JP2838312B2 - Oxide superconducting material - Google Patents
Oxide superconducting materialInfo
- Publication number
- JP2838312B2 JP2838312B2 JP2110145A JP11014590A JP2838312B2 JP 2838312 B2 JP2838312 B2 JP 2838312B2 JP 2110145 A JP2110145 A JP 2110145A JP 11014590 A JP11014590 A JP 11014590A JP 2838312 B2 JP2838312 B2 JP 2838312B2
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- JP
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- Prior art keywords
- oxide
- superconducting material
- present
- sample
- 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.)
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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
- Inorganic Compounds Of Heavy Metals (AREA)
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は酸化物超伝導物質に関する。The present invention relates to an oxide superconducting material.
［従来の技術とその問題点］ 超伝導状態とは抵抗がゼロとなり、電流を損失するこ
と無く流すことのできる状態であり、この性質は強磁場
発生装置や高効率のエネルギー変換装置、電子デバイス
など産業上多岐にわたって利用することのできるもので
ある。[Conventional technology and its problems] The superconducting state is a state in which the resistance becomes zero and current can flow without loss. This property is a strong magnetic field generator, a high-efficiency energy converter, and an electronic device. It can be used in a wide variety of industries.
近年、液体窒素の温度より高い温度での超伝導性を求
めて、Ｙ−Ba−Cu−Ｏ系（以下Ｙ系と略称）、Bi−Sr−
Ca−Cu−Ｏ系（以下Bi系と略称）、Tl−Ba−Cu−Ｏ系
（以下Tl系と略称）等の、Cu−Ｏを含む多元系酸化物を
利用した多くの研究が行われている。In recent years, in pursuit of superconductivity at a temperature higher than the temperature of liquid nitrogen, Y-Ba-Cu-O-based (hereinafter abbreviated as Y-based), Bi-Sr-
Many studies have been made using multi-component oxides containing Cu-O, such as Ca-Cu-O (hereinafter abbreviated as Bi) and Tl-Ba-Cu-O (hereinafter abbreviated as Tl). ing.
これらの系では、いままでのところ、抵抗がゼロにな
る臨界温度（Tc）は、Ｙ系は約90K、Bi系は約110K、Tl
系は約130Kであることが確認されている。近時、これら
の系の構成元素を部分的に他の元素に置換することによ
り更に高いTcを持つものを求めることが試みられている
が、いまのところ上述のTcよりも高い温度で超伝導性を
示す物質は得られていない。In these systems, so far, the critical temperature (Tc) at which the resistance becomes zero is about 90K for the Y system, about 110K for the Bi system, and Tl.
The system has been confirmed to be about 130K. Recently, attempts have been made to obtain a material with a higher Tc by partially substituting the constituent elements of these systems with other elements. No toxic substances have been obtained.
従来の酸化物超伝導体であるＹ系、Bi系、Ti系にはそ
れぞれ次のような問題がある。Conventional oxide superconductors Y-based, Bi-based, and Ti-based have the following problems, respectively.
Ｙ系の場合、このものは水等に対して不安定で、かつ
希土類元素は比較的供給量が少なく高価であり、得られ
る超伝導体の価格は必然的に増大する。In the case of a Y-based material, it is unstable with respect to water and the like, and the rare-earth element has a relatively small supply amount and is expensive, so that the price of the obtained superconductor necessarily increases.
Bi系の超伝導体は、結晶構造的に３種の相を持つもの
が知られているが、これらの相は一般の作製条件では混
相になりやすく、高いTcを示す相の単相化は、作製条件
を厳密に制御しなければならず工業的に問題となる。Bi-based superconductors are known to have three types of phases in terms of crystal structure. However, these phases tend to be mixed phases under general manufacturing conditions, and the formation of a single phase having a high Tc is difficult. In addition, the production conditions must be strictly controlled, which is an industrial problem.
Tl系の場合には、特にTlが人体に害を及ぼす危険性が
有り、実用化には難があると思われる。また、これらの
酸化物系超伝導体は４元系以上の酸化物であり、構成元
素の多さにより、組成の調整、焼成温度等の作製条件の
適正化が難しいものとなっている。加えて、従来の酸化
物超伝導体の超伝導機構においては、Cu−Ｏ層がその超
伝導性に関与しているものと考えられており、Cu−Ｏ層
を持った酸化物超伝導体においては、Tcの大幅な上昇は
限界に近付いていると考えられ、新しい超伝導機構によ
る新規超伝導物質が期待されている。In the case of the Tl system, there is a risk that Tl may harm the human body, and it is considered that practical use is difficult. Further, these oxide-based superconductors are quaternary or higher oxides, and it is difficult to adjust the composition and optimize the production conditions such as the firing temperature due to the large number of constituent elements. In addition, in the superconducting mechanism of the conventional oxide superconductor, it is considered that the Cu-O layer is involved in the superconductivity, and the oxide superconductor having the Cu-O layer is considered. In, it is considered that the large increase in Tc is approaching the limit, and a new superconducting material with a new superconducting mechanism is expected.
［問題点を解決するための手段］ 本発明者等は、鋭意検討を行った結果、少なくともNb
を構成成分としかつNbと他の元素との成分比がある範囲
の酸化物が超伝導性を示す物質であることを見出し本発
明を完成するに至った。即ち本発明は、NbとＭ（ただし
ＭはCa、Sr、Baより選ばれる少なくとも一種以上の元素
である）および酸素より構成され、NbとＭのモル数の比
（Nb/M）が0.2〜10である酸化物超伝導物質に関するも
のである。[Means for Solving the Problems] As a result of intensive studies, the present inventors have found that at least Nb
Was found to be an oxide having superconductivity as a constituent component, and an oxide having a component ratio of Nb to another element in a certain range was found to be the present invention. That is, the present invention comprises Nb and M (where M is at least one element selected from Ca, Sr, and Ba) and oxygen, and the molar ratio of Nb and M (Nb / M) is 0.2 to It relates to an oxide superconducting material of 10.
本発明の超伝導物質は、従来のＹ系、Bi系、Tl系酸化
物超伝導体と異なり、Cuを含んでいないため、従来の酸
化物超伝導体の超伝導機構の重要な因子と思われている
Cu−Ｏ層が存在していない。このことは、従来の酸化物
超伝導体と異なった機構により超伝導状態になっている
とを伺わせ、必然的に従来の酸化物超伝導体と異なった
特性（臨界温度，臨界磁場，臨界電流等）を持つことが
期待されるものである。Unlike the conventional Y-based, Bi-based, and Tl-based oxide superconductors, the superconducting material of the present invention does not contain Cu, and thus is considered to be an important factor in the superconducting mechanism of the conventional oxide superconductor. Have been
There is no Cu-O layer. This suggests that the superconducting state is obtained by a mechanism different from that of the conventional oxide superconductor, and that the properties (critical temperature, critical magnetic field, critical Current, etc.).
次に本発明を、その製造法の例も併せて更に詳述す
る。Next, the present invention will be described in more detail together with examples of its production method.
本発明を製造する際の原料としては、本発明を構成す
る各元素の単体の他に、構成元素群から選択された少な
くとも一種以上の元素の酸化物、炭酸塩、硫酸塩、硝酸
塩または蓚酸塩を使用することができるが、特に純度、
調整の容易さから考えると、酸化物および炭酸塩が好ま
しい。また、原料として炭酸塩、硫酸塩、硝酸塩または
蓚酸塩を使用した場合には、焼成に先立って仮焼を実施
し、これらに含まれる炭素、硫黄、窒素等を除去するこ
とが望ましい。As raw materials for producing the present invention, in addition to the simple substance of each element constituting the present invention, oxides, carbonates, sulfates, nitrates or oxalates of at least one or more elements selected from the constituent element group Can be used, but especially the purity,
Oxides and carbonates are preferred from the viewpoint of ease of adjustment. When carbonate, sulfate, nitrate or oxalate is used as a raw material, it is preferable to perform calcination prior to calcination to remove carbon, sulfur, nitrogen and the like contained therein.
本発明の酸化物超伝導物質は、例えば、以下の方法に
よって作製することができる。The oxide superconducting material of the present invention can be produced, for example, by the following method.
原料としてNb及びＭ（ただし、ＭはCa、Sr、Baより選
ばれる少なくとも一種以上の元素である）の酸化物また
は炭酸塩を用い、まず、それぞれの原料粉末を所定量秤
量し混合する。この際、ＭとNbのモル比が本発明で限定
した範囲となるように秤量し用いるのが好ましいが、後
で行う焼成による組成のズレを考慮して、組成を調整す
ることも好ましい。As raw materials, oxides or carbonates of Nb and M (where M is at least one element selected from Ca, Sr, and Ba) are used. First, a predetermined amount of each raw material powder is weighed and mixed. At this time, it is preferable to weigh and use such that the molar ratio of M and Nb is within the range limited in the present invention, but it is also preferable to adjust the composition in consideration of a deviation of the composition due to the firing performed later.
本発明では、NbとＭのモル数の比（Nb/M）が0.2〜10
であることが必須である。このモル比が0.2より小では
半導体的な挙動を示す酸化物が得られ、また同比が10よ
り大では、金属的な酸化物は得られるが、超伝導性を持
つものは得られない。更に、本発明を構成するNbは、そ
の全部または一部が４価のNbで構成されていることが好
ましく、これは、後述の方法で得られ、得られたものの
色相（黒）で４価のNbで構成されていることが確認でき
る。In the present invention, the molar ratio of Nb and M (Nb / M) is 0.2 to 10%.
Is essential. When the molar ratio is smaller than 0.2, an oxide exhibiting semiconductor behavior is obtained. When the molar ratio is larger than 10, a metal oxide is obtained, but a superconductive one is not obtained. Further, it is preferable that all or a part of Nb constituting the present invention is composed of tetravalent Nb, which is obtained by a method described later, and which has a hue (black) of tetravalent Nb. It can be confirmed that it is composed of Nb.
NbとＭとの混合粉末を加圧し圧粉体とした後、非酸化
性雰囲気中にて温度700〜1500℃、保持時間１〜100時間
の条件で熱処理を行う。ここで言う非酸化性雰囲気は、
具体的には、還元雰囲気、不活性雰囲気、真空状態等で
ある。前記した保持温度、保持時間は試料の大きさ、原
料の混合比などにより、適当に選択するが、保持温度
は、700℃未満では固相反応が不十分なため均一な組成
のものが得られ難く、1500℃より高い温度では原料が一
部溶融する可能性がある。更に好ましい保持温度好は90
0〜1300℃である。After pressing the mixed powder of Nb and M into a green compact, heat treatment is performed in a non-oxidizing atmosphere at a temperature of 700 to 1500 ° C. and a holding time of 1 to 100 hours. The non-oxidizing atmosphere mentioned here is
Specifically, the atmosphere is a reducing atmosphere, an inert atmosphere, a vacuum state, or the like. The above-mentioned holding temperature and holding time are appropriately selected depending on the size of the sample, the mixing ratio of the raw materials, and the like.However, if the holding temperature is less than 700 ° C., a solid composition having a uniform composition can be obtained because the solid phase reaction is insufficient. Difficultly, at temperatures higher than 1500 ° C, the raw materials may partially melt. A more preferred holding temperature is 90.
0 to 1300 ° C.
焼成物の組成を均一にするために、焼成後の試料をあ
る程度の粒度に粉砕した後、再び焼成することが好まし
い。In order to make the composition of the fired product uniform, it is preferable that the fired sample is pulverized to a certain particle size and then fired again.
上述の製造方法では、原料粉末をそのまま混合して所
定の組成比に調整する場合について説明したが、沈澱法
により所定の組成比の蓚酸塩、クエン酸塩等のカルボン
酸塩として沈澱させ焼成原料を調整しこれを用いて前記
した方法で焼成することによっても、本発明の酸化物超
伝導物質を得ることが可能である。In the above-described production method, the case where the raw material powders are directly mixed and adjusted to a predetermined composition ratio has been described. However, a carboxylate such as an oxalate and a citrate having a predetermined composition ratio is precipitated by a precipitation method, The oxide superconducting material of the present invention can also be obtained by adjusting the temperature and firing the mixture using the above method.
［発明の効果］ 本発明は、新規の系の酸化物超伝導物質であり、更に
構成元素を置換、添加し、製造方法、製造条件を適宜選
択することにより、従来の酸化物超伝導体と異なった特
性を示す酸化物超伝導体を得る可能性も考えられる。[Effects of the Invention] The present invention is a novel oxide superconducting material, which can be replaced with a conventional oxide superconductor by appropriately substituting and adding constituent elements and appropriately selecting a production method and production conditions. It is possible to obtain oxide superconductors exhibiting different properties.
［実施例］ 以下、実施例により本発明を更に詳しく説明するが、
本発明は何等これらに限定されるものではない。EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to these.
実施例１ 原料粉末として純度99.9％のSrCo3および純度99.9％
のNb2O5を用いた。Nb2O5は還元雰囲気中（H2:Ar＝1:1）
にて、1000℃、36時間の熱処理を施して、NbO2とした。
次に、SrとNbのモル比が1:2になるようSrCO3とNbO2を秤
量し、乳鉢を用いて大気中で30分間混合した。Example 1 SrCo 3 with 99.9% purity and 99.9% purity as raw material powder
Nb 2 O 5 was used. Nb 2 O 5 is in a reducing atmosphere (H 2 : Ar = 1: 1)
Then, heat treatment was performed at 1000 ° C. for 36 hours to obtain NbO 2 .
Next, SrCO 3 and NbO 2 were weighed so that the molar ratio of Sr to Nb was 1: 2, and mixed in a mortar in the atmosphere for 30 minutes.
この混合粉末0.5gを約700kg/cm2で加圧し、直径約13m
m、厚さ約1mmの円盤状の圧粉体を作製した。この圧粉体
を直径方向に二つに分割し、直径8mmの不透明石英管に
充填し３×10-5torrで真空封入した。同時に、残留ガス
の吸着用として純度99.6％の金属Zrを石英管に同封し
た。0.5 g of this mixed powder is pressed at about 700 kg / cm 2 and the diameter is about 13 m
A disk-shaped green compact having a thickness of about 1 mm and a thickness of about 1 mm was produced. This green compact was divided into two parts in the diameter direction, filled in an opaque quartz tube having a diameter of 8 mm, and sealed in a vacuum at 3 × 10 -5 torr. At the same time, metal Zr having a purity of 99.6% was enclosed in a quartz tube for adsorption of residual gas.
この試料を以下の条件で熱処理した。 This sample was heat-treated under the following conditions.
昇温速度 5.6℃／分 保持温度 1000℃ 保持時間 36時間 降温速度 放冷 焼成後の試料の電気抵抗の温度変化を第１図に示す。
本図からも明らかな通り、この物質の電気抵抗は、12K
以上ではやや半導体的な挙動を示すが、12Kより急激に
落下しており、超伝導性を示している。5Kにおいても残
留抵抗が見られるが、これは不純物相に因るものであ
り、この物質の本質的な特性とは異なるものである。Heating rate 5.6 ° C / min Holding temperature 1000 ° C Holding time 36 hours Cooling rate Cooling Figure 1 shows the temperature change of the electrical resistance of the sample after firing.
As is clear from this figure, the electric resistance of this substance is 12K
Above, it shows a semi-semiconductor behavior, but drops sharply from 12K, indicating superconductivity. Even at 5K, a residual resistance is observed, which is due to the impurity phase and differs from the essential properties of this material.
実施例２ 原料粉末として純度99.9％のSrOを用いた以外は実施
例１と同様して試料を作製した。Example 2 A sample was prepared in the same manner as in Example 1 except that SrO having a purity of 99.9% was used as a raw material powder.
得られた試料は、実施例１と同様にして電気抵抗の温
度変化を測定した結果、抵抗変化は実施例１と同様の挙
動を示し、Tcは約12Kであった。As a result of measuring the temperature change of the electric resistance of the obtained sample in the same manner as in Example 1, the resistance change showed the same behavior as that of Example 1, and Tc was about 12K.
実施例３ SrとNbのモル比を2:1とした以外は実施例１と同様に
して試料を作製した。Example 3 A sample was prepared in the same manner as in Example 1 except that the molar ratio between Sr and Nb was 2: 1.
得られた試料は、実施例１と同様にして電気抵抗の温
度変化を測定した結果、抵抗変化は実施例１と同様の挙
動を示し、Tcは約12Kであった。As a result of measuring the temperature change of the electric resistance of the obtained sample in the same manner as in Example 1, the resistance change showed the same behavior as that of Example 1, and Tc was about 12K.
実施例４ 原料粉末として純度99.9％のBaCO3を用いた以外は実
施例１と同様して試料を作製した。Example 4 A sample was produced in the same manner as in Example 1, except that BaCO 3 having a purity of 99.9% was used as the raw material powder.
得られた試料は、実施例１と同様にして電気抵抗の温
度変化を測定した結果、抵抗変化は実施例１と同様の挙
動を示し、Tcは約12Kであった。As a result of measuring the temperature change of the electric resistance of the obtained sample in the same manner as in Example 1, the resistance change showed the same behavior as that of Example 1, and Tc was about 12K.
第１図は、実施例１で得た試料の、電機抵抗の温度変化
を示す図である。FIG. 1 is a diagram showing a temperature change of electric resistance of a sample obtained in Example 1.
Claims (2)
る少なくとも一種以上の元素である）および酸素より構
成され、NbとＭのモル数の比（Nb/M）が0.2〜10である
酸化物超伝導物質。1. A composition comprising Nb and M (where M is at least one element selected from Ca, Sr and Ba) and oxygen, wherein the molar ratio of Nb to M (Nb / M) is 0.2 to An oxide superconducting material that is 10.
価のNbである特許請求の範囲第（１）項記載の酸化物超
伝導物質。2. All or a part of Nb in the superconducting material is 4
2. The oxide superconducting material according to claim 1, which is a multivalent Nb.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2110145A JP2838312B2 (en) | 1990-04-27 | 1990-04-27 | Oxide superconducting material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2110145A JP2838312B2 (en) | 1990-04-27 | 1990-04-27 | Oxide superconducting material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0412025A JPH0412025A (en) | 1992-01-16 |
| JP2838312B2 true JP2838312B2 (en) | 1998-12-16 |
Family
ID=14528185
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2110145A Expired - Fee Related JP2838312B2 (en) | 1990-04-27 | 1990-04-27 | Oxide superconducting material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2838312B2 (en) |
-
1990
- 1990-04-27 JP JP2110145A patent/JP2838312B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0412025A (en) | 1992-01-16 |
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