JP5098003B2 - Superconducting conductor, superconducting rectifier, and rectifier circuit using the same - Google Patents

Description

  The present invention relates to a superconducting conductor and an element using superconducting characteristics, and more specifically, a superconducting conductor capable of flowing a large current with zero resistance in one direction using the superconducting characteristic, a superconducting rectifier element, and the same It relates to the circuit used.

  The rectifier circuit is configured to convert alternating current into direct current by elements such as a transformer coil, a diode, and a capacitor, and power loss due to resistance occurs in the coil or diode. In addition, the current limiting device is configured to suppress an overcurrent from flowing through the power system using a superconducting conductor, a diode, or the like, and power loss occurs in the diode. In order to reduce these power losses, it has been conventionally considered to use a superconducting coil. Examples of using such a superconducting coil include, for example, Japanese Patent Application Laid-Open No. 2000-350357 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2000-90788 (Patent Document 2).

Further, as a superconducting rectifier element, there is one disclosed in Japanese Patent Laid-Open No. 5-37030 (Patent Document 3), but this is an element used for integration of an arithmetic circuit and its device, and cannot flow a large current. Met.
JP 2000-350357 A JP 2000-90788 A JP-A-5-37030

  In a circuit using a superconducting coil such as the above-described conventional rectifier circuit or current limiting device, power loss is still unavoidable with respect to the diode. For this reason, the rectifying element such as a diode also has a problem that the resistance is reduced, the loss of power is reduced, and that even a larger current can be applied.

  The present invention provides a solution to such a problem, and one or both surfaces of a thin plate-like superconductor are each provided with a recess composed of a plurality of grooves or holes parallel to the direction of current flow. The cross-sectional shape of the substrate is asymmetric with respect to the direction of current flow, and the asymmetric shape causes the quantized magnetic flux to be perpendicular to the current by Lorentz force acting on the quantized magnetic flux in the direction perpendicular to the thin plate-like superconductor. The pinning force generated against the movement in the direction becomes asymmetric with respect to the forward and reverse currents, thereby increasing the critical current in the forward direction and decreasing the critical current in the reverse direction.

  Further, the present invention provides a thin plate-shaped superconductor in which a plurality of rows of pores parallel to the direction of current flow are formed and arranged, and the number of pores in each row of the pores is the current. By arranging the pores so that they gradually change from column to column in the direction perpendicular to the flow direction and the change in the number of pores in each column repeats periodically in the direction perpendicular to the direction of current flow, The pinning force generated to resist the movement of the quantized magnetic flux in the direction perpendicular to the current by the Lorentz force acting on the quantized magnetic flux in the direction perpendicular to the superconductor of the current becomes asymmetric with respect to the forward and reverse directions of the current, Accordingly, the critical current in the forward direction may be increased and the critical current in the reverse direction may be decreased.

Further, according to the present invention, a plurality of fine grooves parallel to the direction of current flow are formed and arranged in a thin plate-like superconductor, and the interval between adjacent fine grooves in the plurality of fine grooves is gradually changed. Quantization with Lorentz force acting on the quantized magnetic flux in the direction perpendicular to the thin plate-like superconductor by arranging the narrow grooves so that the change of the frequency periodically repeats in the direction perpendicular to the direction of current flow Even if the pinning force generated to resist the movement of the magnetic flux in the direction perpendicular to the current becomes asymmetric with respect to the forward / reverse of the current, the critical current in the forward direction is increased and the critical current in the reverse direction is decreased. Good.
(Function)
The present invention provides an anisotropy to the pinning force of the pinning center by the above-described means, so that a large loss-free large amount can be obtained only in one direction using a low-loss superconductor without using a semiconductor diode with loss. This provides an effect that current can flow.

  By providing anisotropy to the pinning center according to the present invention, a rectifying element capable of flowing a large current without loss only in one direction without using a semiconductor diode with loss and using a low-loss superconductor. It can be. Such a rectifier using a superconductor can be applied to a rectifier circuit, a switching circuit or the like in which a conventional semiconductor diode is used, and can greatly reduce the loss associated with the semiconductor element, resulting in a large current. This also has an effect that it can be applied.

  Embodiments of the invention will be described with reference to the drawings. First, the basic principle that is the premise of the superconducting rectifier will be described.

  The superconductor generally exhibits superconducting properties up to the critical current density Jc within the critical temperature Tc and upper critical magnetic field Bc2 shown in FIG. This superconducting characteristic varies depending on the superconducting material such as oxide superconductor and metal-based superconductor, and exhibits superconducting characteristics within this range. It is necessary to select a superconducting material having a high temperature Tc and high upper critical magnetic field Bc2 and to improve and improve the critical current density.

  As shown in FIG. 2, a pure type 2 superconductor that does not contain impurities, lattice defects, etc. is placed perpendicular to the direction of the external magnetic field. Self-magnetic fields, magnetic fields created by other current-carrying conductors and coils, penetrate into the superconductor and are quantized. The quantized magnetic flux generates an electromagnetic force represented by the product of the magnetic flux density and the current density, and is called a Lorentz force. This Lorentz force results in a flow state in which the quantized magnetic flux lines move, and an electromotive force is generated with the movement of the quantized magnetic flux lines. As a result, the superconductor exhibits a finite electrical resistance and the current does not flow in a lossless manner. .

  Actually, there are micro inhomogeneous parts such as fine precipitates, crystal grain boundaries, voids, and the interface between the superconductor and the normal conductor due to heat treatment or plastic working in the superconductor. These micro-inhomogeneous parts capture the quantized magnetic flux and prevent its movement, which is called pinning, and the precipitates, grain boundaries, voids, superconductors and normal conductors that cause pinning The inhomogeneous portion such as the boundary surface is called a pinning center. In the type 2 superconductor including an inhomogeneous portion, the lossless current flows in a magnetic field within a certain critical current density due to such pinning action.

  Such pinning centers of superconductors are inhomogeneous, such as precipitates, grain boundaries, voids, and the interface between the superconductor and the normal conductor, ranging from the diameter of the quantized magnetic flux to the interval of the quantized magnetic flux. Although it is a part, not only metallurgical means such as heat treatment and plastic working, but also a pinning center by creating a micro structure with the size of quantized magnetic flux and the interval of quantized magnetic flux in superconductor by fine processing. It is also considered to form.

  Where the diameter of the quantized magnetic flux is twice the coherent length ξ,

で表され、量子化磁束の間隔ｆ_ｐは

In expressed, the distance f _p of quantization flux

である。ただし、
φ_０：磁束量子（２．０７×１０−１５（Ｗｂ））
Ｂｃ２：上部臨界磁場
Ｂ ：磁束密度
例えば、ξは材料によって異なり、液体ヘリウム温度４．２Ｋにおいて上部臨界磁場が０．４ＴのＮｂにおいては、ξは０．０３μｍ、上部臨界磁場が１１ＴのＮｂＴｉにおいては、０．００５５μｍである。また、磁束線格子間隔は、１ｍＴにおいて１．５μｍ、１Ｔにおいて０．０５μｍである。
図３はこのようなピンニングセンターとしての溝状人工ピンを示したものであり、この図で厚さｔ_０の板状の超伝導体１の上面において電流が流れる方向に幅ｗ、深さｄ_ｐの溝２が複数本、ピッチｐとなるように形成されている。超伝導体１を水平に配置し、これに垂直に外部磁界Ｂが作用している状態で、超伝導体１の長さ方向に電流Ｉを流すと、量子化磁束には前述したローレンツ力が作用する。ただし、超伝導体１の配置は水平方向に限定するものではない。

It is. However,
φ ₀ : Magnetic flux quantum (2.07 × 10 −15 (Wb))
Bc2: Upper critical magnetic field B: Magnetic flux density For example, ξ varies depending on the material, and Nb with an upper critical magnetic field of 0.4 T at a liquid helium temperature of 4.2 K, ξ is 0.03 μm, and NbTi with an upper critical magnetic field of 11 T Is 0.0055 μm. Further, the magnetic flux line lattice spacing is 1.5 μm at 1 mT and 0.05 μm at 1T.
FIG. 3 shows a groove-shaped artificial pin as such a pinning center. In this figure, a width w and a depth d in the direction in which current flows on the upper surface of the plate-like superconductor 1 having a thickness t ₀ . _A plurality of _p grooves 2 are formed to have a pitch p. When the superconductor 1 is disposed horizontally and an external magnetic field B is applied perpendicularly to the superconductor 1 and a current I is passed in the length direction of the superconductor 1, the aforementioned Lorentz force is applied to the quantized magnetic flux. Works. However, the arrangement of the superconductor 1 is not limited to the horizontal direction.

  FIG. 4A is an enlarged view of the groove-shaped artificial pin of FIG. 3, and a certain quantized magnetic flux 3 is located in the groove 2 near the right convex portion in the drawing. From this state, when the quantized magnetic flux moves to the right until it enters the convex portion, the quantized magnetic flux exists in the superconductor by destroying the superconducting state only in the superconductor and the interaction volume V. The difference ΔU occurs in the condensation energy U with respect to the movement of the quantized magnetic flux. This condensation energy difference ΔU is determined by the interaction volume V and the magnetic flux density.

である。ただし、
μ_０： 真空の透磁率
Ｂｃ： 熱力学的臨界磁場
ψ： 秩序パラメータ
Ｖ： 相互作用体
溝の壁が垂直な場合に、ΔＵだけの変化が量子化磁束の直径２ξ程度の移動によって生ずることになる。またこのΔＵの変化は、溝の左側部分に関しても対称的に生ずるはずであるから、結局凝縮エネルギーＵは溝の形状に対応して、図４（ｂ）のように変化すると考えられる。この凝縮エネルギーの変化ΔＵにより量子化磁束の移動に対する要素的ピンニング力が与えられる。要素的ピンニング力ｆｐは、凝縮エネルギーのポテンシャル勾配として、近似的に、

It is. However,
μ ₀ : Permeability of vacuum Bc: Thermodynamic critical field ψ: Order parameter V: When the wall of the interaction groove is vertical, a change of ΔU is caused by movement of the quantized magnetic flux with a diameter of about 2ξ Become. In addition, since the change of ΔU should occur symmetrically also with respect to the left side portion of the groove, it is considered that the condensation energy U eventually changes as shown in FIG. 4B corresponding to the shape of the groove. This change in condensation energy ΔU gives an elemental pinning force for the movement of the quantized magnetic flux. The elemental pinning force fp is approximately as a potential gradient of condensation energy,

ここで、
ξ： コヒーレント長さ
Ｂｃ２： 上部臨界磁場
Ｂ： 印加磁場
であり、また、Ｖ＝πξ２ｄ_ｐである。

here,
ξ: Coherent length Bc2: Upper critical magnetic field
B: Applied magnetic field, and V = πξ2d _p .

In the pinning center having a symmetrical groove shape as shown in FIG. 4A, the pinning force is symmetric, and the magnitude of the pinning force is the same regardless of whether the current is forward or reverse. Actually, a symmetric superconducting element shown in FIG. 4A was fabricated, and data indicating that the critical current density of the element was improved by introducing an artificial pin was obtained. The experimental data shows the same critical current density in both the forward and reverse directions. These results show that the groove-shaped artificial pin works effectively, and the magnetic flux lines quantized with the change of the condensation energy shown in FIG. 4 (b) are pinned. The validity of the derived numbers 1 and 2 is shown.
Therefore, when the artificial pin having the asymmetric structure shown in FIG. 5A is produced, the asymmetrical condensation energy change as shown in FIG. 5B is caused, and the critical current density is changed in the forward direction and the reverse direction. Different superconducting rectifier elements can be obtained.

  As shown in FIG. 5 (a), the cross-sectional shape of the pinning center having such an asymmetrical groove shape is substantially vertical on one wall, but the other wall has a gentle slope. In this case, the range in which the change ΔU of the condensation energy occurs is much larger than 2ξ in the case of the vertical wall, and the change ΔU of the condensation energy becomes much more gradual than in the case of the vertical groove wall corresponding to the gentle slope shape. As shown in FIG.

  For this reason, the pinning force with respect to the quantized magnetic flux is also left-right asymmetrical, and is much weaker than the maximum pinning force expressed by Equation 2 with respect to the wall having a gentle slope shape, and the critical current density becomes small. Since the direction of pinning action varies depending on the direction of the current, the magnitude of the current flowing without loss varies depending on the direction of the current by setting the slope of the asymmetric groove wall in this way. . By making one wall of the groove vertical and making the other wall a gentle slope, the effect of pinning when the current flows in the forward direction is increased, and the effect of pinning when the current flows in the opposite direction is extremely reduced The current-voltage characteristics are as shown in FIG. That is, the rectifying action is generated by the interaction between the pinning center and the quantized magnetic flux.

  The present invention forms an asymmetric artificial pin in this way and uses it as a rectifying element using a superconductor. This is achieved by an artificial pin having an asymmetric cross-sectional groove as shown in FIG. Made. Hereinafter, formation of such an artificial pin having an asymmetric cross-sectional shape will be described.

  When forming an artificial pin with a superconductor having a rectifying action with a cross-sectional shape as shown in FIG. 5 (a), a superconductor is manufactured in order to minimize the pinning force that is smaller due to the groove shape. Therefore, it is necessary to reduce the pinning effect due to the heterogeneous portion introduced when the superconducting Nb film with few defects is formed by the electron beam evaporation method. To do. The thickness of the superconducting Nb film is suitably 0.2 μm to several μm.

  A groove including a gentle slope is formed on the upper surface of the Nb film. In the case of such fine processing, it is practically difficult to form a slope as shown in FIG. 5A by etching. As shown in FIG. 7, a stepped cross section is formed, and this is formed by a plurality of etchings.

  The groove pitch p is about 10 times the quantized magnetic flux diameter 2ξ, and the groove width is set to a value close to the pitch in order to reduce the reverse current. The depth of the groove can be variously set within the range of the thickness of the film, but shows the maximum critical current at about 70% of the thickness of the film.

  As a microfabrication technique used for forming such a groove, any one of microlithography techniques such as photolithography, electron beam lithography, X-ray lithography, ion beam lithography, or the latest nanoprinting techniques Can be applied. Moreover, although Nb was illustrated as a superconducting material material, a superconductor with a high critical temperature can be used in addition to a metallic superconductor other than Nb.

  Parameters affecting the shape of the condensed energy U include groove pitch, depth, and slope angle. In addition, it is possible to form an asymmetric condensation energy potential even if it is not necessarily a plurality of continuous grooves. A plan view when a plurality of grooves are formed is as shown in FIG. 8 (a). As shown in FIG. 8 (b), for example, a large number of asymmetric holes are two-dimensionally distributed. It may be formed as follows. FIG. 8C is a diagram showing a cross section taken perpendicularly to the direction of current flow in a holed portion.

Further, as shown in FIG. 9, a groove having a width w ₁ is formed on the upper surface side instead of the groove or hole approximated in steps, and the width w ₂ is positioned at the position on the lower surface side biased to one side from the center of the groove on the upper surface side. Also by forming the groove of (w ₂ <w ₁ ), an asymmetric distribution shape of the condensation energy U similar to the case of FIG. 5B is generated on the upper surface side.

  Similar asymmetrical artificial pins can be obtained by arranging a large number of pores in a direction perpendicular to the surface of the superconductor instead of forming grooves or holes in the surface of the superconductor. FIG. 10A shows an example in which pores are arranged and FIG. 10B shows a case in which corresponding grooves are formed, and each is shown in a perspective view. In FIG. 10 (a), the pores are formed in a direction substantially perpendicular to the surface of the thin plate-like superconductor, and are arranged in a row in the direction of the groove in the case of FIG. 10 (b). The rows of pores are at least several rows at the pitch (p) of the groove arrangement in FIG. 10B, and the number of pores in each row is gradually changed. Speaking of the case of the groove, the deep side of the groove has a large number of pores, and the shallow side has a small number of pores. In other words, the function of the artificial pin is caused by the density of the pores instead of the depth of the groove or hole.

  The shape of each pore is shown as a circle and is not particularly limited to a circle, but the cross-sectional sizes of the pores are the same. The depth of the pores may be the same as each other without penetrating the superconductor. Then, in order to obtain the same function of the artificial pin as that shown in FIG. 10 (b), in which grooves having a depth gradually increasing from the left side to the right side are formed at the pitch p, FIG. As shown in a), several rows of pores are arranged within the range of the pitch p, and the pores are provided at almost equal intervals in each row, and the number of pores in each row is changed from the left column to the right side. It is designed to increase gradually toward the line. Such a row of pores is formed repeatedly for each pitch p.

  In order to obtain the same effect of artificial pins as in the case of grooves and holes whose depth changes gradually depending on the arrangement of the pores, the diameter of the pores is smaller than a fraction of the size of the grooves and holes. It is necessary to. The diameter of the quantized magnetic flux is about twice the coherent length ξ. In the case of a groove or hole, the width dimension is about the same as the diameter of the quantized magnetic flux or its interval. In the case of an arrayed artificial pin, Lorentz force acts on the quantized magnetic flux according to the change in the distribution density of the pores. Must be dimensionally related.

  This situation will be described as shown in FIG. FIG. 11 shows the relationship between the arrangement state of a large number of pores and the quantized magnetic flux when the superconductor shown in FIG. 10A is viewed from above. In FIG. 11, several rows of pores are included in the range of the diameter of the quantized magnetic flux. When the number of pores in each row of pores is a groove, the side corresponds to the deep side, and when the number of pores is the groove, the side corresponds to the shallow side. In this way, when the pores are arranged so that the number of pores in each row gradually changes, the change in the interaction volume between the pore density distribution and the quantized magnetic flux In this case as well, it changes asymmetrically, and the Lorentz force from the low density side to the high side of the pores acts on the quantized magnetic flux, and the action of the asymmetric artificial pin is obtained.

  FIG. 12A is a perspective view and FIG. 12B is a cross-sectional view showing still another example of a configuration for obtaining the action of the artificial pin. In FIG. 12A, a plurality of narrow grooves are formed on the surface of the superconductor in the direction in which current flows. The widths of the grooves are substantially the same, and in the same manner as the row of pores in the case of FIG. 10A, a plurality of grooves are parallel to each other within the width of the pitch p, and adjacent grooves. Are formed so as to gradually increase from coarse to dense, and a set of parallel narrow grooves in which the interval gradually increases is repeatedly formed with the pitch p as a period. Even with such narrow grooves in which the plurality of intervals gradually change, Lorentz force acting from the low density side to the high density side acts, and the action of an asymmetric artificial pin is obtained.

  As microfabrication techniques used to form a large number of pore rows or a plurality of fine grooves on the surface of the superconductor in this way, photolithography, electron beam lithography, X-ray lithography, ion beam lithography are used. Either a microlithography technique such as a method or a technique including the latest nanoprinting technique can be applied.

  In addition, when the concave portion, pore, or narrow groove of the groove or hole described above is formed, this portion becomes a portion without the superconducting material. However, the concave portion, pore, or narrow groove without the superconducting material is always present. Even if the surface is flattened with a conductor or a superconductor having a critical temperature or magnetic field smaller than that of a superconductor having concave parts, pores or narrow grooves, the condensation energy can be reduced. Since the asymmetric potential is obtained by the change, it is used as a superconducting rectifying element, and it is considered that the mechanical strength is increased by eliminating the recesses, pores or narrow grooves as an overall shape.

  Superconductors with artificial pins as described above can be used as rectifiers in which lossless current flows in a range of critical current density only in one direction, and can be used in rectifiers and switching circuits using conventional diode elements. It becomes possible to apply.

FIG. 13A shows an example of a half-wave rectifier circuit including a superconducting rectifier element D according to the present invention. For example, an alternating current source is connected between terminals a and b to generate a sinusoidal alternating current. When energizing, only the forward current is conducted, a half-wave rectified current as shown in FIG. 13B flows between the terminals cd, and the current I flowing through the rectifying element D is When I <Ic (Ic is a critical current), a current can flow through the load between cd while the voltage v _D of the rectifying element _D = 0.

  FIG. 14 (a) shows an example of a full-wave rectifier circuit including a rectifier element D according to the present invention. An alternating current source is connected between terminals a and b so as to energize a sinusoidal alternating current. In this case, a current in the same direction as shown in FIG. 14B flows between the terminals cd. Furthermore, when a capacitor indicated by a dotted line in FIG. 14A is inserted, a direct current can be supplied as indicated by the dotted line in FIG. 14B, and there is no loss in the rectifying element. However, I is smaller than the critical current in the forward direction of the rectifying element.

It is a figure which shows the critical conditions which operate | move as a superconductor. It is a figure which shows the Lorentz force which acts on a quantization magnetic flux. It is a figure which shows the basic form of a groove-shaped artificial pin. (A) It is the figure which expanded and showed the groove-shaped artificial pin of FIG.

(B) It is a figure which shows the potential distribution of the condensation energy corresponding to the shape of the groove | channel of an artificial pin.
(A) It is a figure which shows the artificial pin made into the asymmetrical groove shape as an example of the superconducting rectifier of this invention.

(B) It is a figure which shows the potential distribution of the condensation energy produced by asymmetrical groove | channel shape.
It is a figure which shows the current-voltage characteristic of the asymmetrical groove-shaped artificial pin. It is sectional drawing which shows what approximated the asymmetrical groove-shaped slope of the artificial pin with the staircase. (A) It is a top view of the artificial pin formed from several groove | channels.

  (B) It is a top view of the artificial pin which formed the hole distributed in two dimensions.

(C) It is a figure which shows a cross section perpendicular | vertical to the direction through which an electric current flows in the part of a hole.
It is sectional drawing which shows the other example of the artificial pin which formed the groove | channel in the surface of the both sides of a superconductor. (A) It is a perspective view which shows the example of the artificial pin formed by arranging many pores in the surface of a superconductor.

(B) It is a perspective view which shows the artificial pin which formed the groove | channel in the surface of the superconductor compared with the case of (a).
It is a figure which shows the relationship between many pore arrangement | sequence states and quantization magnetic flux at the time of seeing the superconductor shown to Fig.10 (a) from upper direction. (A) It is a perspective view which shows the example of the artificial pin formed by arranging a plurality of fine grooves on the surface of the superconductor.

(B) It is sectional drawing which shows the example of the artificial pin formed by arranging a plurality of fine grooves on the surface of the superconductor.
(A) It is a figure which shows the example of the half-wave rectifier circuit provided with the superconducting rectifier of this invention.

(B) It is a figure which shows the output current of the half-wave rectifier circuit of (a).
(A) It is a figure which shows the example of the full wave rectifier circuit provided with the superconducting rectifier of this invention.

  (B) It is a figure which shows the output current of the full wave rectifier circuit of (a).

Claims (18)

  A concave portion consisting of a plurality of grooves or holes is formed on one or both surfaces of the thin plate-like superconductor in parallel to the direction of current flow so that each cross-sectional shape is asymmetric with respect to the direction of current flow. Because of its asymmetrical shape, the pinning force generated by the Lorentz force acting on the quantized magnetic flux in the direction perpendicular to the thin plate-shaped superconductor resists the movement of the quantized magnetic flux in the direction perpendicular to the current. A superconducting conductor having a function of rectification that increases the critical current in the forward direction and decreases the critical current in the reverse direction.   In a thin plate-like superconductor, a plurality of rows of pores parallel to the direction of current flow are drilled and arranged, and the number of pores in each row of the pores is perpendicular to the direction of current flow By aligning the pores so that the change in the number of pores in each row repeats periodically in the direction perpendicular to the direction of current flow, The pinning force generated by the Lorentz force acting on the quantized magnetic flux in any direction to counteract that the quantized magnetic flux moves in the direction perpendicular to the current becomes asymmetric with respect to the forward and reverse currents, thereby making it critical in the forward direction. A superconducting conductor that has the function of rectification to increase current and decrease critical current in the reverse direction.   A plurality of narrow grooves parallel to the direction of current flow are formed and arranged in a thin plate-like superconductor, and the interval between adjacent narrow grooves in the plurality of narrow grooves gradually changes, and the change in the spacing causes the current to flow. By arranging the narrow grooves to repeat periodically in the direction perpendicular to the direction, the quantized magnetic flux is perpendicular to the current by the Lorentz force acting on the quantized magnetic flux in the direction perpendicular to the thin plate superconductor. Superconductivity with the function of rectification to increase the critical current in the forward direction and to reduce the critical current in the reverse direction, with the pinning force generated against the movement in the direction becoming asymmetric with respect to the forward and reverse currents conductor. The thin plate-like superconductor is produced by forming an Nb film, which is a type 2 superconductor, by electron beam evaporation, and includes a plurality of grooves or holes, and a plurality of thin films. The superconducting conductor according to any one of claims 1 to 3, wherein a hole or a plurality of fine grooves are formed by machining . The superconducting conductor according to any one of claims 1 to 4 , wherein the concave portions including the plurality of grooves or holes , the pores forming the plurality of rows, or the plurality of narrow grooves are filled with a normal metal. From the plurality of grooves or holes in other superconductors having a critical temperature and a critical magnetic field smaller than those of the superconductors having the recesses , the plurality of rows of pores, or the plurality of narrow grooves formed of the plurality of grooves or holes. The superconducting conductor according to any one of claims 1 to 4, wherein a concave portion, a plurality of rows of pores or a plurality of fine grooves are filled. The recesses composed of a plurality of grooves or holes are approximated in a staircase shape by microfabrication techniques using photolithography, X-ray lithography, electron beam lithography, microlithography including ion beam lithography, or nanoprinting. The superconducting conductor according to claim 1 , wherein the superconducting conductor is formed.   A concave portion consisting of a plurality of grooves or holes is formed on one or both surfaces of the thin plate-like superconductor in parallel to the direction of current flow so that each cross-sectional shape is asymmetric with respect to the direction of current flow. Because of its asymmetrical shape, the pinning force generated by the Lorentz force acting on the quantized magnetic flux in the direction perpendicular to the thin plate-shaped superconductor resists the movement of the quantized magnetic flux in the direction perpendicular to the current. A superconducting rectifier element characterized in that the critical current in the forward direction is increased and the critical current in the reverse direction is decreased. The concave portion formed of the plurality of grooves or holes is inclined gently on one surface of the thin plate-like superconductor on a surface substantially perpendicular to the superconductor surface on one side and the superconductor surface on the other side. The superconducting rectifying device according to claim 8 , wherein the superconducting rectifying device is formed as a plurality of grooves having a curved surface. A plurality of first grooves having a first width in which concave portions including the plurality of grooves or holes are formed on one surface of the thin plate-like superconductor, and the other surface of the thin plate-like superconductor And a plurality of second grooves formed in a state of being biased with respect to the center in the width direction of the first groove corresponding to the first groove. 8. The superconducting rectifier according to 8 . The recesses comprising the plurality of grooves or holes are formed in a two-dimensional distribution on one surface of the superconductor, each comprising a plurality of holes having an asymmetric cross-sectional shape with respect to the direction of current flow. The superconducting rectifier according to claim 8 .   In a thin plate-like superconductor, a plurality of rows of pores parallel to the direction of current flow are drilled and arranged, and the number of pores in each row of the pores is perpendicular to the direction of current flow By aligning the pores so that the change in the number of pores in each row repeats periodically in the direction perpendicular to the direction of current flow, The pinning force generated by the Lorentz force acting on the quantized magnetic flux in any direction to counteract that the quantized magnetic flux moves in the direction perpendicular to the current becomes asymmetric with respect to the forward and reverse currents, thereby making it critical in the forward direction. A superconducting rectifying device characterized by a large current and a small critical current in the reverse direction.   A plurality of narrow grooves parallel to the direction of current flow are formed and arranged in a thin plate-like superconductor, and the interval between adjacent narrow grooves in the plurality of narrow grooves gradually changes, and the change in the spacing causes the current to flow. By arranging the narrow grooves to repeat periodically in the direction perpendicular to the direction, the quantized magnetic flux is perpendicular to the current by the Lorentz force acting on the quantized magnetic flux in the direction perpendicular to the thin plate superconductor. Superconducting rectification characterized in that the pinning force generated against the movement in the direction becomes asymmetric with respect to the forward and reverse current, thereby increasing the critical current in the forward direction and decreasing the critical current in the reverse direction element. The thin plate-like superconductor is produced by forming an Nb film which is a type 2 superconductor by electron beam evaporation , and a plurality of grooves or holes, and a plurality of rows. The superconducting rectifier according to any one of claims 8 to 13 , wherein a fine hole or a plurality of fine grooves forming the same is processed and formed . The superconducting rectifier according to any one of claims 8 to 14 , wherein the recesses formed by the plurality of grooves or holes , the pores forming the plurality of rows, or the plurality of narrow grooves are filled with a normal metal. From the plurality of grooves or holes in other superconductors having a critical temperature and a critical magnetic field smaller than those of the superconductors having the recesses, the plurality of rows of pores, or the plurality of narrow grooves formed of the plurality of grooves or holes. The superconducting rectifier according to any one of claims 8 to 14, wherein a concave portion, a plurality of rows of pores or a plurality of fine grooves are filled. The recesses composed of a plurality of grooves or holes are approximated in a staircase shape by microfabrication techniques using photolithography, X-ray lithography, electron beam lithography, microlithography including ion beam lithography, or nanoprinting. The superconducting rectifier according to any one of claims 8 , 9 , and 11 , which is formed. A rectifier circuit comprising the superconducting rectifier according to any one of claims 8 to 17 .

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