JP2849431B2 - Magneto-optical recording medium - Google Patents
Magneto-optical recording mediumInfo
- Publication number
- JP2849431B2 JP2849431B2 JP2344590A JP2344590A JP2849431B2 JP 2849431 B2 JP2849431 B2 JP 2849431B2 JP 2344590 A JP2344590 A JP 2344590A JP 2344590 A JP2344590 A JP 2344590A JP 2849431 B2 JP2849431 B2 JP 2849431B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- magneto
- recording medium
- optical recording
- thickness
- 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 - Fee Related
Links
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は光磁気記録媒体に関する ［従来の技術］ 情報の消去および書き換えが可能な光磁気記録媒体
は、一般には、透明基板の上に保護膜、垂直磁気異方性
を有する磁性膜および保護膜をこの順に積層した構造を
有するか、または上記の上層の保護膜上にさらに反射膜
を積層した構造を有している。上記の磁性膜を形成する
材料としては、希土類元素と遷移金属とのアモルフアス
合金が好ましく、例えばTbFeCo、NdCyFeCo、GdTbFeなど
の合金が用いられている。上記の構造を備えた光磁気記
録媒体はカー回転角が１度程度であり、磁気光学効果が
小さいという問題点を有する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording medium. 2. Description of the Related Art A magneto-optical recording medium capable of erasing and rewriting information is generally protected on a transparent substrate. It has a structure in which a film, a magnetic film having perpendicular magnetic anisotropy and a protective film are laminated in this order, or has a structure in which a reflective film is further laminated on the above-mentioned upper protective film. As a material for forming the magnetic film, an amorphous alloy of a rare earth element and a transition metal is preferable. For example, an alloy such as TbFeCo, NdCyFeCo, and GdTbFe is used. The magneto-optical recording medium having the above structure has a problem that the Kerr rotation angle is about 1 degree and the magneto-optical effect is small.
上記の問題点を解決するために、Coからなる膜とPdお
よび／またはPtからなる膜とが１〜200Åの範囲の膜厚
で交互に多数積層されてなり、垂直磁気異方性を有する
組成変調膜を備えた光磁気記録媒体が開発されている
［例えば、特開平１−162257号公報、特開平１−169757
号公報およびアプライト・フイジクス・レターズ（Appl
ied Physics Letters）、第54巻、第24号、第2481頁（1
989年）参照。］ ［発明が解決しようとする課題］ 透明基板上にCoからなる膜とPdおよび／またはPtから
なる膜とが交互に多数積層されてなる組成変調膜を備え
た光磁気記録媒体は大きなカー回転角を有しているが、
保磁力が5000e程度と小さいことから、記録された情報
の安定性が低いという問題点を有している。保磁力を大
きくするためには、基板上に200〜500Å程度の膜厚を有
するPt、PdまたはAuからなる下地膜と上記の組成変調膜
とを積層することによって、該組成変調膜の結晶性を高
めればよいことが知られている（第13回日本応用磁気学
会学術講演会概要集、第56頁（1989年）参照）。上記の
下地膜は高い反射率を有していることから、基板側から
入射した光は下地膜で反射されてしまうので、情報を記
録、再生または消去するためには組成変調膜側から光を
照射しなければならない。上記の場合、組成変調膜上に
付着した塵粒子などの影響で記録エラー、再生エラーま
たは消去エラーが発生し易く、これらのエラーの発生を
防ぐためには、上記の組成変調膜上に誘電体などからな
り、100μｍ程度の膜厚を有する透明保護膜を積層する
必要がある。In order to solve the above-mentioned problems, a composition having a perpendicular magnetic anisotropy in which a large number of films made of Co and a film made of Pd and / or Pt are alternately stacked in a thickness of 1 to 200 °. A magneto-optical recording medium having a modulation film has been developed [for example, Japanese Patent Application Laid-Open Nos. 1-162257 and 1-1695757].
Bulletin and Upright Physics Letters (Appl
ied Physics Letters), Vol. 54, No. 24, page 2481 (1
989). [Problems to be Solved by the Invention] A magneto-optical recording medium provided with a composition modulation film in which a number of films composed of Co and a film composed of Pd and / or Pt are alternately stacked on a transparent substrate has a large Kerr rotation. Has horns,
Since the coercive force is as small as about 5000 e, there is a problem that the stability of recorded information is low. In order to increase the coercive force, by laminating a base film made of Pt, Pd or Au having a thickness of about 200 to 500 ° on the substrate and the above-mentioned composition modulation film, the crystallinity of the composition modulation film is increased. It is known that it is necessary to increase the value (see the 13th Annual Meeting of the Japan Society of Applied Magnetism, p. 56 (1989)). Since the above base film has a high reflectance, light incident from the substrate side is reflected by the base film. Therefore, in order to record, reproduce or erase information, light is applied from the composition modulation film side. Must be irradiated. In the above case, a recording error, a reproduction error, or an erasing error is likely to occur due to the influence of dust particles or the like attached to the composition modulation film, and in order to prevent the occurrence of these errors, a dielectric such as a dielectric material is formed on the composition modulation film. It is necessary to laminate a transparent protective film having a thickness of about 100 μm.
本発明の目的は、大きな保磁力とカー回転角とを有
し、かつ記録された情報が高い安定性を有する光磁気記
録媒体を提供することにある。An object of the present invention is to provide a magneto-optical recording medium having a large coercive force and a Kerr rotation angle and having high stability in recorded information.
［課題を解決するための手段］ 本発明によれば、上記の目的は、１〜30Åの範囲の膜
厚を有するCoからなる膜と１〜100Åの範囲の膜厚を有
するPdおよび／またはPtからなる膜とが交互に積層され
てなる組成変調膜が透明基板上に形成されてなり、該Pd
および／またはPtからなる膜が少なくとも２層存在し、
かつそれらの膜厚が透明基板側から膜厚方向に徐々に小
さくなっていることを特徴とする光磁気記録媒体を提供
することによって達成される。[Means for Solving the Problems] According to the present invention, the object is to provide a film made of Co having a thickness in the range of 1 to 30 ° and a Pd and / or Pt having a film thickness in the range of 1 to 100 °. A composition modulation film formed by alternately laminating a film composed of Pd is formed on a transparent substrate, and the Pd
And / or at least two layers of Pt are present,
In addition, this is attained by providing a magneto-optical recording medium characterized in that their film thickness gradually decreases in the film thickness direction from the transparent substrate side.
［実施例］ 以下、実施例により本発明を具体的に説明する。EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples.
実施例１ 本発明の光磁気記録媒体の一例の概略断面図を第１図
に示す。第１図に示す光磁気記録媒体は透明基板１上に
Co膜とPd膜、Co膜とPt膜またはCo膜とPdPt合金膜とが交
互に積層されてなる組成変調膜２が形成されてなり、上
記の透明基板１側から情報を記録、再生または消去する
ために光が照射される。組成変調膜２を形成するCo膜3
a、3b・・・・・3y、3zの膜厚は１〜30Åの範囲であ
る。少なくとも２層存在し、組成変調膜２を形成するPd
膜、Pt膜およびPdPt合金膜よりなる群から選択される膜
4a、4b・・・・・4y、4zの膜厚は１〜100Åの範囲であ
り、該膜厚は透明基板１側から膜厚方向に徐々に小さく
なっている。Co膜3a、3b、・・・・・3y、3zの膜厚が２
〜９Åの範囲であり、かつ透明基板１に最も近いPd膜、
Pt膜およびPdPt合金膜4aの範囲が25〜80Åの範囲であ
り、透明基板１から最も遠いPd膜、Pt膜およびPdPt合金
膜4zの膜厚が１〜20Åの範囲であることが高い磁気光学
効果が得られる点から好ましい。また組成変調膜２の厚
さは40〜1000Åの範囲であることが好ましい。高い記録
感度が得られ、かつ角形の磁気カー曲線が得られること
から、該厚さは50〜300Åの範囲であることがより好ま
しい。組成変調膜は、各金属膜の界面で異種の金属原子
が混在する領域のない超格子構造を有していてもよく、
異種の金属原子が入り乱れ、界面で異種の金属原子が混
在する領域を有し、かつ組成が周期的に変わる変調構造
を有していてもよい。組成変調膜にAl、Si、Ti、Crなど
の元素を３原子％以下添加することが組成変調曲が有す
るキユリー温度を下げることができる点で好適である。Embodiment 1 FIG. 1 shows a schematic sectional view of an example of the magneto-optical recording medium of the present invention. The magneto-optical recording medium shown in FIG.
A composition modulation film 2 is formed by alternately laminating a Co film and a Pd film, a Co film and a Pt film, or a Co film and a PdPt alloy film, and records, reproduces or erases information from the transparent substrate 1 side. To irradiate light. Co film 3 forming composition modulation film 2
.., 3y and 3z have a thickness in the range of 1 to 30 °. Pd that forms at least two layers and forms the composition modulation film 2
Film selected from the group consisting of a film, a Pt film and a PdPt alloy film
4a, 4b,..., 4y, 4z have a thickness in the range of 1 to 100 °, and the thickness gradually decreases in the thickness direction from the transparent substrate 1 side. The thickness of the Co films 3a, 3b,..., 3y, 3z is 2
A Pd film in the range of about 9 ° and closest to the transparent substrate 1;
The magneto-optic optical system is such that the range of the Pt film and the PdPt alloy film 4a is in the range of 25 to 80 °, and the thickness of the Pd film, the Pt film and the PdPt alloy film 4z farthest from the transparent substrate 1 is in the range of 1 to 20 °. It is preferable because the effect can be obtained. The thickness of the composition modulation film 2 is preferably in the range of 40 to 1000 °. The thickness is more preferably in the range of 50 to 300 ° because high recording sensitivity is obtained and a square magnetic Kerr curve is obtained. The composition modulation film may have a superlattice structure without a region where different kinds of metal atoms are mixed at the interface of each metal film,
It may have a region in which different kinds of metal atoms are mixed and mixed, and different kinds of metal atoms are mixed at the interface, and a modulation structure whose composition changes periodically. It is preferable to add 3 atomic% or less of elements such as Al, Si, Ti, and Cr to the composition modulation film because the Curie temperature of the composition modulation curve can be reduced.
上記の組成変調膜はCoターゲツトと、Ptターゲツト、
PdターゲツトまたはPtPd合金ターゲツトとを用いたスパ
ツタリング法、真空蒸着法などにより形成することがで
きる。スパツタリング法により組成変調膜を形成する場
合には、各ターゲツト上にシヤツターを設置しておき、
該シヤツターを交互に開けばよく、Pd膜、Pt膜またはPd
Pt合金膜を形成するためにシヤツターを開ける時間を徐
々に短くすることによつて、膜厚を徐々に小さくするこ
とができる。The above composition modulation film comprises a Co target, a Pt target,
It can be formed by a sputtering method using a Pd target or a PtPd alloy target, a vacuum evaporation method, or the like. When forming a composition modulation film by the sputtering method, a shutter is set on each target,
The shutter may be opened alternately, and a Pd film, a Pt film, or a Pd film may be used.
The film thickness can be gradually reduced by gradually shortening the time for opening the shutter to form the Pt alloy film.
透明基板１としてはポリカーボネート樹脂、ポリメチ
ルメタクリレート樹脂、エポキシ樹脂、ガラスなどを用
いることができる。As the transparent substrate 1, a polycarbonate resin, a polymethyl methacrylate resin, an epoxy resin, glass, or the like can be used.
本発明の光磁気記録媒体の透明基板１と組成変調膜２
との間に、SiN、AlN、AlSiN、SiO、CoO、FeOなどの誘電
体からなる下地膜を積層することが、高い磁気光学効果
が得られる点から好ましい。下地膜の厚さは５〜10000
Åの範囲が好ましく、特に大きなカー回転角が得るため
には、下地膜の厚さは300〜1500Åの範囲であることが
より好ましい。下地膜は金属ターゲツトを用い、N2ガス
またはO2ガスを導入して行う反応性スパツタリング法、
誘電体ターゲツトを用い、Arガスを導入して行うスパツ
タリング法などにより形成することができる。透明基板
１上に下地膜と組成変調膜２とSiN、AlN、AlSiN、SiO、
CoO、FeOなどの誘電体からなる保護膜とを順次積層する
か、該保護膜上にさらにAl、AlTiなどからなる反射膜を
積層することがより高い磁気光学効果が得られる点で好
適である。Transparent substrate 1 and composition modulation film 2 of magneto-optical recording medium of the present invention
It is preferable to laminate a base film made of a dielectric such as SiN, AlN, AlSiN, SiO, CoO, FeO, etc., from the viewpoint of obtaining a high magneto-optical effect. Underlayer thickness is 5 to 10,000
範 囲 is preferred, and in order to obtain a particularly large Kerr rotation angle, the thickness of the underlayer is more preferably in the range of 300〜1500 Å. The base film uses a metal target and is a reactive sputtering method performed by introducing N 2 gas or O 2 gas,
It can be formed by a sputtering method or the like performed by introducing an Ar gas using a dielectric target. On a transparent substrate 1, a base film, a composition modulation film 2, SiN, AlN, AlSiN, SiO,
It is preferable to sequentially laminate a protective film made of a dielectric material such as CoO or FeO, or to further laminate a reflective film made of Al, AlTi, or the like on the protective film because a higher magneto-optical effect can be obtained. .
本発明の光磁気記録媒体により得られる磁気カー曲線
を測定した結果を第２図に示す。第２図の結果を得た光
磁気記録媒体は、ArガスとN2ガスとをそれぞれガス圧が
0.09Paおよび0.03Paになるように導入し、Siターゲツト
に160Wの高周波電力を印加して行う反応性スパツタリン
グ法によってポリカーボネート基板上にSiN膜を厚さが8
00Åになるように形成し、つぎにArガスをガス圧が0.5P
aになるように導入し、PtターゲツトおよびCoターゲツ
トにそれぞれ40Wの高周波電力を印加し、Ptターゲツト
上およびCoターゲツト上にそれぞれ設置したシヤツター
を交互に開けて行うスパツタリング法により、該SiN膜
上にCo膜とPt膜とを交互にそれぞれ８層ずつになるよう
に積層することによって製造したものである。ここで、
Co膜はその厚さが６Åになるように形成し、Pt膜はその
厚さが透明基板側の膜から順に40Å、25Å、23Å、10
Å、９Å、８Å、７Åおよび６Åになるように形成し
た。FIG. 2 shows the results of measuring the magnetic Kerr curve obtained by the magneto-optical recording medium of the present invention. Magneto-optical recording medium in which the results of the second figure, each gas pressure of Ar gas and N 2 gas
A SiN film having a thickness of 8 was formed on the polycarbonate substrate by a reactive sputtering method in which the Si target was introduced at 0.09 Pa and 0.03 Pa and a high frequency power of 160 W was applied to the Si target.
00 °, and then Ar gas is supplied at a gas pressure of 0.5P
a, a high-frequency power of 40 W is applied to each of the Pt target and the Co target. It is manufactured by alternately laminating Co films and Pt films so as to have eight layers each. here,
The Co film is formed to have a thickness of 6 °, and the Pt film is formed to have a thickness of 40 °, 25 °, 23 °, 10 ° in order from the film on the transparent substrate side.
Å, 9Å, 8Å, 7Å and 6Å.
第２図から明らかなように、本発明の光磁気記録媒体
によれば角形の磁気カー曲線が得られる。また本発明の
光磁気記録媒体は大きな保磁力とカー回転角とを有して
いる。As is clear from FIG. 2, a square magnetic Kerr curve can be obtained according to the magneto-optical recording medium of the present invention. Further, the magneto-optical recording medium of the present invention has a large coercive force and a Kerr rotation angle.
比較例１ ポリカーボネート基板上にSiN膜を厚さを800Åになる
ように形成し、該SiN膜上に膜厚が６ÅのCo膜と膜厚が1
6ÅのPt膜とを交互にそれぞれ８層ずつになるように形
成することによって光磁気記録媒体を得た。この光磁気
記録媒体により得られる磁気カー曲線を測定した結果を
第３図に示す。Comparative Example 1 A SiN film was formed on a polycarbonate substrate so as to have a thickness of 800 mm, and a Co film having a thickness of 6 mm and a Co film having a thickness of 1 mm were formed on the SiN film.
A magneto-optical recording medium was obtained by alternately forming a 6 ° Pt film into eight layers each. FIG. 3 shows the result of measurement of the magnetic Kerr curve obtained with this magneto-optical recording medium.
第２図と第３図とを比較することによって、本発明の
光磁気記録媒体は比較例の光磁気記録媒体よりも大きな
保磁力を有しており、記録された情報の安定性において
優れていることが明らかである。By comparing FIG. 2 with FIG. 3, the magneto-optical recording medium of the present invention has a larger coercive force than the magneto-optical recording medium of the comparative example, and is superior in stability of recorded information. It is clear that there is.
［発明の効果］ 本発明によれば、大きな保磁力とカー回転角とを有
し、記録された情報が高い安定性を有する光磁気記録媒
体が提供される。According to the present invention, a magneto-optical recording medium having a large coercive force and a Kerr rotation angle and having high stability in recorded information is provided.
第１図は本発明の光磁気記録媒体の一例の概略断面図、
第２図は本発明の光磁気記録媒体により得られる磁気カ
ー曲線を示す図、第３図は比較例の光磁気記録媒体によ
り得られる磁気カー曲線を示す図である。 １……透明基板、２……組成変調膜。FIG. 1 is a schematic sectional view of an example of the magneto-optical recording medium of the present invention,
FIG. 2 is a diagram showing a magnetic Kerr curve obtained by a magneto-optical recording medium of the present invention, and FIG. 3 is a diagram showing a magnetic Kerr curve obtained by a magneto-optical recording medium of a comparative example. 1 ... transparent substrate, 2 ... composition modulation film.
Claims (1)
膜と１〜100Åの範囲の膜厚を有するPdおよび／またはP
tからなる膜とが交互に積層されてなる組成変調膜が透
明基板上に形成されてなり、該Pdおよび／またはPtから
なる膜が少なくとも２層存在し、かつそれらの膜厚が透
明基板側から膜厚方向に徐々に小さくなっていることを
特徴とする光磁気記録媒体。1. A film comprising Co having a thickness in the range of 1-30 ° and Pd and / or P having a thickness in the range of 1-100 °.
A composition modulation film formed by alternately laminating a film made of t is formed on a transparent substrate, and there are at least two layers of the film made of Pd and / or Pt, and the film thickness of the film is on the side of the transparent substrate. A magneto-optical recording medium characterized by gradually decreasing in the thickness direction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2344590A JP2849431B2 (en) | 1990-01-31 | 1990-01-31 | Magneto-optical recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2344590A JP2849431B2 (en) | 1990-01-31 | 1990-01-31 | Magneto-optical recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03228238A JPH03228238A (en) | 1991-10-09 |
| JP2849431B2 true JP2849431B2 (en) | 1999-01-20 |
Family
ID=12110702
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2344590A Expired - Fee Related JP2849431B2 (en) | 1990-01-31 | 1990-01-31 | Magneto-optical recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2849431B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2069056C (en) * | 1991-05-23 | 1996-03-05 | Kenji Ohta | Magneto-optical storage device and manufacturing method thereof |
-
1990
- 1990-01-31 JP JP2344590A patent/JP2849431B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03228238A (en) | 1991-10-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH0684212A (en) | Magneto-optical memory element | |
| WO1990011602A1 (en) | Magnetooptical medium | |
| JP2849431B2 (en) | Magneto-optical recording medium | |
| EP0530913A1 (en) | Magneto-optical recording medium | |
| US4999260A (en) | Magneto-optical recording medium comprising a rare-earth-transition metal dispersed in a dielectric | |
| EP0239974B1 (en) | Magneto-optical recording medium | |
| EP0783749B1 (en) | Magneto-optic recording medium having magneto-optic film layers separated by yttrium oxide | |
| JPS6122454A (en) | Photomagnetic recording medium | |
| JPS6332748A (en) | Information recording medium | |
| JP2793083B2 (en) | Magneto-optical recording medium | |
| JPS61117748A (en) | Photomagnetic disk | |
| JP2960767B2 (en) | Magneto-optical recording medium | |
| JPH01178151A (en) | Magneto-optical recording medium | |
| JPH03228239A (en) | Magneto-optical recording medium | |
| JPS62172547A (en) | Photomagnetic recording medium | |
| JP2616120B2 (en) | Magneto-optical recording medium and method of manufacturing the same | |
| JPS6332753A (en) | Information recording method | |
| JP2562219B2 (en) | Magneto-optical disk | |
| JP3237977B2 (en) | Magneto-optical recording medium | |
| JPH0478039A (en) | Magneto-optical recording medium | |
| JPH03252942A (en) | Optical recording medium and method of optical recording and reproducing | |
| JPS62172548A (en) | Photomagnetic recording medium | |
| JPH03235237A (en) | Structure of magneto-optical recording medium | |
| JPH05314559A (en) | Magneto-optical recording medium and its production | |
| JPH06150415A (en) | Magneto-optical recording medium |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |