JPH0744294B2 - Superconducting switching element - Google Patents
Superconducting switching elementInfo
- Publication number
- JPH0744294B2 JPH0744294B2 JP61260917A JP26091786A JPH0744294B2 JP H0744294 B2 JPH0744294 B2 JP H0744294B2 JP 61260917 A JP61260917 A JP 61260917A JP 26091786 A JP26091786 A JP 26091786A JP H0744294 B2 JPH0744294 B2 JP H0744294B2
- Authority
- JP
- Japan
- Prior art keywords
- superconducting
- superconductor
- current
- switching element
- control current
- 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.)
- Expired - Lifetime
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- Superconductor Devices And Manufacturing Methods Thereof (AREA)
Description
【発明の詳細な説明】 〔概要〕 本発明は超伝導を利用した電子的スイッチング素子にお
いて、 超伝導体の超伝導電流が流れる領域の断面積の最小値よ
りも、外部より超伝導体に超伝導オーダーパラメータの
値を制御する制御電流を供給する電極と超伝導体との接
触面積の最小値を小とすることにより、 高い電流増幅率が得られるようにしたものである。DETAILED DESCRIPTION OF THE INVENTION [Outline] The present invention relates to an electronic switching device utilizing superconductivity, in which a superconductor is superposed from the outside rather than the minimum value of the cross-sectional area of the region in which the superconducting current of the superconductor flows. By making the minimum value of the contact area between the electrode that supplies the control current that controls the value of the conduction order parameter and the superconductor small, a high current amplification factor can be obtained.
本発明は超伝導スイッチング素子に係り、特に超伝導を
利用した電子的スイッチング素子に関する。The present invention relates to a superconducting switching element, and more particularly to an electronic switching element utilizing superconductivity.
超伝導現象は抵抗ゼロの理想的な導体を与えるため、低
消費電力のスイッチング回路を作る上で有利である。こ
のようなスイッチング回路を実現するには、高い電流増
幅率をもつ超伝導スイッチング素子が必要とされる。The superconducting phenomenon provides an ideal conductor with zero resistance, which is advantageous in making a switching circuit with low power consumption. In order to realize such a switching circuit, a superconducting switching element having a high current amplification factor is required.
従来の超伝導スイッチング素子の構造の一例を第４図
（最終図）に示す。図中、１及び２は夫々超伝導電極
で、それらの間に極薄の絶縁膜３がトンネルバリアとし
て介在せしめられている。An example of the structure of a conventional superconducting switching element is shown in FIG. 4 (final diagram). In the figure, 1 and 2 are superconducting electrodes, respectively, and an extremely thin insulating film 3 is interposed between them as a tunnel barrier.
この超伝導スイッチング素子はトンネル型のジョセフソ
ン素子で、極低温に冷却した状態において超伝導電極１
及び２間に電流を流すと、しきい値以下の電流では電圧
を発生せず超伝導状態にあり、しきい値以上の電流では
電圧を発生して電圧状態へスイッチする。This superconducting switching element is a tunnel-type Josephson element, and when it is cooled to a cryogenic temperature, the superconducting electrode 1
When a current is flown between 2 and 2, a current below the threshold value does not generate a voltage and is in a superconducting state, and a current above the threshold value generates a voltage and switches to a voltage state.
ジョセフソン素子は本質的に２端子素子であるため、方
向性がなく、電流増幅率を得るためには複数個のジョセ
フソン素子を組み合わせた回路を使用する。しかし、こ
のような回路で得られる電流増幅率は、せいぜい数倍程
度である。これはジョセフソン素子のバラツキ，雑音に
対して回路が誤動作しないように、回路設計に余裕を持
つ必要があることによる。Since the Josephson element is essentially a two-terminal element, it has no directivity, and a circuit combining a plurality of Josephson elements is used to obtain the current amplification factor. However, the current amplification factor obtained by such a circuit is about several times at most. This is because it is necessary to have a margin in the circuit design so that the circuit does not malfunction due to variations in the Josephson element and noise.
このように、従来の超伝導スイッチング素子であるジョ
セフソン素子は、電流増幅率の大なる回路の実現が困難
で、このために複雑な機能を持つ回路を設計する上で不
便であるという問題点があった。As described above, the conventional Josephson device, which is a superconducting switching device, has a problem that it is difficult to realize a circuit having a large current amplification factor, which is inconvenient for designing a circuit having a complicated function. was there.
本発明は上記の点に鑑みて創作されたもので、電流増幅
率の大なる超伝導スイッチング素子を提供することを目
的とする。The present invention has been made in view of the above points, and an object thereof is to provide a superconducting switching element having a large current amplification factor.
第１図は本発明の原理構成を示す。図において、５は単
一構造の超伝導体で、端子5a,5b間に超伝導電流が流さ
れる。また、６は電極で、その先端は超伝導体５に直接
接触せしめられている。電極６は二以上でもよい。FIG. 1 shows the basic configuration of the present invention. In the figure, 5 is a superconductor having a single structure, and a superconducting current is passed between the terminals 5a and 5b. Further, 6 is an electrode, the tip of which is in direct contact with the superconductor 5. There may be two or more electrodes 6.
超伝導体５と電極６との接触面積、すなわち超伝導体５
の超伝導オーバーパラメータの値を制御する制御電流が
注入される領域の面積S1の最小値は、超伝導体５の超伝
導電流が流れる領域の断面積S2の最小値より小なる構成
とされている。Contact area between the superconductor 5 and the electrode 6, that is, the superconductor 5
The minimum value of the area S 1 of the region into which the control current for controlling the value of the superconducting over parameter is injected is smaller than the minimum value of the cross-sectional area S 2 of the region of the superconductor 5 in which the superconducting current flows. Has been done.
電極６を通して超伝導体５に制御電流を供給すると、制
御電流は小なる面積S1に集中して流れる。このため、同
じ値の制御電流をS1より大なる面積の超伝導体５の領域
に流した場合よりも電流密度が高くなる。When a control current is supplied to the superconductor 5 through the electrode 6, the control current concentrates on the small area S 1 . Therefore, the current density becomes higher than that when the control current of the same value is applied to the region of the superconductor 5 having an area larger than S 1 .
また、電流の効果で超伝導の程度を表わす超伝導オーダ
ーパラメータの値は、制御電流が供給されない場合より
も低下せしめられ、超伝導体５の超伝導特性が弱められ
る。ここで、制御電流は小面積S1に集中して注入される
から、その小面積S1の超伝導体５の領域において超伝導
オーダーパラメータの値は最小となる。またこのS1の領
域の超伝導オーダーパラメータのみが低下するのではな
く、超伝導体５のその周囲の領域においても超伝導オー
ダーパラメータは若干低下する。Further, the value of the superconducting order parameter indicating the degree of superconductivity due to the effect of electric current is lowered as compared with the case where the control current is not supplied, and the superconducting property of the superconductor 5 is weakened. Here, the control current from being injected are concentrated in a small area S 1, the value of the superconducting order parameter in the area of the superconductor 5 in the small area S 1 is minimized. Further, not only the superconducting order parameter in the region of S 1 is lowered, but also the superconducting order parameter in the region around the superconductor 5 is slightly lowered.
これにより、超伝導体５の超伝導オーダーパラメータの
値は、面積S1の領域を中心として低下せしめられ、空間
的に不均一な分布を示す。このように超伝導オーダーパ
ラメータの分布が不均一である場合は、超伝導オーダー
パラメータの分布が均一である場合よりも、小なる値の
制御電流で超伝導オーダーパラメータの値を抑圧できる
ことが知られている。As a result, the value of the superconducting order parameter of the superconductor 5 is lowered around the area of the area S 1 and exhibits a spatially non-uniform distribution. It is known that when the distribution of superconducting order parameters is non-uniform in this way, the value of the superconducting order parameters can be suppressed with a smaller control current than when the distribution of superconducting order parameters is uniform. ing.
従って、電極６に流す制御電流が小なる値でも、超伝導
体５の超伝導特性を大きく変えることができる。また、
制御電流を増加させてしきい値を越えると、超伝導体５
は電圧状態へスイッチする。Therefore, even if the control current flowing through the electrode 6 is small, the superconducting characteristics of the superconductor 5 can be greatly changed. Also,
When the control current is increased to exceed the threshold value, the superconductor 5
Switches to the voltage state.
第２図（Ａ），（Ｂ）は夫々本発明の一実施例の断面図
及び平面図を示す。図中、８は前記超伝導体５に相当す
る単一構造の超伝導薄膜で、ニオブ（Nb）より構成され
ている。超伝導薄膜８上にはSiO2からなる絶縁膜９が形
成される。10は前記電極６に相当する電極で、Nb等の超
伝導体又は金（Au），クロム（Cr）等の常伝導金属によ
り構成されている。2 (A) and 2 (B) respectively show a sectional view and a plan view of an embodiment of the present invention. In the figure, 8 is a superconducting thin film having a single structure corresponding to the superconductor 5 and is made of niobium (Nb). An insulating film 9 made of SiO 2 is formed on the superconducting thin film 8. Reference numeral 10 denotes an electrode corresponding to the electrode 6, which is made of a superconductor such as Nb or a normal conductive metal such as gold (Au) or chromium (Cr).
電極10は絶縁膜９に穿設された小なる面積の開口部11及
び12を夫々通して、超伝導薄膜８の表面上に夫々直接接
触せしめられている。すなわち、電極10は実質的に２つ
の電極とされている。The electrode 10 is brought into direct contact with the surface of the superconducting thin film 8 through openings 11 and 12 of small areas formed in the insulating film 9, respectively. That is, the electrode 10 is substantially two electrodes.
電極10に制御電流を流すと、第３図に示す如く、開口部
11及び12を通して直接制御電流が注入された、超伝導薄
膜８の領域14及び15の超伝導オーダーパラメータが最小
となり、かつ、その周辺の16で示す領域の超伝導オーダ
ーパラメータも領域14,15のそれに比し大であるが、そ
れ以外の領域17に比し低下する。すなわち、超伝導オー
ダーパラメータが小なる領域は制御電流が直接に注入さ
れた領域14及び15の他にも或る広がりを持つ。When a control current is applied to the electrode 10, as shown in FIG.
The superconducting order parameter of the regions 14 and 15 of the superconducting thin film 8 in which the control current is directly injected through 11 and 12 is the minimum, and the superconducting order parameter of the surrounding region 16 is also the region 14 and 15. It is larger than that, but lower than other regions 17. That is, the region where the superconducting order parameter is small has a certain spread in addition to the regions 14 and 15 in which the control current is directly injected.
上記の超伝導オーダーパラメータが小なる領域14,15及
び16は実質的に常伝導の特性を示し、これらの領域は制
御電流の値により増減し、超伝導体８の端子8a,8b間に
流れる超伝導電流の通路を塞ぐほど大になると、超伝導
電流は流れなくなるため、超伝導状態から電圧状態へス
イッチし、端子8a,8b間には電圧が発生する。The above-mentioned regions 14, 15 and 16 where the superconducting order parameter is small show substantially normal conduction characteristics, and these regions increase and decrease depending on the value of the control current and flow between the terminals 8a and 8b of the superconductor 8. When it becomes large enough to block the passage of the superconducting current, the superconducting current stops flowing, so that the state is switched from the superconducting state to the voltage state, and a voltage is generated between the terminals 8a and 8b.
ここで、上記の制御電流は小なる値の変化で超伝導電流
の大なる変化を得ることができるから、高い電流増幅率
が得られる。Here, since a large change in the superconducting current can be obtained with a small change in the control current, a high current amplification factor can be obtained.
以上の如く、本発明によれば、小なる制御電流で単一構
造の超伝導体の超伝導特性を大きく変化させることがで
きるので、高い電流増幅率を得ることができ、すなわち
小なる入力電流（制御電流）で大きな出力電流（超伝導
電流）をスイッチできるスイッチング素子が実現できる
等の特長を有するものである。As described above, according to the present invention, the superconducting property of a single-structure superconductor can be greatly changed with a small control current, so that a high current amplification factor can be obtained, that is, a small input current. It has a feature that a switching element that can switch a large output current (superconducting current) with (control current) can be realized.
第１図は本発明の原理構成を示す図、 第２図は本発明の一実施例を示す図、 第３図は本発明の一実施例の動作を説明するための図、 第４図は従来の超伝導スイッチング素子の一例を示す斜
視図である。 図において、 ５は超伝導体、 5a,5bは端子、 ６は電極、 ８は超伝導薄膜、 ９は絶縁膜、 10は電極、 11,12は開口部、 14〜16は超伝導オーダーパラメータの小なる領域であ
る。FIG. 1 is a diagram showing a principle configuration of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention, FIG. 3 is a diagram for explaining an operation of the embodiment of the present invention, and FIG. It is a perspective view which shows an example of the conventional superconducting switching element. In the figure, 5 is a superconductor, 5a and 5b are terminals, 6 is an electrode, 8 is a superconducting thin film, 9 is an insulating film, 10 is an electrode, 11 and 12 are openings, and 14 to 16 are superconducting order parameters. It is a small area.
Claims (1)
された単一構造の超伝導体（５）と、 該超伝導体（５）にその先端が直接接触せしめられてお
り、該超伝導体（５）に外部より超伝導オーダーパラメ
ータの値を制御する制御電流を供給する一又は二以上の
電極（６）とよりなり、 該超伝導体（５）の該制御電流が注入される領域の面積
（S1）の最小値を、該超伝導体（５）の該超伝導電流が
流れる領域の断面積（S2）の最小値より小なる構成とし
たことを特徴とする超伝導スイッチング素子。1. A superconductor (5) having a single structure in which a superconducting current is made to flow between two terminals, and a tip of the superconductor (5) is in direct contact with the superconductor (5). The superconductor (5) comprises one or more electrodes (6) for supplying a control current for controlling the value of the superconducting order parameter from outside, and the control current of the superconductor (5) is injected. The minimum value of the area (S 1 ) of the region is smaller than the minimum value of the cross-sectional area (S 2 ) of the region of the superconductor (5) through which the superconducting current flows. Conduction switching element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61260917A JPH0744294B2 (en) | 1986-10-31 | 1986-10-31 | Superconducting switching element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61260917A JPH0744294B2 (en) | 1986-10-31 | 1986-10-31 | Superconducting switching element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63114281A JPS63114281A (en) | 1988-05-19 |
| JPH0744294B2 true JPH0744294B2 (en) | 1995-05-15 |
Family
ID=17354549
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61260917A Expired - Lifetime JPH0744294B2 (en) | 1986-10-31 | 1986-10-31 | Superconducting switching element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0744294B2 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS592389B2 (en) * | 1980-10-30 | 1984-01-18 | 工業技術院長 | Quasi-particle injection controlled superconducting weak coupling device |
| JPS5846197B2 (en) * | 1980-12-20 | 1983-10-14 | 理化学研究所 | Josephson junction device and its manufacturing method |
-
1986
- 1986-10-31 JP JP61260917A patent/JPH0744294B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63114281A (en) | 1988-05-19 |
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