JPH02260472A - Josephson junction element - Google Patents
Josephson junction elementInfo
- Publication number
- JPH02260472A JPH02260472A JP1078178A JP7817889A JPH02260472A JP H02260472 A JPH02260472 A JP H02260472A JP 1078178 A JP1078178 A JP 1078178A JP 7817889 A JP7817889 A JP 7817889A JP H02260472 A JPH02260472 A JP H02260472A
- Authority
- JP
- Japan
- Prior art keywords
- josephson junction
- link
- thin film
- superconductor
- grain boundary
- 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
- 239000010409 thin film Substances 0.000 claims abstract description 23
- 239000002887 superconductor Substances 0.000 claims abstract description 17
- 239000000758 substrate Substances 0.000 claims abstract description 9
- 239000013078 crystal Substances 0.000 claims description 11
- 229910052684 Cerium Inorganic materials 0.000 claims description 2
- 229910052692 Dysprosium Inorganic materials 0.000 claims description 2
- 229910052691 Erbium Inorganic materials 0.000 claims description 2
- 229910052689 Holmium Inorganic materials 0.000 claims description 2
- 229910052765 Lutetium Inorganic materials 0.000 claims description 2
- 229910052772 Samarium Inorganic materials 0.000 claims description 2
- 229910052771 Terbium Inorganic materials 0.000 claims description 2
- 229910052775 Thulium Inorganic materials 0.000 claims description 2
- 229910052769 Ytterbium Inorganic materials 0.000 claims description 2
- 229910052793 cadmium Inorganic materials 0.000 claims description 2
- 229910052804 chromium Inorganic materials 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 229910052746 lanthanum Inorganic materials 0.000 claims description 2
- 229910052745 lead Inorganic materials 0.000 claims description 2
- 229910052748 manganese Inorganic materials 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 229910052706 scandium Inorganic materials 0.000 claims description 2
- 229910052709 silver Inorganic materials 0.000 claims description 2
- 229910052727 yttrium Inorganic materials 0.000 claims description 2
- 229910052725 zinc Inorganic materials 0.000 claims description 2
- 229910052796 boron Inorganic materials 0.000 claims 1
- 229910052719 titanium Inorganic materials 0.000 claims 1
- 229910052720 vanadium Inorganic materials 0.000 claims 1
- 230000035945 sensitivity Effects 0.000 abstract description 5
- 239000010408 film Substances 0.000 abstract description 4
- 230000008878 coupling Effects 0.000 abstract 1
- 238000010168 coupling process Methods 0.000 abstract 1
- 238000005859 coupling reaction Methods 0.000 abstract 1
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 230000004044 response Effects 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000000395 magnesium oxide Substances 0.000 description 2
- 238000001755 magnetron sputter deposition Methods 0.000 description 2
- 238000000059 patterning Methods 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 229910052693 Europium Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000001259 photo etching Methods 0.000 description 1
- 229920002120 photoresistant polymer Polymers 0.000 description 1
- 230000004043 responsiveness Effects 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 238000000992 sputter etching Methods 0.000 description 1
- 229910052716 thallium Inorganic materials 0.000 description 1
Landscapes
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
Abstract
Description
〔産業上の利用分野］
本発明は、マイクロ波から赤外光にかけての電磁波の検
出に使用されるジョセフソン接合素子に関する。
〔従来の技術］
ジョセフソン接合素子を用いた電磁波検出器は、マイク
ロ波、ミリ波、赤外領域で最も感度が良く、応答の速い
広帯域検出器である。従来の検出器に用いられるジョセ
フソン接合の形式として、ポイントコンタクト型、サン
ドウィッチ型（Ｓ Ｉ Ｓ型）、準平面型、ブリッジ型
等の様々な形態が提案されている。中でも、ブリッジ型
ジョセフソン接合素子は、素子形態が単純な構造である
ために、各種の金属超伝導薄膜及びＢ１ＰｂＢａＯ酸化
物超伝導膜において、様々な形態の検討がなされてきて
いる（Ｊａｐｎ、 Ｊ、 Ａｐｐｌ、 Ｐｈｙｓ、、２
２，５４４（１９８３）、特開昭５９−２１０６７８）
。
し発明が解決すべき課題）
しかしながら、近年発見されたセラミックス超伝導薄膜
、例えば、ＹＢａｚＣｕＪｔ−δ、 ＥｒＢａｚＣｕ３
０ｔ−６（０〈δ＜＋）、 ＢｉｚＳｒｚＣａｚＣｕｓ
Ｏｘ等の多結晶薄膜を用いたブリッジ型粒界ジョセフソ
ン接合素子のミリ波応答性の検討はなされているものの
（Ｊａｐｎ、 Ｊ。
Ａｐｐｌ、 Ｐｈｙｓ、、Ｌｌｌｌｏ （１９８８））
、電磁波検出器として感度向上を目的とした素子形態
の検討には未だ至っていない。[Industrial Application Field] The present invention relates to a Josephson junction device used for detecting electromagnetic waves ranging from microwaves to infrared light. [Prior Art] An electromagnetic wave detector using a Josephson junction element is a broadband detector with the highest sensitivity and quick response in the microwave, millimeter wave, and infrared regions. Various types of Josephson junctions used in conventional detectors have been proposed, such as a point contact type, a sandwich type (SIS type), a quasi-plane type, and a bridge type. Among them, the bridge type Josephson junction device has a simple structure, so various forms have been investigated in various metal superconducting thin films and B1PbBaO oxide superconducting films (Japan, J. , Appl, Phys., 2
2,544 (1983), Japanese Patent Publication No. 59-210678)
. However, recently discovered ceramic superconducting thin films such as YBazCuJt-δ and ErBazCu3
0t-6(0<δ<+), BizSrzCazCus
Although studies have been conducted on the millimeter wave response of bridge-type grain boundary Josephson junction devices using polycrystalline thin films such as Ox (Japan, J. Appl, Phys, Llllo (1988)).
However, studies have not yet been conducted on the element form for the purpose of improving sensitivity as an electromagnetic wave detector.
【課題を解決するための手段１
本発明は、上記点に鑑みなされたものであり、電磁波検
出器に用いられる高感度なブリッジ型ジョセッフソン接
合素子を提供するものである。
即ち、本発明は、基板上に超伝導体多結晶薄膜を備え、
該７Ｉ膜の結晶粒界を用いたブリッジ型ジョセフソン接
合が形成され、前記ジョセフソン接合における超伝導電
橋間を連結するリンクにおけるリンク長りがリンク幅Ｗ
に対しＬ≧２Ｗとなる粒界ジョセフソン接合を形成する
ことにより超伝導ノーマル抵抗ＲＮを大きくし、ＩｃＲ
，積を大きくでき、その結果としてジョセフソンミキサ
の周波数上限（ｆｃ・２ｅＲｓｌｃ／ｈ）を挙げること
が可能となる（「超電導エレクトロニクス」、オーム社
刊Ｐ９３〜）。これにより、ジョセフソンミキサの周波
数上限の高い高感度ブリッジ型ジョセフソン接合素子を
提供することができる。
また、基板上に成膜される超伝導体多結晶薄膜とは、粒
界ジョセフソン接合を構成する超伝導体の組成をＡ−Ｂ
−Ｃ−Ｄと表わすとき、ＡがＬａ、Ｃｅ、Ｐｒ、Ｐｍ、
Ｓｍ、Ｅｕ、Ｇｄ。
Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ。
Ｓｃ、Ｙ、Ｂｉ、Ｔｌよりなる群より選ばれた一種以上
の元素、ＢはＣａ、Ｓｒ、Ｂａ、Ｐｂよりなる群より選
ばれた一種以上の元素、ＣはＶ。
Ｔｉ、Ｃｒ、Ｍｎ、Ｆｅ、Ｎｉ、Ｃｏ、Ａｇ。
Ｃｄ、Ｃｕ、Ｚｎ、Ｈｇ、Ｒｕよりなる群より選ばれた
一種以上の元素、ＤはＯ１９からなる群より選ばれた一
種以上の元素であるような組成を有する超伝導体が最も
好ましい。
以下図面により本発明の詳細な説明する。
第１図は本発明の特徴を最も良く表わす図であり、ブリ
ッジ型粒界ジョセフソン結合の構造を示し、１は基板、
２は超伝導体多結晶薄膜、３は超伝導体結晶粒、４は結
晶粒界、 ６．６゛は超伝導電極、５は電極間を連結す
るリンク部であり、その部分には粒界ジョセフソン接合
が形成されている。リンク長、リンク幅は第１図（Ｃ）
に示す通り、各々Ｌ、ｗで表わす、ブリッジ型ジョセフ
ソン接合の典型的なｔ−Ｖ特性曲線を第２図に示す。図
中、破線から得られる抵抗を超伝導ノーマル抵抗Ｒｓ、
電圧がゼロの時の電流を臨界電流１ｃと定義する。リン
ク長を長くすることで超伝導ノーマル抵抗ＲＮが大きく
なり、リンク幅を広くすることで臨界電流Ｉｃを大きく
取れる。
しかしながら、リンク幅Ｗは超伝導体結晶粒の大きさに
制限を受ける。近年発見されたセラミ・ソクス超伝導薄
膜において、粒界ジョセフソン接合は、超伝導薄膜の作
製方法により決定されるものであり、接合特性を制御し
つるためには、特別な方法を考えなければならない。本
発明は、マグネトロンスパッタ法、クラスクーイオンビ
ーム法。
レーザー蒸着、ＣＶＤ法、電子ビーム加熱蒸着法等の適
当な成膜方法にて作製した超伝導体多結晶薄膜を用いた
ブリッジ型粒界ジョセフソン接合に関するものであり、
結晶粒の大きさに比較し、リンク幅を極めて大きくした
場合、リンク部内にジョセフソン接合が存在するものの
、接合とはならずに超伝導電極として作用する部分の存
在確立が増し、電磁波検出用素子としての性能を著しく
低下せしめることがある。このためブリッジ型粒界ジョ
セフソン接合に用いる適当なリンク幅としては、平均的
結晶粒の大きさの８倍以下程度にする必要がある。また
、リンク幅を結晶粒と同等もしくはそれ以下とした時に
は、リンク部内にジョセフソン接合が存在しない場合も
起こりうることはいうまでもない０以上よりリンク幅と
しては結晶粒の２倍から８倍程度に抑えておく必要があ
る。
本発明においては、基板上に形成した超伝導体多結晶薄
膜に対して第１図（Ｃ）に示すバターン、即ち、ジョセ
フソン接合となるリンク部５とその両側に形成された１
対の電極部６．６°をフォトエツチング等により形成す
る。
〔実施例１
以下実施例により本発明を具体的に説明する。
夫癒■ユ
ＹｒＢａｔＣｕｓＯｔ−６（０＜δ〈１）なる組成のセ
ラミックスを５インチφターゲットとしてマグネトロン
スパッタで、アルゴン気体のガス圧０．５Ｐａ 、スパ
ッタパワー２００Ｗにおいて２０℃の温度に保持したマ
グネシア基板上に厚さ５０００人のＹ＋Ｂａｔ、 ｅａ
ｃｕｓ、 ４９０７−Ｘ（０＜Ｘ＜１）なる組成の薄膜
を形成し、その後酸素雰囲気中で９４０℃において３時
間熱処理を行なった。こうして薄膜はＴｃ７５にの超伝
導体多結晶薄膜となり、結晶粒１〜３μ程度の粒界ジョ
セフソン接合を有するものができる。その後、フォトレ
ジストＯＭＲ−８３（商標、東京応化工業株式会社製）
を用いバターニングした後、アルゴンイオンミーリング
装置によりエツチングし、第１図（Ｃ）のパターンを形
成した。こうして形成したジョセフソン接合素子の特性
を４．５Ｋに冷却したクライオスタット中にて５０ＧＨ
ｚのミリ波を照射して得られるＩ−Ｖ特性上のシャピロ
ステップの次数により評価した。第１表にリンク長及び
リンク幅を変えた時のＩｃＲ５積とミリ波応答性の評価
結果を示す、ミリ波応答性の評価に当っては、５次以上
のステップが得られたものについて０，２〜４次のステ
ップが得られたものをΔ、１次以下のものをＸとした。
第１表
Ｂ１５Ｓｒ＊Ｃａ＊ＣＬｌｓＯｘなる組成のセラミック
スを５インチφターゲットとして、実施例１と同様のス
パッタ条件にてマグネシア基板上に厚さ４０００人のＢ
ｉｚＳｒｚ、 ｏｓｃａａ、 ４ｏｃｕｚ、 ａｔＯｘ
なる組成の薄膜を形成し、その後酸素雰囲気中で８５０
℃において１時間熱処理を行なった。こうして薄膜はＴ
ｃ ６５にの超伝導体多結晶薄膜となり、結晶粒０．８
〜１．５鱗程度の粒界ジョセフソン接合を有するものが
できた。
実施例１と同様の方法でバターニングした後に同様にミ
リ波応答性の評価を行なった。結果を第２表に示す。
第１表
り及びリンク幅Ｗの比Ｌ ／ ｗが２以上となる時、比
較的ＩＣＲＮ積が大きく、５０ＧＨｚのミリ波照射によ
り５次以上のシャピロステップが現われる高感度なジョ
セフソン接合素子を得ることができた。
【発明の効果】
以上説明したように、超伝導体多結晶薄膜を用いたブリ
ッジ型粒界ジョセフソン接合におけるリンク部のリンク
長りがリンク幅Ｗに対しＬ≧２Ｗとなるようにすること
で、ジョセフソン接合素子のＩＣＲＮ積が大きくとれ、
ジョセフソンミキサとしての周波数上限を上げることと
なり、電磁波検出素子としての高感度が図られる。[Means for Solving the Problems 1] The present invention has been made in view of the above points, and provides a highly sensitive bridge-type Josephson junction element used in an electromagnetic wave detector. That is, the present invention includes a superconductor polycrystalline thin film on a substrate,
A bridge-type Josephson junction is formed using the grain boundaries of the 7I film, and the length of the link connecting the superconducting bridges in the Josephson junction is the link width W.
By forming a grain boundary Josephson junction where L≧2W, the superconducting normal resistance RN is increased, and IcR
, product can be increased, and as a result, it becomes possible to raise the upper frequency limit (fc·2eRslc/h) of the Josephson mixer ("Superconducting Electronics", published by Ohmsha, p. 93~). This makes it possible to provide a highly sensitive bridge-type Josephson junction element with a high frequency upper limit for the Josephson mixer. In addition, the superconductor polycrystalline thin film formed on the substrate has a composition of A-B that constitutes the grain boundary Josephson junction.
- When expressed as CD, A is La, Ce, Pr, Pm,
Sm, Eu, Gd. Tb, Dy, Ho, Er, Tm, Yb, Lu. One or more elements selected from the group consisting of Sc, Y, Bi, and Tl; B is one or more elements selected from the group consisting of Ca, Sr, Ba, and Pb; and C is V. Ti, Cr, Mn, Fe, Ni, Co, Ag. Most preferably, the superconductor has a composition in which D is one or more elements selected from the group consisting of Cd, Cu, Zn, Hg, and Ru, and D is one or more elements selected from the group consisting of O19. The present invention will be explained in detail below with reference to the drawings. FIG. 1 is a diagram that best represents the features of the present invention, and shows the structure of a bridge type grain boundary Josephson bond, where 1 is a substrate,
2 is a superconductor polycrystalline thin film, 3 is a superconductor crystal grain, 4 is a grain boundary, 6.6゛ is a superconducting electrode, and 5 is a link connecting the electrodes, and there are grain boundaries in that part. A Josephson junction is formed. The link length and link width are shown in Figure 1 (C).
FIG. 2 shows a typical t-V characteristic curve of a bridge type Josephson junction, denoted by L and w, respectively. In the figure, the resistance obtained from the broken line is superconducting normal resistance Rs,
The current when the voltage is zero is defined as critical current 1c. By increasing the link length, the superconducting normal resistance RN increases, and by increasing the link width, the critical current Ic can be increased. However, the link width W is limited by the size of superconductor crystal grains. In the Cerami-Sox superconducting thin films discovered in recent years, the grain boundary Josephson junction is determined by the method of manufacturing the superconducting thin film, and special methods must be devised to control the bonding properties. No. The present invention is a magnetron sputtering method and a Claskoo ion beam method. It relates to a bridge type grain boundary Josephson junction using a superconductor polycrystalline thin film produced by an appropriate film formation method such as laser deposition, CVD method, electron beam heating evaporation method, etc.
If the link width is made extremely large compared to the size of the crystal grains, although a Josephson junction exists within the link, there is an increased possibility of the existence of a portion that does not act as a junction but acts as a superconducting electrode, which is useful for detecting electromagnetic waves. The performance of the device may be significantly degraded. Therefore, an appropriate link width for use in a bridge type grain boundary Josephson junction needs to be approximately 8 times or less the average crystal grain size. In addition, when the link width is equal to or smaller than the crystal grain, it goes without saying that this can occur even if there is no Josephson junction in the link part, and the link width is from 2 times to 8 times the crystal grain from 0 or more. It is necessary to keep it to a certain extent. In the present invention, the superconductor polycrystalline thin film formed on the substrate is patterned as shown in FIG.
A pair of electrode portions of 6.6° are formed by photoetching or the like. [Example 1] The present invention will be specifically explained below with reference to Examples. A magnesia substrate was prepared by magnetron sputtering using ceramics having a composition of YrBatCusOt-6 (0<δ<1) at a temperature of 20°C using an argon gas pressure of 0.5Pa and a sputtering power of 200W using a 5-inch diameter target. 5000 thick Y+Bat on top, ea
A thin film having a composition of C.cus, 4907-X (0<X<1) was formed, and then heat treatment was performed at 940° C. for 3 hours in an oxygen atmosphere. In this way, the thin film becomes a superconductor polycrystalline thin film of Tc75, and has grain boundary Josephson junctions with crystal grains of about 1 to 3 μm. After that, photoresist OMR-83 (trademark, manufactured by Tokyo Ohka Kogyo Co., Ltd.)
After patterning using an argon ion milling device, the pattern shown in FIG. 1(C) was formed. The characteristics of the Josephson junction device thus formed were tested at 50GH in a cryostat cooled to 4.5K.
Evaluation was made based on the order of the Shapiro step on the IV characteristic obtained by irradiating the millimeter wave of z. Table 1 shows the evaluation results of the IcR5 product and millimeter wave responsiveness when changing the link length and link width. , 2nd to 4th order steps were obtained as Δ, and those of 1st order or less were set as X. Table 1 Using ceramics with the composition B15Sr*Ca*CLlsOx as a 5-inch diameter target, a B of 4000 mm thick was sputtered on a magnesia substrate under the same sputtering conditions as in Example 1.
izSrz, oscaa, 4ocuz, atOx
A thin film with a composition of
Heat treatment was performed at ℃ for 1 hour. In this way, the thin film is T
c 65 superconductor polycrystalline thin film with crystal grains of 0.8
A material having a grain boundary Josephson junction of about 1.5 scales was obtained. After patterning was performed in the same manner as in Example 1, the millimeter wave response was evaluated in the same manner. The results are shown in Table 2. When the ratio L/w of the first surface and the link width W is 2 or more, a highly sensitive Josephson junction element with a relatively large ICRN product and a fifth-order or higher Shapiro step appearing by 50 GHz millimeter wave irradiation is obtained. I was able to do that. [Effects of the Invention] As explained above, by making the link length of the link part in a bridge type grain boundary Josephson junction using a superconductor polycrystalline thin film satisfy L≧2W with respect to the link width W. , the ICRN product of the Josephson junction element can be large,
This increases the upper limit of the frequency of the Josephson mixer, and increases the sensitivity of the electromagnetic wave detection element.
第１図はブリッジ型粒界ジョセフソン結合の構造を示し
、（ａ）は上面図、（ｂ）は断面図、（Ｃ）はジョセフ
ソン接合素子のパターン図であり、第２図はブリッジ型
ジョセフソン接合のＩ−Ｖ特性曲線を示す。
第１表及び第２表からも分るように、リンク長・・・基
板
・・・超伝導体多結晶薄膜
・・・超伝導体結晶粒
・・・結晶粒界
・・・リンク部
、６°・・・超伝導電極Figure 1 shows the structure of a bridge type grain boundary Josephson bond, (a) is a top view, (b) is a cross-sectional view, (C) is a pattern diagram of a Josephson junction element, and Figure 2 is a bridge type 1 shows an IV characteristic curve of a Josephson junction. As can be seen from Tables 1 and 2, link length...substrate...superconductor polycrystalline thin film...superconductor crystal grain...crystal grain boundary...link part, 6 °・・・Superconducting electrode
Claims (1)
粒界を用いたブリッジ型ジョセフソン接合が形成され、
前記ジョセフソン接合における超伝導電極間を連結する
リンクにおけるリンク長Ｌがリンク幅ｗに対しＬ≧２ｗ
となる粒界ジョセフソン接合を形成されたジョセフソン
接合素子。 ２、超伝導体多結晶薄膜の組成をＡ−Ｂ−Ｃ−Ｄと表わ
すとき、ＡがＬａ、Ｃｅ、Ｐｒ、Ｐｍ、Ｓｍ、Ｅｕ、Ｇ
ｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ、Ｓｃ
、Ｙ、Ｂｉ、Ｔｌよりなる群より選ばれた一種以上の元
素、ＢはＣａ、Ｓｒ、Ｂａ、Ｐｂよりなる群より選ばれ
た一種以上の元素、ＣはＶ、Ｔｉ、Ｃｒ、Ｍｎ、Ｆｅ、
Ｎｉ、Ｃｏ、Ａｇ、Ｃｄ、Ｃｕ、Ｚｎ、Ｈｇ、Ｒｕより
なる群より選ばれた一種以上の元素、Ｄは０．５からな
る群より選ばれた一種以上の元素であることを特徴とす
る請求項１記載のジョセフソン接合素子。[Claims] 1. A superconductor polycrystalline thin film is provided on a substrate, and a bridge-type Josephson junction is formed using the crystal grain boundaries of the thin film,
The link length L of the link connecting the superconducting electrodes in the Josephson junction is L≧2w with respect to the link width w.
A Josephson junction element with a grain boundary Josephson junction formed. 2. When the composition of a superconductor polycrystalline thin film is expressed as A-B-C-D, A is La, Ce, Pr, Pm, Sm, Eu, G
d, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc
, Y, Bi, Tl, B is one or more elements selected from the group consisting of Ca, Sr, Ba, Pb, C is V, Ti, Cr, Mn, Fe ,
One or more elements selected from the group consisting of Ni, Co, Ag, Cd, Cu, Zn, Hg, Ru, and D is one or more elements selected from the group consisting of 0.5. The Josephson junction device according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1078178A JPH02260472A (en) | 1989-03-31 | 1989-03-31 | Josephson junction element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1078178A JPH02260472A (en) | 1989-03-31 | 1989-03-31 | Josephson junction element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02260472A true JPH02260472A (en) | 1990-10-23 |
Family
ID=13654711
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1078178A Pending JPH02260472A (en) | 1989-03-31 | 1989-03-31 | Josephson junction element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02260472A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5244870A (en) * | 1990-05-11 | 1993-09-14 | The University Of Tokyo | Superconductive optoelectronic device with the basic substance Cu2 O of superconductive-conjugate photoconductivity |
-
1989
- 1989-03-31 JP JP1078178A patent/JPH02260472A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5244870A (en) * | 1990-05-11 | 1993-09-14 | The University Of Tokyo | Superconductive optoelectronic device with the basic substance Cu2 O of superconductive-conjugate photoconductivity |
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