JPH0297074A - Superconductive weak junction - Google Patents
Superconductive weak junctionInfo
- Publication number
- JPH0297074A JPH0297074A JP63249427A JP24942788A JPH0297074A JP H0297074 A JPH0297074 A JP H0297074A JP 63249427 A JP63249427 A JP 63249427A JP 24942788 A JP24942788 A JP 24942788A JP H0297074 A JPH0297074 A JP H0297074A
- Authority
- JP
- Japan
- Prior art keywords
- composite oxide
- composite
- weak junction
- deposited
- layer
- 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 claims abstract description 42
- 239000002131 composite material Substances 0.000 claims abstract description 38
- 239000013078 crystal Substances 0.000 claims abstract description 13
- 239000010409 thin film Substances 0.000 claims abstract description 10
- 239000000203 mixture Substances 0.000 claims description 3
- 238000000034 method Methods 0.000 abstract description 4
- 230000015572 biosynthetic process Effects 0.000 abstract description 2
- 239000000758 substrate Substances 0.000 abstract description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000004544 sputter deposition Methods 0.000 description 3
- 238000000151 deposition Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 229910014454 Ca-Cu Inorganic materials 0.000 description 1
- 230000005668 Josephson effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
Landscapes
- Physical Vapour Deposition (AREA)
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
- Containers, Films, And Cooling For Superconductive Devices (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、超電導弱接合に関する。より、詳細には、複
合酸化物超電導体でジョセフソン効果を実現する超電導
弱接合に関する。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to superconducting weak junctions. More specifically, the present invention relates to a superconducting weak junction that realizes the Josephson effect in a composite oxide superconductor.
従来の技術
トンネル型ジョセフソン素子は、一対の超電導体の間に
極薄い非超電導体を挟んで成立する。この非超電導体の
厚さは、ジョセフソン素子を構成する超電導体のコヒー
レンス長さにより決定される。このため、複合酸化物超
電導体でトンネル型ジョセフソン素子を作製しようとす
ると、前記の非超電導体の厚さは、数十人程度でなけれ
ばならない。A conventional tunnel-type Josephson device is constructed by sandwiching an extremely thin non-superconductor between a pair of superconductors. The thickness of this non-superconductor is determined by the coherence length of the superconductor constituting the Josephson element. Therefore, if a tunnel-type Josephson device is to be manufactured using a composite oxide superconductor, the thickness of the non-superconductor must be about several tens of layers.
この加工は、非常に困難なため、複合酸化物超電導体を
用いた超電導弱接合は、マイクロブリッジ型と称する一
対の超電導体をいわゆる「くびれ」である微小な超電導
体で結んだ構造のものが報告されているだけである。Because this processing is extremely difficult, superconducting weak junctions using composite oxide superconductors are constructed using a so-called microbridge type, in which a pair of superconductors are connected by a tiny superconductor called a "constriction." It is only reported.
発明が解決しようとする課題
上記のマイクロブリッジ型ジョセフソン素子は、微細加
工を必要とし、工業的には再現性に乏しく、トンネル型
ジョセフソン素子が必然とされている。Problems to be Solved by the Invention The above-mentioned microbridge type Josephson element requires microfabrication and has poor reproducibility industrially, so a tunnel type Josephson element is inevitable.
ところが、非超電導体を数十人の厚さに堆積することは
、困難であるばかりでなく、非超電導体と超電導体との
間の相互拡散により、いわゆるシャープな界面を形成す
ることができない。However, it is not only difficult to deposit non-superconductors to a thickness of several tens of nanometers, but also cannot form a so-called sharp interface due to interdiffusion between non-superconductors and superconductors.
そこで１、本発明の目的は、上記従来技術の問題点を解
決した複合酸化物超電導体によるトンネル型の超電導弱
接合を提供することにある。1. An object of the present invention is to provide a tunnel-type superconducting weak junction using a composite oxide superconductor that solves the problems of the prior art described above.
課題を解決するための手段
本発明に従うと、複合酸化物超電導体の超電導弱接合に
おいて、十分な厚さに堆積された高い超電導臨界温度を
有する一対の複合酸化物超電導体薄膜間に、前記複合酸
化物超電導体薄膜を構成する複合酸化物の結晶に対して
構成する層の数が過大または過少である結晶を有する複
合酸化物が挟まれていることを特徴とする超電導弱接合
が提供される。Means for Solving the Problems According to the present invention, in a superconducting weak junction of composite oxide superconductors, the composite oxide superconductor thin film is deposited to a sufficient thickness and has a high superconducting critical temperature. Provided is a superconducting weak junction characterized by sandwiching a composite oxide having crystals in which the number of layers is too large or too small relative to the crystals of the complex oxide forming the oxide superconductor thin film. .
本発明の超電導弱接合に好適な複合酸化物超電導体とし
ては、
Ｂ１２５ｒ２Ｃａ２Ｃｕ３０ ｌＱ＋ｌ＋で表される組
成を有する複合酸化物を挙げることができる。As a composite oxide superconductor suitable for the superconducting weak junction of the present invention, a composite oxide having a composition represented by B125r2Ca2Cu30 lQ+l+ can be mentioned.
作用
本発明の超電導弱接合は、十分な厚さに堆積された高い
超電導臨界温度を有する一対の複合酸化物超電導体薄膜
間に、前記複合酸化物超電導体薄膜を構成する複合酸化
物の結晶に対して構成する層の数が過大または過少であ
る結晶を有する複合酸化物が挟まれていることを特徴と
する。すなわち、複合酸化物超電導体は、例えば上記の
Ｂ１２５ｒ２Ｃａ２Ｃ１ｌ＊ ０１０４）１で表される
組成を有する複合酸化物の場合、２重Ｂｉ層を挟んでＳ
ｒ原子層が配列し、以下ＣｕＯ□−ＣａＣｕＯ□−Ｃａ
−Ｃｕｂ２の順でペロブスカイト層が並ぶ。この複合酸
化物は、超電導臨界温度Ｔｃが約１０５にの超電導体で
あるが、このＣｕ０２層が１層または２層の複合酸化物
超電導体も確翳忍されている。複合酸化物超電導体にお
いては、一般にＴｃは、ＣｕＯ２層の数と相関関係があ
り、上記のＢｉ系複合酸化物超電導体においては、Ｃｕ
Ｏ２層が１層のもののＴｃは約４０にである。Function The superconducting weak junction of the present invention is formed between a pair of composite oxide superconductor thin films deposited to a sufficient thickness and having a high superconducting critical temperature, and in which the composite oxide crystals constituting the composite oxide superconductor thin film are bonded to each other. It is characterized by sandwiching a composite oxide having crystals in which the number of layers is too large or too small. That is, in the case of a composite oxide having the composition represented by, for example, B125r2Ca2C1l*0104)1, the composite oxide superconductor is composed of S with a double Bi layer in between.
r atomic layer is arranged, and below CuO□-CaCuO□-Ca
- Perovskite layers are arranged in the order of Cub2. This composite oxide is a superconductor with a superconducting critical temperature Tc of approximately 105, but a composite oxide superconductor having one or two Cu02 layers is also being considered. In complex oxide superconductors, Tc generally has a correlation with the number of CuO2 layers, and in the above Bi-based complex oxide superconductors, Tc
The Tc of the one with one O2 layer is about 40.
本発明の超電導弱接合は、上記のＢ１系で実現する場合
は、Ｃｕ０２層が３層のＢ１２５ｒ２Ｃａ２ＣＬＩ３０
１０＋、を約１０００人の厚さに堆積し、その上にＣ０
０２層が１層またはＣｕＯ□層を全く有さないＢｉ −
３ｒ −Ｃａ −Ｃｕ−０系複合酸化物を１層堆積し、
さらにＣ００２層が３層の上記Ｂｉ系複合酸化物超電導
体をやはり約１０００への厚さに堆積することによる。When the superconducting weak junction of the present invention is realized with the above B1 system, the B125r2Ca2CLI30 with three Cu02 layers is used.
10+, to a thickness of about 1000, and on top of that, C0
02 layer has one layer or no CuO□ layer Bi −
Depositing one layer of 3r -Ca -Cu-0 based composite oxide,
Further, the above-mentioned Bi-based composite oxide superconductor having three C002 layers is deposited to a thickness of about 1,000 μm.
［：ｕ０２層が１層のＢｉ −３ｒ −Ｃａ −Ｃｕ
−０系複合酸化物を１層の厚さは約１０人であり、Ｃ１
０２層が３層の上記Ｂｉ系複合酸化物超電導体のコヒー
レンス長さに対して十分な値になる。必要に応じ、Ｃ１
０２層が１層のＢｉ −３ｒ −Ｃａ−Ｃｕ −０系複
合酸化物を２層または３層堆積してもよい。上記の超電
導弱接合は、液体窒素温度でＣ００２層が３層のＢｉ
−５ｒ−Ｃａ −Ｃｕ −０系複合酸化物が超電導体と
なり、（：ｕ０２層が１層のＢｉ −３ｒ −Ｃａ −
Ｃｕ −０系複合酸化物は、非超電導体であることから
実現される。[: Bi-3r-Ca-Cu with one u02 layer
The thickness of one layer of -0-based composite oxide is approximately 10 layers, and C1
The coherence length of the Bi-based composite oxide superconductor having three layers of 02 layers is sufficient for the coherence length. C1 as necessary
Two or three layers of a Bi-3r-Ca-Cu-0 composite oxide having one 02 layer may be deposited. The above superconducting weak junction consists of three C002 layers at liquid nitrogen temperature.
The -5r-Ca-Cu-0-based composite oxide becomes a superconductor, and the (:u02 layer is one layer of Bi-3r-Ca-
The Cu-0-based composite oxide is realized because it is a non-superconductor.
本発明の超電導弱接合は、非超電導体をいわば「層欠陥
」を有するため超電導性を失った複合酸化物超電導体で
構成しているので、複合酸化物超電導体との界面におい
て、相互拡散等の問題は一切生じないので、界面が非常
にシャープになる。In the superconducting weak junction of the present invention, since the non-superconductor is composed of a composite oxide superconductor that has lost superconductivity due to so-called "layer defects," interdiffusion etc. Since this problem does not occur at all, the interface becomes extremely sharp.
本発明の超電導弱接合を形成するには、ＭＢＥ法または
スパッタリング法等で複合酸化物超電導体結晶の各層を
１層ずつ積み上げる方法によることが好ましい。In order to form the superconducting weak junction of the present invention, it is preferable to use a method of stacking each layer of composite oxide superconductor crystals one by one by MBE method, sputtering method, or the like.
実施例
Ｂｉ −３ｒ −Ｃａ−Ｃｕ −０系複合酸化物を用い
て本発明の超電導弱接合を形成した。形成方法は、スパ
ッタリング法であり、ＭｇＯ単結晶基板の（１００）面
に形成した。ターゲットとしてＢｉ 、 Ｓｒ、 Ｃａ
およびＣｕそれぞれが単独にスパッタリング可能である
ようにシャッターにより制御した。最初にＣｕｂ。Example A superconducting weak junction of the present invention was formed using a Bi-3r-Ca-Cu-0 complex oxide. The formation method was a sputtering method, and it was formed on the (100) plane of an MgO single crystal substrate. Bi, Sr, Ca as targets
The sputtering was controlled by a shutter so that each of Cu and Cu could be sputtered independently. Cub first.
層が３層の８！２Ｓｒ２Ｃａ２Ｃｕ＋Ｏ＋ｏ＋ｘを約１
０００人の厚さに堆積し、次にＣｕ０２層が１層のＢＩ
２Ｓｒ２Ｃｕ ０６＋ｌ＋を１層堆積し、さらに３＋２
Ｓｒ２Ｃａ２Ｃｕ３０１０＋）ｌを約１０００人の厚さ
に堆積して本発明の超電導弱接合を作製した。Approximately 1 layer of 8!2Sr2Ca2Cu+O+o+x with 3 layers
000,000 thick, followed by 1 BI layer of Cu02.
Deposit one layer of 2Sr2Cu 06+l+, then 3+2
The superconducting weak junction of the present invention was fabricated by depositing Sr2Ca2Cu3010+)l to a thickness of approximately 1000 nm.
液体窒素温度（７７、３Ｋ ）でＢＩ２ＳｒｚＣａ２Ｃ
ｕｓ ０１００Ｍ層は、完全に抵抗がなくなり、また、
ジョセフソン電流が流れることを確認した。BI2SrzCa2C at liquid nitrogen temperature (77,3K)
The US 0100M layer has completely no resistance, and
It was confirmed that Josephson current flows.
発明の効果
本発明の超電導弱接合によれば、複合酸化物超電導体に
よる高性能なトンネル型ジョセフソン素子が簡単に実現
できるものである。Effects of the Invention According to the superconducting weak junction of the present invention, a high-performance tunnel-type Josephson device using a composite oxide superconductor can be easily realized.
Claims (2)
分な厚さに堆積された高い超電導臨界温度を有する一対
の複合酸化物超電導体薄膜間に、前記複合酸化物超電導
体薄膜を構成する複合酸化物の結晶に対して構成する層
の数が過大または過少である結晶を有する複合酸化物が
挟まれていることを特徴とする超電導弱接合。(1) In a superconducting weak junction of composite oxide superconductors, a composite oxide superconductor thin film is formed between a pair of composite oxide superconductor thin films deposited to a sufficient thickness and having a high superconducting critical temperature. A superconducting weak junction characterized by sandwiching a composite oxide having crystals in which the number of layers is too large or too small relative to the oxide crystals.
で表される組成を有することを特徴とする請求項（１）
に記載の超電導弱接合。(2) The composite oxide superconductor is Bi_2Sr_2Ca_2Cu_3O_1_0_+_x
Claim (1) characterized in that it has a composition represented by
superconducting weak junction described in .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63249427A JP2501629B2 (en) | 1988-10-03 | 1988-10-03 | Superconducting weak junction |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63249427A JP2501629B2 (en) | 1988-10-03 | 1988-10-03 | Superconducting weak junction |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0297074A true JPH0297074A (en) | 1990-04-09 |
| JP2501629B2 JP2501629B2 (en) | 1996-05-29 |
Family
ID=17192812
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63249427A Expired - Fee Related JP2501629B2 (en) | 1988-10-03 | 1988-10-03 | Superconducting weak junction |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2501629B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03127876A (en) * | 1989-10-13 | 1991-05-30 | Matsushita Electric Ind Co Ltd | Superconducting element |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5682655B2 (en) | 2012-10-15 | 2015-03-11 | 株式会社デンソー | Liquid level detector |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63239256A (en) * | 1987-03-27 | 1988-10-05 | Showa Denko Kk | Phenylalanine derivative and proteinase-inhibiting agent |
| JPH02177381A (en) * | 1988-09-22 | 1990-07-10 | Semiconductor Energy Lab Co Ltd | Tunnel junction element of superconductor |
-
1988
- 1988-10-03 JP JP63249427A patent/JP2501629B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63239256A (en) * | 1987-03-27 | 1988-10-05 | Showa Denko Kk | Phenylalanine derivative and proteinase-inhibiting agent |
| JPH02177381A (en) * | 1988-09-22 | 1990-07-10 | Semiconductor Energy Lab Co Ltd | Tunnel junction element of superconductor |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03127876A (en) * | 1989-10-13 | 1991-05-30 | Matsushita Electric Ind Co Ltd | Superconducting element |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2501629B2 (en) | 1996-05-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |