JPH01278449A - Production of oxide superconductor - Google Patents
Production of oxide superconductorInfo
- Publication number
- JPH01278449A JPH01278449A JP63105907A JP10590788A JPH01278449A JP H01278449 A JPH01278449 A JP H01278449A JP 63105907 A JP63105907 A JP 63105907A JP 10590788 A JP10590788 A JP 10590788A JP H01278449 A JPH01278449 A JP H01278449A
- Authority
- JP
- Japan
- Prior art keywords
- oxide superconductor
- based oxide
- phase
- critical temperature
- temperature
- 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
Links
- 239000002887 superconductor Substances 0.000 title claims abstract description 54
- 238000004519 manufacturing process Methods 0.000 title claims description 13
- 229910014454 Ca-Cu Inorganic materials 0.000 claims abstract description 26
- 238000010438 heat treatment Methods 0.000 claims abstract description 15
- 239000013078 crystal Substances 0.000 claims abstract description 14
- 238000002844 melting Methods 0.000 claims abstract description 10
- 230000008018 melting Effects 0.000 claims abstract description 10
- 239000002994 raw material Substances 0.000 claims abstract description 9
- 239000012298 atmosphere Substances 0.000 claims abstract description 8
- 239000000155 melt Substances 0.000 claims abstract description 5
- 239000012071 phase Substances 0.000 claims description 35
- 238000000034 method Methods 0.000 claims description 21
- 239000010409 thin film Substances 0.000 claims description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 9
- 239000001301 oxygen Substances 0.000 claims description 9
- 229910052760 oxygen Inorganic materials 0.000 claims description 9
- 238000001816 cooling Methods 0.000 claims description 7
- 239000012808 vapor phase Substances 0.000 claims description 2
- 239000000126 substance Substances 0.000 abstract description 5
- 239000000470 constituent Substances 0.000 abstract description 4
- 239000000203 mixture Substances 0.000 abstract description 4
- 238000010791 quenching Methods 0.000 abstract description 4
- 230000000171 quenching effect Effects 0.000 abstract description 4
- 150000001875 compounds Chemical class 0.000 abstract description 3
- -1 oxide or carbonate Chemical class 0.000 abstract description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 abstract 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 239000000843 powder Substances 0.000 description 8
- 239000000758 substrate Substances 0.000 description 8
- 239000007788 liquid Substances 0.000 description 5
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 4
- 239000010408 film Substances 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 238000000151 deposition Methods 0.000 description 3
- 239000007858 starting material Substances 0.000 description 3
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 description 2
- 235000010216 calcium carbonate Nutrition 0.000 description 2
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000012768 molten material Substances 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- LEDMRZGFZIAGGB-UHFFFAOYSA-L strontium carbonate Chemical compound [Sr+2].[O-]C([O-])=O LEDMRZGFZIAGGB-UHFFFAOYSA-L 0.000 description 2
- 229910000018 strontium carbonate Inorganic materials 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- WMWLMWRWZQELOS-UHFFFAOYSA-N bismuth(III) oxide Inorganic materials O=[Bi]O[Bi]=O WMWLMWRWZQELOS-UHFFFAOYSA-N 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000004453 electron probe microanalysis Methods 0.000 description 1
- UFZOPKFMKMAWLU-UHFFFAOYSA-N ethoxy(methyl)phosphinic acid Chemical compound CCOP(C)(O)=O UFZOPKFMKMAWLU-UHFFFAOYSA-N 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 239000003507 refrigerant Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
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
- Inorganic Compounds Of Heavy Metals (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
Abstract
Description
【発明の詳細な説明】
［発明の目的］
（産業上の利用分野）
この発明は、Ｂｉ−Ｓｒ−Ｃａ−Ｃｕ−０系酸化物超電
導体の製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a Bi-Sr-Ca-Cu-0 based oxide superconductor.
（従来の技術）
１９８６年に４０に以上の高い臨界温度を有するＬａ−
Ｂａ−Ｃｕ−０系の層状ペロブスカイト型の酸化物超電
導体が発表されて以来、酸化物系の超電導材料が注目を
集めた。また、１９８７年にはＹ−Ｂａ−Ｃｕ−０系で
代表される酸素欠陥を有する欠陥ペロブスカイト型の酸
化物超電導体の臨界温度が液体窒素温度（−７７Ｋ）よ
り高い、約９０にであることが確認された。この発見に
より冷媒として高価な液体ヘリウムに代えて、より安価
な液体窒素を用いた超電導体の応用が可能となり、各所
で盛んに研究が行われている。(Prior art) In 1986, La-
Since the Ba-Cu-0-based layered perovskite-type oxide superconductor was announced, oxide-based superconducting materials have attracted attention. Furthermore, in 1987, it was discovered that the critical temperature of a defective perovskite-type oxide superconductor with oxygen defects, represented by the Y-Ba-Cu-0 system, is about 90°C, higher than the liquid nitrogen temperature (-77K). was confirmed. This discovery has made it possible to apply superconductors using cheaper liquid nitrogen instead of expensive liquid helium as a refrigerant, and research is being actively conducted in various places.
さらに、１９８８年には零抵抗を示す臨界温度が約１０
５にのＢｉ−Ｓｒ−Ｃａ−Ｃｕ−０系の酸化物超電導体
が発見されるに至った（日本経済新聞昭和６３年１月２
２日など）。Furthermore, in 1988, the critical temperature at which zero resistance occurs was approximately 10
5, the Bi-Sr-Ca-Cu-0 based oxide superconductor was discovered (Nihon Keizai Shimbun, January 2, 1988).
2 days, etc.).
このＢｉ−Ｓｒ−Ｃａ−Ｃｕ系の酸化物超電導体は、Ｌ
ａ−Ｂａ−Ｃｕ−０系やＹ−Ｂａ−Ｃｕ−０系の酸化物
超電導体に比ベて臨界温度が高く、たとえば液体窒素に
よって冷却を行う際に実用上充分な熱的マージンがとれ
るばかりでなく、高価な希土類元素が不要であること、
水分に対する化学的安定性が高いこと、酸素が抜けにく
いことなどの利点があり、より優れた酸化物超電導体と
して注目を集めている。This Bi-Sr-Ca-Cu based oxide superconductor is
It has a higher critical temperature than the a-Ba-Cu-0 and Y-Ba-Cu-0 oxide superconductors, and can provide a practically sufficient thermal margin when cooling with liquid nitrogen, for example. In addition, expensive rare earth elements are not required.
It has advantages such as high chemical stability against moisture and resistance to oxygen escape, and is attracting attention as a superior oxide superconductor.
この旧−Ｓｒ−Ｃａ−Ｃｕ系酸化物超電導体は、Ｙ−Ｂ
ａ−Ｃｕ−０系酸化物超電導体と同様に通常の乾式法に
よって合成することができる。すなわち、原料粉末とし
てたとえば旧２０３ 、ＳｒＣＯ３、ＣａＣＯ３、Ｃｕ
Ｏなどの粉末を用い、充分に混合した後に適当な温度で
保持して焼成し、焼結体やその粉末として得ることがで
きる。このＢｉ−Ｓｒ−Ｃａ−Ｃｕ系酸化物超電導体の
焼成温度は、融点近傍の８９０℃程度が最適であるとい
う報告が多い。This old-Sr-Ca-Cu based oxide superconductor is Y-B
Like the a-Cu-0 based oxide superconductor, it can be synthesized by a normal dry method. That is, raw material powders such as old 203, SrCO3, CaCO3, Cu
A sintered body or its powder can be obtained by thoroughly mixing powders such as O and then holding and firing them at an appropriate temperature. There are many reports that the optimal firing temperature for this Bi-Sr-Ca-Cu based oxide superconductor is about 890°C, which is near the melting point.
ところで、上述したような通常の焼成法によって得た旧
−Ｓｒ−Ｃａ−Ｃｕ系酸化物超電導体の焼結体では電気
抵抗が急激に減少しはじめる臨界温度、すなわち抵抗の
オンセット温度（以下Ｔｃｏｎと示す）が約１２０にと
高く、この抵抗の急激な減少グラフ上に外挿すると零抵
抗を示す臨界温度（以下Ｔｅｏｒｒと示す）が１１０に
程度となるにも拘らず、実際のＴｃｏ［’［’は７５Ｘ
〜８５に前後と低いという性質がある。By the way, in the sintered body of the former -Sr-Ca-Cu based oxide superconductor obtained by the above-mentioned normal sintering method, the critical temperature at which the electrical resistance begins to rapidly decrease, that is, the resistance onset temperature (hereinafter referred to as Tcon) The actual Tco ['[' is 75X
There is a property that it is low around ~85.
これは、臨界温度の異なる２種類の超電導相がＢｉ−Ｓ
ｒ−Ｃａ−Ｃｕ系酸化物超電導体には存在しているため
に生じる性質であると、現在のところほぼ解明されてい
る。This is because two types of superconducting phases with different critical temperatures are Bi-S.
At present, it has been largely clarified that this property is caused by the presence of r-Ca-Cu-based oxide superconductors.
また、最近の研究で高臨界温度相および低臨界温度相は
、それぞれほぼ下記の結晶構造を有していることが確認
されつつある。Furthermore, recent research has confirmed that the high critical temperature phase and the low critical temperature phase each have approximately the following crystal structures.
高臨界温度相： Ｂｉ２ Ｓｒ２ Ｃａ２ Ｃｕ３０
ｘ（結晶格子のＣ軸の長さが約３６人）
低臨界温度相： Ｂｉ２ Ｓｒ２ Ｃａ１Ｃｕ２０ ｘ
（結晶格子のＣ軸の長さが約３０人）
（発明が解決しようとする課題）
上述したように、Ｂｉ−Ｓｒ−Ｃａ−Ｃｕ系酸化物超電
導体は、高臨界温度相と低臨界温度相の２８類の超電導
相を有しているため、Ｔｃｏｆｆ’を高めるためには高
臨界温度相の比率を高めることが必要となるが、現在の
ところ高臨界温度相単相のＢｉ−Ｓｒ−Ｃａ−Ｃｕ系酸
化物超電導体の製造方法は見出されていないのが現状で
ある。High critical temperature phase: Bi2 Sr2 Ca2 Cu30
x (The length of the C axis of the crystal lattice is approximately 36 people) Low critical temperature phase: Bi2 Sr2 Ca1Cu20 x
(The length of the C axis of the crystal lattice is about 30.) (Problem to be solved by the invention) As mentioned above, Bi-Sr-Ca-Cu based oxide superconductors have a high critical temperature phase and a low critical temperature phase. Since it has 28 class superconducting phases, it is necessary to increase the ratio of high critical temperature phase in order to increase Tcoff', but at present, Bi-Sr- At present, no method for producing a Ca-Cu-based oxide superconductor has been found.
そこで、高臨界温度相を単相で取出す研究が各所で行わ
れているが、今だ有効な方法は見出されていない。Therefore, research is being conducted in various places to extract the high critical temperature phase as a single phase, but no effective method has yet been found.
この発明は、このような従来技術の課題に対処するため
になされたもので、Ｔｅｏｎが１２０に前後の高臨界温
度相の比率の高いＢｉ−Ｓｒ−Ｃａ−Ｃｕ系酸化物超電
導体、さらには高臨界温度相単相のＢｉ−Ｓｒ−Ｃａ−
Ｃｕ系酸化物超電導体を得ることを可能にする酸化物超
電導体の製造方法を提供することを目的としている。This invention was made in order to address the problems of the prior art, and includes a Bi-Sr-Ca-Cu based oxide superconductor having a high ratio of high critical temperature phase with a Teon of around 120, and furthermore, High critical temperature single phase Bi-Sr-Ca-
It is an object of the present invention to provide a method for producing an oxide superconductor that makes it possible to obtain a Cu-based oxide superconductor.
［発明の構成］
（課題を解決するための手段）
この発明の酸化物超電導体の製造方法は、まず第１にＢ
ｉ−Ｓｒ−Ｃａ−Ｃｕ系酸化物超電導体原料を加熱溶融
する工程と、この溶融物を急冷する工程と、この急冷体
を酸素含有雰囲気中において４００”０〜８００℃の温
度条件下で熱処理し高臨界温度相を生じせしめる工程と
を有することを特徴としており、第２に非晶質あるいは
完全な結晶を構成していない旧−９ｒ−Ｃａ−Ｃｕ系酸
化物超電導体薄膜を気相形成する工程と、このＢｉ−Ｓ
ｒ−Ｃａ−Ｃｕ系酸化物超電導体薄膜を酸素含有雰囲気
中において４００℃〜８００℃の温度条件下で熱処理し
高臨界温度相を生じせしめる工程とを有することを特徴
としている。[Structure of the Invention] (Means for Solving the Problems) The method for producing an oxide superconductor of the present invention first includes B.
A process of heating and melting the i-Sr-Ca-Cu based oxide superconductor raw material, a process of rapidly cooling this melt, and a heat treatment of this rapidly cooled body in an oxygen-containing atmosphere at a temperature of 400°C to 800°C. and a step of generating a high critical temperature phase.Secondly, the process involves vapor phase formation of a prior-9r-Ca-Cu based oxide superconductor thin film that is amorphous or does not constitute a perfect crystal. This process and this Bi-S
The method is characterized by a step of heat-treating an r-Ca-Cu based oxide superconductor thin film under a temperature condition of 400° C. to 800° C. in an oxygen-containing atmosphere to generate a high critical temperature phase.
この発明の第１の酸化物超電導体の製造方法における溶
融物の出発原料は、たとえば以下のようにして作製され
る。The starting material for the melt in the first method for producing an oxide superconductor of the present invention is produced, for example, as follows.
Ｂｉ、Ｓｒｓ Ｃａｓ ＣｕなどのＢｉ−９ｒ−Ｃａ−
Ｃｕ系酸化物超電導体の構成元素の単体または化合物を
充分に混合する。この構成元素の化合物としては、炭酸
塩、酸化物を用いることができるほか、炭酸塩以外の加
熱により酸化物に転化する硝酸塩、水酸化物など、さら
に有機酸塩や有機金属などを用いてもよい。Bi-9r-Ca- such as Bi, Srs Cas Cu
The constituent elements or compounds of the Cu-based oxide superconductor are sufficiently mixed. As compounds of this constituent element, carbonates and oxides can be used, as well as nitrates and hydroxides that are converted to oxides by heating other than carbonates, and organic acid salts and organic metals. good.
このＢｉ−Ｓｒ−Ｃａ−Ｃｕ系酸化物超電導体を構成す
る元素は、基本的に高臨界温度の超電導相として解明さ
れた、
一般式： Ｂｌ２ Ｓｒ２ Ｃａ２ Ｃｕ３０ ｘ（結
晶格子のＣ軸長さが約３６人）
の原子比を満足する組成となるように混合するが、たと
えば蒸気圧の比較的低いＢｌを多少多めに配合するなど
、溶融温度や溶融時間などの製造条件との関係で多少、
たとえばｌＯ％程度ずれていても差支えず、これらに応
じて適宜設定する。The elements constituting this Bi-Sr-Ca-Cu-based oxide superconductor are basically elucidated as a superconducting phase with a high critical temperature, and have the general formula: Bl2 Sr2 Ca2 Cu30 x (the C-axis length of the crystal lattice is However, depending on manufacturing conditions such as melting temperature and melting time, for example, blending a slightly larger amount of Bl, which has a relatively low vapor pressure,
For example, there is no problem even if there is a difference of about 10%, and the setting is made appropriately according to this.
このようにして得た各構成元素を所定の比率で含有する
混合物を出発原料として用いてもよいし、あるいは８０
０℃以上、融点以下の温度で仮焼して、予め結晶化させ
た酸化物超電導体を用いてもよい。A mixture containing each constituent element in a predetermined ratio obtained in this way may be used as a starting material, or
An oxide superconductor that has been pre-crystallized by calcining at a temperature of 0° C. or higher and lower than the melting point may be used.
次に、これら出発原料を融点以上に加熱して溶融させた
後、所定の速度で急冷して酸化物超電導体の急冷体を作
製する。Next, these starting materials are heated to a temperature higher than their melting point to melt them, and then rapidly cooled at a predetermined rate to produce a rapidly cooled body of an oxide superconductor.
この急冷工程は、非晶質体あるいは結晶性の悪い状態、
すなわち部分的に結晶格子の配列が乱れているような状
態の急冷体を作製するものである。This rapid cooling process removes the amorphous or poorly crystalline state.
In other words, a rapidly cooled body is produced in which the crystal lattice arrangement is partially disordered.
このため、急冷速度の制御が重要であり、■×１０２℃
／秒〜ＩＸＩＱ’℃／秒の範囲、望ましくはｌＸｌ０’
℃／秒〜ｌＸｌ０’℃／秒の範囲が好適している。For this reason, it is important to control the rapid cooling rate, and
/sec to IXIQ'°C/sec, preferably lXl0'
A range of 1X10'C/sec to 1X10'C/sec is suitable.
また、この急冷工程によって作製する酸化物超電導体の
急冷体は、ブロック状のものに限らず、たとえば下部に
ノズルを有するるつぼなどによって溶融し、ノズルから
溶融物を噴出させることによって条体、長尺な板状体を
作製することも可能である。In addition, the quenched oxide superconductor produced by this quenching process is not limited to a block shape; for example, it is melted in a crucible with a nozzle at the bottom, and the molten material is jetted from the nozzle to form a strip or a long body. It is also possible to produce a long plate-like body.
また、この発明の第２の酸化物超電導体の製造方法にお
ける薄膜の形成方法としては、スパッタ法、蒸着法、Ｃ
ＶＤ法など、各種公知の気相における薄膜形成方法を用
いることが可能であるが、上述した溶融急冷後の急冷体
と同様に、非晶質体あるいは結晶性の悪い状態の薄膜を
作製する。これは、たとえば着膜時の飛翔粒子の形態、
薄膜作製時の基板温度、着膜時にエピタキシャル成長を
起こさせないような基板の使用など、適用する形成方法
に合せて適宜条件を設定することによって容品に達成で
きる。In addition, as a method for forming a thin film in the second method for manufacturing an oxide superconductor of the present invention, sputtering method, vapor deposition method, C
Although it is possible to use various known methods for forming a thin film in the gas phase, such as the VD method, a thin film in an amorphous state or with poor crystallinity is produced, similar to the quenched body after melting and quenching described above. For example, the shape of flying particles during film deposition,
This can be achieved by appropriately setting conditions according to the applied forming method, such as the substrate temperature during thin film production and the use of a substrate that does not allow epitaxial growth during film deposition.
使用する基板としては、ＭｇＯ１Ｚｒ０２ （安定化
剤としてＹを含む。以下ＹＳｚと示す。）など、各種セ
ラミックス基板が例示される。Examples of the substrate used include various ceramic substrates such as MgO1Zr02 (contains Y as a stabilizer, hereinafter referred to as YSz).
そして、このようにして作製した結晶性の悪い酸化物超
電導体の急冷体および薄膜に、所定の条件下で長時間熱
処理を施すことによって、上述した結晶のＣ軸長さが約
３６人である高臨界温度相の体積比が６０％以上、さら
には上記Ｃ軸が約３６人のＢｉ２ Ｓｒ２ Ｃａ２ Ｃ
ｕ３０ ｘ単相のＢｉ−Ｓｒ−Ｃａ−Ｃｕ系酸化物超電
導体が得られる。Then, by subjecting the quenched body and thin film of the oxide superconductor with poor crystallinity produced in this manner to heat treatment for a long time under predetermined conditions, the C-axis length of the crystal described above is approximately 36 mm. The volume ratio of the high critical temperature phase is 60% or more, and furthermore, the C axis is about 36 Bi2 Sr2 Ca2 C
A u30 x single-phase Bi-Sr-Ca-Cu based oxide superconductor is obtained.
この熱処理は、空気中、好ましくは酸素を含有するガス
雰囲気中において４００℃〜８００℃の温度条件下で長
時間かけて行う。熱処理時の温度が４００℃未満である
と結晶化が不十分であり、また８００℃を超えるとＣ軸
長さが約３０人である低臨界温度の超電導相が安定して
、高臨界温度の超電導相の出現率が低下する。好ましく
は６００℃〜８００℃の範囲である。熱処理時間は、充
分に結晶化させるために長時間行う必要があり、温度条
件によっても異なるが、４０時間以上行うことが好まし
い。This heat treatment is performed in air, preferably in a gas atmosphere containing oxygen, at a temperature of 400°C to 800°C over a long period of time. If the temperature during heat treatment is less than 400°C, crystallization will be insufficient, and if it exceeds 800°C, the low critical temperature superconducting phase with a C-axis length of approximately 30 mm will become stable, and the high critical temperature superconducting phase will become stable. The appearance rate of superconducting phase decreases. Preferably it is in the range of 600°C to 800°C. The heat treatment needs to be carried out for a long time in order to achieve sufficient crystallization, and although it varies depending on the temperature conditions, it is preferable to carry out the heat treatment for 40 hours or more.
あまり長時間かけても飽和してしまい、それ以上の効果
が得られないため、１２０時間以下が実用的である。If it is applied for too long, it will become saturated and no further effect can be obtained, so 120 hours or less is practical.
また、この熱処理の際の昇温は、たとえば所定の温度に
加熱された炉内に直接投入するなど、急熱することによ
って低臨界温度の超電導相を経ずに直接高臨界温度の超
電導相を結晶化することができ、おおよそ１０℃／分〜
１０００℃／分程度の昇温速度となるように設定するこ
とが好ましい。In addition, the temperature increase during this heat treatment can be done by rapid heating, for example, by directly placing it in a furnace heated to a predetermined temperature, so that the high critical temperature superconducting phase is directly generated without passing through the low critical temperature superconducting phase. Can be crystallized, approximately 10℃/min~
It is preferable to set the temperature increase rate to about 1000° C./min.
（作 用）
この発明の酸化物超電導体の製造方法においては、溶融
物を急冷することによって、あるいは原子やイオン状態
での飛翔によって着膜させることにより、結晶性の悪い
状態、すなわち部分的に結晶格子の配列が乱れているよ
うな状態の旧−Ｓｒ−Ｃａ−Ｃｕ系酸化物超電導体をま
ず作製する。そして、この状態から熱処理を施すことに
よって、結晶格子のＣ軸長さが約３０人の低臨界温度の
超電導相の形成が防止され、結晶格子のＣ軸長さが約３
６人の高臨界温度の超電導相として結晶化させることが
可能となる。したがって、得られる酸化物超電導体焼結
体あるいは薄膜は、高臨界温度の超電導相の体積比率が
高いものとなり、さらには単一相となる。(Function) In the method for producing an oxide superconductor of the present invention, by rapidly cooling a molten material or depositing a film by flying in an atomic or ionic state, a film with poor crystallinity, that is, a partially First, a prior-Sr-Ca-Cu based oxide superconductor with a disordered crystal lattice arrangement is produced. Then, by applying heat treatment from this state, the formation of a low critical temperature superconducting phase with a crystal lattice C-axis length of about 30 is prevented, and the crystal lattice C-axis length is about 3
It becomes possible to crystallize it as a superconducting phase with a high critical temperature. Therefore, the obtained oxide superconductor sintered body or thin film has a high volume ratio of the high critical temperature superconducting phase, and furthermore, has a single phase.
また、得られる酸化物超電導体焼結体あるいは薄膜は、
非晶質状態に近い状態から長時間かけて熱処理して結晶
化させているため、高密度化して臨界電流密度も向上す
る。In addition, the obtained oxide superconductor sintered body or thin film is
Since it is heat-treated for a long time from a state close to an amorphous state to crystallize it, the density is increased and the critical current density is also improved.
（実施例） 次に、この発明の実施例について説明する。(Example) Next, embodiments of the invention will be described.
実施例ｌ
Ｂｉ２０３ 、ＳｒＣＯ３、ＣａＣＯ３、ＣｕＯの各粉
末を原子比でＢａ：Ｓｒ：Ｃａ：Ｃｕ＝２：２：２：３
の比率となるように所定量計量し、これを充分に混合し
て原料粉末とした。Example 1 Each powder of Bi203, SrCO3, CaCO3, and CuO was prepared in an atomic ratio of Ba:Sr:Ca:Cu=2:2:2:3
A predetermined amount was weighed so as to have a ratio of 1, and the mixture was thoroughly mixed to obtain a raw material powder.
この原料粉末をるつぼに収容し、１１００℃〜１２００
℃で約３０分間溶融した後、この溶融物を鉄板上に流出
させて急冷した。この際の冷却速度は、約ｌＸｌ０’℃
／秒であった。This raw material powder was placed in a crucible and heated to 1100°C to 1200°C.
After melting at .degree. C. for about 30 minutes, the melt was poured onto a steel plate and quenched. The cooling rate at this time is approximately 1X10'℃
/second.
次に、この急冷体を６００℃に昇温した加熱炉内に直接
投入し、この温度で１００時間保持して熱処理した後、
炉冷してＢｉ−Ｓｒ−Ｃａ−Ｃｕ系酸化物超電導体を得
た。Next, this rapidly cooled body was directly put into a heating furnace heated to 600°C, and after being heat-treated by holding it at this temperature for 100 hours,
The mixture was cooled in a furnace to obtain a Bi-Sr-Ca-Cu based oxide superconductor.
このようにして得たＢｉ−Ｓｒ−Ｃａ−Ｃｕ系酸化物超
電導体に銀ペーストで電流、電圧端子を形成した後、４
端子法で室温から液体窒素温度までの電気抵抗をｎ１定
したところ、Ｔｃ ｏｎ １１５Ｋ 、 Ｔｅ ｏ（’
ｒ ｌｌ０Ｋと良好な結果が得られた。また、このＢ［
−！Ｓｒ−Ｃａ−Ｃｕ−Ｃｕ系酸化物超電導体の結晶相
をＸ線回折とＥＭＰＡにより同定したところ、結晶格子
のＣ軸長さが約３８人の、
一般式： Ｂｉ２５ｒ２Ｃａ２Ｃｕａ Ｏｔｏ−６で表
される高臨界温度の超電導相が体積比で約８０％存在し
ていた。After forming current and voltage terminals on the thus obtained Bi-Sr-Ca-Cu based oxide superconductor using silver paste,
When the electrical resistance from room temperature to liquid nitrogen temperature was determined as n1 using the terminal method, Tc on 115K, Te o('
A good result was obtained. Also, this B[
-! When the crystal phase of the Sr-Ca-Cu-Cu-based oxide superconductor was identified by X-ray diffraction and EMPA, it was found that the C-axis length of the crystal lattice was approximately 38 mm, and was expressed by the general formula: Bi25r2Ca2Cua Oto-6. A superconducting phase with a high critical temperature existed in an amount of about 80% by volume.
また、７７Ｋにおける臨界電流密度を測定したところ、
ＩＸ １０’ Ａ／ｃｊであった。In addition, when we measured the critical current density at 77K,
IX 10' A/cj.
一方、この発明との比較のために、上記実施例で作製し
た原料粉末を空気中、８００℃、１０時間の条件で仮焼
し、この焼成物を粉砕、分級した後、プレス加工により
ペレット化し、酸素雰囲気中、８７０℃、２４時間の条
件で焼結させてＢｉ−Ｓｒ−Ｃａ−Ｃｕ系酸化物超電導
体を得た。この酸化物超電導体についても上記実施例と
同様にして電気抵抗を測定したところ、ｌｌ０Ｋから急
激に電気抵抗が減少したが、ＴｃｏＮ’は７５Ｋ テあ
ツタ。On the other hand, for comparison with the present invention, the raw material powder produced in the above example was calcined in air at 800°C for 10 hours, and the calcined product was crushed and classified, and then pelletized by pressing. A Bi-Sr-Ca-Cu based oxide superconductor was obtained by sintering in an oxygen atmosphere at 870°C for 24 hours. When the electrical resistance of this oxide superconductor was measured in the same manner as in the above example, the electrical resistance decreased rapidly from 110K, but TcoN' was only 75K.
実施例２
実施例１で作製した原料粉末をプレス加工により円板状
に成形した後、酸素雰囲気中、８７０℃、・２４時間の
条件で焼結させてスパッタターゲットを作製した。Example 2 The raw material powder produced in Example 1 was formed into a disk shape by press working, and then sintered in an oxygen atmosphere at 870° C. for 24 hours to produce a sputter target.
このスパッタターゲットを用い、また着膜基板としてＹ
ＳＺ基板を使用して、ｌＸ１０°’ Ｔｏｒｒのアルゴ
ン雰囲気中、印加電圧２００ｖの条件で高周波スパッタ
を行い、ＹＳＺ基板上に厚さ１０００人の結晶性の悪い
状態のＢｉ−９ｒ−Ｃａ−Ｃｕ系酸化物超電導体薄膜を
形成した。なお、基板温度は１００℃に設定した。Using this sputter target, Y
Using an SZ substrate, high frequency sputtering was performed under the conditions of an applied voltage of 200 V in an argon atmosphere of 1 x 10°' Torr, and a Bi-9r-Ca-Cu system with poor crystallinity was deposited on the YSZ substrate to a thickness of 1000 mm. An oxide superconductor thin film was formed. Note that the substrate temperature was set at 100°C.
次に、この薄膜が形成されたＹＳｚ基板を、実施例１と
同一条件で熱処理し、結晶化させた。Next, the YSz substrate on which this thin film was formed was heat-treated under the same conditions as in Example 1 to crystallize it.
このようにして得たＢｉ−Ｓｒ−Ｃａ−Ｃｕ系酸化物超
電導体薄膜の電気抵抗を実施例１と同様にして測定した
ところ、Ｔｃ ｏｎ １１５Ｋ ＳＴｃ ｏｆｆ ｌｌ
０Ｋと良好な結果が得られた。また、このＢｉ−Ｓｒ−
Ｃａ−Ｃｕ系酸化物超電導体の結晶相を実施例１と同様
に同定したところ、高臨界温度の超電導相が体積比で約
８０％存在していた。また、７７Ｋにおける臨界電流密
度を測定したところ、ＬＸ １０’ Ａｄｄであった。The electrical resistance of the Bi-Sr-Ca-Cu based oxide superconductor thin film thus obtained was measured in the same manner as in Example 1, and it was found that Tc on 115K STc off ll
A good result of 0K was obtained. Moreover, this Bi-Sr-
When the crystalline phase of the Ca-Cu-based oxide superconductor was identified in the same manner as in Example 1, it was found that a high critical temperature superconducting phase existed in a volume ratio of about 80%. Further, when the critical current density at 77K was measured, it was LX 10' Add.
［発明の効果］
以上の実施例からも明らかなように、この発明の酸化物
超電導体の製造方法によれば、零抵抗を示す臨界温度・
Ｔｃｏｒｆ’の高い超電導相の比率が高いＢｉ−Ｓｒ−
Ｃａ−Ｃｕ系酸化物超電導体が得られ、安定して高臨界
温度の酸化物超電導体を得ることが可能となる。[Effects of the Invention] As is clear from the above examples, according to the method for producing an oxide superconductor of the present invention,
Bi-Sr- with a high proportion of superconducting phase with high Tcorf'
A Ca-Cu-based oxide superconductor is obtained, and it becomes possible to stably obtain an oxide superconductor with a high critical temperature.
出願人 株式会社 東芝 代理人 弁理士 須 山 佐 −Applicant: Toshiba Corporation Agent Patent Attorney Suyama Sa
Claims (2)
加熱溶融する工程と、この溶融物を急冷する工程と、こ
の急冷体を酸素含有雰囲気中において４００℃〜８００
℃の温度条件下で熱処理し高臨界温度相を生じせしめる
工程とを有することを特徴とする酸化物超電導体の製造
方法。(1) A process of heating and melting the Bi-Sr-Ca-Cu based oxide superconductor raw material, a process of rapidly cooling this melt, and a process of heating this rapidly cooled body at 400°C to 800°C in an oxygen-containing atmosphere.
1. A method for producing an oxide superconductor, comprising the step of heat-treating under a temperature condition of °C to generate a high critical temperature phase.
−Ｓｒ−Ｃａ−Ｃｕ系酸化物超電導体薄膜を気相形成す
る工程と、このＢｉ−Ｓｒ−Ｃａ−Ｃｕ系酸化物超電導
体薄膜を酸素含有雰囲気中において４００℃〜８００℃
の温度条件下で熱処理し高臨界温度相を生じせしめる工
程とを有することを特徴とする酸化物超電導体の製造方
法。(2) Bi that is amorphous or does not form a complete crystal
- A step of forming a Sr-Ca-Cu based oxide superconductor thin film in a vapor phase, and a step of forming the Bi-Sr-Ca-Cu based oxide superconducting thin film at 400°C to 800°C in an oxygen-containing atmosphere.
1. A method for producing an oxide superconductor, comprising the step of heat-treating under temperature conditions to generate a high critical temperature phase.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63105907A JPH01278449A (en) | 1988-04-28 | 1988-04-28 | Production of oxide superconductor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63105907A JPH01278449A (en) | 1988-04-28 | 1988-04-28 | Production of oxide superconductor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01278449A true JPH01278449A (en) | 1989-11-08 |
Family
ID=14419942
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63105907A Pending JPH01278449A (en) | 1988-04-28 | 1988-04-28 | Production of oxide superconductor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01278449A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02129009A (en) * | 1988-11-04 | 1990-05-17 | Mitsubishi Metal Corp | Production of oxide superconductor |
| US6216333B1 (en) | 1997-02-28 | 2001-04-17 | Dowa Mining Co., Ltd. | Oxide superconductor current lead and method of manufacturing the same |
-
1988
- 1988-04-28 JP JP63105907A patent/JPH01278449A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02129009A (en) * | 1988-11-04 | 1990-05-17 | Mitsubishi Metal Corp | Production of oxide superconductor |
| US6216333B1 (en) | 1997-02-28 | 2001-04-17 | Dowa Mining Co., Ltd. | Oxide superconductor current lead and method of manufacturing the same |
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