JPH054899A - Production of bi-based oxide superconductor single crystal - Google Patents
Production of bi-based oxide superconductor single crystalInfo
- Publication number
- JPH054899A JPH054899A JP5849891A JP5849891A JPH054899A JP H054899 A JPH054899 A JP H054899A JP 5849891 A JP5849891 A JP 5849891A JP 5849891 A JP5849891 A JP 5849891A JP H054899 A JPH054899 A JP H054899A
- Authority
- JP
- Japan
- Prior art keywords
- single crystal
- based oxide
- oxide superconductor
- magnetic field
- superconductor single
- 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
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- Inorganic Compounds Of Heavy Metals (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、超伝導特性、特にピ
ンニングポテンシャル(Uo)が大きく、磁場中での臨界電
流密度(Jc)が大きいBi系酸化物超伝導体の単結晶を製造
する方法に関する。FIELD OF THE INVENTION The present invention relates to a method for producing a single crystal of a Bi-based oxide superconductor having a high superconducting property, particularly a large pinning potential (Uo) and a large critical current density (Jc) in a magnetic field. Regarding
【０００２】[0002]
【従来の技術】高温超伝導物質の一つとしてBi−Sr−Ca
−Cu−0 系のBi系酸化物超伝導体が知られているが、溶
融法で作製したBi系酸化物超伝導体の単結晶は、そのま
ま（無加工）では超伝導状態を保持する力が弱く、特に
磁場中では臨界電流密度(Jc)が激減する。Bi-Sr-Ca is one of the high-temperature superconducting materials.
-Cu-0-based Bi-based oxide superconductors are known, but single crystals of Bi-based oxide superconductors produced by the melting method have the ability to maintain the superconducting state as they are (unprocessed). Is weak, and the critical current density (Jc) is drastically reduced especially in a magnetic field.
【０００３】超伝導酸化物の超伝導特性を向上させる方
法としては熱処理(アニール) が一般的であるが、他に
原料粉混合時にAgを少量混入するという方法も下記の文
献に報告されている。Heat treatment (annealing) is generally used as a method for improving the superconducting properties of superconducting oxides, but a method of mixing a small amount of Ag when mixing raw material powders is also reported in the following document. .
【０００４】 Yukio Kubo et.ａl. JJAP,vol.28, N
o.11(1989) LL1936−1938 Noriyuki Shimizu et.al.JJAP,vol.28, No.11(198
9) LL1955−1958 Bi系単結晶体においても、その超伝導特性を向上させる
方法としては、下記の文献に紹介されているように、
熱処理が一般的である。 M.Chihaya et.al.第37回応用物理学会学術講演会、
講演予稿集(1990 年春季)28a−SD−４Yukio Kubo et.al. JJAP, vol.28, N
o.11 (1989) LL1936-1938 Noriyuki Shimizu et.al.JJAP, vol.28, No.11 (198
9) Even in the LL1955-1958 Bi-based single crystal body, as a method for improving its superconducting property, as described in the following documents,
Heat treatment is common. M. Chihaya et.al. 37th Annual Meeting of the Japan Society of Applied Physics,
Lecture Proceedings (Spring 1990) 28a-SD-4
【０００５】[0005]
【発明が解決しようとする課題】単結晶の作製方法は幾
つかあるが、その一つの溶融法は、 KCl−flux法のよ
うにKCl 等の余分の成分による悪影響がない、 FZ 法
のように作製装置に可動部分を必要とせず、装置が簡単
である、他の方法によるよりも大きな面（ａｂ面) を
持った単結晶ができる、という利点がある。しかし、前
記のように、溶融法で作製したBi系酸化物超伝導体の単
結晶は、そのままでは磁場中での超伝導特性の低下（特
にJcの低下) が激しく、実用化が難しい。Although there are several methods for producing a single crystal, one of the melting methods is, like the FCl method, which does not have an adverse effect due to extra components such as KCl as in the KCl-flux method. There are advantages that the manufacturing apparatus does not require a movable part, the apparatus is simple, and a single crystal having a larger surface (ab surface) than that obtained by other methods can be formed. However, as described above, the single crystal of the Bi-based oxide superconductor produced by the melting method has a severe deterioration in the superconducting property (especially a decrease in Jc) in a magnetic field and is difficult to put into practical use.
【０００６】本発明の目的は、ピンニングポテンシャル
(Uo)が大きく、磁場中でのJcの低下の小さいBi系酸化物
超伝導体の単結晶を製造する方法の提供にある。The object of the present invention is to provide a pinning potential.
It is to provide a method for producing a single crystal of a Bi-based oxide superconductor having a large (Uo) and a small decrease in Jc in a magnetic field.
【０００７】[0007]
【課題を解決するための手段】本発明は、「溶融法によ
ってBi系酸化物超伝導体の単結晶を作製し、その単結晶
の表面に銀を蒸着した後、熱処理を施すことを特徴とす
るBi系酸化物超伝導体の単結晶の製造方法」を要旨とす
る。The present invention is characterized in that "a single crystal of a Bi-based oxide superconductor is produced by a melting method, silver is vapor-deposited on the surface of the single crystal, and then heat treatment is performed. The method for producing a single crystal of a Bi-based oxide superconductor is as a gist.
【０００８】[0008]
【作用】溶融法には前記のような利点があり、Bi系超伝
導酸化物単結晶をこの方法で作製すると約７mm×７mmの
面（ａｂ面) を持った単結晶が得られる。しかし、この
単結晶は、同じBi系酸化物の超伝導薄膜や線材と比べる
と超伝導特性 (Uo、Jc)が悪い。The melting method has the above advantages, and when a Bi-based superconducting oxide single crystal is produced by this method, a single crystal having a surface (ab surface) of about 7 mm × 7 mm can be obtained. However, this single crystal is inferior in superconducting properties (Uo, Jc) to the same superconducting thin film of Bi-based oxide or wire.
【０００９】一方、バルク体の場合、銀 (Ag) 等の不純
物を少量混入することにより、Uoが向上することが知ら
れている。On the other hand, in the case of a bulk body, it is known that Uo is improved by incorporating a small amount of impurities such as silver (Ag).
【００１０】本発明方法では、溶融法で作製したBi系超
伝導酸化物の単結晶にAgを蒸着した後、熱処理を施すこ
とによりAgを単結晶内部に入り込ませ、そのAgをピンニ
ングセンターとしてUoを大きくし、磁場中におけるJcの
低下の小さいものにするのである。In the method of the present invention, Ag is vapor-deposited on a single crystal of a Bi-based superconducting oxide produced by a melting method, and then heat treatment is performed to allow Ag to enter the inside of the single crystal, and the Ag is used as a pinning center for Uo. To make Jc smaller in the magnetic field.
【００１１】蒸着材料としてAgを用いるのは、前掲の
およびの文献にも記載されているように、酸化物超伝
導体の特性の向上には最も有効だからである。Bi系超伝
導酸化物の単結晶の表面にAgを蒸着し、次いで熱処理を
施せば、Agは単結晶の内部に拡散して結晶内にドープさ
れ、ピンニングセンターとして作用しUoを高める。The reason why Ag is used as the vapor deposition material is that it is most effective in improving the characteristics of the oxide superconductor, as described in the above-mentioned documents and. When Ag is vapor-deposited on the surface of a Bi-based superconducting oxide single crystal and then heat-treated, Ag diffuses inside the single crystal and is doped into the crystal, which acts as a pinning center and increases Uo.
【００１２】[0012]
【実施例】Bi2O3 、SrCO3 、CaCO3 およびCuO の粉末を
原料とし、出発組成がBi：Sr：Ca：Cu＝２: １: １: ２
となるように混合し、800 ℃で12時間の加熱を２回行っ
て仮焼粉を作製した。この仮焼粉200gをアルミナるつぼ
（径50cm、高さ5.6cm)に入れて 1000 ℃で10時間で溶融
し、４℃/hで 825℃まで温度を下げ、この温度(825℃)
で 24 時間保持したのち再び４℃/hで800 ℃まで下げ、
その後、炉冷で室温まで下げて単結晶を作製した。これ
らの処理はすべて大気中で行った。EXAMPLE Using powders of Bi 2 O 3 , SrCO 3 , CaCO 3 and CuO as starting materials, the starting composition is Bi: Sr: Ca: Cu = 2: 1: 1: 1: 2.
The mixture was mixed so that it was heated at 800 ° C. for 12 hours twice to prepare a calcined powder. 200g of this calcined powder is put into an alumina crucible (diameter 50cm, height 5.6cm) and melted at 1000 ℃ for 10 hours, and the temperature is lowered to 825 ℃ at 4 ℃ / h.
After holding it for 24 hours at 4 ℃ / h, reduce it to 800 ℃ again.
Then, the temperature was lowered to room temperature by furnace cooling to produce a single crystal. All these treatments were performed in the atmosphere.
【００１３】単結晶は、アルミナるつぼごとプレス機で
破壊し、５mm×３mm以上のへき開面を持った塊を採取
し、蒸着用試料 (素体) とした。The single crystal was broken together with the alumina crucible by a pressing machine, and a lump having a cleavage plane of 5 mm × 3 mm or more was sampled to obtain a vapor deposition sample (element body).
【００１４】次に、その素体のへき開面に真空度10-5〜
10-4の真空蒸着装置で厚さ約 500ÅのAgを蒸着した。Next, the degree of vacuum on the cleaved surface of the element body is 10 -5 〜.
Ag was vapor-deposited with a thickness of about 500Å using a 10 -4 vacuum vapor deposition device.
【００１５】上記によって得られたAgの蒸着膜を有する
単結晶を電気炉に入れて 400℃/hの昇温速度で、900 ℃
まで加熱した後、20分で 820℃から860 ℃までの種々の
温度に下げ、それらの温度で12時間保持したのち室温ま
で炉冷した。The single crystal having the Ag vapor-deposited film obtained above was put in an electric furnace and heated at a temperature rising rate of 400 ° C./h to 900 ° C.
After heating to 20 ° C., the temperature was lowered to various temperatures from 820 ° C. to 860 ° C. in 20 minutes, the temperature was maintained for 12 hours, and then the furnace was cooled to room temperature.
【００１６】こうして作製した試料について、超伝導特
性(Jc 、Uo) の測定を行った。表１に、磁場 0と 0.05T
(印加磁場は単結晶のＣ軸に垂直の方向) における臨界
電流密度(Jc)と０磁場中でのピンニングポテンシャル(U
o)とを、前記熱処理の保持温度ごとに示す。また、同表
にAg蒸着を行う前の素体のJcとUoを示す。The superconducting properties (Jc, Uo) of the samples thus prepared were measured. Table 1 shows magnetic field 0 and 0.05T
The critical current density (Jc) in (the applied magnetic field is the direction perpendicular to the C axis of the single crystal) and the pinning potential (U
o) and are shown for each holding temperature of the heat treatment. Also, in the same table, Jc and Uo of the element body before Ag vapor deposition are shown.
【００１７】表１から明らかなように、本発明方法で作
製した試料はUoが大きく、磁場中でのJcの低下は僅かで
ある。As is clear from Table 1, the sample produced by the method of the present invention has a large Uo and a slight decrease in Jc in the magnetic field.
【００１８】[0018]
【表１】 [Table 1]
【００１９】[0019]
【発明の効果】本発明の方法によれば、磁場中でも高い
臨界電流密度を保持するBi系酸化物超伝導体単結晶の製
造が可能である。According to the method of the present invention, it is possible to produce a Bi-based oxide superconductor single crystal which maintains a high critical current density even in a magnetic field.
【００２０】[0020]
───────────────────────────────────────────────────── フロントページの続き (72)発明者 遠藤 昭彦 大阪府大阪市中央区北浜４丁目５番33号 住友金属工業株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiko Endo 4-53-3 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Sumitomo Metal Industries, Ltd.
Claims (1)
晶を作製し、その単結晶の表面に銀を蒸着した後、熱処
理を施すことを特徴とするBi系酸化物超伝導体の単結晶
の製造方法。Claim: What is claimed is: 1. A Bi-based oxide superconductor single crystal is produced by a melting method, and silver is vapor-deposited on the surface of the single crystal, followed by heat treatment. A method for producing a single crystal of an oxide superconductor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5849891A JPH054899A (en) | 1991-03-22 | 1991-03-22 | Production of bi-based oxide superconductor single crystal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5849891A JPH054899A (en) | 1991-03-22 | 1991-03-22 | Production of bi-based oxide superconductor single crystal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH054899A true JPH054899A (en) | 1993-01-14 |
Family
ID=13086090
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5849891A Pending JPH054899A (en) | 1991-03-22 | 1991-03-22 | Production of bi-based oxide superconductor single crystal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH054899A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111768926A (en) * | 2020-07-31 | 2020-10-13 | 西北有色金属研究院 | Preparation method of Bi-2212 superconducting coating |
-
1991
- 1991-03-22 JP JP5849891A patent/JPH054899A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111768926A (en) * | 2020-07-31 | 2020-10-13 | 西北有色金属研究院 | Preparation method of Bi-2212 superconducting coating |
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