JPH03131595A - Formation of superconductor thin film - Google Patents

Formation of superconductor thin film

Info

Publication number
JPH03131595A
JPH03131595A JP1271038A JP27103889A JPH03131595A JP H03131595 A JPH03131595 A JP H03131595A JP 1271038 A JP1271038 A JP 1271038A JP 27103889 A JP27103889 A JP 27103889A JP H03131595 A JPH03131595 A JP H03131595A
Authority
JP
Japan
Prior art keywords
thin film
substrate
superconducting
superconductor
single crystal
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.)
Pending
Application number
JP1271038A
Other languages
Japanese (ja)
Inventor
Toshihiro Kotani
敏弘 小谷
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sumitomo Electric Industries Ltd
Original Assignee
Sumitomo Electric Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sumitomo Electric Industries Ltd filed Critical Sumitomo Electric Industries Ltd
Priority to JP1271038A priority Critical patent/JPH03131595A/en
Publication of JPH03131595A publication Critical patent/JPH03131595A/en
Pending legal-status Critical Current

Links

Classifications

    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/60Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment

Landscapes

  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Superconductor Devices And Manufacturing Methods Thereof (AREA)

Abstract

PURPOSE:To enable to form a superconductor thin film exhibiting excellent superconductor characteristics without requiring any thermal treatment after vacuum deposition by employing a specific substrate when a Bi or Tl oxide superconductor thin film is formed on the substrate by the vacuum deposition method. CONSTITUTION:When the thin film of a Bi oxide superconductor or Tl oxide superconductor is formed on a substrate, a Bi2(Sr, Ca)2CuOx single crystal is employed for the substrate. Since the single crystal has a pseudo-tetragonal crystalline structure and lattice constants of a b=3.8Angstrom and c=24Angstrom and the lattice constants a and b of the superconductor are substantially the same, the thin film can epitaxially grow on the substrate.

Description

【発明の詳細な説明】 [産業上の利用分野コ この発明は、Bi系酸化物超電導材料およびTE系酸化
物超電導材料の薄膜を形成する方法に関するものである
DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for forming thin films of Bi-based oxide superconducting materials and TE-based oxide superconducting materials.

[従来の技術] 酸化物超電導材料の薄膜を形成する方法としては、従来
より、RFスパッタ法、イオンビームスパッタ法、レー
ザアブレーション法、および電子ビーム蒸着法等の物理
的広告方法と、蒸着源として有機金属を用いるMOCV
D法等の化学的蒸着方法が知られている。これらの蒸着
において従来より用いられている基板は、Ao、20a
(サファイア)、MgO1S r T t O3、L 
a A fLO3、LaGa0.、ZrO2(YSZ)
等の酸化物の結晶が用いられている。
[Prior Art] Conventionally, methods for forming thin films of oxide superconducting materials include physical advertising methods such as RF sputtering, ion beam sputtering, laser ablation, and electron beam evaporation, and methods for forming thin films of oxide superconducting materials. MOCV using organometallic
Chemical vapor deposition methods such as D method are known. The substrates conventionally used in these depositions are Ao, 20a
(Sapphire), MgO1S r T t O3, L
a A fLO3, LaGa0. , ZrO2 (YSZ)
Crystals of oxides such as

〔発明が解決しようとする課題〕[Problem to be solved by the invention]

これらの従来の酸化物結晶を基板として上記の蒸着法に
より薄膜を形成させた場合、いずれもアズグロウン、す
なわち蒸着直後の状態では薄膜がアモルファス状態であ
り、超電導を示さない。したがって、従来は蒸着後に6
00〜900℃の温度で蒸若膜を熱処理することによっ
て超電導を発揮し得る状態にしている。しかしながら、
このようにして形成される超電導薄膜は、基板のC軸に
配向した多結晶膜であり、エピタキシャル成長した薄膜
ではない。また、従来の超電導薄膜の形成方法では、高
温での熱処理が必要なため、熱処理の際に生じる基板と
の反応、および熱膨張差による熱歪の発生等により超電
導特性か劣化するという問題があった。
When a thin film is formed using these conventional oxide crystals as a substrate by the above-described vapor deposition method, the thin film is as-grown, that is, the thin film is in an amorphous state immediately after vapor deposition, and does not exhibit superconductivity. Therefore, conventionally, 6
By heat-treating the young film at a temperature of 00 to 900°C, it is brought into a state where it can exhibit superconductivity. however,
The superconducting thin film thus formed is a polycrystalline film oriented along the C-axis of the substrate, and is not an epitaxially grown thin film. Furthermore, since conventional methods for forming superconducting thin films require heat treatment at high temperatures, there is the problem that superconducting properties deteriorate due to reactions with the substrate that occur during heat treatment, and thermal distortion caused by thermal expansion differences. Ta.

このように、従来から用いられているAQ。0、等の酸
化物基板を用いた場合、結晶構造の差異に基づく格子不
整合や、基板と超電導材料との界面での構成原子の相互
拡散および反応、ならびに熱膨張率の差異に基づく熱歪
の発生等により、良質なエピタキシャル単結晶薄膜を成
長させることが困難であった。
In this way, AQ has been used conventionally. When using an oxide substrate such as 0, there will be lattice mismatch due to differences in crystal structure, mutual diffusion and reactions of constituent atoms at the interface between the substrate and superconducting material, and thermal strain due to differences in thermal expansion coefficients. It has been difficult to grow a high quality epitaxial single crystal thin film due to the occurrence of .

この発明の目的は、Bi系酸化物超電導材料またはT痣
系酸化物超電導材料の薄膜を基板上にエピタキシャル成
長させることにより、従来必要であった熱処理を行なわ
ずとも良好な超電導特性を示す超電導薄膜を形成させる
ことのできる方法を提供することにある。
The purpose of this invention is to epitaxially grow a thin film of Bi-based oxide superconducting material or T-based oxide superconducting material on a substrate, thereby producing a superconducting thin film that exhibits good superconducting properties without the conventional heat treatment. The objective is to provide a method that allows the formation of

[課題を解決するための手段および作用]この発明の超
電導薄膜の形成方法では、基板としてBi2  (Sr
、Ca) 2Cubx単結晶を用いることを特徴として
いる。
[Means and effects for solving the problems] In the method for forming a superconducting thin film of the present invention, Bi2 (Sr
, Ca) 2Cubx single crystal is used.

Bi系酸化物超電導材料およびTα系酸化物超電導材料
は、ともに100に以上の高い臨界温度を有する超電導
材料であり、層状構造を持つことが知られている。また
、これらの材料において、構成元素を他の元素で置換あ
るいは添加したものも、高い臨界温度を示すことが知ら
れている。このようなものは、以下の一般式で示すこと
ができる。
Both Bi-based oxide superconducting materials and Tα-based oxide superconducting materials are superconducting materials that have high critical temperatures of 100 or higher, and are known to have a layered structure. Furthermore, it is known that materials in which constituent elements are replaced or added with other elements also exhibit high critical temperatures. Such a product can be represented by the following general formula.

(TQ、Bi、Pb)m  (Ba、5r)2 Can
cun++  (ここでm−1,2; n=0.1,2
゜3.4,5.6である。) 上記のように構成元素を他の元素で置換したものおよび
添加した超電導材料を含め、Bi系酸化物超電導材料お
よびTI系酸化物超電導材料は、いずれも正方晶または
擬正方晶であり、C軸方向に構成原子面が積層した構造
を有している。しかも、これらの超電導祠料の結晶構造
の格子定数は、a軸およびb軸のいずれにおいても、a
−3,8人であり、はとんど変わらない。C軸のみが、
材料によって積層構造(積層周期)が異なるため、異な
る値となる。
(TQ, Bi, Pb)m (Ba, 5r)2 Can
cun++ (here m-1,2; n=0.1,2
゜3.4, 5.6. ) Bi-based oxide superconducting materials and TI-based oxide superconducting materials, including superconducting materials in which constituent elements have been replaced with other elements and added as described above, are both tetragonal or pseudotetragonal; It has a structure in which constituent atomic planes are stacked in the axial direction. Moreover, the lattice constant of the crystal structure of these superconducting abrasive materials is a
- There are 3.8 people, and there is almost no difference. Only the C axis is
Since the laminated structure (lamination period) differs depending on the material, the values will be different.

一方、これらの超電導材料は、蒸着により薄膜を形成し
た場合、C軸に配向しやすいことが知られている。した
がって、これらの超電導材料をエピタキシャル成長させ
るためには、格子定数のaおよびbが、蒸着させる超電
導材料とほぼ一致した格子定数を有する基板が必要とな
る。この発明下基板として用いるBi2  (Sr、C
a)2 CuO3単結晶は、擬正方晶の結晶構造を有し
、格子定数がa#b−3,8A、c−24Aであり、超
電導材料の格子定数aおよびbとほぼ一致した直を有す
る。
On the other hand, it is known that these superconducting materials tend to be oriented along the C axis when a thin film is formed by vapor deposition. Therefore, in order to epitaxially grow these superconducting materials, a substrate is required whose lattice constants a and b substantially match those of the superconducting material to be deposited. Bi2 (Sr, C
a) 2 CuO3 single crystal has a pseudotetragonal crystal structure, has lattice constants a#b-3, 8A, c-24A, and has a straightness that almost matches the lattice constants a and b of the superconducting material. .

また、この発明で基板として用いるBi2 (Sr、C
a)2 Cu0x単結晶は、超電導材料と同一の構成元
素を有しているため、従来、問題となった基板界面での
反応による異種元素の拡散や、熱膨張率の差異に基づく
熱歪等の問題を発生しない。
Furthermore, Bi2 (Sr, C
a) Since the 2 Cu0x single crystal has the same constituent elements as the superconducting material, it suffers from the conventional problems of diffusion of different elements due to reactions at the substrate interface and thermal distortion due to differences in thermal expansion coefficients. does not cause any problems.

さらに、Bi2  (Sr、Ca)2 Cubxは、非
超電導相であるため、この基板上に形成した超電導材料
との間で相互に干渉を起こすこともない。
Furthermore, since Bi2 (Sr, Ca)2 Cubx is a non-superconducting phase, it does not interfere with the superconducting material formed on this substrate.

[実施例] 基板として、フラツクス性により作製したBi2  (
Sr、Ca)2 Cub、単結晶であり、10mm10
mmX10.1mmの大きさのものを用いた。
[Example] As a substrate, Bi2 (
Sr, Ca)2 Cub, single crystal, 10mm10
A size of mm x 10.1 mm was used.

RFマグネトロンスパッタ法により、B12(S r、
Ca)、Cu3 o、の組成の超電導薄膜を以下の条件
で基板上に蒸着して形成させた。
B12 (S r,
A superconducting thin film having a composition of Ca) and Cu3o was deposited on a substrate under the following conditions.

ターゲット組成:Bi :Sr:Ca:Cu−1,5:
1:1:1.5 ガス:Ar(80%) + 02  (2096)ガス
圧:0.03Torr 基板温度ニア00〜850℃ 厚み: 500nm 以上のようにして基板上に蒸着した薄膜を電子線回折(
RHEED)およびX線回折で調べたところ、エピタキ
シャル成長した単結晶薄膜であることが確認された。ま
たこの薄膜のTciは105にであり、Jcは101;
A/cm2 (OT、77K)であった。
Target composition: Bi:Sr:Ca:Cu-1,5:
1:1:1.5 Gas: Ar (80%) + 02 (2096) Gas pressure: 0.03 Torr Substrate temperature near 00 to 850°C Thickness: 500 nm Electron beam diffraction of the thin film deposited on the substrate as described above (
When examined by RHEED) and X-ray diffraction, it was confirmed that it was an epitaxially grown single crystal thin film. Also, the Tci of this thin film is 105, and the Jc is 101;
A/cm2 (OT, 77K).

比較として、上記の基板に代えて、従来から用いられて
いるMgOの基板を用いて、超電導薄膜を蒸着により形
成させた。得られた超電導薄膜は多結晶膜であり、Tc
iは約60に、Jcは10’A/cm2以下であった。
For comparison, a conventionally used MgO substrate was used in place of the above substrate, and a superconducting thin film was formed by vapor deposition. The obtained superconducting thin film is a polycrystalline film, and Tc
i was approximately 60, and Jc was 10'A/cm2 or less.

以上の結果から明らかなように、この発明に従t、sB
 i2  (S r、Ca) 2Cubx単結晶を基板
として用いることにより、エピタキシャル成長により超
電導特性に優れた超電導薄膜を形成できることが確認さ
れた。
As is clear from the above results, according to the present invention, t, sB
It was confirmed that by using an i2 (S r, Ca) 2Cubx single crystal as a substrate, a superconducting thin film with excellent superconducting properties can be formed by epitaxial growth.

[発明の効果] この発明の超電導薄膜形成ノj法では、Bi系酸化物超
電導材料およびTi系酸化物超電導材料の格子定数aお
よびbとほぼ同一の格子定数を有するBi2  (Sr
、Ca):l Cubx単結晶を基板に用いているため
、超電導薄膜を基板上にエピタキシャル成長させること
ができ、高い臨界温度および高い臨界電流密度を有する
超電導薄膜を形成させることができる。
[Effects of the Invention] In the superconducting thin film forming method of the present invention, Bi2 (Sr
, Ca):l Cubx single crystal is used as the substrate, a superconducting thin film can be epitaxially grown on the substrate, and a superconducting thin film having a high critical temperature and a high critical current density can be formed.

Claims (1)

【特許請求の範囲】[Claims] (1)基板上にBi系酸化物超電導材料またはTl系酸
化物超電導材料の薄膜を形成する方法において、 前記基板としてBi_2(Sr、Ca)_2CuO_x
単結晶を用いることを特徴とする、超電導薄膜の形成方
法。
(1) In a method of forming a thin film of Bi-based oxide superconducting material or Tl-based oxide superconducting material on a substrate, the substrate is Bi_2(Sr, Ca)_2CuO_x
A method for forming a superconducting thin film characterized by using a single crystal.
JP1271038A 1989-10-17 1989-10-17 Formation of superconductor thin film Pending JPH03131595A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1271038A JPH03131595A (en) 1989-10-17 1989-10-17 Formation of superconductor thin film

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1271038A JPH03131595A (en) 1989-10-17 1989-10-17 Formation of superconductor thin film

Publications (1)

Publication Number Publication Date
JPH03131595A true JPH03131595A (en) 1991-06-05

Family

ID=17494538

Family Applications (1)

Application Number Title Priority Date Filing Date
JP1271038A Pending JPH03131595A (en) 1989-10-17 1989-10-17 Formation of superconductor thin film

Country Status (1)

Country Link
JP (1) JPH03131595A (en)

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