JP2613885B2 - Magneto-optical multilayer media - Google Patents
Magneto-optical multilayer mediaInfo
- Publication number
- JP2613885B2 JP2613885B2 JP62110518A JP11051887A JP2613885B2 JP 2613885 B2 JP2613885 B2 JP 2613885B2 JP 62110518 A JP62110518 A JP 62110518A JP 11051887 A JP11051887 A JP 11051887A JP 2613885 B2 JP2613885 B2 JP 2613885B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- recording
- magneto
- recording film
- coercive force
- 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
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は光磁気メモリー、磁気記録素子等に用いられ
る垂直磁化膜に係り、特に再生出力を向上するのに好適
な磁気光学効果大の光磁気多層膜媒体に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a perpendicular magnetic film used for a magneto-optical memory, a magnetic recording element, and the like, and particularly to a light having a large magneto-optical effect suitable for improving a reproduction output. The present invention relates to a magnetic multilayer medium.
光磁気記録で高再生出力を得るための記録膜として、
例えば、特開昭57−78652号,特開昭59−168954号,特
開昭60−177455号に記載のように、高い保磁力HCと低い
キユリー温度TCを有する垂直磁化膜と、低い保磁力HCと
高いキユリー温度TCを有する磁性膜を積層した2層膜が
提案され、層間を磁気相互作用により結合させて高いカ
ー回転角θKをもつ垂直磁化膜を得る試みがなされてい
る。As a recording film for obtaining high reproduction output in magneto-optical recording,
For example, JP 57-78652, JP 59-168954, as described in JP-A-60-177455, a perpendicular magnetization film having a high coercive force H C and lower Kiyuri temperature T C, low A two-layer film in which a magnetic film having a coercive force H C and a high Curie temperature T C is laminated has been proposed, and an attempt has been made to obtain a perpendicular magnetization film having a high Kerr rotation angle θ K by coupling the layers by magnetic interaction. I have.
上記従来の2層膜記録媒体では、光磁気記録膜として
好適な2つの膜の膜厚比については配慮がなされておら
ず、そのために従来の例えばTbFeCoの単層膜媒体と比べ
て、記録感度や再生出力等の点で実用的な優位性が得ら
れていない等の問題があつた。In the above-mentioned conventional two-layer film recording medium, no consideration is given to the film thickness ratio of two films suitable as a magneto-optical recording film, and therefore, the recording sensitivity is higher than that of a conventional single-layer film medium of, for example, TbFeCo. And practical advantages in terms of reproduction output and the like have not been obtained.
本発明の目的は、記録感度が高く、高再生出力が得ら
れる光磁気多層膜媒体を提供することにある。SUMMARY OF THE INVENTION It is an object of the present invention to provide a magneto-optical multilayer film medium having a high recording sensitivity and a high reproduction output.
上記目的は、上記の2層膜において、高HC低HTCを有
する第1の膜の膜厚に対する、低HC高TCを有する第2の
膜の膜厚の比、すなわち膜厚比を、0.01以上0.3以下と
し、第2の記録膜を再生光の入射される側に配置し、か
つ、上記の2つの膜のカーヒステリシスの極性を同一に
することにより達成される。The above objects are achieved by a two-layer film of the above, the high H C with respect to the film thickness of the first film having a low HT C, the thickness of the second film having a low H C High T C ratio, i.e. the thickness ratio Is set to 0.01 or more and 0.3 or less, the second recording film is arranged on the side where the reproduction light is incident, and the polarities of the car hysteresis of the two films are made the same.
尚、上記第1の膜の膜特性については、記録感度の観
点から、そのキユリー温度は100℃以上200℃下および/
または補償温度が0℃以上150℃以下とすることが望ま
しく、高密度の微少ビツトを安定に得るという観点か
ら、その保磁力は1kOeより大きいことが望ましい。The film temperature of the first film is from 100 ° C. to 200 ° C. and / or from the viewpoint of recording sensitivity.
Alternatively, the compensation temperature is desirably 0 ° C. or more and 150 ° C. or less, and the coercive force is desirably greater than 1 kOe from the viewpoint of stably obtaining high-density fine bits.
また、上記第2の膜の膜特性については、高温でのθ
Kの劣化を防ぐという観点から、そのキユリー温度は20
0℃以上とすることが望ましく、300℃以上にすればより
好ましい。保磁力については1kOe以下であることが望ま
しい。As for the film characteristics of the second film, θ at high temperature
From the standpoint of preventing K from deteriorating, its Kyrie temperature is 20
The temperature is desirably 0 ° C or higher, and more desirably 300 ° C or higher. The coercive force is desirably 1 kOe or less.
第2図は、上記膜厚比を横軸にとり、上記2層記録膜
のカー回転角θK(図中番号6)および保磁力比H
C(2)/HC(1)の変化(図中番号7)の例を示したも
のである。ここで保磁力比HC(2)/HC(1)は、2層
膜の構成する第1の記録膜部分の保磁力HC(1)に対す
る第2の記録膜部分の保磁力HC(2)の比を表わし、HC
(2)/HC(1)=1は、この2つの記録膜が交換相互
作用で磁気的に結合し、2つの膜が同一の保磁力を有し
ていることを示す。FIG. 2 shows the Kerr rotation angle θ K (No. 6 in the figure) and the coercive force ratio H of the two-layer recording film, with the film thickness ratio on the horizontal axis.
It shows an example of the change (No. 7 in the figure) of C (2) / H C (1). Here coercivity ratio H C (2) / H C (1) , the first coercive force H C of the second recording film portion relative to the coercive force H C (1) of the recording film portion constituting the two-layer film H C represents the ratio of (2)
(2) / H C (1) = 1 indicates that the two recording films are magnetically coupled by the exchange interaction, and the two films have the same coercive force.
第2図から明らかなように、2層膜のカー回転角は、
膜厚比0.01付近から急激に高まり、0.3付近までなだら
かな変化で高い値を示し、それ以上で急激に低下する。
また、膜厚比が0.3以下においてはHC(2)/HC(1)=
1であり、交換相互作用によつて2つの膜が磁気的に結
合していることを示している。As is clear from FIG. 2, the Kerr rotation angle of the two-layer film is
The film thickness ratio sharply increases from around 0.01, shows a high value with a gradual change to around 0.3, and sharply decreases above that.
When the thickness ratio is 0.3 or less, H C (2) / H C (1) =
1, which indicates that the two films are magnetically coupled by the exchange interaction.
また、第3図は、カーヒステリシス極性が異なる2つ
の記録膜を積層した場合(a)およびカーヒステリシス
の極性が同一の2つの記録膜を積層した場合(b)にお
ける、カーヒステリシスを示したものである。(a),
(b)各々について、左欄が第2の記録膜のカーヒステ
リシス、中欄が第1の記録膜のカーヒステリシス、右欄
が2層膜全体のカーヒステリシスであり、2層膜全体と
しては第1の記録膜と第2の記録膜のカーヒステリシス
を合成した形となつている。FIG. 3 shows the car hysteresis when two recording films having different car hysteresis polarities are laminated (a) and when two recording films having the same car hysteresis polarity are laminated (b). It is. (A),
(B) In each case, the left column shows the Kerr hysteresis of the second recording film, the middle column shows the Kerr hysteresis of the first recording film, and the right column shows the Kerr hysteresis of the entire two-layer film. It has a form in which the car hysteresis of the first recording film and the second recording film is synthesized.
第3図から明らかなように、カーヒステリシス極性が
異なる2つの記録膜を積層しても、(a)右欄に示した
ような複雑なカーヒステリシスとなつてしまい、カー回
転角も大きくならない。一方、カーヒステリシス極性が
同一の2つの記録膜を積層すると、(b)右欄に示した
ような角型の大きくカー回転角の大きな2層膜が得られ
る。As is apparent from FIG. 3, even if two recording films having different Kerr hysteresis polarities are stacked, (a) complicated Kerr hysteresis as shown in the right column is obtained, and the Kerr rotation angle does not increase. On the other hand, when two recording films having the same Kerr hysteresis polarity are stacked, (b) a two-layer film having a square shape and a large Kerr rotation angle as shown in the right column is obtained.
尚、第2図および第3図は、第1の記録膜として膜厚
2000ÅのTb22Fe78の膜を用い、第2の記録膜としてGd23
Tb5Fe35Co37の膜を用いたときの例を示したものであ
る。しかしながら、他の希土類−鉄族系非晶質膜やフエ
ライト,ガーネツト等の酸化物系の膜を選んだ場合で
も、カー回転角の絶対値こそ異なるものの、上述の作用
に全く異なることろはない。すなわち膜厚比0.3以下に
てHC(2)/HC(1)=1となり、0.01以上0.3以下にて
高いθKが得られる。第3のカーヒステリシス極性につ
いても、他の膜においても同じことが言える。FIGS. 2 and 3 show the film thickness of the first recording film.
A film of Tb 22 Fe 78 of 2000 Å was used, and Gd 23 was used as a second recording film.
This is an example when a film of Tb 5 Fe 35 Co 37 is used. However, even when other rare earth-iron group amorphous films and oxide films such as ferrite and garnet are selected, the absolute value of the Kerr rotation angle is different, but there is no difference in the above operation. . That is, H C (2) / H C (1) = 1 when the film thickness ratio is 0.3 or less, and a high θ K is obtained when the film thickness ratio is 0.01 or more and 0.3 or less. The same can be said for the third Kerr hysteresis polarity for the other films.
以下、本発明を実施例により説明する。 Hereinafter, the present invention will be described with reference to examples.
第1図は、本発明の2層膜を用いたデイスク媒体の断
面図である。基板3として、直径130mm,溝間距離0.6μ
mの溝付きポリカーボネイトデイスクを用いた。マグネ
トロンスパツタ装置により、Ar圧5×10-3Torr、投入高
周波電力1kWの条件下で、Si3N4膜4(厚さ800Å)、第
2の記録膜としてのGd15Tb3Fe41Co41膜2(厚さ100
Å)、第1の記録膜としてのTb23Fe77膜1(厚さ200
Å)、Si3N4膜5(厚さ1000Å)の順に各膜を形成し
た。作製したデイスクの、基板側から測定したカー回転
角θKは0.8゜、保磁力HCは3kOeであつた。FIG. 1 is a sectional view of a disk medium using a two-layer film of the present invention. The substrate 3 has a diameter of 130 mm and a distance between grooves of 0.6 μm.
An m-grooved polycarbonate disk was used. Using a magnetron sputter device, under an Ar pressure of 5 × 10 −3 Torr and an applied high-frequency power of 1 kW, a Si 3 N 4 film 4 (thickness 800 mm) and a Gd 15 Tb 3 Fe 41 Co as a second recording film 41 film 2 (thickness 100
Å), Tb 23 Fe 77 film 1 as a first recording film (thickness 200
Ii), and each film was formed in the order of Si 3 N 4 film 5 (thickness: 1000 Å). Of the produced disc, the Kerr rotation angle theta K is 0.8 ° as measured from the substrate side, the coercivity H C was found to be 3 kOe.
記録,再生動特性評価は半導体レーザ光を用いて、書
き込みレーザ光パワー7mW,読み出しレーザ光パワー3mW,
記録時の外部磁場300Oe、デイスク回転数2400rpmの条件
下で行なつた。この時の再生出力の搬送波対雑音比C/N
は、測定周波数1.77Hz,バンド幅Δf=30k Hz,ビツトピ
ツチ1μmにおいて60dBと高再生出力を得た。Recording and reproduction dynamic characteristics were evaluated using a semiconductor laser beam, with a writing laser beam power of 7 mW, a reading laser beam power of 3 mW,
The recording was performed under the conditions of an external magnetic field of 300 Oe and a disk rotation speed of 2400 rpm. Carrier-to-noise ratio C / N of the reproduced output at this time
In the measurement, a high reproduction output of 60 dB was obtained at a measurement frequency of 1.77 Hz, a bandwidth Δf = 30 kHz, and a bit pitch of 1 μm.
尚、本実施例では、記録膜としてGdTbFeCo/TbFeなる
希土類−鉄族系非晶質膜だけを用いたが、例えば、PtMn
Sb/TbFeではθK=1゜の垂直磁化膜が、またGdFeCo/Co
−フエライトあるいはBu−フエライトあるいはガーネツ
ト膜ではθK=0.7゜の垂直磁化膜が得られ、再生出力
でも60dB以上の高再生出力が得られた。In the present embodiment, only the rare earth-iron group amorphous film of GdTbFeCo / TbFe was used as the recording film.
In Sb / TbFe, a perpendicular magnetization film with θ K = 1 ゜ is used, and GdFeCo / Co
In the case of -ferrite, Bu-ferrite or garnet film, a perpendicular magnetization film having θ K = 0.7 ° was obtained, and a high reproduction output of 60 dB or more was obtained in the reproduction output.
本発明によれば、従来の記録膜を2層化した多層膜記
録媒体に比べて、記録感度が高く、高再生出力の得られ
る多層膜記録膜体を得ることができる。According to the present invention, it is possible to obtain a multilayer recording medium having a higher recording sensitivity and a higher reproduction output than a conventional multilayer recording medium having two recording layers.
【図面の簡単な説明】 第1図は本発明の一実施例におけるデイスク媒体の断面
図、第2図は膜厚比に対するカー回転角θKと保磁力比
HC(2)/HC(1)の変化例を示す図、第3図は2層記
録膜全体およびそれを構成する2つの膜各々のカーヒス
テリシスにつき、カーヒステリシス極性が異なる場合
(a)と同一の場合(b)を示した図である。 1……第1の記録膜、2……第2の記録膜、3……ポリ
カーボネイト基板、4,5……Si3N4膜、6……膜厚比に対
するθKの変化、7……膜厚比に対する保磁力比H
C(2)/HC(1)の変化。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a disk medium in one embodiment of the present invention, and FIG. 2 is a Kerr rotation angle θ K and a coercive force ratio with respect to a film thickness ratio.
FIG. 3 shows an example of a change in H C (2) / H C (1), and FIG. 3 shows a case where the car hysteresis polarity is different for the entire two-layer recording film and the car hysteresis of each of the two films constituting the recording film. It is the figure which showed the case (b) which is the same as. 1 ...... first recording film, 2 ...... second recording layer, 3 ...... polycarbonate substrate, 4, 5 ...... Si 3 N 4 film, a change in theta K for 6 ...... thickness ratio, 7 ...... Coercive force ratio H to film thickness ratio
Change in C (2) / H C (1).
Claims (4)
1の記録膜と、高いキユリー温度と低い保磁力を有する
第2の記録膜とを少なくとも有し、該第2の記録膜を再
生光の入射する側に配置し、上記第1の記録膜の膜厚に
対する上記第2の記録膜の膜厚の比が0.01以上0.3以下
であり、上記第1と第2の記録膜のカーヒステリシスの
極性が同一であることを特徴とする光磁気多層膜媒体。1. A recording medium having at least a first recording film having a low Curie temperature and a high coercive force and a second recording film having a high Curie temperature and a low coercive force. Where the ratio of the thickness of the second recording film to the thickness of the first recording film is 0.01 or more and 0.3 or less, and the Kerr hysteresis of the first and second recording films is A magneto-optical multilayer film medium having the same polarity.
りも大きなカー回転角を有することを特徴とする特許請
求の範囲第1項記載の光磁気多層膜媒体。2. The magneto-optical multi-layered medium according to claim 1, wherein said second recording film has a Kerr rotation angle larger than that of said first recording film.
以上200℃以下および/または補償温度が0℃以上150℃
以下であり、その保磁力が1kOeより大きいことを特徴と
する特許請求の範囲第1項または第2項記載の光磁気多
層膜媒体。3. The method according to claim 1, wherein the first recording film has a Curie temperature of 100 ° C.
Not less than 200 ° C and / or compensation temperature is 0 ° C or more and 150 ° C
3. A magneto-optical multi-layered medium according to claim 1, wherein the coercive force is larger than 1 kOe.
以上であり、その保磁力が1kOe以下であることを特徴と
する特許請求の範囲第1項、第2項または第3項記載の
光磁気多層膜媒体。4. The method according to claim 1, wherein the second recording film has a Curie temperature of 200 ° C.
4. The magneto-optical multilayer medium according to claim 1, wherein the coercive force is 1 kOe or less.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP62110518A JP2613885B2 (en) | 1987-05-08 | 1987-05-08 | Magneto-optical multilayer media |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP62110518A JP2613885B2 (en) | 1987-05-08 | 1987-05-08 | Magneto-optical multilayer media |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS63276729A JPS63276729A (en) | 1988-11-15 |
JP2613885B2 true JP2613885B2 (en) | 1997-05-28 |
Family
ID=14537826
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP62110518A Expired - Lifetime JP2613885B2 (en) | 1987-05-08 | 1987-05-08 | Magneto-optical multilayer media |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2613885B2 (en) |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63237237A (en) * | 1987-03-26 | 1988-10-03 | Canon Inc | Magneto-optical recording medium and recording method |
-
1987
- 1987-05-08 JP JP62110518A patent/JP2613885B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JPS63276729A (en) | 1988-11-15 |
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