JPH04192381A - Josephson junction element - Google Patents
Josephson junction elementInfo
- Publication number
- JPH04192381A JPH04192381A JP2320399A JP32039990A JPH04192381A JP H04192381 A JPH04192381 A JP H04192381A JP 2320399 A JP2320399 A JP 2320399A JP 32039990 A JP32039990 A JP 32039990A JP H04192381 A JPH04192381 A JP H04192381A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- josephson
- weak
- superconducting thin
- josephson junction
- 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 38
- 230000008878 coupling Effects 0.000 claims description 16
- 238000010168 coupling process Methods 0.000 claims description 16
- 238000005859 coupling reaction Methods 0.000 claims description 16
- 239000012212 insulator Substances 0.000 abstract description 14
- 239000013078 crystal Substances 0.000 abstract description 10
- 239000000758 substrate Substances 0.000 abstract description 8
- 238000000034 method Methods 0.000 abstract description 5
- 238000004544 sputter deposition Methods 0.000 abstract description 5
- 229910052691 Erbium Inorganic materials 0.000 abstract description 4
- 229910052693 Europium Inorganic materials 0.000 abstract description 4
- 230000006866 deterioration Effects 0.000 abstract description 4
- 229910052769 Ytterbium Inorganic materials 0.000 abstract description 3
- 238000010438 heat treatment Methods 0.000 abstract description 3
- 238000000059 patterning Methods 0.000 abstract description 3
- 229920002120 photoresistant polymer Polymers 0.000 abstract description 3
- 238000000992 sputter etching Methods 0.000 abstract description 3
- 229910052779 Neodymium Inorganic materials 0.000 abstract description 2
- 239000002184 metal Substances 0.000 abstract description 2
- 229910052751 metal Inorganic materials 0.000 abstract description 2
- 229910052727 yttrium Inorganic materials 0.000 abstract description 2
- 229910052772 Samarium Inorganic materials 0.000 abstract 1
- 230000008020 evaporation Effects 0.000 abstract 1
- 238000001704 evaporation Methods 0.000 abstract 1
- 239000002887 superconductor Substances 0.000 description 16
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 239000004020 conductor Substances 0.000 description 5
- 238000005468 ion implantation Methods 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000010408 film Substances 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 206010021143 Hypoxia Diseases 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- -1 YBaCuO/ Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 210000003323 beak Anatomy 0.000 description 1
- 230000005465 channeling Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000013077 target material Substances 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Landscapes
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
Abstract
Description
【発明の詳細な説明】
（イ）産業上の利用分野
本発明は酸化物超電導体を用いたジョセフソン接合素子
に関し、特に、ジョセフソン弱結合部を上記酸化物超電
導体と同様の結晶構造を有するジョセフソン接合素子に
関する。Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a Josephson junction device using an oxide superconductor, and in particular, to a Josephson junction device using an oxide superconductor, in which a Josephson weak junction is formed into a crystal structure similar to that of the oxide superconductor. The present invention relates to a Josephson junction device having a Josephson junction element.
（ロ）従来の技術
ジョセフソン接合素子は、その高速性、低消費電力性の
ため半導体を凌ぐ高速素子として期待され、ジョセフソ
ンコンピュータの試作が精力的に進められている。この
ために試作されている素子嘴遺は、ＮｂあるいはＮｂＮ
の間に、ごく薄い絶縁膜を挾んだトンネル接合型のもの
が主流を占めている。(b) Prior Art Josephson junction devices are expected to be high-speed devices that surpass semiconductors due to their high speed and low power consumption, and prototype Josephson computers are being actively developed. The element beak that is being prototyped for this purpose is Nb or NbN
In between, tunnel junction type devices, which sandwich a very thin insulating film, are the mainstream.
一方、酸化物超電導体が高温の臨界温度を有することが
発見されて以来、この酸化物超電導体を用いるジョセフ
ソン接合素子の開発が進められている。On the other hand, since it was discovered that oxide superconductors have a high critical temperature, development of Josephson junction devices using these oxide superconductors has been progressing.
しかしながら、超電導体の臨界温度が高い超電導体はど
その超電導体のコヒーレンス長が短くなり、超電導臨界
温度が８０に以上である酸化物超電導体においては、コ
ヒーレンス長はＣ軸方向で数十穴であり、ジョセフソン
接合素子を構成する超電導体・絶縁体（又は常電導体）
・超電導体における絶縁体（又は常電導体）（以下絶縁
体等という）の厚みをその超電導体のコヒーレンス長以
下に薄くする必要があり、また、ジョセフソン電流を大
きくするためには、その絶縁体等の結晶構造を隣接する
超電導体と同様にすることが必要である。However, the coherence length of a superconductor with a high superconductor temperature is short, and in the case of an oxide superconductor with a superconducting critical temperature of 80 or higher, the coherence length is several tens of holes in the C-axis direction. Yes, superconductor/insulator (or normal conductor) that constitutes the Josephson junction element
・The thickness of the insulator (or normal conductor) (hereinafter referred to as insulator) in a superconductor must be made thinner than the coherence length of the superconductor, and in order to increase the Josephson current, the insulation It is necessary to make the crystal structure of the superconductor similar to that of the adjacent superconductor.
ところで、酸化物ｖｉ電導体を用いた従来のジョセフソ
ン接合素子として、ＹＢａＣｕＯ／、Ａｕ／ＹＢａＣｕ
Ｏを基板上に積層したトンネル接合型ものが提案されて
いる（Ｐ、Ｍ、Ｍａｎｋｉｅｗｉｃｈ ｅｔｃ、 ’
ＦＥＤ ＨｉＳｃ−ＥＤ Ｗｏｒｋｓｈｏｐ” Ｍｉｙ
ａｇｉ−Ｚａｏ、１５７．１９８８）。By the way, as conventional Josephson junction elements using oxide vi conductors, YBaCuO/, Au/YBaCu
A tunnel junction type device in which O is laminated on a substrate has been proposed (P, M, Mankiewich, etc., '
FED HiSc-ED Workshop” Miy
agi-Zao, 157.1988).
しかしこの提案されたものにおいては、ＹＢａＣｕＯと
Ａｕの界面における結晶構造の不連続性と、ＹＢａＣｕ
Ｏの、Ａｕ対接面における酸素濃度の減少によるＹ Ｂ
ａ Ｃｕ０Ｌ７）超電導性の劣化とに基ずき、素子と
して動作するために必要な２つのＹＢａＣｕＯ間のジョ
セフソン電流を得ることは困難である。このため、Ａｕ
以外のバリヤー材料であって、ＹＢａＣｕＯとの反応性
に乏しく、且つＹＢａＣｕＯと結晶性において相性のよ
い材料の選定が望まれている。However, in this proposal, the discontinuity of the crystal structure at the interface between YBaCuO and Au and the
YB due to decrease in oxygen concentration at the surface facing Au
aCu0L7) Based on the deterioration of superconductivity, it is difficult to obtain the Josephson current between two YBaCuOs necessary to operate as a device. For this reason, Au
It is desired to select a barrier material other than YBaCuO that has poor reactivity with YBaCuO and is compatible with YBaCuO in terms of crystallinity.
このような要望に応えるものとして、前述のＡｕに代わ
ってＰｒＢａＣｕＯ酸化物薄膜を用いるものを検討した
。このＰｒＢａＣｕＯは絶縁性を示し、しかもその結晶
構造がＹＢａＣｕＯと同じである。In order to meet these demands, we have investigated the use of a PrBaCuO oxide thin film instead of the above-mentioned Au. This PrBaCuO exhibits insulating properties and has the same crystal structure as YBaCuO.
ところが、このＰ ｒＢａｃｕｏ酸化物薄膜においては
、素子として動作するために必要なジョセフソン電流を
得るための１０ ”／ｃｍ’以上のキャリヤ濃度を得る
ことができなかった。However, in this PrBacuo oxide thin film, it was not possible to obtain a carrier concentration of 10''/cm' or more to obtain the Josephson current necessary to operate as a device.
（ハ） 発明が解決しようとする課題
本発明はかかる背景の下に、超電導体と絶縁体等の界面
における結晶構造の連続性の向上、超電導体の絶縁体等
との対接面における酸素欠乏の緩和及び絶縁体等におけ
る適正なキャリヤ濃度を得ることができるジョセフソン
接合素子を提供することを解決課題とする。(c) Problems to be Solved by the Invention With this background in mind, the present invention aims to improve the continuity of the crystal structure at the interface between a superconductor and an insulator, etc., and to improve the oxygen deficiency at the interface between a superconductor and an insulator, etc. An object of the present invention is to provide a Josephson junction element that can reduce the stress and obtain an appropriate carrier concentration in an insulator or the like.
（ニ）課題を解決するための手段
本発明によるジョセフソン接合素子は、ＬｎＢａ＋ＣＵ
、Ｏ，（但し、ＬｎｉｉＹ、Ｙｂ、 Ｅｒ、 Ｅｕ、
Ｈｏ、Ｓｍ、 Ｎｄの一種又は複数種からなる）酸化物
超電導薄膜の所定部位に、Ｌ ｎ ＋ −ｙ Ｐ ｒ
ｙ Ｂ ａ ２ Ｃｕ ｓ Ｏ＊ （但し、０．１＜ｙ
＜０．５）薄膜部を設け、この薄膜部をジョセフソン弱
結合部にしたことを特徴とするものである。(d) Means for Solving the Problems The Josephson junction element according to the present invention is made of LnBa+CU
, O, (However, LniiY, Yb, Er, Eu,
L n + −y Pr
y B a 2 Cu s O * (However, 0.1<y
<0.5) A thin film portion is provided, and this thin film portion is a Josephson weak coupling portion.
（ホ）作用
超電導薄膜を構成するＬｎＢａｘＣｕ＋Ｏ，と、絶縁体
等を構成するＬ ｎ １− ｙ Ｐ ｒ ｙ Ｂ ａ
ｒ Ｃｕ ｒ Ｏｔとが酸化物であって、同様の結晶構
造をもつため、前述の従来例におけるＡｕを用いたもの
に比して、超電導薄膜と絶縁体等の界面における結晶構
造の連続性を向上することができるとともに超電導薄膜
の絶縁体等との対接面における酸素の欠乏に対してもそ
の性質が維持されることがらその対接面近傍の酸素欠乏
を緩和する効果があり、超電導特性の劣化防止にもなる
。また、前記Ｌｎ＋−，Ｐｒ、ＢａｔＣＬＩ＋Ｏｔにお
けるｙが０． ｘ＜ｙ＜ｏ、 ５であることがら、絶縁
体等における適正なキャリヤ濃度を得ることができ、ジ
ョセフソン接合素子として動作するために必要なジョセ
フソン電流を得ることができる。(e) LnBaxCu+O, which constitutes the functional superconducting thin film, and Ln1-yPryBa, which constitutes the insulator, etc.
Since r Cu r Ot is an oxide and has a similar crystal structure, it is possible to improve the continuity of the crystal structure at the interface between the superconducting thin film and the insulator, compared to the conventional example using Au. At the same time, the properties of the superconducting thin film are maintained even when oxygen is depleted at the contact surface with an insulator, etc., which has the effect of alleviating oxygen depletion near the contact surface, improving the superconducting properties. It also prevents deterioration. Further, y in the above Ln+-, Pr, and BatCLI+Ot is 0. Since x<y<o, 5, an appropriate carrier concentration in the insulator etc. can be obtained, and a Josephson current necessary for operating as a Josephson junction element can be obtained.
（へ）実施例
〔第１実施例〕
この実施例はマイクロブリッジ型ジョセフソン接合素子
に関するものである。(F) Embodiment [First Embodiment] This embodiment relates to a microbridge type Josephson junction element.
第１図はマイクロブリッジ型ジョセフソン接合素子の斜
視図である。この図面がら明らかなように、基板１上に
ＬｎＢａｔＣｕｓＯ−（但し、Ｌｎｉ、ｔＹ、 Ｙｂ、
Ｅｒ、 Ｅｕ、 Ｈｏ、Ｓｍ、Ｎｄの一種又は複数種
からなる）酸化物超電導薄膜２をスパッタリング法また
は蒸着法により数百λ〜数μｍの厚さに形成する。基板
１としては、Ａｌｌ０＋、５ｒＴｉ○８、ＬａＡｌ０＋
、ＬａＧａＯ４、ＭｇＯを用いることができる。FIG. 1 is a perspective view of a microbridge type Josephson junction element. As is clear from this drawing, LnBatCusO- (Lni, tY, Yb,
An oxide superconducting thin film 2 (consisting of one or more of Er, Eu, Ho, Sm, and Nd) is formed to a thickness of several hundred λ to several μm by sputtering or vapor deposition. As the substrate 1, All0+, 5rTi○8, LaAl0+
, LaGaO4, and MgO can be used.
実施例においては、基板ｌとしてＭｇＯを用い、超電導
薄膜２としてＹＢａｔＣｕ＋０．組成のものをスパッタ
リング法により形成した。即ち、スパッタリング装置の
ペルジャー内の対抗電極の陽極側に基板１を載置すると
ともにその陽極を掻を接地し、陰極電極をＹ Ｂ ａ
！ Ｃｕ ｓ Ｏ＊酸化物超電導体の焼結体からなるタ
ーゲツト材にて構成する。ペルジャー内にアルゴンガス
を３．０〜３０．０ｍＴｏｒｒの圧力で供給するととも
に陰極電極に負の高い電圧を印加し、スパッタ出力を２
００〜２５０Ｗをして基板ｌに薄膜を形成した。In the example, MgO is used as the substrate 1, and YBatCu+0. A material having the same composition was formed by a sputtering method. That is, the substrate 1 is placed on the anode side of the counter electrode in the Pel jar of the sputtering device, the anode is grounded, and the cathode electrode is connected to YBa.
! The target material is a sintered body of Cu s O* oxide superconductor. Argon gas was supplied into the Pelger at a pressure of 3.0 to 30.0 mTorr, and a high negative voltage was applied to the cathode electrode to reduce the sputtering output to 2.
A thin film was formed on the substrate 1 by applying a power of 00 to 250 W.
その後、基板１をペルジャー内から取り８巳て電気炉に
入れ、流量２１／分の酸素雰囲気中において室温から１
℃／秒で９４０℃まで昇温し、９４０℃で１０分間焼成
処理を行い、−２０℃／秒で室温まで降温して、基板１
上にＹＢａ＋ＣＬｌ＋汎超電導薄膜２全超電導薄膜
次にこのようにして得られた超電導薄膜２に、７オトレ
ジスト、メタルマスク等を用いたパターニング、又はマ
スクレススパッタエツチングによるパターニングにより
、第１図に示すように弱結合部３を有するパターンを形
成する。実施例ではフォトレジストを用いたパターニン
グによりこのパターンを形成した。このときの弱結合部
３の長さ及び幅は０．１−１００μｍであった。Thereafter, the substrate 1 was taken out of the Pelger and put into an electric furnace, and heated from room temperature to
The temperature was raised to 940°C at a rate of 940°C/second, a baking process was performed at 940°C for 10 minutes, and the temperature was lowered to room temperature at a rate of -20°C/second.
Then, the superconducting thin film 2 obtained in this way is patterned by patterning using a photoresist, a metal mask, etc., or by maskless sputter etching, as shown in FIG. 1. A pattern having weak coupling portions 3 is formed. In the example, this pattern was formed by patterning using a photoresist. The length and width of the weak coupling portion 3 at this time were 0.1-100 μm.
この弱結合部３に対して、Ｐｒをイオン注入して改質す
る。実施例においては、集束イオンビームによりＰｒを
加速電圧数ＫｅＶ〜数百ＫｅＶ、ドーズ量１０”−１０
” （イオン量／ｃｍ’）で注入した。その後５００〜
６５０℃の熱処理により結晶性を回復させてジョセフソ
ン弱結合部を構成する薄膜４を形成した。Ｘ＠回折によ
りで調べたところ（交流帯磁率で調べてもよい）、この
薄膜４はＹｌ−、Ｐｒ、ＢａｔＣｕｓＯｘ（但し、ｏ、
１＜ｙ＜０．５）薄膜であり、常電導体であることが
分かった。上記ｙの値は加速電圧又はドーズ量を変える
ことにより調整することができる。This weak coupling portion 3 is modified by ion implantation of Pr. In the example, Pr is accelerated by a focused ion beam at a voltage of several KeV to several hundred KeV and a dose of 10''-10
” (ion amount/cm'). After that, 500 ~
The crystallinity was restored by heat treatment at 650° C., and a thin film 4 constituting a weak Josephson bond was formed. When examined by
1<y<0.5) and was found to be a thin film and a normal conductor. The value of y can be adjusted by changing the acceleration voltage or dose amount.
このような構成により、薄膜４を〜ジョセフソン弱結合
部とするジョセフソン接合素子を形成する。With this configuration, a Josephson junction element is formed in which the thin film 4 serves as a ~Josephson weak coupling portion.
尚、弱結合部３の厚みが大のときは、この弱結合部３を
イオンエツチングにより数十Å以下に巳で、旨をイオン
注入するようにすればよい。また、このように弱結合部
３の厚みを薄くしない場合には、ＦＩＢのチャンネリン
グ効果を利用してさらに深い層までＰｒをイオン注入す
るようにしてもよい。When the thickness of the weak bonding portion 3 is large, ions may be implanted into the weak bonding portion 3 to a thickness of several tens of angstroms or less by ion etching. Further, in the case where the thickness of the weak coupling portion 3 is not reduced in this manner, Pr may be ion-implanted to a deeper layer by utilizing the channeling effect of the FIB.
改質によるジョセフソン弱結合部（薄膜）４の形成とし
て、以上の実施例ではＰｒのイオン注入による方法につ
いて説明したが、Ｐｒの熱拡散により弱結合部３を改質
するようにしてもよい。この場合には、弱結合部３上に
Ｐｒ＊Ｑ＋の薄膜を１００λ程度形成し、大気中で５０
０〜６５０ ”Ｃの温度で熱処理することにより、’ｌ
’１−ｙＰｒｙＢａｔＣｕｓＯ−が形成される。In the above embodiments, the method of forming the Josephson weak bond (thin film) 4 by modification was explained using Pr ion implantation, but the weak bond 3 may be modified by thermal diffusion of Pr. . In this case, a thin film of Pr*Q+ of about 100 λ is formed on the weak coupling part 3, and 50
By heat treatment at a temperature of 0~650''C, 'l
'1-yPryBatCusO- is formed.
〔第２実施例〕
この実施例はトンネル接合型ジョセフソン接合素子に関
するものである。[Second Embodiment] This embodiment relates to a tunnel junction type Josephson junction element.
第２図はトンネル接合型ジョセフソン接合素子の斜視図
である。この図面において、基板１上にＬｎＢａ＋Ｃｕ
３０．酸化物超電導薄膜２を形成する点においては、第
１実施例で形成したものを用いた。FIG. 2 is a perspective view of a tunnel junction type Josephson junction element. In this drawing, LnBa+Cu is deposited on the substrate 1.
30. In forming the oxide superconducting thin film 2, the one formed in the first example was used.
この酸化物超電導薄膜２の一部にＰｒをイオン注入して
ジョセフソン弱結合部を構成する改質部５を形成する。Pr is ion-implanted into a part of this oxide superconducting thin film 2 to form a modified portion 5 constituting a Josephson weak bond.
この場合のイオン注入の深さは、Ｃ軸方向のコヒーレン
ス長が短いことから、加速電圧が数百ｅＶ〜数十ＫｅＶ
とされ、イオンの注入深さが浅く （数十Å以下）され
ている。このジョセフソン弱結合部（改質部）５は第１
実施例における薄膜４と同じ（Ｙ＋−ｙＰｒｙＢａｘｃ
ｕ！○バ但し、０．１＜ｙ＜０．５）薄膜であり、常電
導体であることが分かった。その後、この改質部５上に
ＬｎＢａｔＣｕｓＯ−酸化物超電導薄膜６を酸化物超電
導薄膜２と同じ方法で形成した。In this case, the depth of ion implantation is determined by the acceleration voltage ranging from several hundred eV to several tens of KeV because the coherence length in the C-axis direction is short.
The ion implantation depth is shallow (several tens of Å or less). This Josephson weak coupling part (modified part) 5 is the first
Same as thin film 4 in Example (Y+-yPryBaxc
u! ○ However, it was found that the film was thin (0.1<y<0.5) and was a normal conductor. Thereafter, a LnBatCusO-oxide superconducting thin film 6 was formed on the modified portion 5 in the same manner as the oxide superconducting thin film 2.
このような構成により、改質部５をジョセフソン弱結合
部とするジョセフソン接合素子を形成する。With such a configuration, a Josephson junction element is formed in which the modified portion 5 is a Josephson weak coupling portion.
ジョセフソン弱結合部（改質部）５の形成法として、第
１実施例で説明したように、Ｐｒのイオン注入による方
法に代わってＰｒの熱拡散により改質部５を形成するよ
うにしてもよい。As a method of forming the Josephson weak coupling portion (modified portion) 5, as explained in the first embodiment, the modified portion 5 is formed by thermal diffusion of Pr instead of the method of Pr ion implantation. Good too.
以上の第１及び第２の実施例におけるジョセフソン弱結
合部を構成する薄膜４及び改質部５がＹｌ−ｙＰｒｙＢ
ａ宜ｃｕｓｏｍ（但し、０．１＜ｙ＜ｏ、 ５）で構成
されているので、Ｐ ｒ Ｂ ａ ＊ Ｃｕ ｓ Ｏｘ
で構成したものに比べてジョセフソン弱結合部における
キャリア濃度を１０１１／ａｍ″以上に高めることがで
きる。The thin film 4 and modified portion 5 constituting the Josephson weak coupling portion in the above first and second embodiments are made of Yl-yPryB.
Since it is composed of aycusom (however, 0.1<y<o, 5), P r B a * Cu s Ox
The carrier concentration in the Josephson weak coupling region can be increased to 10 11 /am″ or more compared to the structure constructed with the following.
また、以上の実施例においては、超電導薄膜としてＹＢ
ａｌＣｕｌＯ□組成のものを用いたが、この組成Ｙの代
わりにＹｂ、 Ｅｒ、 Ｅｕ、 Ｈａ、 Ｓｍ、Ｎｄの
一種又は複数種からなるもの、あるいはこれらとＹとの
組み合わせからなるものを使用しもよい。In addition, in the above embodiments, YB is used as the superconducting thin film.
Although a material having the composition alCulO good.
（ト）発明の効果
本発明によるジョセフソン接合素子は、ＬｎＢａ＋Ｃｕ
３０ｍ（但し、ＬｎはＹ、 Ｙｂ、 Ｅｒ、 Ｅｕ、
Ｈｏ、Ｓｍ、Ｎｄの一種又は複数種からなる）酸化物超
電導薄膜の所定部位に、Ｌｎ、−、Ｐｒ、ＢａｔＣｕ＋
Ｏｘ（但し、０．１＜ｙ（０，５）薄膜部を設け、この
薄膜部をジョセフソン弱結合部にしたことを特徴とする
ものであるから、次の効果を有する。即ち、超電導薄膜
を構成するＬｎＢａ、Ｃｕ、Ｏｌと、絶縁体等を構成す
るＬｒ＋＋−、Ｐｒ、Ｂａ＊Ｃｕ５Ｏｘとが酸化物であ
って、同様の結晶構造をもつため、超電導薄膜と絶縁体
等の界面における結晶構造の連続性を向上することがで
きるとともに超電導薄膜の絶縁体等との対接面における
酸素の欠乏に対してもその性質が維持されることからそ
の対接面近傍の酸素欠乏を緩和する効果があり、超電導
特性の劣化防止にもなる。また、前記Ｌｎ＋−アＰｒ。(g) Effects of the invention The Josephson junction element according to the invention is made of LnBa+Cu
30m (However, Ln is Y, Yb, Er, Eu,
Ln, -, Pr, BatCu+
Ox (however, 0.1<y(0,5)) Since it is characterized by providing a thin film part and making this thin film part a Josephson weak coupling part, it has the following effects. Namely, superconducting thin film The LnBa, Cu, and Ol that make up the superconducting thin film and the Lr++-, Pr, and Ba*Cu5Ox that make up the insulator are oxides and have similar crystal structures, so crystals at the interface between the superconducting thin film and the insulator, etc. The continuity of the structure can be improved, and the properties of the superconducting thin film are maintained even when oxygen is depleted at the contact surface with an insulator, etc., so it is effective in alleviating oxygen depletion near the contact surface. This also prevents deterioration of the superconducting properties.Furthermore, the above-mentioned Ln+-A Pr.
ＢａｆＣｕＩ帆におけるｙがＯ，ｌ＜ｙ＜Ｑ、 ５であ
ることから、ジョセフソン弱結合部における適正なキャ
リヤ濃度を得ることができ、ジョセフソン接合素子とし
て動作するために必要なジョセフソン電流を得ることが
できる。Since y in the BafCuI sail is O, l < y < Q, 5, an appropriate carrier concentration in the Josephson weak coupling can be obtained, and the Josephson current required to operate as a Josephson junction element can be obtained. Obtainable.
図面は本発明の一実施例を示し、第１図はマイクロブリ
ッジ型ジョセフソン接合素子の斜視図、第２図はトンネ
ル接合型ジョセフソン接合素子の斜視図である。
１−−一−−−−蚤板、２−−−−−−一酸化物超電導
薄膜、３−−−−−−−弱結合部、４−−−−−−−ジ
ョセフソン弱結合部（薄膜）、 ３−−−−−ｍ−・
ジョセフソン弱結合部（改質部）、６、−−−−−−一
俵化物超電導薄膜。The drawings show an embodiment of the present invention; FIG. 1 is a perspective view of a microbridge type Josephson junction element, and FIG. 2 is a perspective view of a tunnel junction type Josephson junction element. 1--1-----Flea plate, 2-----Monoxide superconducting thin film, 3--------Weak bond, 4--Josephson weak bond ( thin film), 3------m-・
Josephson weak coupling part (modified part), 6, ------- Monobalide superconducting thin film.
Claims (1)
Ｙｂ、Ｅｒ、Ｅｕ、Ｈｏ、Ｓｍ、Ｎｄの一種又は複数種
からなる）酸化物超電導薄膜の所定部位に、Ｌｎ＿１＿
−＿ｙＰｒ＿ｙＢａ＿２Ｃｕ＿３Ｏ＿ｘ（但し、０．１
＜ｙ＜０．５）薄膜部を設け、この薄膜部をジョセフソ
ン弱結合部にしたことを特徴とするジョセフソン接合素
子。(1) LnBa_2Cu_3O_x (Ln is Y,
Ln_1_
−_yPr_yBa_2Cu_3O_x (however, 0.1
<y<0.5) A Josephson junction element characterized in that a thin film portion is provided and the thin film portion is a Josephson weak coupling portion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2320399A JPH04192381A (en) | 1990-11-22 | 1990-11-22 | Josephson junction element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2320399A JPH04192381A (en) | 1990-11-22 | 1990-11-22 | Josephson junction element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04192381A true JPH04192381A (en) | 1992-07-10 |
Family
ID=18121036
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2320399A Pending JPH04192381A (en) | 1990-11-22 | 1990-11-22 | Josephson junction element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04192381A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3968395A1 (en) * | 2020-09-15 | 2022-03-16 | Kabushiki Kaisha Toshiba | Oxide superconductor and method for manufacturing the same |
| EP3968396A1 (en) * | 2020-09-15 | 2022-03-16 | Kabushiki Kaisha Toshiba | Oxide superconductor and method for manufacturing the same |
-
1990
- 1990-11-22 JP JP2320399A patent/JPH04192381A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3968395A1 (en) * | 2020-09-15 | 2022-03-16 | Kabushiki Kaisha Toshiba | Oxide superconductor and method for manufacturing the same |
| EP3968396A1 (en) * | 2020-09-15 | 2022-03-16 | Kabushiki Kaisha Toshiba | Oxide superconductor and method for manufacturing the same |
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