JPS59168954A - Optical magnetic recording medium - Google Patents
Optical magnetic recording mediumInfo
- Publication number
- JPS59168954A JPS59168954A JP4537483A JP4537483A JPS59168954A JP S59168954 A JPS59168954 A JP S59168954A JP 4537483 A JP4537483 A JP 4537483A JP 4537483 A JP4537483 A JP 4537483A JP S59168954 A JPS59168954 A JP S59168954A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- magnetic
- low
- amorphous
- alloy
- 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
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】
（イ〉 産業上の利用分野
本発明は、レーザ光に依って情報の記録再生が行われる
アモルファス磁性薄膜から成る光磁気記録媒体に関する
。DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Application Field The present invention relates to a magneto-optical recording medium comprising an amorphous magnetic thin film on which information is recorded and reproduced using laser light.
（ロ） 従来技術
直線偏光が磁性体表面で反射したり、磁性体を透過する
際に偏光面が回転する現象を利用して、光による磁気記
録情報の読み出しの応用が試みられている。このような
光磁気記録媒体としては情報記録の高密度化、また磁気
カー効果を利用して記録情報の読み出しを行う場合、磁
気カー効果が大きくなること等から磁性体膜面に垂直な
方向に磁化容易軸を有した垂直磁化膜を備えた光磁気記
録媒体が一般に用いられている。この光磁気記録媒体へ
の情報の書込みは、通常磁気記録層をあらかじめ同一方
向に一様に垂直磁化し、この磁気記録媒体をキュリ一点
又は補償点までレーザ光等によって加熱し、前記磁化方
向と逆方向の小さな磁場を印加して、レーザ光等による
加熱領域の磁化を反転させるという方法が用いられる。(b) Prior Art Attempts have been made to utilize the phenomenon of linearly polarized light reflecting on the surface of a magnetic material or rotating the plane of polarization when transmitted through a magnetic material to read magnetically recorded information using light. For such magneto-optical recording media, it is necessary to increase the density of information recording, and when reading recorded information using the magnetic Kerr effect, the magnetic Kerr effect becomes large. Magneto-optical recording media equipped with a perpendicularly magnetized film having an easy axis of magnetization are commonly used. In order to write information to this magneto-optical recording medium, the magnetic recording layer is normally perpendicularly magnetized in the same direction in advance, and the magnetic recording medium is heated with a laser beam or the like to the Curie point or compensation point, so that the magnetic recording layer is uniformly perpendicularly magnetized in the same direction. A method is used in which a small magnetic field in the opposite direction is applied to reverse the magnetization of a region heated by laser light or the like.
記録情報の読み出しは前述の偏光回転の原理を利用し、
磁性薄膜からの戻り光の偏光の回転角を検出することに
よって行う。このような磁気記録媒体としては高保磁力
で垂直磁気異方性を有するＭｎ−ＢｉｘＧｄ −Ｆｅ、
Ｔｂ −Ｆｅ等の希土類−遷移金属系のアモルファス
合金の磁性薄膜が用いられる。磁気記録媒体の中で、Ｍ
ｎ−Ｂ１合金や、Ｇｄ−Ｆｅ合金等の磁気記録媒体はカ
ー回転角が大きく再生時のＳ／Ｎが大であるが、キュリ
一点が高く、情報書込みに要するエネルギーが大という
欠点があり、一方、Ｔｂ−Ｆｅ合金やＤｙ−Ｆｅ合金等
はキュリ一点がＭｎ−Ｂ１合金やＧｄ−Ｆｅ合金より低
く、情報書込みに要するエネルギーが小であるが、カー
回転角が小ｔ ＜ Ｓ／Ｎが小さいという互いに相反す
る長所と短所を有している。また、一般にカー回転角は
非常に小さいもので、大きなものでもたかだか１″′程
度のものであり、記録情報再生にあたってはカー回転角
を大きくすることが大きな問題点となっている。Reading out recorded information uses the principle of polarization rotation mentioned above.
This is done by detecting the rotation angle of the polarization of the returned light from the magnetic thin film. Such magnetic recording media include Mn-BixGd-Fe, which has high coercive force and perpendicular magnetic anisotropy;
A magnetic thin film of an amorphous rare earth-transition metal alloy such as Tb-Fe is used. Among magnetic recording media, M
Magnetic recording media such as n-B1 alloy and Gd-Fe alloy have a large Kerr rotation angle and a high S/N ratio during reproduction, but have the disadvantage of a high Curie point and a large amount of energy required to write information. On the other hand, the Curie point of Tb-Fe alloys and Dy-Fe alloys is lower than that of Mn-B1 alloys and Gd-Fe alloys, and the energy required to write information is small, but the Kerr rotation angle is small and t < S/N. It has contradictory advantages and disadvantages, such as being small. Further, the Kerr rotation angle is generally very small, at most about 1'', and increasing the Kerr rotation angle is a major problem when reproducing recorded information.
（ハ〉 発明の目的
本発明は以上の点を改善し、低エネルギーで情報書込み
ができ、再生時のカー回転角を大きくしてＳ／Ｎの大き
な光磁気記録媒体を提供する事を目的としている。(C) Purpose of the Invention The present invention aims to improve the above-mentioned points, and to provide a magneto-optical recording medium that can write information with low energy, has a large Kerr rotation angle during reproduction, and has a high S/N ratio. There is.
（ニ）発明の構成
本発明は、低保持力で磁気光学効果の大きな垂直磁気異
方性を有するアモルファス磁性薄膜と、高保持力でキュ
リ一点の低い垂直磁気異方性を有するアモルファス磁性
薄膜と、の積層体から成る。(D) Structure of the Invention The present invention provides an amorphous magnetic thin film having low coercive force and perpendicular magnetic anisotropy with a large magneto-optic effect, and an amorphous magnetic thin film having high coercive force and perpendicular magnetic anisotropy as low as a Curie point. It consists of a laminate of .
（ホ）実施例
第１図は本発明光磁気記録媒体を模型的に示した断面図
であって、（１）はガラス等の非磁性体の基板、（２）
は該基板（１）上に蒸着或いはスバタリング法等に依っ
て形成された第１のアモルファス磁性薄膜で、低保磁力
で磁気光学効果は大きいがキュリ一点が高い垂直磁気異
方性を有するＧｄ−Ｆｅ合金、Ｍｎ−Ｂ１合金等から成
り、その厚みは１０００人程度である。り３）はこの第
１のアモルファス磁性薄膜＜２〉上に蒸着或いはスパタ
リング法等に依って形成された第２のアモルファス磁性
薄膜３−
で、高保持力でキュリ一点は低いが磁気光学効果が低い
垂直磁気異方性を有するＴｂ−Ｆｅ合金、Ｄｙ−Ｆｅ合
金等から成り、その厚みは５００人程度である。（４）
はこの第２のアモルファス磁性薄膜（３）表面に設けら
れた酸化シリコン膜等の保護膜である。斯る構成の記録
媒体（５）に情報を書き込む際の構成を第２図に示す。(E) Example FIG. 1 is a cross-sectional view schematically showing a magneto-optical recording medium of the present invention, in which (1) is a substrate made of a non-magnetic material such as glass, (2)
is the first amorphous magnetic thin film formed on the substrate (1) by vapor deposition or sputtering method, and is made of Gd-, which has a low coercive force, a large magneto-optic effect, and a perpendicular magnetic anisotropy with a high Curie point. It is made of Fe alloy, Mn-B1 alloy, etc., and its thickness is about 1000. 3) is a second amorphous magnetic thin film 3- formed on the first amorphous magnetic thin film <2> by vapor deposition or sputtering, and has a high coercive force and a low Curie point, but a magneto-optic effect. It is made of Tb-Fe alloy, Dy-Fe alloy, etc., which have low perpendicular magnetic anisotropy, and its thickness is about 500 mm. (4)
is a protective film such as a silicon oxide film provided on the surface of this second amorphous magnetic thin film (3). FIG. 2 shows a configuration for writing information to a recording medium (5) having such a configuration.
記録媒体（５）を所定の磁場（６）に置くと共に情報書
き込みエリアにレーザ光（７）を照射する。その結果、
レーザ光（７）の照射を受けた箇所が温度上昇し、キュ
リ一点が低い第２のアモルファス磁性薄膜（３）の保磁
力が低下して外部磁場（６）に依って磁化方向が反転（
８）する。この第２のアモルファス磁性薄膜（３）は高
保磁力である為に書き込まれた情報は安定に保持きれ、
そして磁化方向が反転したエリア（８）の真下に位置す
る第１のアモルファス磁性薄膜（２）の磁区がその反転
エリア（８）の磁界に依って反転し、情報が記録（９）
される（第３図）。この書き込み時に要するエネルギー
はレーザ光（７）が照射される第２のアモルファス磁性
薄膜（３）が低キュリ一点４−
を有しているので小さくて済み、また保磁力の小きなＧ
ｄ−Ｆｅ合金薄膜等では問題となる書き込み１＼Ａ
ビットの不安定性も二層構造を採る事に依り解消され、
書き込まれた情報は安定に保持される。このようにして
書き込まれた情報を読み出す際の構成を第４図に示す。The recording medium (5) is placed in a predetermined magnetic field (6) and the information writing area is irradiated with a laser beam (7). the result,
The temperature of the area irradiated with the laser beam (7) increases, the coercive force of the second amorphous magnetic thin film (3) with a low Curie point decreases, and the magnetization direction is reversed (by the external magnetic field (6)).
8) Do. This second amorphous magnetic thin film (3) has a high coercive force, so written information can be stably retained.
Then, the magnetic domain of the first amorphous magnetic thin film (2) located directly below the area (8) where the magnetization direction has been reversed is reversed by the magnetic field of the reversed area (8), and information is recorded (9).
(Figure 3). The energy required for this writing is small because the second amorphous magnetic thin film (3) to which the laser beam (7) is irradiated has a low Curie point 4-.
The instability of the writing 1\A bit, which is a problem with d-Fe alloy thin films, is also resolved by adopting a two-layer structure.
The written information is stably retained. FIG. 4 shows a configuration for reading information written in this manner.
（１０）は読み出しレーザ光源９、・ □
で、書き込み時に使用したレーザ光（７）よりは弱い光
を出す。該レーザ光源（１０）からのレーザ光は偏光子
（１１）にて直線偏光ときれ、ハーフミラ−（１２）及
びレンズ（１３）を介して記録媒体（５）に到達する。(10) is a reading laser light source 9, □, which emits light weaker than the laser light (7) used for writing. The laser light from the laser light source (10) is split into linearly polarized light by a polarizer (11), and reaches the recording medium (5) via a half mirror (12) and a lens (13).
記録媒体（５）に達した直線偏光は第２のアモルファス
磁性薄膜（３）の表面にて反射する光と透過する光とに
分れる。反射光はカー効果に依って偏光面が回転し、透
過光も一般、にカー効果に依る偏光面の回転より回転角
の大きいファラデー効果に依り偏光面が回転する。一方
、透過光は更に、磁気光学効果の大きい第１のアモルフ
ァス磁性薄膜（２〉表面で反射する際のカー効果、戻り
光の磁性薄膜透過に依るファラデー効果に依り、回転角
は増し、みかけ上、回転角は増加する事となる。磁性薄
膜はその組成を選択することに依ってカー回転角の回転
方向を選ぶことができるので作成時に磁性薄膜の組成を
適当に選べば、回転角が増加する方向に持っていくこと
ができる。透過光も利用するため第２のアモルファス磁
性薄膜（３〉の厚みを垂直磁化となる範囲で薄くし、透
過を大きくすることが必要である。このように該磁性薄
膜（３）の反射光と、透過による戻り光のたしあわせで
みかけ上の偏光回転量は大きくなり、磁気記録媒体（５
〉からのかえり光を検光子（１４）を介して偏光面の回
転量の変化を検出し、その検出量を光電変換素子（１５
）により電気信号に変換し、記録情報を再生することが
できる。みかけ上の偏光面の回転量が大きいため電気信
号の変化も大きいものとなる。The linearly polarized light that has reached the recording medium (5) is divided into light that is reflected on the surface of the second amorphous magnetic thin film (3) and light that is transmitted. The plane of polarization of reflected light is rotated by the Kerr effect, and the plane of polarization of transmitted light is generally rotated by the Faraday effect, which has a larger rotation angle than the rotation of the plane of polarization by the Kerr effect. On the other hand, the transmitted light further increases the rotation angle due to the Kerr effect when reflected on the surface of the first amorphous magnetic thin film (2), which has a large magneto-optic effect, and the Faraday effect due to the return light passing through the magnetic thin film, increasing the apparent angle of rotation. , the rotation angle will increase.The rotation direction of the Kerr rotation angle can be selected by selecting the composition of the magnetic thin film, so if the composition of the magnetic thin film is appropriately selected at the time of creation, the rotation angle will increase. In order to utilize transmitted light, it is necessary to reduce the thickness of the second amorphous magnetic thin film (3) to the extent that it has perpendicular magnetization and increase its transmission.In this way, The apparent amount of polarization rotation increases due to the combination of the reflected light from the magnetic thin film (3) and the returned light due to transmission, and the magnetic recording medium (5)
The return light from the
), it is possible to convert the recorded information into an electrical signal and reproduce the recorded information. Since the amount of rotation of the apparent plane of polarization is large, the change in the electrical signal is also large.
（へ） 発明の効果
以上のように、本発明は、低保磁力で磁気光学効果の大
きい垂直磁性薄膜の上に高保磁力でキュリ一点の低い垂
直磁性薄膜を形成した二層膜構造にし、キュリ一点の低
い磁性薄膜側からレーザ光７−
にて情報を書き込むことにより、低エネルギーで情報を
書き込むことができ、かつ、記録情報（書込みビット）
の安定性が高く、また°、再生においては偏光の回転量
が大きく、大きな信号変化量が得られる。(f) Effects of the Invention As described above, the present invention has a two-layer film structure in which a perpendicular magnetic thin film with a high coercive force and a low Curi point is formed on a perpendicular magnetic thin film with a low coercive force and a large magneto-optical effect, and By writing information with a laser beam 7- from one point on the low magnetic thin film side, information can be written with low energy, and the recorded information (written bit)
The stability is high, and the amount of rotation of polarization is large during reproduction, resulting in a large amount of signal change.
第１図は本発明磁気記録媒体を模型的に示した断面図、
第２図は情報書込みの際の原理を説明する概念図、第３
図は情報が記録された状態を示す断面図、第４図は記録
情報の読み出しの際の構成を示す構成図であって、（２
）（３）は第１、第２のアモルファス磁性薄膜、（５）
は磁気記録媒体、（６）は磁場、（７）はレーザ光、を
夫々示している。
出願人 三洋電機株式会社
代理人 弁理士 佐野静夫
８−FIG. 1 is a cross-sectional view schematically showing the magnetic recording medium of the present invention;
Figure 2 is a conceptual diagram explaining the principle of writing information, Figure 3
The figure is a sectional view showing the state in which information is recorded, and FIG. 4 is a configuration diagram showing the configuration when reading the recorded information.
) (3) are the first and second amorphous magnetic thin films, (5)
(6) represents a magnetic recording medium, (6) represents a magnetic field, and (7) represents a laser beam. Applicant Sanyo Electric Co., Ltd. Agent Patent Attorney Shizuo Sano 8-
Claims (1)
効果の大きな垂直磁気異方性を有する第１のアモルファ
ス磁性薄膜と、該薄膜上に形成した高保磁力でキュリ一
点の低い垂直磁気異方性を有する第２のアモルファス磁
性薄膜と、から成り、情報の記録に際しては、所定の磁
場を掛けた状態で第２のアモルファス磁性薄膜側からレ
ーザ光を照射してこの第２のアモルファス磁性薄膜に情
報を磁気的に記録せしめる事に依ってその硼区の磁場に
依る磁気転写により第２のアモルファス磁性薄膜に情報
が転写記録され、一方、その記録情報の読み出しは記録
時と同方向から偏光を照射し、上記両磁性薄膜の戻り光
の反射と透過に依る偏光面の回転量の変化に基づいて行
われる事を特徴とした光磁気記録媒体。l) A first amorphous magnetic thin film having perpendicular magnetic anisotropy with a low coercive force and a large magneto-optic effect formed on the surface of a non-magnetic substrate, and a perpendicular magnetic film with a high coercive force and a low Curie point formed on the thin film. and a second amorphous magnetic thin film having anisotropy. When recording information, a laser beam is irradiated from the second amorphous magnetic thin film side with a predetermined magnetic field applied to the second amorphous magnetic thin film. By magnetically recording information on the thin film, the information is transferred and recorded on the second amorphous magnetic thin film by magnetic transfer caused by the magnetic field in the area, and on the other hand, the recorded information is read out from the same direction as when recording. A magneto-optical recording medium characterized in that polarized light is irradiated and the rotation is performed based on changes in the amount of rotation of the plane of polarization due to reflection and transmission of the returned light by the bimagnetic thin film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58045374A JPH0614416B2 (en) | 1983-03-17 | 1983-03-17 | Magneto-optical recording / reproducing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58045374A JPH0614416B2 (en) | 1983-03-17 | 1983-03-17 | Magneto-optical recording / reproducing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59168954A true JPS59168954A (en) | 1984-09-22 |
| JPH0614416B2 JPH0614416B2 (en) | 1994-02-23 |
Family
ID=12717488
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58045374A Expired - Lifetime JPH0614416B2 (en) | 1983-03-17 | 1983-03-17 | Magneto-optical recording / reproducing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0614416B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2588406A1 (en) * | 1985-10-04 | 1987-04-10 | Thomson Csf | THERMOMAGNETIC RECORDING HEAD AND METHOD OF MAKING |
| JPS6314342A (en) * | 1986-07-05 | 1988-01-21 | Canon Inc | Magneto-optical recording medium |
| US5626965A (en) * | 1993-04-27 | 1997-05-06 | Nikon Corporation | Magnetooptical recording medium |
| JP2002184340A (en) * | 2000-09-29 | 2002-06-28 | Schlumberger Technol Inc | Small size high efficiency scintillation detector for secondary electron detection |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5424008A (en) * | 1977-07-26 | 1979-02-23 | Fujitsu Ltd | Magnetic recording and photo reproducing system |
| JPS57189362A (en) * | 1981-05-13 | 1982-11-20 | Nippon Columbia Co Ltd | Magnetic recording and reproducing device |
| JPS58153244A (en) * | 1982-03-05 | 1983-09-12 | Matsushita Electric Ind Co Ltd | Photomagnetic recording medium |
-
1983
- 1983-03-17 JP JP58045374A patent/JPH0614416B2/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5424008A (en) * | 1977-07-26 | 1979-02-23 | Fujitsu Ltd | Magnetic recording and photo reproducing system |
| JPS57189362A (en) * | 1981-05-13 | 1982-11-20 | Nippon Columbia Co Ltd | Magnetic recording and reproducing device |
| JPS58153244A (en) * | 1982-03-05 | 1983-09-12 | Matsushita Electric Ind Co Ltd | Photomagnetic recording medium |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2588406A1 (en) * | 1985-10-04 | 1987-04-10 | Thomson Csf | THERMOMAGNETIC RECORDING HEAD AND METHOD OF MAKING |
| US4949198A (en) * | 1985-10-04 | 1990-08-14 | Thomson-Csf | Thermomagnetic recording head and mode of embodiment |
| JPS6314342A (en) * | 1986-07-05 | 1988-01-21 | Canon Inc | Magneto-optical recording medium |
| US5626965A (en) * | 1993-04-27 | 1997-05-06 | Nikon Corporation | Magnetooptical recording medium |
| JP2002184340A (en) * | 2000-09-29 | 2002-06-28 | Schlumberger Technol Inc | Small size high efficiency scintillation detector for secondary electron detection |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0614416B2 (en) | 1994-02-23 |
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