JPH0577344B2 - - Google Patents
Info
- Publication number
- JPH0577344B2 JPH0577344B2 JP63089550A JP8955088A JPH0577344B2 JP H0577344 B2 JPH0577344 B2 JP H0577344B2 JP 63089550 A JP63089550 A JP 63089550A JP 8955088 A JP8955088 A JP 8955088A JP H0577344 B2 JPH0577344 B2 JP H0577344B2
- Authority
- JP
- Japan
- Prior art keywords
- superconducting material
- oxide superconducting
- magnetic memory
- oxide
- 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 - Fee Related
Links
Landscapes
- Inorganic Compounds Of Heavy Metals (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
Description
【発明の詳細な説明】
「発明の利用分野」
本発明は超伝導体、特に高い臨界温度（以下
Tcという）を有する酸化物超伝導体のバルクあ
るいは薄膜を用いて形成される超伝導素子に関す
る。特に酸化物超伝導体において生じる粒界や格
子欠陥を積極的に利用することに特徴を持つ超伝
導素子についてのものである。すなわち超伝導体
の粒界や格子欠陥に外部からの印加磁場の磁束が
トラツプされるという性質によつて動作する超伝
導記憶素子に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention relates to superconductors, particularly those with high critical temperatures (
This invention relates to a superconducting device formed using a bulk or thin film of an oxide superconductor (referred to as Tc). In particular, it concerns superconducting elements that are characterized by the active use of grain boundaries and lattice defects that occur in oxide superconductors. In other words, it relates to a superconducting memory element that operates due to the property that the magnetic flux of an externally applied magnetic field is trapped in the grain boundaries and lattice defects of a superconductor.
「従来の技術およびその問題点」
超伝導体の特異な磁気的性質を利用した記憶素
子には、従来、トンネル型やマイクロブリツジ型
のジヨセフソン接合を用いて外部からの印加磁場
をトラツプすることによつて記憶する素子が知ら
れていた。しかし、これらの素子はTcの低い
（約30K付近）ニオブ等の材料が使われていたた
め、液体ヘリウムが必要でコストがかかりすぎる
という問題があつた。一方、近年液体窒素温度以
上の高温で超伝導特性を示す酸化物超伝導体（例
えばYBa2Cu3O7-xやBi2（Sr，Ca）3Cu2O9-x等）が
発見され、これらをデバイスに利用する研究がな
されている。"Conventional technology and its problems" Conventionally, memory elements that utilize the unique magnetic properties of superconductors have been constructed using tunnel-type or microbridge-type Josephson junctions to trap externally applied magnetic fields. Elements that store data based on are known. However, since these elements used materials such as niobium that have a low Tc (around 30K), they required liquid helium, making them expensive. On the other hand, in recent years, oxide superconductors (such as YBa 2 Cu 3 O 7-x and Bi 2 (Sr, Ca) 3 Cu 2 O 9-x ) that exhibit superconducting properties at temperatures higher than liquid nitrogen temperatures have been discovered. , research is being conducted to utilize these in devices.
しかしながら、これらの酸化物超伝導体は高温
（500℃以上）での処理が必要であるばかりか、他
の金属・非金属元素と非常に反応し易いため、数
百オングストロームのサイズのジヨセフソン接合
を形成することは非常に困難であつた。 However, these oxide superconductors not only require processing at high temperatures (above 500°C) but also are highly reactive with other metals and nonmetallic elements, making it difficult to fabricate Josephson junctions with a size of several hundred angstroms. It was very difficult to form.
「発明の構成」
本発明人はこの様な酸化物超伝導体において外
部から磁場を印加すると酸化物超伝導体の粒界に
磁束が侵入し、印加磁場を取り去つた後でも磁束
がトラツプされているという現象を見出した。さ
らに、このような状態では侵入した磁束によつて
電流を流すと電圧を生じこの状態は印加磁場を取
り去つた後でも変わらないことを発見した。この
ような現象は超伝導特性のよくない試料ほど顕著
であることが分り、本発明人は粒界や格子欠陥を
より多く作るために意図的に組成をずらしたり、
不純物を加えたりした結果わずか10ガウスで動作
する素子を再現性よく作成することが出来、これ
によつて酸化物超伝導体においてもジヨセフソン
接合を用いたのと同様な記憶素子を作成すること
ができるものである。"Structure of the Invention" The present inventor discovered that when an external magnetic field is applied to such an oxide superconductor, magnetic flux invades the grain boundaries of the oxide superconductor, and even after the applied magnetic field is removed, the magnetic flux remains trapped. We discovered the phenomenon that Furthermore, they discovered that in such a state, when a current is caused to flow due to the penetrating magnetic flux, a voltage is generated, and this state does not change even after the applied magnetic field is removed. This phenomenon was found to be more pronounced in samples with poor superconducting properties, and the inventors intentionally changed the composition to create more grain boundaries and lattice defects.
As a result of adding impurities, it was possible to create a device that operates at only 10 Gauss with good reproducibility, and this made it possible to create a memory device similar to that using Josephson junctions in oxide superconductors. It is possible.
本発明は以下に示す３つの発明よりなるもので
ある。 The present invention consists of the following three inventions.
（第１の発明）
組成比率が理想的な組成比率からずらして構成
されているバルク状あるいは薄膜状の酸化物超伝
導材料を用いた超伝導磁気メモリーであつて、該
超伝導磁気メモリーは、前記酸化物超伝導材料に
磁場を印加する手段と、
前記酸化物超伝導材料に電流を流す手段と、
前記電流により生じる電圧を検出する手段と、
を有していることを特徴とする超伝導磁気メモリ
ー。(First invention) A superconducting magnetic memory using a bulk or thin film oxide superconducting material whose composition ratio is shifted from an ideal composition ratio, the superconducting magnetic memory comprising: A superconductor characterized by comprising: means for applying a magnetic field to the oxide superconducting material; means for passing an electric current through the oxide superconducting material; and means for detecting a voltage generated by the electric current. magnetic memory.
（第２の発明）
組成比率が理想的な組成比率からずらして構成
されているバルク状あるいは薄膜状の酸化物超伝
導材料を用いた超伝導磁気メモリーの動作方法で
あつて、
前記磁気メモリーに情報を読み込ませるため
に、前記酸化物超伝導材料に磁場を印加し、前記
酸化物超伝導材料中に磁束をトラツプさせる動作
と、
前記磁気メモリーから情報を読みだすために、
前記酸化物超伝導材料に電流を流し、前記酸化物
超伝導材料中の前記磁束がトラツプされた領域に
電圧を生じさせ該電圧を検出する動作と、
を有することを特徴とする超伝導磁気メモリーの
動作方法。(Second invention) A method for operating a superconducting magnetic memory using a bulk or thin film oxide superconducting material whose composition ratio is shifted from an ideal composition ratio, comprising: applying a magnetic field to the oxide superconducting material to trap magnetic flux in the oxide superconducting material in order to read information; and reading information from the magnetic memory;
A superconducting magnetic memory comprising the following steps: passing a current through the oxide superconducting material, generating a voltage in a region in the oxide superconducting material where the magnetic flux is trapped, and detecting the voltage. How it works.
（第３の発明）
超伝導磁気メモリーの作製方法であつて
組成比率を理想的な組成比率からずらして酸化
物超伝導材料を形成する工程と、
前記酸化物超伝導材料に磁場を印加する手段を
形成する工程と、
前記酸化物超伝導材料に電流を流す手段を形成
する工程と、
前記酸化物超伝導材料において電圧を検出する
手段を形成する工程と、
を有することを特徴とする超伝導磁気メモリーの
作製方法。(Third invention) A method for producing a superconducting magnetic memory, comprising: forming an oxide superconducting material by shifting the composition ratio from an ideal composition ratio; and means for applying a magnetic field to the oxide superconducting material. A superconductor characterized by comprising the steps of: forming a means for passing a current through the oxide superconducting material; and forming a means for detecting voltage in the oxide superconducting material. How to make magnetic memory.
以下に本発明を利用した実施例を示し動作原理
等を詳細に説明する。 Embodiments using the present invention will be shown below, and the operating principle etc. will be explained in detail.
実施例 １
原材料として酸化イツトリウム、炭酸バリウ
ム、酸化銅の粉末（いずれも純度は99.99％）を
イツトリウム、バリウム、銅の理想的なモル比
１：２：３から少しずらして１：2.2：３の比率
で混合した。十分に混合した後、空気中900℃で
12時間焼成した。焼成後、反応生成物をとりだ
し、細かく、粉砕し、1000Kg/cm2の圧力でペレツ
トに成形した。このペレツトを再び、空気中900
℃で３時間焼結した後、10℃／minで徐冷した。
このペレツトから10mm×１mm×１mmの直方体を切
出し、銀ペーストで電極をつけた。４端子法によ
る抵抗測定の結果、第１図のような抵抗−温度曲
線が得られた。これを第２図のようにコイルの横
に置きコイルと試料は液体窒素中に置いた。コイ
ルに電流を流さない時の試料の電圧−電流曲線は
第３図ａで示された。次にコイルに電流を流して
試料に磁場を印加したところ電圧−電流曲線は第
３図ｂのようになつた。このとき試料表面の磁場
の強さは10ガウスであつた。さらに、コイルに流
れている電流を切り、試料に磁場がかからないよ
うにしたときの電圧−電流曲線は第３図ｃのよう
になつた。この特性はコイルの電流を切つて数時
間放置しても変わらなかつた。Example 1 As raw materials, powders of yttrium oxide, barium carbonate, and copper oxide (all of which have a purity of 99.99%) were used in a molar ratio of 1:2.2:3, slightly different from the ideal molar ratio of 1:2:3 for yttrium, barium, and copper. Mixed in proportion. After mixing well, at 900℃ in air
Baked for 12 hours. After calcination, the reaction product was taken out, finely ground, and formed into pellets at a pressure of 1000 Kg/cm 2 . This pellet again in the air 900
After sintering at ℃ for 3 hours, it was slowly cooled at 10 ℃/min.
A rectangular parallelepiped of 10 mm x 1 mm x 1 mm was cut out from this pellet and electrodes were attached with silver paste. As a result of resistance measurement using the four-terminal method, a resistance-temperature curve as shown in FIG. 1 was obtained. This was placed next to the coil as shown in Figure 2, and the coil and sample were placed in liquid nitrogen. The voltage-current curve of the sample when no current is applied to the coil is shown in Figure 3a. Next, when a current was passed through the coil and a magnetic field was applied to the sample, the voltage-current curve became as shown in Figure 3b. At this time, the strength of the magnetic field on the sample surface was 10 Gauss. Furthermore, when the current flowing through the coil was cut off so that no magnetic field was applied to the sample, the voltage-current curve became as shown in Figure 3c. This characteristic remained unchanged even after the coil current was turned off and the coil was left for several hours.
この現象は次のように理解できる。即ち、酸化
物超伝導体の結晶粒界に第４図ａで示されるよう
なトンネル型のジヨセフソン接合が自然に形成さ
れる。特に組成がずれていたり不純物が添加され
た場合には非超伝導相が粒界に析出してジヨセフ
ソン接合がより形成されやすくなる。このような
接合部に磁場をかけると磁束が侵入する。（第４
図ａ）。さらに接合に電流を流すとローレンツ力
によつて磁束が動き、電圧が生じる。（第４図
ｂ）。一旦侵入した磁束は超伝導円電流によつて
接合部にとらわれるため、外部磁場を取り除いて
も、接合部に電流を流すと電圧を生じる。かくし
て、一度弱い磁場を印加するだけで半永久的に記
憶が保たれる素子を製作することが出来た。すな
わち、定電流を流すことによつて電圧が生ずれば
“１”、電圧が生じなければ“０”としてデジタル
記憶素子として動作する。記憶された信号は素子
をTc以上の温度にすることによつて簡単に消す
ことが出来る。 This phenomenon can be understood as follows. That is, a tunnel-type Josephson junction as shown in FIG. 4a is naturally formed at the grain boundaries of the oxide superconductor. In particular, when the composition is misaligned or impurities are added, non-superconducting phases precipitate at grain boundaries, making it easier to form Josephson junctions. When a magnetic field is applied to such a junction, magnetic flux penetrates. (4th
Diagram a). Furthermore, when a current is passed through the junction, the magnetic flux moves due to the Lorentz force, producing a voltage. (Figure 4b). Once the magnetic flux has entered, it is trapped in the junction by the superconducting circular current, so even if the external magnetic field is removed, a voltage will be generated when a current flows through the junction. In this way, we were able to create an element that retains memory semi-permanently by simply applying a weak magnetic field once. That is, when a voltage is generated by flowing a constant current, it becomes "1" and when no voltage is generated, it becomes "0" and operates as a digital storage element. The stored signal can be easily erased by heating the device to a temperature above Tc.
実施例 ２
YBa2Cu3O7-x薄膜を用いて上述の素子を作成
した。薄膜はrfスパツタ法によつて酸化マグネシ
ウム単結晶状に形成され、Tcは85Kであつた。
この薄膜上にアルミニウムを約1000オングストロ
ーム蒸着し、700℃の空気中で30分アニールし、
アルミニウムを膜中に拡散させた。このようにし
て作成された素子においても実施例１と同様な特
性を示した。Example 2 The above-described device was fabricated using a YBa 2 Cu 3 O 7-x thin film. The thin film was formed in the form of a magnesium oxide single crystal by an RF sputtering method, and its Tc was 85K.
Approximately 1000 angstroms of aluminum was deposited on this thin film, annealed in air at 700°C for 30 minutes,
Aluminum was diffused into the film. The device produced in this manner also exhibited characteristics similar to those of Example 1.
本発明により、Tcの高い酸化物超伝導体を用
いて新規な磁気メモリーを実現することができ
た。
The present invention has made it possible to realize a novel magnetic memory using an oxide superconductor with a high Tc.
第１図 素子の抵抗−温度曲線、第２図 素子
とコイルの配置、第３図 素子の電圧−電流曲
線、 ａ…磁場を印加する前、ｂ…磁場を印加し
ているとき（印加磁場10ガウス）、ｃ…磁場を取
り去つた後、第４図 素子の動作原理。
Fig. 1 Resistance-temperature curve of the element, Fig. 2 Arrangement of the element and coil, Fig. 3 Voltage-current curve of the element, a... Before applying a magnetic field, b... While applying a magnetic field (applied magnetic field 10 Gauss), c...After removing the magnetic field, Fig. 4 Principle of operation of the element.
Claims (1)
成されているバルク状あるいは薄膜状の酸化物超
伝導材料を用いた超伝導磁気メモリーであつて、 該超伝導磁気メモリーは、前記酸化物超伝導材
料に磁場を印加する手段と、 前記酸化物超伝導材料に電流を流す手段と、 前記電流により生じる電圧を検出する手段と、 を有していることを特徴とする超伝導磁気メモリ
ー。 ２ 組成比率が理想的な組成比率からずらして構
成されているバルク状あるいは薄膜状の酸化物超
伝導材料を用いた超伝導磁気メモリーの動作方法
であつて、 前記磁気メモリーに情報を読み込ませるため
に、前記酸化物超伝導材料に磁場を印加し、前記
酸化物超伝導材料中に磁束をトラツプさせる動作
と、 前記磁気メモリーから情報を読みだすために、
前記酸化物超伝導材料に電流を流し、前記酸化物
超伝導材料中の前記磁束がトラツプされた領域に
電圧を生じさせ該電圧を検出する動作と、 を有することを特徴とする超伝導磁気メモリーの
動作方法。 ３ 超伝導磁気メモリーの作製方法であつて、 組成比率を理想的な組成比率からずらして酸化
物超伝導材料を形成する工程と、 前記酸化物超伝導材料に磁場を印加する手段を
形成する工程と、 前記酸化物超伝導材料に電流を流す手段を形成
する工程と、 前記酸化物超伝導材料において電圧を検出する
手段を形成する工程と、 を有することを特徴とする超伝導磁気メモリーの
作製方法。[Claims] 1. A superconducting magnetic memory using a bulk or thin film oxide superconducting material whose composition ratio is deviated from the ideal composition ratio, the superconducting magnetic memory comprising: , a means for applying a magnetic field to the oxide superconducting material, a means for passing a current through the oxide superconducting material, and a means for detecting a voltage generated by the current. Conduction magnetic memory. 2. A method for operating a superconducting magnetic memory using a bulk or thin film oxide superconducting material whose composition ratio is deviated from the ideal composition ratio, and for reading information into the magnetic memory. applying a magnetic field to the oxide superconducting material to trap magnetic flux in the oxide superconducting material; and reading information from the magnetic memory.
A superconducting magnetic memory comprising the following steps: passing a current through the oxide superconducting material, generating a voltage in a region in the oxide superconducting material where the magnetic flux is trapped, and detecting the voltage. How it works. 3. A method for producing a superconducting magnetic memory, comprising: forming an oxide superconducting material by shifting the composition ratio from an ideal composition ratio; and forming a means for applying a magnetic field to the oxide superconducting material. A method for producing a superconducting magnetic memory, comprising: forming a means for passing a current through the oxide superconducting material; and forming a means for detecting voltage in the oxide superconducting material. Method.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63089550A JPH01260866A (en) | 1988-04-12 | 1988-04-12 | Superconducting magnetic memory, its operating method, and its manufacturing method |
| US07/719,040 US5377141A (en) | 1988-04-12 | 1991-06-21 | Superconducting magnetic memory device having intentionally induced non-superconducting regions |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63089550A JPH01260866A (en) | 1988-04-12 | 1988-04-12 | Superconducting magnetic memory, its operating method, and its manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01260866A JPH01260866A (en) | 1989-10-18 |
| JPH0577344B2 true JPH0577344B2 (en) | 1993-10-26 |
Family
ID=13973932
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63089550A Granted JPH01260866A (en) | 1988-04-12 | 1988-04-12 | Superconducting magnetic memory, its operating method, and its manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01260866A (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61195390A (en) * | 1985-02-26 | 1986-08-29 | 株式会社島津製作所 | Superconducting shield body |
| JPS61287181A (en) * | 1985-06-13 | 1986-12-17 | Nec Corp | Josephson integrated circuit |
-
1988
- 1988-04-12 JP JP63089550A patent/JPH01260866A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01260866A (en) | 1989-10-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1341499C (en) | Compositions electrically superconducting above 120.degree.k and processes for their preparation | |
| US8688181B1 (en) | Superconductive compounds having high transition temperature, and methods for their use and preparation | |
| JPH0643268B2 (en) | Oxide high temperature superconductor | |
| CA2004576C (en) | Oxide superconducting material, process for preparing the same and applications thereof | |
| US5070070A (en) | High temperature superconducting memory storage device and cryotron | |
| JP2719518B2 (en) | Manufacturing method of oxide superconducting material | |
| Kumakura et al. | Superconductivity and magnetic properties of high T c Bi‐Sr‐Ca‐Cu‐O superconductors | |
| JPH0577344B2 (en) | ||
| CA1341636C (en) | Superconductive compounds having high transition temperature, and methods for their use and preparation | |
| US4988668A (en) | Ti-Ca-Ba-Cu-D compositions electrically superconducting above 120 degrees K and processes for their preparation | |
| US5377141A (en) | Superconducting magnetic memory device having intentionally induced non-superconducting regions | |
| Rowell | The status, recent progress and promise of superconducting materials for practical applications | |
| JPH06263441A (en) | Metal oxide material and its production | |
| Shi et al. | Superconductivity enhancement in the (Tl, Pb)(A, R) 2CuO5 system (A= Sr, Ba; R= La, Pr, Nd) | |
| JPH0577345B2 (en) | ||
| Bai et al. | Melt-textured YBa/sub 2/Cu/sub 3/O/sub 7/for low-field applications in microwave devices | |
| JPH10330117A (en) | Oxide superconductor, its production and current lead using the same | |
| JP2817170B2 (en) | Manufacturing method of superconducting material | |
| JP2838312B2 (en) | Oxide superconducting material | |
| JP2749194B2 (en) | Method for producing Bi-Sr-Ca-Cu-O-based superconductor | |
| JP2855127B2 (en) | Oxide superconductor | |
| US5360786A (en) | Superconductive material | |
| JPH01208319A (en) | Oxide superconducting material | |
| Nakano et al. | A study of annealing Bi-Pb-Sr-Ca-Cu-O thin films with Pb or PbO | |
| EP0431170A1 (en) | Oxide superconductor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |