JPH05335640A - Superconductive element - Google Patents

Abstract

PURPOSE:To provide a superconductive element which can be manufactured easily and has improved amplification characteristics or switching characteristics. CONSTITUTION:Substances 3 and 4 in non-superconductive state are allowed to contact a copper oxide semiconductor 2 and a groove with a width of 1mum or less is provided between the substances 3 and 4 in non-conductive state thus inducing superconductivity within the oxide. By adding an insulation film 5 and a gate electrode 6 to the structure, an element which is controlled by electric field can also be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of superconducting electronics such as superconducting switching elements, and more particularly to superconducting elements applied to the fields of digital circuits and analog circuits.

[0002]

2. Description of the Related Art Superconducting elements using oxide-based materials include a superconducting element in which crystal grain boundaries of an oxide superconductor are weakly bonded, and a superconducting element in which two layers of oxide superconducting thin films are connected by a noble metal. Has been obtained. Furthermore, Applied Physics Letters, Vol. 55, p. 2032 (1989)
YBa ₂ Cu ₃ O _y crystallographically similar PrBa ₂ Cu ₃ O _y as a weakly bonded portion, and a structure sandwiched between YBa ₂ Cu ₃ O _y thin films is YBa ₂ Cu ₃ O. _y- PrBa ₂ C
u ₃ layered structure of O _y -YBa ₂ Cu ₃ O _y is described. It was shown by the current-voltage characteristics during microwave irradiation that this structure has weak coupling characteristics. Further, a superconducting element for controlling superconductivity induced by stacking BaBi _1-x Pb _x O _3-y having different compositions by an electric field is disclosed in JP-A-1-205.
578.

[0003]

However, according to the above-mentioned conventional technique, YBa ₂ Cu ₃ O _y -PrBa ₂ Cu ₃ O _y -YBa ₂ Cu is used.
BaO _1-x Pb _x O with different laminated structure or composition of ₃ O _{y
Since a 3-y} laminated structure is required, it is difficult to manufacture these laminated structures, and the laminated structures are likely to include lattice defects and element diffusion that lead to deterioration of device performance. Also, BaBi _1-x
In an element in which superconductivity induced by stacking Pb _x O _3-y is controlled by using an electric field, the electric field effect is small and the amplification characteristic or switching characteristic is small in order to control the superconductivity induced through a layer having a high carrier concentration. bad.

It is an object of the present invention to utilize a property peculiar to an oxide semiconductor having a layered perovskite structure to bring a substance not having a complicated crystal structure into contact with a single-layer oxide semiconductor, so that To provide a superconducting element that does not require a layered structure that is difficult to fabricate by using superconductivity induced by the electric field, and to control the induced superconductivity by an electric field to obtain an element having good amplification characteristics or switching characteristics. To provide.

[0005]

As shown in FIG. 2, the above object is to achieve the oxide semiconductor R _{1 + x} Ba _2-x Cu ₃ O _y (R is a rare earth element other than Pr, 0.3 <x < 0.8, 6 <y <8),
Oxide semiconductor Pr _{1 + x} Ba _2-x Cu ₃ O _y (0 ≦ x ≦ 0.5,
6 <y <8), oxide semiconductor Y _1-x Pr _x Ba ₂ Cu ₃ O
_y (0.6≤x≤1, 6 <y <8), oxide semiconductor Bi ₂
Sr ₂ Ca _1-x R _x Cu ₂ O _y (R is a rare earth element, 0.6 ≦ x ≦
1.0, 8 <y <8.5), and RBa ₂ Cu ₃ O
_y (where R is Y or a rare earth element, 6.0 <y <6.4) is brought into contact with the non-superconducting substances 9 and 10, and the non-superconducting state in contact with the oxide semiconductor 8 This is achieved by providing a groove having a width of 1 μm or less between the substances 9 and 10.

[0006]

[Function] Oxide semiconductor R _{1 + x} Ba _2-x Cu ₃ O _y (R is a rare earth element other than Pr, 0.3 <x <0.8, 6 <y <8),
Oxide semiconductor Pr _{1 + x} Ba _2-x Cu ₃ O _y (0 ≦ x ≦ 0.5,
6 <y <8), oxide semiconductor Y _1-x Pr _x Ba ₂ Cu ₃ O
_y (0.6≤x≤1, 6 <y <8), oxide semiconductor Bi ₂
Sr ₂ Ca _1-x R _x Cu ₂ O _y (R is a rare earth element, 0.6 ≦ x ≦
1.0, 8 <y <8.5), and RBa ₂ Cu ₃ O
_y (where R is Y or a rare earth element, 6.0 <y <6.4) is brought into contact with the non-superconducting substances 9 and 10, and the non-superconducting state in contact with the oxide semiconductor 8 Due to the structure in which a groove having a width of 1 μm or less is provided between the substances 9 and 10, the electronic state of the oxide semiconductor 8 is in the non-superconducting state near the interface between the non-superconducting substances 9 and 10 and the oxide semiconductor 8. It is affected by substances 9 and 10. This is because the carrier densities of the oxide semiconductor 8 and the non-superconducting substances 9 and 10 are different, and
It occurs because the vacuum levels of both substances are different. As a result, the Fermi level moves near the interface between the oxide semiconductor 8 and the substances 9 and 10 in the non-superconducting state, so that the charge transfer type gap is broken. Therefore, the oxide semiconductor 8 becomes superconducting near the interface. In the oxide semiconductor 8, the applied physics letters 5
8 (1991) 2707, the superconducting state distance is as long as 0.4 μm, so 0.1 to 0.1.
The superconducting current flows between the two non-superconducting substances separated by 4 μm due to the induced superconductivity. For this reason,
With the above structure, good weak coupling characteristics can be obtained. further,
The density of mobile carriers inside the oxide semiconductor is low (1
0 about ¹⁹ / cm ^3), so the effect of the electric field is large when performing the induced control superconducting by an electric field. Therefore, good device performance can be obtained.

[0007]

EXAMPLES Example 1 Hereinafter, the present invention will be described using an example of a field effect superconducting three-terminal element.

The structure of this device is shown in FIG. SrTiO ₃
La _1.5 Ba formed on the (110) plane-oriented single crystal substrate 1
_{On the} Cu ₃ O _y semiconductor thin film 2, an Au electrode (source) 3,
An Au electrode (drain) 4 is formed, and the dimension between 3 and 4 is 0.1.
A μm gap was formed. Then, a CaF ₂ insulating film 6 is provided and an Au electrode (gate) 7 is formed.

The La _1.5 Ba _1.5 Cu ₃ O _y thin film was formed by a reactive vapor deposition system using microwave oxygen plasma. The atmosphere gas is pure oxygen gas, and the total pressure is 8 × 1.
Was 0- ⁵ torr. The raw materials are La, Ba, and
It was evaporated using Cu and a Knudsen cell. In order to increase the oxidizing power, microwave of 2.45 GHz and 120 W was applied. The substrate temperature during film formation was 450 ° C. The La _1.5 Ba _1.5 Cu ₃ O _y thin film 2 formed under such conditions has crystallinity in which the (110) plane is perpendicular to the substrate surface. A reactive vapor deposition apparatus was also used for forming the Au electrode and the CaF ₂ insulating film, but the film was formed in a vacuum without irradiation with microwaves. Au was evaporated using an electron gun vapor deposition device.

The manufacturing process of the superconducting device was as follows. That is, the La _1.5 Ba _1.5 Cu ₃ O _y thin film 2 is replaced with SrTiO ₃
It was formed on the (110) plane-oriented single crystal substrate 1. The film thickness was 100 nm. A bar-shaped Au thin film was formed on this by a mask vapor deposition method. The Au thin film had a thickness of 30 nm and a size of 0.2 × 5 mm. After coating the electron beam resist on it, Au was made parallel to the side of 0.2 mm by the electron beam drawing device.
A 0.1 μm linear pattern was drawn in the center of the electrode. A groove-shaped pattern was formed on the Au thin film based on the resist pattern by the reactive ion beam etching method to form Au electrode (source) 3 and Au electrode (drain) 4, respectively. A CaF ₂ insulating film 6 was formed on this groove-shaped channel 5 to form a gate insulating film. Au is vapor-deposited on the gate insulating film,
The electrode (gate) 7 was used.

The source of this superconducting element at 60K,
The current-voltage characteristics between the drains are about 1.0 mA.
Of superconducting current flows, and a voltage is generated for a bias current higher than this. Furthermore, when a voltage of 200 mV is applied to the gate, the superconducting current decreases to 0.2 mA,
A voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Similar characteristics were also obtained when a device was manufactured by using a rare earth element other than Pr instead of La. In this case, rare earth elements other than Eu were evaporated using an electron gun vapor deposition device instead of the Knudsen cell. Further, instead of Au, Ag, Bi, Sb, PbBi, Pb, Sn, Zn, Ga, Nb, I
An element using n, Al, V, Ta and W was also manufactured, but similar characteristics were obtained in this case as well.

Example 2 In the same thin film structure as in Example 1, only the distance between the Au electrode (source) 3 and the Au electrode (drain) 4 was changed, and the line width was set to 0.5 μm. The manufacturing process and the like are the same as in Example 1. In the current-voltage characteristic between the source and the drain at 30 K of this superconducting element, a superconducting current of about 0.8 mA flows, and a voltage is generated for a bias current higher than this. Furthermore, when a voltage of 200 mV is applied to the gate, the superconducting current decreases to 0.15 A, and a voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Also, instead of La, Pr
Similar characteristics were obtained when devices were manufactured using rare earth elements other than. In this case, rare earth elements other than Eu were evaporated using an electron gun vapor deposition device instead of the Knudsen cell. Furthermore, instead of Au, Ag, Bi, Sb, PbBi, P
An element using b, Sn, Zn, Ga, Nb, In, Al, V, Ta, W was also manufactured, but similar characteristics were obtained in this case as well.

Example 3 In the same thin film structure as in Example 1, only the distance between the Au electrode (source) 3 and the Au electrode (drain) 4 was changed, and the line width was set to 1 μm. The manufacturing process and the like are the same as in Example 1. 4. of this superconducting element
In the current-voltage characteristic between the source and drain at 2K, a superconducting current of about 0.2 mA flows, and a voltage is generated for a bias current higher than this. Further, when a voltage of 200 mV is applied to the gate, the superconducting current decreases to 0.01 mA, and a voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Also, instead of La, Pr
Similar characteristics were obtained when devices were manufactured using rare earth elements other than. In this case, rare earth elements other than Eu were evaporated using an electron gun vapor deposition device instead of the Knudsen cell. Furthermore, instead of Au, Ag, Bi, Sb, PbBi, P
An element using b, Sn, Zn, Ga, Nb, In, Al, V, Ta, W was also manufactured, but similar characteristics were obtained in this case as well.

<Embodiment 4> In the same thin film structure as in Embodiment 1, only the composition of the oxide semiconductor was changed to obtain La _1.3 Ba _1.7.
Cu ₃ O _y was used. The manufacturing process and the like are the same as in Example 1. In the current-voltage characteristic between the source and the drain at 60 K of this superconducting element, a superconducting current of about 1.3 mA flows, and a voltage is generated for a bias current higher than this. Further, when a voltage of 200 mV is applied to the gate, the superconducting current is reduced to 0.3 mA, and a voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Similar characteristics were also obtained when a device was manufactured by using a rare earth element except Pr instead of La. In this case, Eu
Other rare earth elements were evaporated using an electron gun vapor deposition device instead of the Knudsen cell. Further, instead of Au, Ag, Bi, Sb, PbBi, Pb, Sn, Zn, Ga, Nb, In, Al, V,
An element using Ta and W was also manufactured, but similar characteristics were obtained in this case as well.

<Embodiment 5> In the same thin film structure as in Embodiment 1, only the composition of the oxide semiconductor was changed to obtain La _1.7 Ba _1.3.
Cu ₃ O _y was used. The manufacturing process and the like are the same as in Example 1. In the current-voltage characteristics between the source and the drain at 60 K of this superconducting element, a superconducting current of about 0.8 mA flows, and a voltage is generated for a bias current higher than this. Furthermore, when a voltage of 200 mV is applied to the gate, the superconducting current is reduced to 0.1 mA, and a voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. In this case, rare earth elements other than Eu were evaporated using an electron gun vapor deposition device instead of the Knudsen cell. Furthermore, A
Ag, Bi, Sb, PbBi, Pb, Sn, Zn, Ga, Nb, instead of u
A device using In, Al, V, Ta and W was also manufactured, but similar characteristics were obtained in this case as well.

[0016] In the same film structure as <Example 6> Example 1, changing only the oxide _{semiconductor, Pr 1.5 Ba 1.5 Cu 3 O} y
Was used. However, Pr, Ba, and Cu in a metallic state were used as raw materials for the semiconductor thin film, and Pr was evaporated by using an electron gun vapor deposition apparatus. The other manufacturing steps are the same as in the first embodiment.

The source of this superconducting element at 60K,
The current-voltage characteristics between the drains are about 0.5 mA.
Of superconducting current flows, and a voltage is generated for a bias current higher than this. Further, when a voltage of 200 mV is applied to the gate, the superconducting current is reduced to 0.05 mA, and a voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Also, instead of Au, Ag, Bi, Sb, PbBi, P
An element using b, Sn, Zn, Ga, Nb, In, Al, V, Ta, W was also manufactured, but similar characteristics were obtained in this case as well.

<Embodiment 7> In the same thin film structure as in Embodiment 6, only the composition of the oxide semiconductor was changed to obtain Pr _1.1 Ba _1.9.
Cu ₃ O _y was used. The current-voltage characteristics between the source and drain at 60 K of this superconducting element are about 0.
A superconducting current of 7 mA flows, and a voltage is generated for a bias current higher than this. 200m to the gate
When a voltage of V is applied, the superconducting current decreases to 0.1 mA, and a voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Also, instead of Au, Ag, Bi, Sb, PbBi,
A device using Pb, Sn, Zn, Ga, Nb, In, Al, V, Ta, W was also manufactured, but similar characteristics were obtained in this case as well.

Example 8 In the same thin film structure as in Example 6, only the oxide semiconductor was changed and PrBa ₂ Cu ₃ O _y was used. However, Pr, Ba, and Cu in a metallic state were used as raw materials for the semiconductor thin film, and Pr was evaporated by using an electron gun vapor deposition apparatus.

The source of this superconducting element at 60K,
The current-voltage characteristic between the drains is about 0.8 mA.
Of superconducting current flows, and a voltage is generated for a bias current higher than this. Further, when a voltage of 200 mV is applied to the gate, the superconducting current decreases to 0.15 mA, and a voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Also, instead of Au, Ag, Bi, Sb, PbBi, P
An element using b, Sn, Zn, Ga, Nb, In, Al, V, Ta, W was also manufactured, but similar characteristics were obtained in this case as well.

<Embodiment 9> In the same thin film structure as in Embodiment 1, only the oxide semiconductor is changed to Y _0.4 Pr _0.6 Ba ₂ Cu.
₃ O _y was used. However, Y, Pr, Ba, and Cu in a metallic state were used as raw materials for the semiconductor thin film, and Y and Pr were vaporized by using an electron gun vapor deposition apparatus.

The source of this superconducting element at 60K,
About 2.0 mA in current-voltage characteristics between drains
Of superconducting current flows, and a voltage is generated for a bias current higher than this. Furthermore, when a voltage of 200 mV is applied to the gate, the superconducting current decreases to 0.4 mA,
A voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Also, instead of Au, Ag, Bi, Sb, PbBi, Pb, S
A device using n, Zn, Ga, Nb, In, Al, V, Ta, W was also manufactured, but similar characteristics were obtained in this case as well.

<Embodiment 10> In the same thin film structure as in Embodiment 9, an Au electrode (source) 3 and an Au electrode (drain) 4 are used.
Only the distance between them was changed, and the line width was set to 0.5 μm.
The manufacturing process and the like are the same as in Example 9. In the current-voltage characteristic between the source and the drain at 30 K of this superconducting element, a superconducting current of about 1.2 mA flows, and a voltage is generated for a bias current higher than this. Further, when a voltage of 200 mV is applied to the gate, the superconducting current is reduced to 0.2 mA, and a voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Further, instead of Au, Ag, Bi, Sb, PbBi, Pb, Sn, Zn, Ga, Nb, In, Al, V,
An element using Ta and W was also manufactured, but similar characteristics were obtained in this case as well.

<Embodiment 11> In the same thin film structure as that of Embodiment 9, an Au electrode (source) 3 and an Au electrode (drain) 4 are provided.
Only the distance between them was changed, and the line width was set to 1 μm. The manufacturing process and the like are the same as in Example 9. In the current-voltage characteristic between the source and drain at 4.2K of this superconducting element, a superconducting current of about 0.5 mA flows, and a voltage is generated for a bias current higher than this. Further, when a voltage of 200 mV is applied to the gate, the superconducting current decreases to 0.01 mA, and a voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Further, instead of Au, Ag, Bi, Sb, PbBi, Pb, Sn, Zn, Ga, Nb, In, Al,
An element using V, Ta, and W was also manufactured, but similar characteristics were obtained in this case as well.

<Embodiment 12> In the same thin film structure as in Embodiment 1, only the oxide semiconductor is changed, and Bi ₂ Sr ₂ NdYCu is used.
₃ Oy was used. However, Bi, Sr, Nd, and Cu in the metallic state were used as the raw materials of the semiconductor thin film, Y was evaporated using the electron gun vapor deposition apparatus, and the other raw materials were evaporated using the Knudsen cell. Other steps are similar to those described in Example 1. The current-voltage characteristics between the source and drain at 50 K of this superconducting device are about 1.0.
A superconducting current of mA flows, and a voltage is generated for a bias current higher than this. Furthermore, 100 mV to the gate
When the voltage of 1 is applied, the superconducting current is reduced to 0.2 mA, and the voltage is generated by the bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Similar characteristics were also obtained when Y or another rare earth element was used instead of Nd. In this case, rare earth elements other than Eu and Y were evaporated using an electron gun vapor deposition device instead of the Knudsen cell. Further, instead of Au, Ag, Bi, Sb, PbBi, Pb, Sn, Zn, G
An element using a, Nb, In, Al, V, Ta, W was also manufactured,
Similar characteristics were obtained in this case as well.

<Embodiment 13> In the same thin film structure as that of Embodiment 12, only the composition of the oxide semiconductor is changed, and Bi ₂ Sr ₂ is added.
Ca _0.4 Nd _0.6 YCu ₃ O _y was used. 6 of this superconducting element
In the current-voltage characteristic between the source and the drain at 0K, a superconducting current of about 1.8 mA flows, and a voltage is generated for a bias current higher than this. Further, when a voltage of 200 mV is applied to the gate, the superconducting current is reduced to 0.3 mA, and a voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Similar characteristics were also obtained when Y or another rare earth element was used instead of Nd. In this case, rare earth elements other than Eu and Y were evaporated using an electron gun vapor deposition device instead of the Knudsen cell. Furthermore, instead of Au, Ag, Bi, Sb, PbBi, P
An element using b, Sn, Zn, Ga, Nb, In, Al, V, Ta, W was also manufactured, but similar characteristics were obtained in this case as well.

<Embodiment 14> In the same thin film structure as that of Embodiment 12, an Au electrode (source) 3 and an Au electrode (drain).
Only the distance between 4 was changed and the line width was 0.5 μm. The manufacturing process and the like are the same as in Example 12. In the current-voltage characteristics between the source and drain at 60K of this superconducting element, a superconducting current of about 0.3 mA flows,
A voltage is generated for a bias current higher than this. Further, when a voltage of 200 mV is applied to the gate, the superconducting current decreases to 0.01 mA, and a voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Also, Au
Instead of Ag, Bi, Sb, PbBi, Pb, Sn, Zn, Ga, Nb,
A device using In, Al, V, Ta and W was also manufactured, but similar characteristics were obtained in this case as well.

<Embodiment 15> In the same thin film structure as that of Embodiment 12, an Au electrode (source) 3 and an Au electrode (drain).
Only the distance between 4 was changed and the line width was 1 μm. The manufacturing process and the like are the same as in Example 12. In the current-voltage characteristics between the source and drain at 25K of this superconducting element, a superconducting current of about 0.2 mA flows, and a voltage is generated for a bias current higher than this. Further, when a voltage of 200 mV is applied to the gate, the superconducting current decreases to 0.01 mA, and a voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Further, instead of Au, Ag, Bi, Sb, PbBi, Pb, Sn, Zn, Ga, Nb, In, Al,
An element using V, Ta, and W was also manufactured, but similar characteristics were obtained in this case as well.

<Example 16> In the same thin film structure as in Example 1, only the oxide semiconductor was changed, and YBa ₂ Cu ₃ O _{6 + y} was added.
Was used. However, Y, Ba, and Cu in a metallic state were used as raw materials of the semiconductor thin film, and Y was evaporated by using an electron gun vapor deposition apparatus. Moreover, after forming the oxide thin film, in order to make oxygen in the chain site sufficiently deficient, in Ar, 4
Annealed at 50 ° C. for 6 hours. All other steps are similar to those described in Example 1.

The source of this superconducting element at 30K,
The current-voltage characteristic between the drains is about 0.9 mA.
Of superconducting current flows, and a voltage is generated for a bias current higher than this. Furthermore, when a voltage of 200 mV is applied to the gate, the superconducting current decreases to 0.1 mA,
A voltage is generated with a bias current higher than this. As described above, the present superconducting element has the basic characteristics as a three-terminal element. Similar characteristics were also obtained when a rare earth element was used instead of Y. Furthermore, instead of Au, Ag, Bi,
An element using Sb, PbBi, Pb, Sn, Zn, Ga, Nb, In, Al, V, Ta, W was also manufactured, but similar characteristics were obtained in this case as well.

Although the thin film forming method in the examples is the reactive vapor deposition method, it goes without saying that other film forming methods such as the laser ablation method, the sputtering method and the MOVPE method can be applied. In this embodiment, SrTiO ₃ was used as the substrate, but MgO and LaAlO ₃ were used.
Needless to say, it can be formed on another substrate such as ₃ .
Further, although the description has been made regarding the three-terminal element in the present embodiment, it is needless to say that another superconducting element such as a weak coupling element which is a constituent element of the three-terminal element can be manufactured.

[0032]

As described in the embodiments, the device having the structure according to the present invention has the following effects.

(1) The superconductivity induced in the oxide semiconductor is used by bringing the oxide semiconductor into contact with a simple non-superconducting substance having a crystal structure and setting the distance between the non-superconducting substances to 1 μm or less. Since it is a device that operates, a complicated laminated structure is not required, and the device can be simply manufactured.

(2) Since elements other than oxide semiconductors can be formed at room temperature, diffusion near the interface is reduced and device performance is improved.

(3) Since the superconducting exudate is controlled, the effect of the electric field is great and the device has good device performance.

(4) A superconducting logic circuit and a memory circuit using the above superconducting element can be constructed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a layout drawing for conducting a principle experiment on superconducting induction and superconducting exudation.

[Explanation of symbols]

1. SrTiO ₃ substrate 2. La _1.5 Ba _1.5 Cu ₃ O _y thin film 3. Au electrode (source) 4. Au electrode (drain) 5. Channel 6. CaF ₂ insulating film 7. Au electrode (gate) 8. Oxide semiconductor 9. Non-superconducting substance 10. Non-superconducting substance

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tokumi Fukasawa 1-280 Higashi Koikeku, Kokubunji City, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. (72) Shoichi Akamatsu 1-280 Higashi Koikeku, Kokubunji, Tokyo Hitachi Central Research Laboratory (72) Inventor Akira Tsukamoto 1-280 Higashi Koigokubo, Kokubunji, Tokyo Hitachi Central Research Institute Co., Ltd. (72) Yoshinobu Tarutani 1-280 Higashi Koikeku, Kokubunji, Tokyo Hitachi Central Research Co., Ltd. In-house (72) Inventor Kazumasa Takagi 1-280, Higashi-Kengokubo, Kokubunji-shi, Tokyo Inside Central Research Laboratory, Hitachi, Ltd.

Claims (8)

[Claims] 1. A superconducting element comprising: an oxide semiconductor containing copper; and first and second non-superconducting electrodes provided on the oxide semiconductor so as to oppose each other. 2. The superconducting element according to claim 1, wherein the electrode in the non-superconducting state is a non-superconducting substance which does not enter the superconducting state even at a low temperature. 3. The electrode according to claim 1, wherein the non-superconducting state electrode is a superconducting substance which is in a superconducting state at a low temperature, and which operates at a temperature equal to or higher than the superconducting transition temperature of the superconducting substance. Characteristic superconducting element. 4. The electrode according to claim 1, wherein the non-superconducting electrode is at least Au, Ag, Bi, Sb, Pb,
A superconducting device comprising one substance selected from Sn, Zn, Ga, Nb, In, Al, V, Ta and W. 5. The superconducting device according to claim 2, wherein the non-superconducting substance contains at least one substance selected from Au, Ag, Bi and Sb. 6. The superconducting material according to claim 3, wherein the superconducting material is at least PbBi, Pb, Sn, Zn, Ga, Nb, I.
Superconducting device containing one substance selected from n, Al, V, Ta and W 7. The superconducting element according to claim 1, wherein the oxide semiconductor containing copper has a Cu—O ₂ plane. 8. The oxide semiconductor containing copper according to claim ₁ , wherein R _{1 + x} Ba _2-x Cu ₃ O _y (R is a rare earth element other than Pr, 0.3 < x <0.8, 6 <y <
8), Pr _{1 + x} Ba _2-x Cu ₃ O _y (0 ≦ x ≦ 0.5, 6 <y <
8), Y _1-x Pr _x Ba ₂ Cu ₃ O _y (0.6 <x ≦ 1,6 <y
<8), Bi ₂ Sr ₂ Ca _1-x R _x Cu ₂ O _y (R is a rare earth element,
0.6 ≦ x ≦ 1.0, 8 <y <8.5), and RBa
₂ Cu ₃ O _y (R is Y or a rare earth element, 6.0 <y <6.
4) A superconducting element which is any one of 4).