JPH04300209A - Superconductor - Google Patents
SuperconductorInfo
- Publication number
- JPH04300209A JPH04300209A JP3066275A JP6627591A JPH04300209A JP H04300209 A JPH04300209 A JP H04300209A JP 3066275 A JP3066275 A JP 3066275A JP 6627591 A JP6627591 A JP 6627591A JP H04300209 A JPH04300209 A JP H04300209A
- Authority
- JP
- Japan
- Prior art keywords
- superconductor
- layer
- block layer
- oxide
- rare earth
- 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.)
- Granted
Links
- 239000002887 superconductor Substances 0.000 title claims abstract description 43
- 239000013078 crystal Substances 0.000 claims abstract description 16
- 229910052802 copper Inorganic materials 0.000 claims description 10
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 10
- 229910052745 lead Inorganic materials 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 8
- 239000000126 substance Substances 0.000 claims description 5
- 150000002910 rare earth metals Chemical class 0.000 claims 1
- 230000002194 synthesizing effect Effects 0.000 abstract description 3
- 239000010410 layer Substances 0.000 description 31
- 239000010409 thin film Substances 0.000 description 13
- 239000010949 copper Substances 0.000 description 12
- 239000000463 material Substances 0.000 description 9
- 230000007704 transition Effects 0.000 description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 239000010408 film Substances 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 238000004544 sputter deposition Methods 0.000 description 5
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical class [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229910002480 Cu-O Inorganic materials 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000010849 ion bombardment Methods 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 239000005751 Copper oxide Substances 0.000 description 1
- 229910052693 Europium Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 229910000431 copper oxide Inorganic materials 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- YADSGOSSYOOKMP-UHFFFAOYSA-N dioxolead Chemical compound O=[Pb]=O YADSGOSSYOOKMP-UHFFFAOYSA-N 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000011133 lead Substances 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 238000005477 sputtering target Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 229910052716 thallium Inorganic materials 0.000 description 1
- BKVIYDNLLOSFOA-UHFFFAOYSA-N thallium Chemical compound [Tl] BKVIYDNLLOSFOA-UHFFFAOYSA-N 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
- Superconductors And Manufacturing Methods Therefor (AREA)
- Compositions Of Oxide Ceramics (AREA)
- 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】本発明は、高臨界温度をもつ新し
い結晶構造の鉛系酸化物超伝導体に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead-based oxide superconductor having a new crystal structure and having a high critical temperature.
【０００２】0002
【従来の技術】高温超伝導体として、ミューラー（Ｍｕ
ｌｌｅｒ）等によりペロブスカイト類型構造の酸化物超
伝導体が発見された。それ以後、種々の酸化物系で超伝
導性の確認が為され、主体成分が、鉛，アルカリ土類元
素，希土類元素，銅の酸化物からなるＰｂ系超伝導体は
、７０Ｋ程度の超伝導臨界温度をもつということが発見
された。［Ｒ． Ｊ． ケイハ゛（Ｃａｖａ） 他，
ネイチャー （Ｎａｔｕｒｅ）， Ｖｏｌ．３３６，
２１１−２１４ （１９８８）］詳細な解析の結果、こ
の物質は他の高温酸化物超伝導体と同様に層状構造をと
り、１原子層のＡ元素を介して向かい合ったＣｕＯ５ピ
ラミッドおよびピラミッドの頂点に隣接したＢ元素から
なるペロブスカイト類型層（Ｂ２ＡＣｕ２Ｏ６層）が、
隣接するＰｂＯ−Ｃｕ−ＰｂＯブロック層で挟まれた構
造となっている。化学式はＰｂ２Ｂ２ＡＣｕ３Ｏ８と表
わされる。ここでＡ元素は少なくとも一種類以上のアル
カリ土類元素および希土類元素の混合からなる元素、Ｂ
元素は少なくとも一種類以上のアルカリ土類元素からな
る元素を示す。この構造ではペロブスカイト類型層中に
２面のＣｕＯ２面が存在する。このような超伝導体、す
なわちＰｂおよびＣｕを主体成分とする酸化物ブロック
層と、ペロブスカイト類型構造をとるブロック層とが、
交互に積層された結晶構造をもつ超伝導体をＰｂ系超伝
導体といい、ＣｕＯ２の２面構造の他に１面構造が見つ
かっている。[Prior Art] As a high-temperature superconductor, Mueller (Mu
An oxide superconductor with a perovskite-type structure was discovered by Robert Ller et al. Since then, superconductivity has been confirmed in various oxide systems, and Pb-based superconductors whose main components are lead, alkaline earth elements, rare earth elements, and copper oxides have superconductivity of about 70K. It was discovered that it has a critical temperature. [R. J. Cava et al.
Nature, Vol. 336,
211-214 (1988)] As a result of detailed analysis, this material has a layered structure similar to other high-temperature oxide superconductors, with CuO5 pyramids facing each other via one atomic layer of the A element and the apex of the pyramid. A perovskite type layer (B2ACu2O6 layer) consisting of adjacent B elements is
It has a structure sandwiched between adjacent PbO--Cu--PbO block layers. The chemical formula is expressed as Pb2B2ACu3O8. Here, element A is an element consisting of a mixture of at least one alkaline earth element and rare earth element, and B
The element refers to an element consisting of at least one kind of alkaline earth element. In this structure, two CuO2 planes exist in the perovskite type layer. Such a superconductor, that is, an oxide block layer mainly composed of Pb and Cu, and a block layer having a perovskite-type structure,
A superconductor with a crystal structure in which layers are alternately stacked is called a Pb-based superconductor, and in addition to the two-sided structure of CuO2, a one-sided structure has been found.
【０００３】Ｐｂ系超伝導体は、従来のものより合成温
度が低いという特長があり、また焼成中の酸素をあまり
必要としないので、作製時の取り扱いが容易であり実用
に向いている。Pb-based superconductors have the advantage of having a lower synthesis temperature than conventional ones, and do not require much oxygen during firing, making them easy to handle during production and suitable for practical use.
【０００４】0004
【発明が解決しようとする課題】しかしながらこのＰｂ
系超伝導体を実際に応用する場合に、超伝導臨界温度が
低いという欠点があった。安価な液体窒素を冷却媒体と
して使うには、少なくとも８０Ｋ以上の臨界温度が必要
とされるが、Ｐｂ系超伝導体の臨界温度は７０〜８０Ｋ
といわれており、再現性よく液体窒素温度で使用するに
は臨界温度の向上が望まれていた。[Problem to be solved by the invention] However, this Pb
When actually applying superconductors, there is a drawback that the superconducting critical temperature is low. To use inexpensive liquid nitrogen as a cooling medium, a critical temperature of at least 80K is required, but the critical temperature of Pb-based superconductors is 70-80K.
Therefore, it was desired to improve the critical temperature in order to use it at liquid nitrogen temperatures with good reproducibility.
【０００５】[0005]
【課題を解決するための手段】本発明は、Ｐｂ系超伝導
体の結晶構造が、ＰｂとＣｕの酸化物からなるブロック
層と、１枚のＣｕＯ２面および両側の１原子層のＡ元素
を介して向かい合ったＣｕＯ５ピラミッドおよびピラミ
ッドの頂点に隣接したＢ元素からなるペロブスカイト類
型ブロック層（Ｂ２Ａ２Ｃｕ３Ｏ８層）とが、交互に積
層された構造をとるものである。ここでＡ元素は少なく
とも一種類以上のアルカリ土類元素および希土類元素の
混合からなる元素、Ｂ元素は少なくとも一種類以上のア
ルカリ土類元素からなる元素を示す。[Means for Solving the Problems] The present invention provides that the crystal structure of a Pb-based superconductor includes a block layer made of oxides of Pb and Cu, one CuO2 surface and one atomic layer of A element on both sides. It has a structure in which CuO5 pyramids facing each other with a perovskite type block layer (B2A2Cu3O8 layer) made of B element adjacent to the apex of the pyramid are stacked alternately. Here, element A is an element consisting of a mixture of at least one kind of alkaline earth element and rare earth element, and element B is an element consisting of at least one kind of alkaline earth element.
【０００６】[0006]
【作用】上記構造をとるＰｂ系超伝導体は、ＰｂとＣｕ
の酸化物より構成されるブロック層に挟まれたペロブス
カイト類型ブロック層中に、３面のＣｕＯ２面をもつ。
Ｐｂ系超伝導体では従来１面、２面構造は見つかってい
たが、３面構造は未だ実現されていなかった。本発明者
らは上記構造の物質の作製に成功し、その超伝導臨界温
度が従来のＰｂ系超伝導体より高いという発見に基づき
、本発明に至った。この場合、ＣｕＯ２の３面構造が１
、２面構造より臨界温度が高い理由は明らかでないが、
他の酸化物超伝導体（ビスマス系、タリウム系）の場合
にもこの関係は成り立っており、銅酸化物超伝導体の発
現機構となんらかの関係があるものと考えられる。[Operation] The Pb-based superconductor with the above structure is composed of Pb and Cu.
The perovskite-type block layer sandwiched between block layers composed of oxides has three CuO2 planes. In Pb-based superconductors, one-plane and two-plane structures have been discovered, but a three-plane structure has not yet been realized. The present inventors succeeded in producing a material with the above structure, and based on the discovery that its superconducting critical temperature is higher than that of conventional Pb-based superconductors, the present invention was achieved. In this case, the three-sided structure of CuO2 is
Although it is not clear why the critical temperature is higher than that of the two-sided structure,
This relationship also holds true in the case of other oxide superconductors (bismuth-based, thallium-based), and it is thought that there is some connection with the expression mechanism of cuprate superconductors.
【０００７】[0007]
【実施例】本発明のＰｂ系超伝導体は、図１の結晶構造
、すなわち対向するＣｕＯ５ピラミッド１１およびピラ
ミッドの頂点に隣接したＢ元素１２の間にさらに１枚の
ＣｕＯ２面１３とその両側のＡ元素１原子層１４を挟ん
だブロック層１５と、鉛と銅の酸化物からなるブロック
層１６とが、交互に積層された構造をもち、Ｐｂ系層状
物質において従来にないＣｕＯ２面の３面構造を実現し
たものである。この結果、他の酸化物超伝導体のように
１、２面構造より超伝導臨界温度の高い物質が実現した
。[Example] The Pb-based superconductor of the present invention has the crystal structure shown in FIG. It has a structure in which a block layer 15 sandwiching a single atomic layer 14 of element A and a block layer 16 made of lead and copper oxide are laminated alternately. This is the realization of the structure. As a result, a material with a higher superconducting critical temperature than the one- and two-sided structures like other oxide superconductors was realized.
【０００８】本発明のＰｂとＣｕの酸化物ブロック層と
しては、Ｐｂ−Ｃｕ−Ｐｂの順序で酸化物が積み重ねら
れた３層ブロック層、ＰｂとＣｕがほぼ１対１でランダ
ムに２層重なった２層ブロック層、ＰｂとＣｕがほぼ１
対１でランダムに１層ならんだ単層ブロック層などがあ
り、どの場合においてもＣｕＯ２の３面構造が作製でき
る。特にＰｂ−Ｃｕ−Ｐｂ酸化物で構成された３層ブロ
ック層の場合には、中間のＣｕイオンの価数が低いため
、合成雰囲気に酸素をほとんど必要とせず、作製が容易
である。The Pb and Cu oxide block layer of the present invention includes a three-layer block layer in which oxides are stacked in the order of Pb-Cu-Pb, and two layers in which Pb and Cu are stacked randomly in an approximately 1:1 ratio. Two-layer block layer, Pb and Cu are approximately 1
There are monolayer block layers arranged randomly in a pair-one manner, and a three-sided structure of CuO2 can be produced in any case. In particular, in the case of a three-layer block layer composed of Pb--Cu--Pb oxide, since the valence of the intermediate Cu ion is low, almost no oxygen is required in the synthesis atmosphere, and production is easy.
【０００９】また本発明の結晶構造は、特に薄膜の形態
において多くの割合で存在することが確認された。この
理由としては、薄膜作製プロセスが非熱平衡過程である
場合が多く、この種の準安定相の合成に向いているため
であると考えられる。特にスパッタリング法などのイオ
ン衝撃蒸着が本発明の結晶構造の構築に有効であること
も、本発明者らは合わせて確認した。It has also been confirmed that the crystal structure of the present invention exists in a large proportion, especially in the form of a thin film. The reason for this is thought to be that the thin film fabrication process is often a non-thermal equilibrium process, which is suitable for synthesizing this type of metastable phase. The present inventors have also confirmed that ion bombardment deposition such as sputtering is particularly effective for constructing the crystal structure of the present invention.
【００１０】本発明のより詳しい理解のために、詳細な
実施例により以下に説明を行なう。高周波マグネトロン
スパッタ装置を用い、Ｐｂ系酸化物超伝導体の薄膜作製
を行なった。直径８０ｍｍで任意の割合を持つＰｂ−Ｓ
ｒ−Ｙ−Ｃａ−Ｃｕ−Ｏ焼成酸化物をスパッタリングタ
ーゲットとした。５８０℃に加熱したＭｇＯ単結晶（１
００）面基体上に、アルゴン０．５Ｐａのスパッタガス
のもと、１００Ｗのスパッタリング放電を行ない、約３
０分で２０００Å程度の薄膜を形成した。膜組成がＰｂ
：Ｓｒ：Ｙ：Ｃａ：Ｃｕ＝２：２：０．５：０．５：３
近傍の時には従来のＣｕＯ２面の２面構造が合成された
が、この組成よりＣａとＣｕを多くした場合、従来の構
造の他にさらに長周期の構造が得られた。膜組成がＰｂ
：Ｓｒ：Ｙ：Ｃａ：Ｃｕ＝２：２：０．５：１．５：４
の薄膜のＸ線回折パターンを図２に示す。回折パターン
はｃ軸配向膜が形成されていることを示しており、三角
印で示された従来のＰｂ系超伝導体のパターンの他に丸
印で示されている新しいパターンが現われている。新し
い相のｃ軸長は１９．０Åと見積られ、従来のＰｂ系物
質より３Å程度の長周期であった。この相の結晶構造は
図１の結晶構造においてＰｂとＣｕの酸化物層がＰｂＯ
−Ｃｕ−ＰｂＯの３層ブロック層になっており、従来の
構造に比べてＣｕＯ２面とＡ元素イオンがＣｕＯ５ピラ
ミッド間に挿入されてＣｕＯ２３面構造となっているこ
とが判った。[0010] For a more detailed understanding of the invention, the following description is provided by detailed examples. A thin film of a Pb-based oxide superconductor was fabricated using a high-frequency magnetron sputtering device. Pb-S with arbitrary proportions with a diameter of 80 mm
An r-Y-Ca-Cu-O fired oxide was used as a sputtering target. MgO single crystal (1
00) Sputtering discharge of 100 W was performed on the surface substrate under sputtering gas of 0.5 Pa of argon, and the
A thin film of about 2000 Å was formed in 0 minutes. Film composition is Pb
:Sr:Y:Ca:Cu=2:2:0.5:0.5:3
In the vicinity, a conventional two-plane structure of CuO2 planes was synthesized, but when Ca and Cu were increased from this composition, a structure with an even longer period was obtained in addition to the conventional structure. Film composition is Pb
:Sr:Y:Ca:Cu=2:2:0.5:1.5:4
The X-ray diffraction pattern of the thin film is shown in Figure 2. The diffraction pattern shows that a c-axis oriented film is formed, and in addition to the conventional Pb-based superconductor pattern shown by triangles, a new pattern shown by circles appears. The c-axis length of the new phase was estimated to be 19.0 Å, which was about 3 Å longer period than the conventional Pb-based material. The crystal structure of this phase is that in the crystal structure of Figure 1, the Pb and Cu oxide layer is PbO
It was found that it has a three-layer block layer of -Cu-PbO, and compared to the conventional structure, the CuO2 plane and A element ions are inserted between the CuO5 pyramids, resulting in a CuO23 plane structure.
【００１１】この新構造Ｐｂ系超伝導体は、大概的にＣ
ａとＣｕが膜中に多いほど合成され易い事が判った。Ｐ
ｂ系超伝導セラミックスの合成においては、通常はＣａ
量が希土類元素Ｒの量より少なく（Ｒ／Ｃａ＞０．５）
、Ｃａ量が希土類元素Ｒの量より多い場合、結晶構造中
に取り込まれず未反応物として析出する。本実施例のよ
うな薄膜の形態にする事により、Ｐｂ系超伝導体におい
てＣａ量がＲ量より多い、すなわちＲ／Ｃａ＜０．５が
実現された。微細組成分析により調べたところ、特にＣ
ｕＯ２３面構造の結晶粒の組成はＲ／Ｃａ＜１／３とな
っていることが判った。 また他の元素の割合も分析
した結果、本実施例で得られたＰｂ系超伝導体はＰｂ２
Ｓｒ２（ＲｘＣａ１−ｘ）２Ｃｕ４Ｏ１０なる化学式で
表わされる物質であった。ただしｘは０．２５以下の数
である。[0011] This new structure Pb-based superconductor is mostly composed of C
It was found that the more a and Cu are in the film, the easier it is to synthesize. P
In the synthesis of b-based superconducting ceramics, Ca
The amount is less than the amount of rare earth element R (R/Ca>0.5)
When the amount of Ca is larger than the amount of rare earth element R, it is not incorporated into the crystal structure and precipitates as an unreacted substance. By forming a thin film as in this example, the amount of Ca was greater than the amount of R in the Pb-based superconductor, that is, R/Ca<0.5 was realized. When investigated by microcomposition analysis, it was found that especially C
It was found that the composition of the crystal grains having the uO23 plane structure was R/Ca<1/3. Furthermore, as a result of analyzing the proportions of other elements, it was found that the Pb-based superconductor obtained in this example was Pb2
It was a substance represented by the chemical formula Sr2(RxCa1-x)2Cu4O10. However, x is a number of 0.25 or less.
【００１２】新しい結晶構造が出現した膜の超伝導特性
を測定した。そのままの状態でも薄膜は超伝導転移を示
したが、空気中で３００℃，３０分間熱処理を加えるこ
とにより再現性および特性が向上した。図３に作製され
た薄膜の電気抵抗の温度特性を示す。図のように、オン
セット超伝導転移温度１００Ｋを示し、９２Ｋでゼロ抵
抗になる超伝導転移をみせた。この温度は従来のＣｕＯ
２面が２面構造の鉛系超伝導体の超伝導転移温度に比べ
て１０Ｋ以上高いものである。すなわち３面構造が部分
的に合成されて混在することにより、超伝導転移温度の
高い３面構造の特性が支配的に現われたものと解釈され
る。３面構造の割合が多いほど、超伝導転移は急峻であ
り、従来の２面構造が支配的になるほど転移は散漫にな
って２段転移の様相を示し、ゼロ抵抗温度は従来のＰｂ
系超伝導体程度に低下した。[0012] The superconducting properties of the film in which a new crystal structure had appeared were measured. Although the thin film showed superconducting transition even in its original state, the reproducibility and properties improved by heat treatment at 300° C. for 30 minutes in air. FIG. 3 shows the temperature characteristics of the electrical resistance of the fabricated thin film. As shown in the figure, it exhibited an onset superconducting transition temperature of 100K, and a superconducting transition with zero resistance at 92K. This temperature is the same as that of conventional CuO
The superconducting transition temperature is 10 K or more higher than the superconducting transition temperature of a lead-based superconductor with a two-sided structure. In other words, it is interpreted that the characteristics of the three-sided structure, which has a high superconducting transition temperature, appeared dominantly because the three-sided structure was partially synthesized and coexisted. The higher the proportion of the three-plane structure, the steeper the superconducting transition, and the more the conventional two-plane structure becomes dominant, the more the transition becomes diffuse, showing the appearance of a two-step transition, and the zero resistance temperature is lower than that of the conventional Pb.
It has decreased to the level of a system superconductor.
【００１３】このように従来には得られないＰｂ系超伝
導体のＣｕＯ２３面構造が得られたのは、スパッタリン
グのような非熱平衡過程の薄膜プロセスによるところが
大きいと考えられる。すなわちスパッタリングのような
イオン衝撃蒸着が、本発明の新Ｐｂ系超伝導体の合成に
適している。またＰｂ系超伝導体の一種なので形成温度
も従来の酸化物超伝導体より５０〜１００℃程度低く、
酸素をあまり必要としないので、実用的に優れた材料で
ある。[0013] The reason why the CuO23 plane structure of the Pb-based superconductor, which could not be obtained conventionally, was obtained is considered to be largely due to the non-thermal equilibrium thin film process such as sputtering. That is, ion bombardment deposition such as sputtering is suitable for synthesizing the new Pb-based superconductor of the present invention. In addition, since it is a type of Pb-based superconductor, the formation temperature is about 50 to 100 degrees Celsius lower than that of conventional oxide superconductors.
It is an excellent material for practical use because it does not require much oxygen.
【００１４】なお本実施例では、非超伝導層の一原子層
の希土類元素がＹで構成される材料を用いたが、Ｇｄ、
Ｅｕ、Ｙｂなどの多くの他の希土類元素を用いたもので
も、同様に良好な超伝導体が実現できること勿論である
。またアルカリ土類元素の組合せも、本実施例以外の組
合せが幾つかあること勿論である。In this example, a material in which the rare earth element in one atomic layer of the non-superconducting layer was composed of Y was used, but Gd,
Of course, similarly good superconductors can be realized using many other rare earth elements such as Eu and Yb. Furthermore, it goes without saying that there are several combinations of alkaline earth elements other than those in this example.
【００１５】[0015]
【発明の効果】本発明による超伝導体は、Ｐｂ系酸化物
超伝導体の新規の結晶構造を持つ高臨界温度の物質を実
現したものである。この結果Ｐｂ系超伝導体が液体窒素
温度で安定に使用できるようになった。特にこの種の材
料は、非熱平衡の薄膜プロセスにおいてよく合成される
ため薄膜の形態で存在し易い。また低温で作製可能で酸
化プロセスに気を使う必要ないので、膜形成プロセスの
取り扱いが容易である。従って、デバイス応用上最適な
超伝導材料を提供するもので、本発明の工業的価値は大
きい。The superconductor according to the present invention is a high critical temperature material having a novel crystal structure of a Pb-based oxide superconductor. As a result, Pb-based superconductors can now be used stably at liquid nitrogen temperatures. In particular, this type of material is often synthesized in a non-thermal equilibrium thin film process and therefore tends to exist in the form of a thin film. Furthermore, since it can be produced at low temperatures and there is no need to pay attention to the oxidation process, the film formation process is easy to handle. Therefore, the present invention has great industrial value because it provides a superconducting material that is optimal for device applications.
【図１】本発明の実施例におけるＰｂ系超伝導体の結晶
構造図。FIG. 1 is a crystal structure diagram of a Pb-based superconductor in an example of the present invention.
【図２】本発明の一実施例におけるＰｂ−Ｓｒ−Ｙ−Ｃ
ａ−Ｃｕ−Ｏ薄膜のＸ線回折パターン図。FIG. 2: Pb-Sr-Y-C in one embodiment of the present invention
FIG. 3 is an X-ray diffraction pattern diagram of a-Cu-O thin film.
【図３】本発明の実施例で得た薄膜における電気抵抗の
温度特性の図である。FIG. 3 is a diagram showing the temperature characteristics of electrical resistance in a thin film obtained in an example of the present invention.
１１ ＣｕＯ５ピラミッド １２ Ｂ元素 １３ ＣｕＯ２面 １４ Ａ元素 11 CuO5 pyramid 12 B element 13 CuO2 side 14 Element A
Claims (4)
ｂとＣｕの酸化物からなるブロック層と、１枚のＣｕＯ
２面および両側の１原子層のＡ元素を介して向かい合っ
たＣｕＯ５ピラミッドおよびピラミッドの頂点に隣接し
たＢ元素からなるペロブスカイト類型ブロック層とが、
交互に積層された構造であることを特徴とする超伝導体
。 ここでＡ元素は少なくとも一種類以上のアルカリ土類元
素および希土類元素の混合からなる元素、Ｂ元素は少な
くとも一種類以上のアルカリ土類元素からなる元素を示
す。[Claim 1] The crystal structure of the lead-based oxide superconductor is P
A block layer consisting of oxides of b and Cu, and one sheet of CuO
A perovskite-type block layer consisting of a CuO5 pyramid facing one atomic layer of A element on two sides and one atomic layer on both sides, and an element B adjacent to the apex of the pyramid,
A superconductor characterized by a structure in which layers are alternately stacked. Here, element A is an element consisting of a mixture of at least one kind of alkaline earth element and rare earth element, and element B is an element consisting of at least one kind of alkaline earth element.
リ土類元素（Ｅ）の元素比率がＲ／Ｅ ＜ １／３であ
ることを特徴とする請求項１記載の超伝導体。2. The superconductor according to claim 1, wherein the element ratio of rare earth element (R) to alkaline earth element (E) in element A is R/E < 1/3.
層が、Ｐｂ−Ｃｕ−Ｐｂからなる３層の酸化物で構成さ
れたことを特徴とする請求項１記載の超伝導体。3. The superconductor according to claim 1, wherein the block layer made of oxides of Pb and Cu is composed of three layers of oxides made of Pb-Cu-Pb.
土類（Ｒ）元素とＣａの混合で構成され、Ｐｂ２Ｓｒ２
（ＲｘＣａ１−ｘ）２Ｃｕ４Ｏ１０なる化学式を持つ請
求項３記載の超伝導体。ただしｘは、０．２５以下の数
を示す。4. Element A is composed of Sr, element B is composed of a mixture of a rare earth (R) element and Ca, and Pb2Sr2
The superconductor according to claim 3, having the chemical formula (RxCa1-x)2Cu4O10. However, x indicates a number of 0.25 or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3066275A JP2906711B2 (en) | 1991-03-29 | 1991-03-29 | Superconductor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3066275A JP2906711B2 (en) | 1991-03-29 | 1991-03-29 | Superconductor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04300209A true JPH04300209A (en) | 1992-10-23 |
| JP2906711B2 JP2906711B2 (en) | 1999-06-21 |
Family
ID=13311128
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3066275A Expired - Fee Related JP2906711B2 (en) | 1991-03-29 | 1991-03-29 | Superconductor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2906711B2 (en) |
-
1991
- 1991-03-29 JP JP3066275A patent/JP2906711B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2906711B2 (en) | 1999-06-21 |
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