring a high-output laser for recording. Among these, the rare earth-transition metal amorphous system is expected to compensate for the drawbacks of both.
このような磁気光学記録媒体の再生方式には、
フアラデー効果とカー効果を利用する方法があ
る。カー効果再生方式ではカー回転角を大きくし
再生信号レベルを向上させるために、磁気記録層
上にSiOやSiO2などの誘電体層を形成して磁気記
録層面上への多重反射を利用する方法などが検討
されてきた。また、特開昭55−6541号、特開昭58
−6542号等に開示されているように、磁気記録層
を薄膜化し、裏面に金属反射層を形成することに
より、カー効果とフアラデー効果を利用してカー
回転角を増加させる方法も知られている。一方、
GdCo，GdFeなどの比較的大きなカー回転角を
有する磁性層と、DyFe，TbFeなどの保磁力の
大きい磁性層とを積層することによりカー回転角
を増加させ、再生信号レベルを向上させる方法も
知られている。 The playback method for such magneto-optical recording media includes:
There is a method that uses Faraday effect and Kerr effect. The Kerr effect reproduction method uses multiple reflections on the surface of the magnetic recording layer by forming a dielectric layer such as SiO or SiO 2 on the magnetic recording layer in order to increase the Kerr rotation angle and improve the reproduction signal level. etc. have been considered. Also, JP-A-55-6541, JP-A-58
There is also a known method of increasing the Kerr rotation angle by utilizing the Kerr effect and Faraday effect by thinning the magnetic recording layer and forming a metal reflective layer on the back surface, as disclosed in No. 6542. There is. on the other hand,
There is also a method of increasing the Kerr rotation angle and improving the reproduction signal level by laminating a magnetic layer with a relatively large Kerr rotation angle such as GdCo or GdFe and a magnetic layer with a large coercive force such as DyFe or TbFe. It is being
このようにカー回転角を大きくし、再生信号レ
ベルを向上させる方法が試みられているが、未だ
十分なものではない。また記録されるビツトの安
定性はバイアス磁界の大きさによつて影響を受け
易く、安定したビツトを記録するためには最適な
バイアス磁界を印加して記録しなければならな
い。 Although attempts have been made to increase the Kerr rotation angle and improve the reproduced signal level, these methods are still not satisfactory. Furthermore, the stability of recorded bits is easily affected by the magnitude of the bias magnetic field, and in order to record stable bits, it is necessary to apply an optimum bias magnetic field for recording.
また、上述したような磁気記録層は酸素の存在
下で高温高湿の雰囲気に放置すると容易に酸化さ
れる。特に、磁気記録層を薄膜化した場合には、
その程度が著しい。従つて、時間が経つにつれ
て、媒体の記録感度の低下、記録再生時のエラー
の増加、信号の劣化などの欠点が生じやすい。 Further, the magnetic recording layer as described above is easily oxidized when left in a high temperature and high humidity atmosphere in the presence of oxygen. In particular, when the magnetic recording layer is made thinner,
The extent of this is remarkable. Therefore, as time passes, disadvantages such as a decrease in the recording sensitivity of the medium, an increase in errors during recording and reproduction, and signal deterioration are likely to occur.
本発明は上述の如き欠点に鑑みなされたもので
あり、本発明の目的は、再生信号レベルが高く、
しかも安定した記録ビツトを形成することがで
き、結果的に高密度記録が可能な磁気光学記録媒
体を提供することにある。
The present invention was made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a high reproduction signal level,
Moreover, it is an object of the present invention to provide a magneto-optical recording medium in which stable recording bits can be formed and, as a result, high-density recording can be performed.
本発明の他の目的は、保存安定性に優れた磁気
光学記録媒体を提供することにある。この目的は
次の本発明の磁気光学記録媒体によつて達成する
ことができる。すなわち本発明は、基板と、該基
板上に設けられ、膜面に垂直方向に磁気異方性を
有する第１の磁性層と、該第１の磁性層に相接し
て設けられ、第１の磁性層よりも高い保磁力を有
し、膜面に垂直方向に磁気異方性を有する第２の
磁性層とから成る磁気光学記録媒体において、前
記第１の磁性層が、誘電体中に希土類元素または
遷移金属元素のいずれか一方のみを分散させた薄
膜から成ることを特徴とする磁気光学記録媒体で
ある。 Another object of the present invention is to provide a magneto-optical recording medium with excellent storage stability. This object can be achieved by the following magneto-optical recording medium of the present invention. That is, the present invention provides a substrate, a first magnetic layer provided on the substrate and having magnetic anisotropy in a direction perpendicular to the film surface, and a first magnetic layer provided adjacent to the first magnetic layer, and a second magnetic layer having a coercive force higher than that of the magnetic layer and having magnetic anisotropy in a direction perpendicular to the film surface, the first magnetic layer is formed in a dielectric material. This is a magneto-optical recording medium characterized by comprising a thin film in which only either a rare earth element or a transition metal element is dispersed.
以下、図面を参照にして本発明による磁気光学
記録媒体を説明する。 Hereinafter, a magneto-optical recording medium according to the present invention will be explained with reference to the drawings.
第１図は、本発明の基本的態様を示す模式断面
図である。この図において、ａはプラスチツク又
はガラス等からなる透光性基板である。１は上記
薄膜の代表例、すなわち、遷移金属の１種以上の
金属元素、又は、希土類金属の１種以上の金属元
素のいずれか一方のみを誘電体中に分散させた厚
み方向に垂直な磁化容易軸を有する第１の磁性層
である。例えば、Fe，Co，Ni等の遷移金属の１
種以上の金属元素又はGd，Tb，Dy等の希土類
金属の１種以上の金属元素をAlN，Si3N4，
MgF2，BiF3，SiO，SiO2，TiO2及びTa2O5から
なる群より選ばれた１種以上からなる誘電体中に
分散させて構成される。 FIG. 1 is a schematic sectional view showing a basic aspect of the present invention. In this figure, a is a translucent substrate made of plastic, glass, or the like. 1 is a typical example of the above-mentioned thin film, that is, magnetization perpendicular to the thickness direction in which only one of one or more metal elements of transition metals or one or more metal elements of rare earth metals is dispersed in a dielectric material. The first magnetic layer has an easy axis. For example, one of transition metals such as Fe, Co, Ni, etc.
AlN, Si 3 N 4 , or one or more metal elements of rare earth metals such as Gd, Tb, Dy, etc.
It is configured by being dispersed in a dielectric material made of one or more selected from the group consisting of MgF 2 , BiF 3 , SiO, SiO 2 , TiO 2 and Ta 2 O 5 .
誘電体中に含まれる遷移金属または希土類金属
の体積の割合（体積充填率：ｑ）は、0.5≦ｑ≦
0.95が好ましい。体積充填率ｑが0.5以下である
と、厚み方向に垂直磁気異方性を有する磁化が安
定に存在しにくくなり、またｑが0.95以上である
と、酸素、水分等の雰囲気によつて磁性層が酸化
され易くなるからである。このような体積充填率
の好ましい範囲内に於いて、記録光に対する第１
の磁性層の光吸収率が30〜40％程度になるように
膜厚及び体積充填率等を設定することが好まし
い。最適な膜厚は磁性層の材料、充填率により異
なるが、通常250〜1000Åの範囲に設定される。
光吸収率は、後述するようにこの記録媒体への記
録、再生の性能に大きな影響を及ぼす。 The volume ratio of the transition metal or rare earth metal contained in the dielectric (volume filling factor: q) is 0.5≦q≦
0.95 is preferred. If the volume filling factor q is less than 0.5, it will be difficult for magnetization with perpendicular magnetic anisotropy to exist stably in the thickness direction, and if q is more than 0.95, the magnetic layer will be damaged by the atmosphere such as oxygen and moisture. This is because it becomes easier to oxidize. Within this preferred range of volume filling factor, the first
It is preferable to set the film thickness, volume filling rate, etc. so that the light absorption rate of the magnetic layer is about 30 to 40%. The optimum film thickness varies depending on the material of the magnetic layer and the filling rate, but is usually set in the range of 250 to 1000 Å.
As will be described later, the light absorption rate has a large effect on the recording and reproducing performance of this recording medium.
以上説明したような第１の磁性層１の好ましい体
積充填率、膜厚及び光吸収率を考慮して、第１の
磁性層１を構成する各原料を多元蒸着源として、
スパツタリング法、イオンプレーテイング法、電
子ビーム蒸着法等により基板の上へ成膜すること
によつて、第１の磁性層１を形成することができ
る。Considering the preferable volume filling factor, film thickness, and light absorption rate of the first magnetic layer 1 as explained above, each raw material constituting the first magnetic layer 1 is used as a multi-source vapor deposition source.
The first magnetic layer 1 can be formed by forming a film on a substrate using a sputtering method, an ion plating method, an electron beam evaporation method, or the like.
２は第１の磁性層１よりも高い保磁力を有し、
かつ厚み方向に磁気異方性を有する第２の磁性層
であり、例えば、Fe，Co，Ni等の遷移金属及び
Gd，Tb，Dy等の希土類金属の中から任意に選
び出した一種以上の金属元素からなる金属薄膜、
バリウムフエライト薄膜（BaFe2O4）、コバルト
−クロム合金薄膜（Co−Cr）、マンガン−ビスマ
ス系合金薄膜（MnBi，MnCuBi）等の磁性薄膜
を使用することができる。 2 has a higher coercive force than the first magnetic layer 1,
and has magnetic anisotropy in the thickness direction, for example, a transition metal such as Fe, Co, Ni, etc.
A metal thin film made of one or more metal elements arbitrarily selected from rare earth metals such as Gd, Tb, Dy, etc.
A magnetic thin film such as a barium ferrite thin film (BaFe 2 O 4 ), a cobalt-chromium alloy thin film (Co-Cr), a manganese-bismuth alloy thin film (MnBi, MnCuBi), etc. can be used.
このような磁性薄膜成分を構成する各原料金属
又はフエライトを多元蒸着源として、スパツタリ
ング法、イオンプレーテイング法、電子ビーム蒸
着法等の成膜法によつて第１の磁性層１上へ成膜
することによつて、第２の磁性層２を形成するこ
とができる。第２の磁性層２の厚さは、材質によ
つて異なるが通常500Å〜2000Å程度が好ましい。 A film is formed on the first magnetic layer 1 by a film forming method such as a sputtering method, an ion plating method, or an electron beam evaporation method using each of the raw material metals or ferrites constituting the magnetic thin film component as a multi-dimensional vapor deposition source. By doing so, the second magnetic layer 2 can be formed. The thickness of the second magnetic layer 2 varies depending on the material, but is preferably about 500 Å to 2000 Å.
第２図は、本発明の磁気光学記録媒体の別の実
施態様を示す模式断面図である。この記録媒体
は、第１図に示した磁気光学記録媒体の基板ａと
第１磁性層１との間に反射防止層ｂを、第２の磁
性層２上に保護層３を形成して構成される。反射
防止層ｂは、第１の磁性層表面での反射率が最小
となるような反射防止構造に膜厚を設定した誘電
体からなり磁性層の場合と同様な方法により成膜
できる。この反射防止層ｂはレーザー光が入射し
た時に、第１の磁性層表面からの反射光を減少さ
せることにより、レーザー光を効率良く磁性層に
与える機能を果つ。 FIG. 2 is a schematic cross-sectional view showing another embodiment of the magneto-optic recording medium of the present invention. This recording medium is constructed by forming an antireflection layer b between the substrate a and the first magnetic layer 1 of the magneto-optical recording medium shown in FIG. 1, and forming a protective layer 3 on the second magnetic layer 2. be done. The antireflection layer b is made of a dielectric material whose thickness is set to have an antireflection structure that minimizes the reflectance on the surface of the first magnetic layer, and can be formed by the same method as that for the magnetic layer. This antireflection layer b functions to efficiently apply laser light to the magnetic layer by reducing reflected light from the surface of the first magnetic layer when laser light is incident thereon.
保護層３は、有機高分子膜あるいは酸化物、硫
化物などの無機材料や金属材料からなり、磁性層
の保存安定性を向上させる効果がある。この保護
層３は、材料が有機物ならば、各種の塗工法プラ
ズマ重合法等によつて成膜でき、材料が無機物な
らば、磁性層の場合と同様な方法によつて成膜で
きる。 The protective layer 3 is made of an organic polymer film, an inorganic material such as an oxide or a sulfide, or a metal material, and has the effect of improving the storage stability of the magnetic layer. If the material is organic, this protective layer 3 can be formed by various coating methods such as plasma polymerization, and if the material is inorganic, it can be formed by the same method as for the magnetic layer.
この磁気光学記録媒体の示すように第１の磁性
層１は必ずしも基板ａに直接、接して成膜される
必要はない。 As shown in this magneto-optical recording medium, the first magnetic layer 1 does not necessarily need to be formed in direct contact with the substrate a.
また、第３図の示すように、第２図で示した態
様の磁気光学記録媒体に接着層４を介して保護板
a′を貼り合わせてもよい。 Further, as shown in FIG. 3, a protective plate is attached to the magneto-optical recording medium of the embodiment shown in FIG. 2 via an adhesive layer 4.
You can also paste a' together.
更に、磁気光学記録媒体の両面で記録、再生が
できるように両面に磁性層を設けた構成も可能で
ある。 Furthermore, a configuration in which magnetic layers are provided on both sides of the magneto-optical recording medium is also possible so that recording and reproduction can be performed on both sides of the magneto-optical recording medium.
本発明の磁気光学記録媒体の記録及び再生の機
構を第１図に示した記録媒体に於いて説明する。 The recording and reproducing mechanism of the magneto-optical recording medium of the present invention will be explained using the recording medium shown in FIG.
この記録媒体に、基板ａ側からレーザー光を照
射すると、前述したように第１の磁性層の光吸収
率は、30〜40％程度であるので、このレーザー光
の残りの部分は、第１の磁性層１を通過し、第２
の磁性層２へ達して吸収される。従つて、第２の
磁性層２に於いて、光エネルギーは大部分熱エネ
ルギーに交換され、第２の磁性層の温度が上昇
し、キユリー点に達するとこの第２の磁性層の磁
化が反転する。第１の磁性層１の保磁力は第２の
磁性層２の保磁力より小さいので、この磁化反転
に伴ない第１の磁性層の磁化も反転しビツトが記
録される。このように第２の磁性層２は第１の磁
性層１の磁化反転を容易にすると同時に、第１の
磁性層１の記録ビツトの安定化を可能にする。 When this recording medium is irradiated with a laser beam from the substrate a side, the light absorption rate of the first magnetic layer is about 30 to 40% as described above, so the remaining part of this laser beam is applied to the first magnetic layer. passes through the magnetic layer 1 of the second
reaches the magnetic layer 2 and is absorbed. Therefore, in the second magnetic layer 2, most of the optical energy is exchanged with thermal energy, the temperature of the second magnetic layer increases, and when the Curie point is reached, the magnetization of the second magnetic layer is reversed. do. Since the coercive force of the first magnetic layer 1 is smaller than the coercive force of the second magnetic layer 2, the magnetization of the first magnetic layer is also reversed along with this magnetization reversal, and a bit is recorded. In this way, the second magnetic layer 2 facilitates the magnetization reversal of the first magnetic layer 1 and at the same time makes it possible to stabilize the recorded bits of the first magnetic layer 1.
このようにして記録されたビツトの再生は、基
板ａ側よりこの記録媒体へレーザー光を照射し、
その反射光の偏光角度を検出することにより行
う。 To reproduce the bits recorded in this way, a laser beam is irradiated onto the recording medium from the substrate a side,
This is done by detecting the polarization angle of the reflected light.
照射されたレーザー光は第１の磁性層１で一部
は反射され、一部は透過して第２の磁性層２で反
射される。この２つの反射光の合成されたものが
再生の際に検出される。第１の磁性層１で反射さ
れたレーザー光は、この層１のキー効果を受け、
また第１の磁性層１を透過し第２の磁性層２で反
射されたレーザー光は、第１の磁性層１のフアラ
デー効果と第２の磁性層２のカー効果を受ける。
このそれぞれの反射光が合成されたものが再生の
際に検出されるので、みかけのカー回転角が増加
し、高い再生信号レベルを得ることができる。 A portion of the irradiated laser beam is reflected by the first magnetic layer 1 , and a portion thereof is transmitted and reflected by the second magnetic layer 2 . A combination of these two reflected lights is detected during reproduction. The laser beam reflected by the first magnetic layer 1 receives the key effect of this layer 1,
Further, the laser beam transmitted through the first magnetic layer 1 and reflected by the second magnetic layer 2 is subjected to the Faraday effect of the first magnetic layer 1 and the Kerr effect of the second magnetic layer 2.
Since a combination of these respective reflected lights is detected during reproduction, the apparent Kerr rotation angle increases and a high reproduction signal level can be obtained.
また、第２の磁性層２のキユリー点が低く、再
生光により磁化が反転するおそれがあるときに
は、再生光が第２の磁性層２に達つしないような
構成も可能である。この場合は、第１の磁性層１
にカー回転角の大きい材料を用いて、第１の磁性
層１からの反射光のみの検出で再生を行えばよ
い。 Furthermore, if the second magnetic layer 2 has a low Curie point and there is a risk that the magnetization will be reversed by the reproducing light, a configuration in which the reproducing light does not reach the second magnetic layer 2 is also possible. In this case, the first magnetic layer 1
It is sufficient to use a material with a large Kerr rotation angle and perform reproduction by detecting only the reflected light from the first magnetic layer 1.
このような本発明の磁気光学記録媒体は以下に
述べる実施例から明らかなように、記録の際に印
加するバイアス磁界の影響を受けることなく、安
定した記録ビツトが形成でき、保存安定性も向上
する。 As is clear from the examples described below, the magneto-optical recording medium of the present invention can form stable recorded bits without being affected by the bias magnetic field applied during recording, and has improved storage stability. do.
本発明による磁気光学記録媒体を実施例を挙げ
て更に詳細に説明する。 The magneto-optical recording medium according to the present invention will be explained in more detail by giving examples.
〔実施例 １〕
76×26mm、厚さ１mmのスライドガラス基板上
に、一酸化ケイ素SiOの中にコバルトCoを分散さ
せた第１の磁性層を成膜した。この成膜はプラズ
マ中において、SiOとCoの二元蒸着源からのイオ
ンプレーテイング法によつて実施した。SiOの中
に含まれるCoの体積充填率は、0.60であり、膜厚
は約450Åである。この上に、Tb，Dy，Fe薄膜
を第２の磁性層として成膜した。これは、スパツ
タリング法によつて膜厚約1000Åに作製し、保磁
力は約3KOeであつた。この磁気光学記録媒体に
基板側から波長633nm，出力20mWのHe−Neレ
ーザー光を照射し、厚み方向に垂直に10KOeの
磁界を印加した状態でカー回転角の測定をした結
果、θk≒1.0゜が得られた。[Example 1] A first magnetic layer in which cobalt Co was dispersed in silicon monoxide SiO was formed on a slide glass substrate of 76×26 mm and 1 mm thick. This film formation was carried out in plasma using an ion plating method from a binary vapor deposition source of SiO and Co. The volume filling factor of Co contained in SiO is 0.60, and the film thickness is about 450 Å. On top of this, a thin film of Tb, Dy, and Fe was formed as a second magnetic layer. This was fabricated by sputtering to a thickness of about 1000 Å, and had a coercive force of about 3 KOe. This magneto-optical recording medium was irradiated with a He-Ne laser beam with a wavelength of 633 nm and an output of 20 mW from the substrate side, and the Kerr rotation angle was measured with a magnetic field of 10 KOe applied perpendicular to the thickness direction. As a result, θk≒1.0° was gotten.
〔実施例 ２〕
直径200mm、厚さ1.5mmのデイスク状ガラス基板
の上に、電子ビーム蒸着法を用いて使用するHe
−Neレーザー波長633nmに対して反射防止構造
となる約800Åの膜厚にジルコニア薄膜を形成し
た。次に、その上に実施例１と同様に第１の磁性
層、第２の磁性層を成膜した。更に電子ビーム蒸
着法を用いて膜厚約4000ÅのSiO保護層を成膜し
た後、接着剤を用いてガラス保護板を貼り合わせ
磁気光学記録媒体を作製した。[Example 2] He was deposited using electron beam evaporation on a disk-shaped glass substrate with a diameter of 200 mm and a thickness of 1.5 mm.
A zirconia thin film with a thickness of approximately 800 Å was formed to provide an antireflection structure for -Ne laser wavelength of 633 nm. Next, a first magnetic layer and a second magnetic layer were formed thereon in the same manner as in Example 1. Furthermore, a SiO protective layer with a thickness of approximately 4000 Å was formed using electron beam evaporation, and then a glass protective plate was attached using an adhesive to produce a magneto-optical recording medium.
この磁気光学記録媒体に、基板側からレーザー
光を照射し、記録を行なつた、光源には、出力
20mWのHe−Neレーザーを用い、磁性層の厚さ
方向にバイアス磁界を印加した。このデイスク状
磁気光学記録媒体を1000rpmで回転させながら、
磁性層を一様に磁化し、レーザーをパルス発振し
て周波数2MHzの信号をビツト記録した。このと
き印加したバイアス磁界は、0.5KOeである。こ
れを、出力7mWのHzｅ−Neレーザーを用いて再
生した結果、記録周波数2MHzのとき、約300mV
の再生信号が得られ、良好な信号波形であつた。
また、バイアス磁界を0.4〜0.8KOeの範囲で変化
させて記録を行ない、記録ビツトの顕微鏡観察を
行なつた結果、バイアス磁界の変化に対しても安
定して記録ビツトが存在していることが確認され
た。また、この磁気光学記録媒体を温度45℃、湿
度95％R.Hz．の雰囲気に放置して時間経過によ
る保磁力の変化を測定して保存安定性の試験を行
なつたところ1000時間経過後もほとんど保磁力が
低下せず、従来の磁気光学記録媒体と比較して保
存安定性が優れていることがわかつた。 This magneto-optical recording medium is irradiated with a laser beam from the substrate side to perform recording.The light source has an output
A bias magnetic field was applied in the thickness direction of the magnetic layer using a 20 mW He-Ne laser. While rotating this disk-shaped magneto-optical recording medium at 1000 rpm,
The magnetic layer was uniformly magnetized and a laser was pulsed to record a signal at a frequency of 2MHz in bits. The bias magnetic field applied at this time was 0.5KOe. As a result of reproducing this using a Hze-Ne laser with an output of 7 mW, the result was approximately 300 mV at a recording frequency of 2 MHz.
A reproduced signal with a good signal waveform was obtained.
Furthermore, as a result of performing recording while varying the bias magnetic field in the range of 0.4 to 0.8 KOe and observing the recorded bits under a microscope, it was found that the recorded bits remained stable even with changes in the bias magnetic field. confirmed. In addition, this magneto-optical recording medium was stored at a temperature of 45°C and a humidity of 95% R.Hz. We conducted a storage stability test by leaving the media in an atmosphere of It was found that the storage stability was excellent.
また、第１の磁性層として、Fe，Co，Niの１
種以上あるいはGd，Tb，Dyの１種以上をAlN，
Si3N4，MgF2，BiF3，SiO，SiO2，TiO2，
Ta2O5の１種以上からなる誘電体中に分散させて
構成したものを用い、第２の磁性層として前記の
金属薄膜、フエライト薄膜を用い種々の磁気光学
記録媒体を作製し同様な実験をしたところ、再生
信号レベルが高く、また記録ビツトの安定性はバ
イアス磁界の影響をほとんど受けず、更に保存安
定性が向上することがわかつた。 In addition, as the first magnetic layer, 1 of Fe, Co, and Ni is used.
AlN, or one or more of Gd, Tb, and Dy
Si 3 N 4 , MgF 2 , BiF 3 , SiO, SiO 2 , TiO 2 ,
Similar experiments were carried out by fabricating various magneto-optical recording media using the metal thin film or ferrite thin film described above as the second magnetic layer, using one or more of Ta 2 O 5 dispersed in a dielectric material. As a result, it was found that the reproduced signal level was high, the stability of the recorded bits was hardly affected by the bias magnetic field, and the storage stability was further improved.
以上説明したように、本発明は基板上に第１の
磁性層と第１の磁性層よりも高い保持力を有する
第２の磁性層とを積層して成る磁気光学記録媒体
において、第１の磁性層を、誘電体中に希土類元
素または遷移金属元素のいずれか一方のみを分散
させた薄膜から形成したので、再生信号のレベル
が高く、安定した記録ビツトが形成できる媒体を
得ることができ、且つ、媒体の保存安定性を向上
させる効果を奏するものである。
As explained above, the present invention provides a magneto-optical recording medium in which a first magnetic layer and a second magnetic layer having a higher coercive force than the first magnetic layer are laminated on a substrate. Since the magnetic layer is formed from a thin film in which only either a rare earth element or a transition metal element is dispersed in a dielectric material, it is possible to obtain a medium in which the reproduction signal level is high and stable recorded bits can be formed. Moreover, it has the effect of improving the storage stability of the medium.
第１図、第２図及び第３図は本発明による磁気
光学記録媒体の実施例を示す模式断面図である。
ａ…基板、a′…保護板、ｂ…反射防止層、１…
第１の磁性層、２…第２の磁性層、３…保護層、
４…接着層。
FIGS. 1, 2, and 3 are schematic cross-sectional views showing embodiments of the magneto-optical recording medium according to the present invention. a... Substrate, a'... Protective plate, b... Antireflection layer, 1...
First magnetic layer, 2... Second magnetic layer, 3... Protective layer,
4...Adhesive layer.
Claims (1)
向に磁気異方性を有する第１の磁性層と、該第１
の磁性層に相接して設けられ、第１の磁性層より
も高い保磁力を有し、膜面に垂直方向に磁気異方
性を有する第２の磁性層とから成る磁気光学記録
媒体において、 前記第１の磁性層が、誘電体中に希土類元素ま
たは遷移金属元素のいずれか一方のみを分散させ
た薄膜から成ることを特徴とする磁気光学記録媒
体。[Claims] 1. A substrate, a first magnetic layer provided on the substrate and having magnetic anisotropy in a direction perpendicular to the film surface, and
In a magneto-optical recording medium, the second magnetic layer is provided adjacent to a magnetic layer, has a higher coercive force than the first magnetic layer, and has magnetic anisotropy in a direction perpendicular to the film surface. . A magneto-optical recording medium, wherein the first magnetic layer is made of a thin film in which only either a rare earth element or a transition metal element is dispersed in a dielectric material.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14227884A JPS6122454A (en) | 1984-07-11 | 1984-07-11 | magneto-optical recording medium |
| US07/246,970 US4999260A (en) | 1984-05-31 | 1988-09-21 | Magneto-optical recording medium comprising a rare-earth-transition metal dispersed in a dielectric |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14227884A JPS6122454A (en) | 1984-07-11 | 1984-07-11 | magneto-optical recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6122454A JPS6122454A (en) | 1986-01-31 |
| JPH0350343B2 true JPH0350343B2 (en) | 1991-08-01 |
Family
ID=15311641
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14227884A Granted JPS6122454A (en) | 1984-05-31 | 1984-07-11 | magneto-optical recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6122454A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62219348A (en) * | 1986-03-20 | 1987-09-26 | Fuji Photo Film Co Ltd | Photomagnetic recording medium |
| JPH0614480Y2 (en) * | 1988-04-26 | 1994-04-13 | 信越石英株式会社 | Semiconductor heat treatment equipment |
| JPH0752674Y2 (en) * | 1993-05-19 | 1995-12-06 | 克則 松沢 | Barbecue grill |
| US7371471B2 (en) | 2004-03-08 | 2008-05-13 | Nec Tokin Corporation | Electromagnetic noise suppressing thin film |
-
1984
- 1984-07-11 JP JP14227884A patent/JPS6122454A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6122454A (en) | 1986-01-31 |
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