JP2567416B2 - Preparation method of superconducting thin film - Google Patents
Preparation method of superconducting thin filmInfo
- Publication number
- JP2567416B2 JP2567416B2 JP62253187A JP25318787A JP2567416B2 JP 2567416 B2 JP2567416 B2 JP 2567416B2 JP 62253187 A JP62253187 A JP 62253187A JP 25318787 A JP25318787 A JP 25318787A JP 2567416 B2 JP2567416 B2 JP 2567416B2
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- JP
- Japan
- Prior art keywords
- thin film
- producing
- superconducting thin
- film according
- composite oxide
- 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.)
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Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
- Physical Vapour Deposition (AREA)
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は超電導薄膜の製造方法に関する。より詳細に
は、高い超電導臨界温度および臨界電流を有し、優れた
超電導特性を持つ超電導薄膜の作製方法に関する。TECHNICAL FIELD The present invention relates to a method for producing a superconducting thin film. More specifically, it relates to a method for producing a superconducting thin film having a high superconducting critical temperature and a critical current and having excellent superconducting properties.
従来の技術 電子の相転移であるといわれる超電導現象は、特定の
条件下で導体の電気抵抗が零の状態となり完全な反磁性
を示す現象である。2. Description of the Related Art The superconducting phenomenon, which is said to be a phase transition of electrons, is a phenomenon in which the electric resistance of a conductor becomes zero under certain conditions and shows perfect diamagnetism.
エレクトロニクスの分野では各種の超電導素子が知ら
れている。代表的なものとしては、超電導材料どうしを
弱く接合した場合に、印加電流によって量子効果が巨視
的に現れるジョセフソン効果を利用した素子が挙げられ
る。Various superconducting elements are known in the field of electronics. A typical example is an element utilizing the Josephson effect in which quantum effects appear macroscopically by an applied current when superconducting materials are weakly joined.
トンネル接合型ジョセフソン素子は、超電導材料のエ
ネルギーギャップが小さいことから、極めて高速な低電
力消費のスイッチング素子として期待されている。ま
た、電磁波が磁場に対するジョセフソン効果が正確な量
子現象として現れることから、ジョセフソン素子を磁
場、マイクロ波、放射線等の超高感度センサとして利用
することも期待されている。さらに、電子回路の集積度
が高くなるにつれて単位面積当たりの消費電力が冷却能
力の限界に達する。そこで超高速計算機には超電導素子
の開発が要望されている。Since the energy gap of the superconducting material is small, the tunnel junction type Josephson device is expected as a switching device with extremely high speed and low power consumption. In addition, since the Josephson effect of an electromagnetic wave on a magnetic field appears as an accurate quantum phenomenon, it is expected that the Josephson device will be used as an ultra-sensitive sensor for magnetic fields, microwaves, radiation and the like. Furthermore, as the degree of integration of electronic circuits increases, the power consumption per unit area reaches the limit of cooling capacity. Therefore, the development of superconducting elements has been demanded for ultra-high-speed computers.
一方、様々な努力にもかかわらず、超電導材料の超電
導臨界温度Tcは長期間に亘ってNb3Geの23Kを越えること
ができなかったが、昨年末来、〔La,Ba〕2CuO4または
〔La,Sr〕2CuO4等の酸化物の焼結材が高いTcをもつ超電
導材料として発見され、非低温超電導を実現する可能性
が大きく高まっている。これらの物質では、30乃至50K
という従来に比べて飛躍的に高いTcが観測され、70K以
上のTcも観測されている。On the other hand, despite various efforts, the superconducting critical temperature Tc of superconducting materials could not exceed 23K of Nb 3 Ge for a long time, but since the end of last year, [La, Ba] 2 CuO 4 or Sintered oxides such as [La, Sr] 2 CuO 4 have been discovered as superconducting materials with high Tc, and the possibility of realizing non-low temperature superconductivity is increasing greatly. For these substances, 30-50K
Tc significantly higher than before, and Tc of 70K or more has been observed.
また、YBCOと称されるY1Ba2Cu3O7-xで表される複合酸
化物は、100K級の超電導体であることが発表されてい
る。これら複合酸化物超電導体の超電導特性には、結晶
中の酸素欠陥が大きな役割を果たしている。すなわち、
結晶中の酸素欠陥が適正でないと、Tcは低く、また、オ
ンセット温度と抵抗が完全に０となる温度との差も大き
くなる。Further, it has been announced that a composite oxide represented by Y 1 Ba 2 Cu 3 O 7-x called YBCO is a 100K-class superconductor. Oxygen defects in the crystal play a major role in the superconducting properties of these complex oxide superconductors. That is,
If oxygen deficiency in the crystal is not proper, Tc will be low, and the difference between the onset temperature and the temperature at which the resistance becomes zero will be large.
発明が解決しようとする問題点 従来、上記複合酸化物超電導体薄膜を作製する際に
は、焼結等で生成した酸化物を蒸着源として物理蒸着を
行っていた。Problems to be Solved by the Invention Conventionally, when the above-mentioned composite oxide superconductor thin film was prepared, physical vapor deposition was performed using an oxide generated by sintering or the like as a vapor deposition source.
しかしながら、上記の複合酸化物焼結体を蒸発源とし
て、真空蒸着により複合酸化物超電導薄膜を作製しよう
とすると、焼結体から発生するガスのため真空度が上げ
られず、得られる薄膜は緻密ではなく、また、ガス中の
不純物も取り込まれるため特性が悪かった。However, when an attempt is made to produce a composite oxide superconducting thin film by vacuum vapor deposition using the above-mentioned composite oxide sintered body as an evaporation source, the degree of vacuum cannot be raised due to the gas generated from the sintered body, and the resulting thin film is dense. Moreover, the characteristics were poor because impurities in the gas were also taken in.
そこで、本発明の目的は、上記従来技術の問題点を解
決し、高い臨界温度Tcを始めとする優れた超電導諸特性
を安定的に有し、均一な組成および組織の複合酸化物超
電導材料の薄膜を作製する方法を提供することにある。Therefore, the object of the present invention is to solve the problems of the above-mentioned conventional techniques, stably have excellent superconducting properties including a high critical temperature Tc, and a composite oxide superconducting material having a uniform composition and structure. It is to provide a method for forming a thin film.
問題点を解決するための手段 本発明に従うと、アルカリ土類元素から選択された少
なくとも１種の元素α、希土類元素から選択された少な
くとも１種の元素βおよびCuを含有する複合酸化物超電
導体薄膜を作製する方法において、上記元素α、βおよ
びCuを含有する焼結体酸化物を溶融し、冷却固化して作
製した蒸発源を用い、真空蒸着法により成膜することを
特徴とする超電導薄膜の作製方法が提供される。Means for Solving the Problems According to the present invention, a composite oxide superconductor containing at least one element α selected from alkaline earth elements, at least one element β selected from rare earth elements, and Cu. In the method for producing a thin film, a superconducting film is formed by a vacuum evaporation method using an evaporation source produced by melting and cooling and solidifying a sintered body oxide containing the above elements α, β and Cu. A method of making a thin film is provided.
本発明の方法で作製される複合酸化物超電導薄膜は、
下記一般式： （α1-xβx）CuyOz （但し、αはアルカリ土類元素であり、βは希土類元素
でありｘ、ｙ、ｚはそれぞれ0.1≦ｘ≦0.9、それぞれ0.
4≦ｙ≦3.0、１≦ｚ≦５を満たす数である） で示される複合酸化物で構成されることが好ましい。こ
れらの複合酸化物はペロブスカイト型または擬似ペロブ
スカイト型酸化物を主体としたものと考えられる。The composite oxide superconducting thin film produced by the method of the present invention,
The following general formula: (α 1-x β x ) Cu y O z (where α is an alkaline earth element, β is a rare earth element, and x, y, and z are each 0.1 ≦ x ≦ 0.9, respectively.
4 ≦ y ≦ 3.0, and 1 ≦ z ≦ 5). It is considered that these complex oxides are mainly composed of perovskite type or pseudo perovskite type oxides.
上記アルカリ土類元素αとしては、Ba、Sr、Ca等が好
ましく、この元素αの10〜80％をCa、Srから選択された
１種または２種の元素で置換することもできる。また希
土類元素βはとしては、Ｙ、La、Sc、Ce、Gd、Ho、Er、
Tm、Yb、Lu等が好ましく、例えばＹ、La、Hoとすること
ができ、この元素βのうち、10〜80％をScまたはLa以外
のランタノイド元素から選択された１種または２種の元
素で置換することもできる。The alkaline earth element α is preferably Ba, Sr, Ca or the like, and 10 to 80% of this element α can be replaced with one or two elements selected from Ca and Sr. The rare earth element β includes Y, La, Sc, Ce, Gd, Ho, Er,
Tm, Yb, Lu and the like are preferable, and they can be, for example, Y, La and Ho, and 10 to 80% of this element β is one or two elements selected from lanthanoid elements other than Sc or La. You can also replace with.
本発明の態様では、上記焼結体酸化物を酸素含有雰囲
気中で溶融し、冷却固化して蒸発源を作製することが好
ましく、その際、冷却速度は10℃／分以下であることが
好ましい。In the aspect of the present invention, it is preferable that the above-mentioned sintered oxide is melted in an oxygen-containing atmosphere and cooled to solidify to produce an evaporation source, at which time, the cooling rate is preferably 10 ° C./minute or less. .
また、上記真空蒸着は、５×10-5Torr以下の圧力で、
電子ビームガンを用い、基板を150〜1000℃に加熱しな
がら行うことが好ましい。Further, the vacuum deposition is performed at a pressure of 5 × 10 −5 Torr or less,
It is preferable to use an electron beam gun and heat the substrate at 150 to 1000 ° C.
本発明の態様に従うと、上記の複合酸化物超電導薄膜
を形成する基板としては、MgO単結晶、SrTiO3単結晶ま
たはZrO2単結晶が好ましく、特に、MgO単結晶またはSrT
iO3単結晶基板の成膜面を、｛001｝面または｛011｝面
とすることが好ましい。According to the embodiment of the present invention, as the substrate for forming the above-mentioned complex oxide superconducting thin film, MgO single crystal, SrTiO 3 single crystal or ZrO 2 single crystal is preferable, and in particular, MgO single crystal or SrT.
The film formation surface of the iO 3 single crystal substrate is preferably a {001} surface or a {011} surface.
さらに、本発明の態様では、成膜後薄膜を酸素分圧１
〜10気圧の酸素含有雰囲気で500〜1000℃に加熱し、20
℃／分以下の冷却速度で冷却するか、または0.1〜5Torr
の圧力のもとで酸素プラズマに曝すプラズマ酸化のいず
れかのアニールを行うことが好ましい。Further, in the aspect of the present invention, the oxygen partial pressure of the thin film after film formation is 1
Heat to 500-1000 ℃ in an oxygen-containing atmosphere at ~ 10 atm,
Cool at a cooling rate of ℃ / min or less, or 0.1 to 5 Torr
It is preferable to perform either annealing of plasma oxidation exposing to oxygen plasma under the pressure of.
作用 本発明の超電導薄膜の作製方法は、焼結で作製した複
合酸化物を酸素含有雰囲気中で加熱溶融し、10℃／分以
下の冷却速度で徐冷することで作製した蒸発源を用い
て、真空蒸着により成膜するところにその主要な特徴が
ある。Action The method for producing a superconducting thin film of the present invention uses an evaporation source produced by heating and melting a composite oxide produced by sintering in an oxygen-containing atmosphere and gradually cooling it at a cooling rate of 10 ° C./min or less. The main feature is that the film is formed by vacuum evaporation.
すなわち、YBCOと称されるY1Ba2Cu3O7-xで代表される
複合酸化物超電導体の薄膜を真空蒸着で作製するのに、
従来はＹ、BaおよびCuの酸化物等の化合物の粉末を焼結
して蒸発源を作製していた。しかしながら、上記の焼結
体は、中にガスを含むため、蒸発源として使用すると、
ガスを発生する。従って、真空蒸着時の真空度は10-4To
rrのオーダーにしかならなかった。That is, to prepare a thin film of a composite oxide superconductor represented by Y 1 Ba 2 Cu 3 O 7-x called YBCO by vacuum deposition,
Conventionally, an evaporation source was produced by sintering powders of compounds such as Y, Ba and Cu oxides. However, since the above-mentioned sintered body contains gas therein, when used as an evaporation source,
Generates gas. Therefore, the vacuum degree during vacuum deposition is 10 -4 To
It was only an order of rr.
真空蒸着により、上記の薄膜を作製する場合、真空度
が高いほど薄膜の組織は緻密になり、特性も優れたもの
になる。特に、上記の複合酸化物超電導体薄膜を真空蒸
着で作製するには、真空度が５×10-5Torr以下となるこ
とが好ましい。しかしながら、従来は、焼結体を蒸着源
として用いていたので上記のように真空度が上がらなか
った。When the above thin film is produced by vacuum evaporation, the higher the degree of vacuum, the finer the structure of the thin film, and the more excellent the characteristics. In particular, in order to produce the above-mentioned composite oxide superconductor thin film by vacuum vapor deposition, the degree of vacuum is preferably 5 × 10 −5 Torr or less. However, in the past, since the sintered body was used as the vapor deposition source, the degree of vacuum could not be increased as described above.
本発明の方法で用いる蒸着源は、焼結体を酸素含有雰
囲気中で溶融して、さらに徐冷して作製する。焼結体が
吸着していた気体は、溶融時に放出されるので、上記の
ように作製した蒸発源から蒸着時に発生するガスの量は
大幅に減少する。従って、本発明の方法では、望ましい
５×10-5Torr以下の圧力での真空蒸着が可能になる。The vapor deposition source used in the method of the present invention is produced by melting a sintered body in an oxygen-containing atmosphere and further slowly cooling it. Since the gas adsorbed by the sintered body is released at the time of melting, the amount of gas generated at the time of vapor deposition from the evaporation source manufactured as described above is significantly reduced. Therefore, the method of the present invention enables vacuum deposition at a pressure of 5 × 10 −5 Torr or less which is desirable.
本発明の方法で用いる蒸発源は、従来蒸発源として用
いていた焼結体を溶融して作製してもよいが、焼結体の
蒸発源と溶融して作製した蒸発源では、多少蒸着特性等
が異なるため、薄膜の組成、結晶構造等が所望のものと
なるよう溶融する焼結体の組成を調整し、作製すること
が好ましい。The evaporation source used in the method of the present invention may be prepared by melting a sintered body that has been used as an evaporation source in the past, but the evaporation source of the sintered body and the evaporation source prepared by melting may have a slightly different vapor deposition characteristic. Therefore, it is preferable that the composition of the melted sintered body is adjusted and produced so that the composition of the thin film, the crystal structure, and the like become desired.
上記のように組成を調整し、焼結した焼結体を酸素雰
囲気中で溶融し、組織が均一になるまで放置する。その
後冷却して固化させるが、その際冷却速度は、10℃／分
以下であることが好ましい。The composition is adjusted as described above, and the sintered sintered body is melted in an oxygen atmosphere and left to stand until the structure becomes uniform. After that, it is cooled and solidified, and the cooling rate at that time is preferably 10 ° C./minute or less.
この理由は、上記の複合酸化物は、溶融状態から冷却、
固化していく過程で酸素を取り込む。従って、冷却速度
が大きすぎると酸素の取り込み量が少なく、酸素不足の
酸化物となり、蒸発源として用いたとき得られる薄膜の
特性が大幅に低下するからである。The reason for this is that the above complex oxide is cooled from the molten state,
It takes in oxygen during the process of solidification. Therefore, if the cooling rate is too high, the amount of oxygen taken up is small and the oxide becomes oxygen deficient, and the characteristics of the thin film obtained when used as an evaporation source are significantly deteriorated.
本発明の方法では、上記の蒸発源を用いて真空蒸着を
行うが、真空蒸着時には基板温度を150〜1000℃に加熱
することが好ましい。基板温度が150℃未満の場合、複
合酸化物の結晶性が悪くアモルファス状になり、超電導
薄膜は得られない。また、基板温度が1000℃を超える
と、結晶構造が変わってしまい、上記の複合酸化物は超
電導体とはならない。In the method of the present invention, vacuum evaporation is performed using the above evaporation source, but it is preferable to heat the substrate temperature to 150 to 1000 ° C. during vacuum evaporation. When the substrate temperature is lower than 150 ° C, the crystallinity of the composite oxide is poor and the composite oxide becomes amorphous, so that a superconducting thin film cannot be obtained. Also, when the substrate temperature exceeds 1000 ° C., the crystal structure changes, and the above composite oxide does not become a superconductor.
また、本発明の好ましい態様に従うと、蒸着時に蒸発
源を電子ビームガンで加熱する。電子ビームガンで加熱
すると、他の方法で加熱するよりも、蒸発源気体のエネ
ルギー状態が好ましくなり、結晶性よく成膜する。According to a preferred embodiment of the present invention, the evaporation source is heated by the electron beam gun during vapor deposition. When heated with an electron beam gun, the energy state of the evaporation source gas becomes more preferable than when heated by other methods, and a film is formed with good crystallinity.
本発明の態様に従うと、上記の複合酸化物超電導薄膜
を形成する基板としては、MgO単結晶、SrTiO3単結晶ま
たはZrO2単結晶基板が好ましい。特に、MgO単結晶基板
またはSrTiO3単結晶基板の｛001｝面または｛011｝面を
成膜面として用いることが好ましい。According to the embodiment of the present invention, a MgO single crystal, SrTiO 3 single crystal or ZrO 2 single crystal substrate is preferable as the substrate for forming the above-mentioned composite oxide superconducting thin film. In particular, it is preferable to use the {001} plane or {011} plane of the MgO single crystal substrate or the SrTiO 3 single crystal substrate as the film formation surface.
本発明の複合酸化物超電導体は、その電気抵抗に結晶
異方性を有する。すなわち、結晶のａ軸およびｂ軸で決
定される面に平行な方向に電流が流れ易い。上記の基板
の上記成膜面上に形成された複合酸化物超電導薄膜は、
その結晶のｃ軸が基板成膜面に対し垂直または垂直に近
い角度となるため、特に臨界電流密度Jcが大きくなる。
従って、MgO単結晶基板またはSrTiO3単結晶基板の｛00
1｝面を成膜面として用いることが好ましい。また、｛0
01｝面を用いてｃ軸を基板と平行にし、ｃ軸と垂直な方
向を特定して用いることもできる。さらに、MgO、SrTiO
3は、熱膨脹率が上記の複合酸化物超電導体と近いた
め、加熱、冷却の過程で薄膜に不必要な応力を加えるこ
とがなく、薄膜を破損する恐れもない。The composite oxide superconductor of the present invention has a crystalline anisotropy in its electric resistance. That is, current easily flows in a direction parallel to a plane determined by the a-axis and the b-axis of the crystal. The composite oxide superconducting thin film formed on the film-forming surface of the substrate,
Since the c-axis of the crystal is perpendicular or nearly perpendicular to the film formation surface of the substrate, the critical current density Jc becomes particularly large.
Therefore, the MgO single crystal substrate or the SrTiO 3 single crystal substrate
It is preferable to use the 1} plane as the film formation surface. Also, ｛0
It is also possible to make the c-axis parallel to the substrate by using the 01} plane and specify and use the direction perpendicular to the c-axis. In addition, MgO, SrTiO
No. 3 has a coefficient of thermal expansion close to that of the above complex oxide superconductor, so that unnecessary stress is not applied to the thin film during heating and cooling, and there is no risk of damage to the thin film.
本発明の態様に従うと、成膜後の薄膜を酸素分圧１〜
10気圧の酸素含有雰囲気中で500〜1000℃に加熱、20℃
／分以下の冷却速度で冷却する熱処理を施すか、あるい
は0.1〜5Torrの圧力下で酸素プラズマに曝すプラズマ酸
化処理を行うことが好ましい。この処理は、上記の複合
酸化物中の酸素欠陥を調整するもので、このいずれかの
処理を経ない薄膜の超電導特性は悪く、超電導性を示さ
ない場合もある。従って、上記の熱処理またはプラズマ
酸化処理を行うことが好ましい。According to an embodiment of the present invention, the thin film after film formation has an oxygen partial pressure of 1 to
Heat to 500-1000 ℃ in an atmosphere containing oxygen at 10 atm, 20 ℃
It is preferable to perform a heat treatment for cooling at a cooling rate of not more than 1 minute / min or perform a plasma oxidation treatment by exposing to oxygen plasma under a pressure of 0.1 to 5 Torr. This treatment adjusts the oxygen deficiency in the above-mentioned composite oxide, and the superconducting property of the thin film not subjected to any one of the treatments is poor and the superconducting property may not be exhibited in some cases. Therefore, it is preferable to perform the above heat treatment or plasma oxidation treatment.
実施例 以下に本発明を実施例により説明するが、本発明の技
術的範囲は、以下の開示に何等制限されるものではない
ことは勿論である。EXAMPLES The present invention will be described below with reference to examples, but it goes without saying that the technical scope of the present invention is not limited to the following disclosure.
本発明の方法により、超電導薄膜を作製した。蒸発源
は、Y2O3、BaCO3をＹ、Baのモル比1:2で混合し、CuOを
Ｙ、Ba、Cuのモル比が1:2:3となる量よりも10重量％過
剰に混合し、950℃で焼結して得たY1Ba2Cu3O7-x焼結体
を溶融して作製した。溶融は、白金るつぼを用い、酸素
分圧１気圧の酸素雰囲気中で、1400℃で10時間溶解した
後、４℃／分で徐冷、固化させた。A superconducting thin film was produced by the method of the present invention. As the evaporation source, Y 2 O 3 and BaCO 3 were mixed at a molar ratio of Y and Ba of 1: 2, and CuO was added in an amount of 10% by weight in excess of the molar ratio of Y, Ba and Cu of 1: 2: 3. Was mixed and sintered at 950 ° C. to obtain a Y 1 Ba 2 Cu 3 O 7-x sintered body which was obtained by melting. The melting was performed using a platinum crucible in an oxygen atmosphere with an oxygen partial pressure of 1 atm at 1400 ° C. for 10 hours, followed by slow cooling at 4 ° C./min and solidification.
上記のように作製した蒸着源を用いて、真空蒸着を行
い、超電導薄膜を作製した。尚、比較のため、上記の焼
結体をそのまま蒸発源として用いる従来の方法でも超電
導薄膜を作製した。Using the vapor deposition source produced as described above, vacuum vapor deposition was performed to produce a superconducting thin film. For comparison, a superconducting thin film was produced by the conventional method using the above sintered body as it is as an evaporation source.
成膜条件を以下に示す。 The film forming conditions are shown below.
電子ビームガン加速電圧 4kV 電 流 5mA 基 板 MgO単結晶（100）面 基板温度 800℃ 本発明の蒸発源を用いた場合、真空度１×10-5Torrで
蒸着することが可能であったが、従来の焼結体の蒸着源
を用いた場合は、１×10-4Torrまでしか真空度は上がら
なかった。また、成膜時間は180分で、得られた薄膜の
膜厚は約0.2μｍであった。Electron beam gun Accelerating voltage 4kV Current 5mA Substrate MgO single crystal (100) surface Substrate temperature 800 ° C When the evaporation source of the present invention was used, it was possible to deposit at a vacuum degree of 1 × 10 -5 Torr. When the conventional vapor deposition source of the sintered body was used, the degree of vacuum could be increased only up to 1 × 10 −4 Torr. The film formation time was 180 minutes, and the thickness of the obtained thin film was about 0.2 μm.
次いで、それぞれの薄膜を１気圧のO2中で900℃、２
時間加熱した後、４℃／分の冷却速度で徐冷した。Then, each thin film was placed in O 2 at 1 atm at 900 ° C for 2
After heating for an hour, it was gradually cooled at a cooling rate of 4 ° C./min.
得られたそれぞれの超電導薄膜の主な超電導特性を以
下に示す。The main superconducting properties of the obtained superconducting thin films are shown below.
上記のように本発明の方法により作製された超電導薄
膜は、従来のものより良好な超電導特性を示す。これ
は、本発明の蒸発源を用いることにより、１×10-5Torr
と従来より１桁低い圧力で真空蒸着が可能になったため
だと考えられる。 As described above, the superconducting thin film produced by the method of the present invention exhibits better superconducting properties than conventional ones. This is achieved by using the evaporation source of the present invention at 1 × 10 −5 Torr.
It is thought that this is because vacuum deposition has become possible at a pressure that is an order of magnitude lower than in the past.
発明の効果 以上詳述のように、本発明の方法によって得られた超
電導薄膜は、従来の方法で作製されたものに較べ、高い
Tc、Jcを示す。EFFECTS OF THE INVENTION As described above in detail, the superconducting thin film obtained by the method of the present invention is higher than that produced by the conventional method.
Indicates Tc and Jc.
これは、本発明の方法では、焼結体酸化物を酸素中で
溶融して作製した蒸発源を用いて真空蒸着を行うため、
従来よりも１桁真空度が向上したためである。This is because in the method of the present invention, vacuum deposition is performed using an evaporation source prepared by melting a sintered oxide in oxygen.
This is because the vacuum degree is improved by one digit as compared with the conventional one.
また、本発明の方法に従えば、従来よりも不純物が少
ない超電導薄膜が得られるため、より安定に高性能な超
電導薄膜を供給することが可能となる。Further, according to the method of the present invention, since a superconducting thin film having less impurities than the conventional one can be obtained, it becomes possible to more stably supply a high-performance superconducting thin film.
フロントページの続き (72)発明者 矢津 修示 兵庫県伊丹市昆陽北１丁目１番１号 住 友電気工業株式会社伊丹製作所内 (72)発明者 上代 哲司 兵庫県伊丹市昆陽北１丁目１番１号 住 友電気工業株式会社伊丹製作所内Front page continuation (72) Inventor Shuji Yazu 1-1-1 Kunyokita, Itami City, Hyogo Prefecture Sumitomo Electric Industries, Ltd. Itami Works (72) Inventor Tetsuji Kamishiro 1-1-1 Kunyokita, Itami City, Hyogo Prefecture No. 1 Sumitomo Electric Industries, Ltd. Itami Works
Claims (25)
も１種の元素α、希土類元素から選択された少なくとも
１種の元素βおよびCuを含有する複合酸化物超電導体薄
膜を作製する方法において、上記元素α、βおよびCuを
含有する焼結体酸化物を溶融し、冷却固化して作製した
蒸発源を用い、真空蒸着法により成膜することを特徴と
する超電導薄膜の作製方法。1. A method for producing a composite oxide superconductor thin film containing at least one element α selected from alkaline earth elements, at least one element β selected from rare earth elements, and Cu. A method for producing a superconducting thin film, characterized in that a sintered oxide containing elements α, β and Cu is melted, cooled and solidified to form a film by a vacuum evaporation method using an evaporation source.
＋βに対するβの原子比で、0.1≦ｘ≦0.9であり、ｙお
よびｚは（α1-xβx）を１とした場合に0.4≦ｙ≦3.0、
１≦ｚ≦５となる原子比である） で表される組成の酸化物であることを特徴とする特許請
求の範囲第１項に記載の超電導薄膜の作製方法。2. The complex oxide superconductor has the general formula: (α 1-x β x ) Cu y O z (where α, β and γ are elements defined above, and x is α
The atomic ratio of β to + β is 0.1 ≦ x ≦ 0.9, and y and z are 0.4 ≦ y ≦ 3.0 when (α 1−x β x ) is 1,
A method for producing a superconducting thin film according to claim 1, characterized in that the oxide has a composition represented by the following atomic ratio: 1 ≦ z ≦ 5.
ト型酸化物であることを特徴とする特許請求の範囲第１
項または第２項に記載の超電導薄膜の作製方法。3. The composite oxide superconductor is a perovskite type oxide.
Item 2. A method for producing a superconducting thin film according to Item 2 or Item 2.
Cuを含むことを特徴とする特許請求の範囲第１項乃至第
３項のいずれか１項に記載の超電導薄膜の作製方法。4. The composite oxide superconductor comprises Ba, Y and
The method for producing a superconducting thin film according to any one of claims 1 to 3, which contains Cu.
Cuを含むことを特徴とする特許請求の範囲第１項乃至第
３項のいずれか１項に記載の超電導薄膜の作製方法。5. The composite oxide superconductor comprises Ba, La and
The method for producing a superconducting thin film according to any one of claims 1 to 3, which contains Cu.
Cuを含むことを特徴とする特許請求の範囲第１項乃至第
３項のいずれか１項に記載の超電導薄膜の作製方法。6. The composite oxide superconductor comprises Sr, La and
The method for producing a superconducting thin film according to any one of claims 1 to 3, which contains Cu.
Cuを含むことを特徴とする特許請求の範囲第１項乃至第
３項のいずれか１項に記載の超電導薄膜の作製方法。7. The composite oxide superconductor comprises Ba, Ho and
The method for producing a superconducting thin film according to any one of claims 1 to 3, which contains Cu.
る） で表される複合酸化物であることを特徴とする特許請求
の範囲第４項に記載の超電導薄膜の作製方法。8. The composite oxide superconductor is a composite oxide represented by Y 1 Ba 2 Cu 3 O 7-x (where x is a number satisfying 0 <x <1). 5. The method for producing a superconducting thin film according to claim 4.
る） で表される複合酸化物であることを特徴とする特許請求
の範囲第５項に記載の超電導薄膜の作製方法。9. The composite oxide superconductor is a composite oxide represented by La 1 Ba 2 Cu 3 O 7-x (where x is a number satisfying 0 <x <1). The method for producing a superconducting thin film according to claim 5, wherein
る） で表される複合酸化物であることを特徴とする特許請求
の範囲第６項に記載の超電導薄膜の作製方法。10. The complex oxide superconductor is a complex oxide represented by La 1 Sr 2 Cu 3 O 7-x (where x is a number satisfying 0 <x <1). 7. The method for producing a superconducting thin film according to claim 6.
る） で表される複合酸化物であることを特徴とする特許請求
の範囲第７項に記載の超電導薄膜の作製方法。11. The composite oxide superconductor is a composite oxide represented by Ho 1 Ba 2 Cu 3 O 7-x (where x is a number satisfying 0 <x <1). The method for producing a superconducting thin film according to claim 7.
および冷却固化して蒸発源を作製することを特徴とする
特許請求の範囲第１項乃至第11項のいずれか１項に記載
の超電導薄膜の作製方法。12. The evaporation source is produced by melting and cooling and solidifying the sintered body in an oxygen-containing atmosphere, to thereby form an evaporation source. Method for producing superconducting thin film.
速度が、10℃／分以下であることを特徴とする特許請求
の範囲第12項に記載の超電導薄膜の作製方法。13. The method for producing a superconducting thin film according to claim 12, wherein the cooling rate after cooling the sintered body is 10 ° C./min or less.
しながら行うことを特徴とする特許請求の範囲第１項乃
至第13項のいずれか１項に記載の超電導薄膜の作製方
法。14. The method for producing a superconducting thin film according to claim 1, wherein the film formation by vacuum evaporation is performed while heating the substrate.
あることを特徴とする特許請求の範囲第14項に記載の超
電導薄膜の作製方法。15. The method for producing a superconducting thin film according to claim 14, wherein the heating temperature of the substrate is 150 to 1000 ° C.
面間隔と近い面間隔を有する酸化物単結晶の基板を用い
ることを特徴とする特許請求の範囲第１項乃至第15項の
いずれか１項に記載の超電導薄膜の作製方法。16. The substrate according to claim 1, wherein the substrate is an oxide single crystal substrate having a surface spacing close to that of the complex oxide crystal. Item 1. The method for producing a superconducting thin film according to item 1.
結晶またはZrO2単結晶を用いることを特徴とする特許請
求の範囲第16項に記載の超電導薄膜の作製方法。17. The method for producing a superconducting thin film according to claim 16, wherein MgO single crystal, SrTiO 3 single crystal or ZrO 2 single crystal is used as the substrate.
の成膜面を、｛001｝面または｛011｝面とすることを特
徴とする特許請求の範囲第17項に記載の超電導薄膜の作
製方法。18. The superconducting thin film according to claim 17, wherein the film-forming surface of the MgO single crystal or SrTiO 3 single crystal substrate is a {001} plane or a {011} plane. Manufacturing method.
以下であることを特徴とする特許請求の範囲第１項乃至
第18項のいずれか１項に記載の超電導薄膜の作製方法。19. The vacuum deposition pressure is 5 × 10 −5 Torr.
The method for producing a superconducting thin film according to any one of claims 1 to 18, wherein:
ることを特徴とする特許請求の範囲第１項乃至第19項の
いずれか１項に記載の超電導薄膜の作製方法。20. The method for producing a superconducting thin film according to claim 1, wherein the evaporation source is heated by an electron beam gun.
素含有雰囲気で加熱−徐冷する熱処理または酸素プラズ
マに曝すプラズマ酸化処理を行うことを特徴とする特許
請求の範囲第１項乃至第20項のいずれか１項に記載の超
電導薄膜の作製方法。21. The method according to claim 1, wherein after the film formation by the vacuum vapor deposition, a heat treatment for heating / slow cooling in an oxygen-containing atmosphere or a plasma oxidation treatment for exposing to oxygen plasma is performed. Item 21. A method for producing a superconducting thin film according to any one of items 20.
℃の範囲であることを特徴とする特許請求の範囲第21に
記載の超電導薄膜の作製方法。22. The heating temperature during the heat treatment is 500 to 1000.
22. The method for producing a superconducting thin film according to claim 21, wherein the superconducting thin film is in the range of ° C.
下であることを特徴とする特許請求の範囲第21項または
22項に記載の超電導薄膜の作製方法。23. The cooling method according to claim 21, wherein the cooling temperature during the heat treatment is 20 ° C./minute or less.
Item 23. A method for producing a superconducting thin film according to Item 22.
あることを特徴とする特許請求の範囲第21項乃至第23項
のいずれか１項に記載の超電導薄膜の作製方法。24. The method for producing a superconducting thin film according to claim 21, wherein the oxygen partial pressure during the heat treatment is 1 to 10 atmospheres.
Torrの範囲であることを特徴とする特許請求の範囲第21
項に記載の超電導薄膜の作製方法。25. The pressure during the plasma oxidation is 0.1 to 5
Claim 21 characterized by being in the range of Torr
A method for producing a superconducting thin film according to item.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62253187A JP2567416B2 (en) | 1987-10-07 | 1987-10-07 | Preparation method of superconducting thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62253187A JP2567416B2 (en) | 1987-10-07 | 1987-10-07 | Preparation method of superconducting thin film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0195414A JPH0195414A (en) | 1989-04-13 |
| JP2567416B2 true JP2567416B2 (en) | 1996-12-25 |
Family
ID=17247758
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|---|---|---|---|
| JP62253187A Expired - Fee Related JP2567416B2 (en) | 1987-10-07 | 1987-10-07 | Preparation method of superconducting thin film |
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| Country | Link |
|---|---|
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63307269A (en) * | 1987-06-08 | 1988-12-14 | Nippon Cement Co Ltd | Production of superconducting oxide target |
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