JPH0412575A - Tunnel junction element - Google Patents
Tunnel junction elementInfo
- Publication number
- JPH0412575A JPH0412575A JP2115387A JP11538790A JPH0412575A JP H0412575 A JPH0412575 A JP H0412575A JP 2115387 A JP2115387 A JP 2115387A JP 11538790 A JP11538790 A JP 11538790A JP H0412575 A JPH0412575 A JP H0412575A
- Authority
- JP
- Japan
- Prior art keywords
- film
- single crystal
- oxide superconducting
- axis oriented
- superconducting thin
- 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
- 239000010408 film Substances 0.000 claims abstract description 31
- 239000010409 thin film Substances 0.000 claims abstract description 16
- 239000013078 crystal Substances 0.000 claims abstract description 15
- 239000000758 substrate Substances 0.000 claims abstract description 14
- 239000000919 ceramic Substances 0.000 claims description 2
- 229910002370 SrTiO3 Inorganic materials 0.000 abstract description 3
- 238000010030 laminating Methods 0.000 abstract description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 abstract 1
- 229910052593 corundum Inorganic materials 0.000 abstract 1
- 229910001845 yogo sapphire Inorganic materials 0.000 abstract 1
- 239000002887 superconductor Substances 0.000 description 11
- 229910052760 oxygen Inorganic materials 0.000 description 3
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910001882 dioxygen Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 238000001771 vacuum deposition Methods 0.000 description 2
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000005641 tunneling Effects 0.000 description 1
Landscapes
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
Abstract
Description
【発明の詳細な説明】
［技術分野］
本発明は、Ｙ系、Ｂｉ系等を含む酸化物超伝導薄膜を用
いたトンネル接合素子に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a tunnel junction element using an oxide superconducting thin film containing Y-based, Bi-based, etc.
［従来技術］
ジョセフソン素子に代表されるいわゆるトンネル効果を
利用する素子の研究は、金属・合金系超伝導体において
これまで行われてきたが、最近は酸化物超伝導体を用い
た研究が盛んである。基板はＳｒＴｉＯ３、ＭｇＯ等の
単結晶基板で、！縁物を介してＹ系やＢｉ系超伝導薄膜
を積層する。しかしながら、酸化物超伝導体単独では臨
界温度の高い薄膜が作成されているが、超伝導体−絶縁
体−超伝導体接合にすると素子全体の臨界温度が低下し
、しかもトンネル電流はさらに低温でないと流れなかっ
たりする。その原因としては、接合の界面がうまく超伝
導体と絶縁体に分離されていないこと、酸化物超伝導体
のコヒーレンス長が短いことなどが挙げられる。[Prior art] Research on devices that utilize the so-called tunneling effect, such as Josephson devices, has been conducted in metal/alloy superconductors, but recently research using oxide superconductors has been conducted. It's thriving. The substrate is a single crystal substrate of SrTiO3, MgO, etc.! Y-based or Bi-based superconducting thin films are laminated via a border. However, when using oxide superconductors alone, thin films with high critical temperatures have been created, but when superconductor-insulator-superconductor junctions are used, the critical temperature of the entire device decreases, and the tunnel current is even lower. Sometimes it doesn't flow. The reasons for this are that the junction interface is not well separated into superconductors and insulators, and that the coherence length of oxide superconductors is short.
ところが、トンネル電流値は前記原因以外に超伝導体の
臨界電流密度の小さいことにも影響をうけていることが
判明した。However, it has been found that the tunnel current value is also affected by the low critical current density of the superconductor, in addition to the above-mentioned causes.
［発明の目的］
本発明の目的は、酸化物超伝導薄膜をもちいるトンネル
接合素子において、前記酸化物超伝導薄膜の臨界電流密
度が大きくできる構造を提供する点にある６
［構 成］
本発明は、（１）セラミックス単結晶基板上に、（２）
ｃ軸配向させた酸化物超伝導薄膜、 （３）Ｍｇ○のよ
うな単結晶膜、（４）ａ軸配向させた酸化物超伝導薄膜
の順で積層したことを特徴とするトンネル接合素子に関
する。[Object of the Invention] An object of the present invention is to provide a structure in which the critical current density of the oxide superconducting thin film can be increased in a tunnel junction device using an oxide superconducting thin film. The invention provides (1) on a ceramic single crystal substrate, (2)
A tunnel junction device characterized in that a c-axis oriented oxide superconducting thin film, (3) a single crystal film such as Mg○, and (4) an a-axis oriented oxide superconducting thin film are laminated in this order. .
前記酸化物超伝導体としては、Ｙ系あるいはＢｉ系ある
いはＬａ系等のいずれでもよく、例えば、Ｙ 、 Ｂ
ａ２Ｃｕ、０７−Ｘ（０＜ Ｘ ＜０．５）、Ｙ□Ｂ、
ａ２Ｃａ３０７−１＋ Ｂｉ２５ｒ２Ｃａ、Ｃｕ２０ｔ
、Ｂｉ、５ｒ２Ｃａ、Ｃｕ２０ｓ、Ｂｉ２５ｒ２Ｃａ、
ＣｕｚＯｔｏ−（Ｍ ｘ Ｌ ａｌ−ｘ）ｚ Ｃｕ Ｏ
４−ｓ （ＭはＳ ｒ ｐ Ｃａ ＃ Ｂ ａ ）など
を挙げることができる。The oxide superconductor may be Y-based, Bi-based, La-based, etc., for example, Y, B, etc.
a2Cu, 07-X (0<X<0.5), Y□B,
a2Ca307-1+ Bi25r2Ca, Cu20t
, Bi, 5r2Ca, Cu20s, Bi25r2Ca,
CuzOto-(M x L al-x)z Cu O
4-s (M is S r p Ca # B a ), and the like.
また、（２）の酸化物超伝導体と（４）の酸化物超伝導
体は通常同一のものを使用するが、これに限定されるわ
けではなく、必要に応じて任意の組合せとすることがで
きる。In addition, although the oxide superconductor in (2) and the oxide superconductor in (4) are usually the same, they are not limited to this, and any combination may be used as necessary. I can do it.
Ｙ系、Ｂｉ系等の超伝導体はペロブスカイト型構造を基
本とし、電気伝導はＣｕ−○の結合した平面（ａｂ面）
で起きているとされている。Y-based, Bi-based, etc. superconductors are based on a perovskite structure, and electrical conduction occurs in the Cu-○ bonded plane (ab-plane).
It is said to occur in
それは、臨界電流密度を調べると、Ｙ系の場合Ｃ軸に平
行に電流を流した時と、Ｃ軸に垂直に電流を流した時と
で値が異なり、異方性を持つことから理解できる。Ｙ系
においては、７７に付近でＣ軸方向、Ｃ軸に垂直な方向
で電流密度が１ケタ違うという報告がある（高温超伝導
データブック［］新技術事業団監修）。従って、薄膜を
積層する場合、現在Ｃ軸配向した膜がほとんどである。This can be understood from the fact that when examining the critical current density, in the Y system, the value is different when the current is passed parallel to the C-axis and when the current is passed perpendicular to the C-axis, and it has anisotropy. . In the Y system, there is a report that the current density differs by one order of magnitude in the C-axis direction and in the direction perpendicular to the C-axis near 77 (High Temperature Superconductivity Data Book [] supervised by the New Technology Corporation). Therefore, when laminating thin films, most of the films are currently C-axis oriented.
積層膜に電流を流す場合、Ｃ軸配向膜ではＣ軸方向に電
流が流れるため、これをａ軸配向した膜にすれば電流は
より大きく流れる。そこで、ＭｇＯ（１００）単結晶基
板上かあるいは、Ｓ ｒＴｉｏ、 （１１０）または（
１００）単結晶基板などの単結晶絶縁膜上に、Ｙ１Ｂａ
２ＣｕｆｆＯｔ−ｘ（０＜Ｘ＜Ｏ，Ｓ）等の超伝導薄膜
を作製し、そのうえに絶縁膜（例えばＭｇＯ、ＡＱ２０
１等）を形成した後、さらに酸化物超伝導膜を形成する
。なお、前記単結晶絶縁膜としてはＭｇＯが最も好まし
く、ついでＳｒＴｉＯ３であるが、そのほかにもＺｒＯ
２、ＬａＡｎＯ，、ＮｄＧａ○８等を挙げることができ
る。When a current is passed through a laminated film, the current flows in the C-axis direction in a C-axis oriented film, so if this is made into an a-axis oriented film, a larger current flows. Therefore, on MgO (100) single crystal substrate or S rTio, (110) or (
100) Y1Ba on a single crystal insulating film such as a single crystal substrate
A superconducting thin film such as 2CuffOt-x (0<X<O, S) is fabricated, and an insulating film (e.g. MgO, AQ20
1 etc.), an oxide superconducting film is further formed. The single crystal insulating film is most preferably MgO, followed by SrTiO3, but ZrO3 is also preferred.
2, LaAnO, and NdGa○8.
以下に、実施例を示しながら膜構成について説明する。The membrane structure will be described below with reference to Examples.
第１図はトンネル接合を示したものである。ＭｇＯ（１
００）単結晶基板１の上に真空蒸着法でＹ系超伝導膜３
をつける。真空蒸着法は、Ｙ、Ｂａ、Ｃｕ金属を電子銃
を用いて蒸発させる。FIG. 1 shows a tunnel junction. MgO(1
00) Y-based superconducting film 3 is deposited on the single crystal substrate 1 by vacuum evaporation method.
Attach. In the vacuum evaporation method, Y, Ba, and Cu metals are evaporated using an electron gun.
酸素ガス圧はＩ Ｘｌ０−２〜５ Ｘｌ０−２Ｐａにし
、蒸着速度は２人／Ｓ以下にして成膜する。このとき、
酸素は、高周波電界によりプラズマ状態にし基板加熱温
度は６００℃付近で行う。成膜後、基板を徐冷する際、
数Ｐａの酸素を流しておく。The oxygen gas pressure is set to I Xl0-2 to 5 Xl0-2 Pa, and the deposition rate is set to 2 persons/S or less to form a film. At this time,
Oxygen is brought into a plasma state by a high-frequency electric field, and the substrate is heated at a temperature around 600°C. After film formation, when slowly cooling the substrate,
Oxygen at several Pa is passed through it.
このとき、超伝導膜はａ軸に配向した。基板温度は５８
０℃から６００℃程度が良い。次に絶縁膜２を積層する
場合、基板と同じＭｇＯ膜をつける。At this time, the superconducting film was oriented along the a-axis. The board temperature is 58
A temperature of about 0°C to 600°C is good. Next, when laminating the insulating film 2, the same MgO film as the substrate is applied.
ＭｇＯ膜はｒｆマグネトロンスパッタリングにより行う
。酸素ガス圧は２Ｘ１０−”Ｐａで基板温度は６５０℃
にする。この時、膜はａ軸配向していた。膜厚は４０人
〜５０人であった。そして、さらに先と同様超伝導膜３
を作成した。The MgO film is formed by RF magnetron sputtering. Oxygen gas pressure is 2X10-”Pa and substrate temperature is 650℃.
Make it. At this time, the film was oriented along the a-axis. The film thickness was 40 to 50. Then, as before, superconducting film 3
It was created.
従来のもののトンネル電流が〜１Ｘ１０’Ａ／ｃＩＩ２
であったのに対し、この素子のトンネル電流は〜Ｉ Ｘ
１０’ Ａ ／ ｃｍ”とすることができた。The tunnel current of the conventional one is ~1X10'A/cII2
On the other hand, the tunnel current of this element is ~I
10'A/cm".
［効 果］
本発明の構成をとることによりトンネル電流の大きなト
ンネル接合素子が得られた。[Effects] By adopting the configuration of the present invention, a tunnel junction element with a large tunnel current was obtained.
第１図は１本発明実施例のトンネル接合素子の断面図で
ある。
１・・・単結晶基板 ２・・・絶縁膜３・・・超伝
導膜
特許出願人 株式会社 リ コ −
代理人弁理士 友 松 英 爾・′ゝ【“・：＼
−勇一′FIG. 1 is a sectional view of a tunnel junction element according to an embodiment of the present invention. 1...Single crystal substrate 2...Insulating film 3...Superconducting film Patent applicant Rico Co., Ltd. − Representative patent attorney Tomo Hideji Matsu
Claims (1)
向させた酸化物超伝導薄膜、（３）単結晶絶縁膜、（４
）ａ軸配向させた酸化物超伝導薄膜の順で積層したこと
を特徴とするトンネル接合素子。1. (1) On a ceramic single crystal substrate, (2) c-axis oriented oxide superconducting thin film, (3) single crystal insulating film, (4
) A tunnel junction device characterized in that a-axis oriented oxide superconducting thin films are laminated in this order.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2115387A JPH0412575A (en) | 1990-05-01 | 1990-05-01 | Tunnel junction element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2115387A JPH0412575A (en) | 1990-05-01 | 1990-05-01 | Tunnel junction element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0412575A true JPH0412575A (en) | 1992-01-17 |
Family
ID=14661285
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2115387A Pending JPH0412575A (en) | 1990-05-01 | 1990-05-01 | Tunnel junction element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0412575A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0677545A (en) * | 1992-08-24 | 1994-03-18 | Nippon Telegr & Teleph Corp <Ntt> | Superconducting thin film vertical type junction element and its manufacture |
-
1990
- 1990-05-01 JP JP2115387A patent/JPH0412575A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0677545A (en) * | 1992-08-24 | 1994-03-18 | Nippon Telegr & Teleph Corp <Ntt> | Superconducting thin film vertical type junction element and its manufacture |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH02260674A (en) | Tunnel type josephson element and manufacture thereof | |
| JPH05894A (en) | Compound oxide superconducting thin film | |
| JPH03153089A (en) | Tunnel junction element wherein compound oxide superconductive material is used | |
| JPH03218686A (en) | Josephson element | |
| JPH0412575A (en) | Tunnel junction element | |
| JPH0286014A (en) | Composite oxide superconducting thin film and film forming method | |
| JPH0221676A (en) | Tunnel junction between superconductors | |
| JP2644284B2 (en) | Superconducting element | |
| JPS62170108A (en) | Super conductor containing nb, si and al and oxide thereof having transition temperature 77k or more | |
| JPH01100022A (en) | Preparation of superconducting thin film | |
| JP3061634B2 (en) | Oxide superconducting tape conductor | |
| JPH0414881A (en) | Tunnel junction element | |
| JP2813287B2 (en) | Superconducting wire | |
| JPH02281765A (en) | Superconducting element using oxide superconductor thin-film | |
| JP2920496B2 (en) | Method of forming oxide dispersed particles | |
| JP2950958B2 (en) | Superconducting element manufacturing method | |
| Meng et al. | YBCO/metallic oxide/YBCO trilayers for high-T/sub c/superconducting SNS junctions | |
| JP2849721B2 (en) | Superconducting switch element | |
| JPH0446098A (en) | Superconducting member | |
| JP2840475B2 (en) | Method for producing oxide superconducting thin film | |
| JP2835203B2 (en) | Superconducting element manufacturing method | |
| JPH0227612A (en) | Oxide superconducting wire rod | |
| JPH01179779A (en) | Method for protecting multi-ply oxide superconductor | |
| JPH05160448A (en) | Abrupt josephson device | |
| Usagawa et al. | Transport properties of PBCO thin films on (110)/(001) RBCO single crystal substrates |