Abstract: A superconducting element is disclosed which includes a substrate and a superconducting layer provided on the substrate and formed of an oxide having the following chemical formula:RBa.sub.2 (Cu.sub.1-x M.sub.x).sub.3 O.sub.7wherein R represents at least one element selected from the group consisting of Y, La, Nd, Pm, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu, M represents at least one element selected from the group consisting of Al, Ti, V, Cr, Mn, Fe, Co, Ni, Zn and Ga, and x represents a number of less than 1 but greater than 0.

Abstract: A superconducting device includes a substrate, a projecting insulating region formed in a principal surface of the substrate, and a first thin film portion of an oxide superconductor formed on the projecting insulating region. Second and third thin film portions of an oxide superconductor are positioned at opposite sides of the projecting insulating region to be continuous to the first thin film portion, respectively, so that a superconducting current can flow through the first thin film portion between the second thin film portion and the third thin film portion. The second thin film portion and the third thin film portion has a thickness larger than that of the first thin film portion. The projecting insulating region is formed of an oxide which is composed of the same constituent elements of the oxide superconductor but which has the oxygen content smaller than that of said oxide superconductor.

Abstract: The present invention discloses a process for forming an a-axis superconducting junction by adjusting the deposition temperature of an oxide normal conductor layer/and oxide superconductor layer/an oxide insulating layer/an oxide normal conductor layer/and an oxide superconductor layer, which are sequentially multilayered on an oxide single crystalline substrate. According to the present invention, the oxide superconductor layer and the oxide insulating layer have an a-axis oriented perpendicularly, and the oxide normal conductor layer have a b-axis oriented perpendicularly, so that a superconductor Josephson junction may be obtained.

Abstract: A method of fabricating a superconducting quantum interference device (DC-SQUID) constructed from short weak links with untrafine wires. The method comprises the following steps: successive forming a niobium nitride film and a silicon nitride film on a substrate; oblique etching of the niobium nitride film and said silicon nitride film with respect to the substrate by a reactive ion etching process using a mixture of oxygen and CF.sub.4 gases to form an olique edge; and successive forming a barrier thin film and a counterelectrode of niobium on the said edge. The short weak links wire fabricated by field evaporation technique. The counterelectrode material were field-evaporated and formed the conductive paths in the pinholes in the insulating thin film.

Abstract: The present invention provides a superconducting device having a weak link junction with an angle at the grain boundary between the two superconductor crystals being variable. The angle at the junction is substantially equivalent to a vicinal angle for the substrate. Accordingly, the magnitude of the angle at the junction can be varied by varying the vicinal angle of the substrate. This result can be realized by using buffer layers of different compositions underlying the superconducting materials on either side of the weak link junction. Weak link junctions and reproducible properties are essential for a variety of electronic and magnetic sensing devices.

Abstract: A HTSC Josephson device wherein the barrier layer is a cubic, conductive material.

Abstract: A SQUID includes a substrate and a superconducting current path of a patterned oxide superconductor material thin film formed on a surface of the substrate. A c-axis of an oxide crystal of the oxide superconductor material thin film is oriented in parallel to the surface of the substrate.

Abstract: A Josephson junction device is disclosed that includes a single crystalline substrate having a NaCl type crystal structure. The device includes a principal surface having two horizontal planes and a slope inclined at an angle of 5.degree. to 30.degree. between the two horizontal planes. An oxide superconductor thin film is formed on the principal surface of the substrate, which includes first and a second superconducting portions of a first single crystalline oxide superconductor and a second single crystalline oxide superconductor respectively positioned on the two horizontal planes of the substrate. A junction portion of a single crystalline oxide superconductor has a different crystal orientation from the first and the second superconducting portions, and is positioned on the slope of the substrate. Two grain boundaries between each of the first and the second superconducting portions and the junction portion constitute one weak link of the Josephson junction.

Abstract: A method of forming a high-Tc microbridge superconductor device is disclosed, which comprises the steps of forming an inclined step on the surface of a substrate, the inclined step having an angle of inclination of from about 20 to about 80 degrees; depositing a layer of c-axis oriented superconductor material overlying the substrate such that there is a break in the layer of superconductor material at the inclined step; and depositing a layer of normal material overlying the layer of c-axis oriented superconductor material.

Abstract: A lattice matching device includes a substrate having thereon monocrystal regions having different lattice mismatches with respect to a LnBa.sub.2 Cu.sub.3 O.sub.x superconductor. A superconducting thin film is formed on the substrate, which film consists essentially of a superconductor of LnBa.sub.2 Cu.sub.3 O.sub.x wherein Ln represents yttrium or a lanthanide, and 6<x<7. The first and second superconducting thin film portions have different axes of orientation perpendicular to a main surface of the substrate, and arranged in contact with each other or at a distance which allows transmission of electron pairs from one to another.

Abstract: This invention relates to a process of forming multilayered thallium-containing superconducting composites, wherein a first thallium-containing superconducting layer, an intermediate thallium-containing oxide layer and a second thallium-containing superconducting layer are successively deposited on a substrate by a vapor phase process by controlling the heating temperature, pressure of oxidizing gas and thallium vapor pressure during post-deposition annealing of the superconducting films.

Abstract: For manufacturing a superconducting device having a tunnel junction formed of an extremely thin insulator layer sandwiched between a pair of oxide superconductor thin films, a first superconducting layer of oxide superconductor thin film is formed on a substrate, and a MgO thin film is deposited on the first superconducting layer at a substrate temperature of not higher than 200.degree. C. The MgO thin film is heat-treated so that crystallinity of the deposited MgO thin film is improved, and thereafter, a second superconducting layer of oxide superconductor thin film is formed on the MgO thin film.

Abstract: A Josephson junction device is disclosed having a substrate upon which are located overlying and underlying high critical temperature crystalline oxide superconductive layers separated by an interposed impedance controlling layer. The underlying superconductive layer is limited to a selected area of the substrate while the overlying and interposed layers overlie only a portion of the underlying superconductive layer. Nonsuperconducting oxide layer portions laterally abut the superconductive and interposed layers. A first electrical conductor is attached to the underlying superconductive layer at a location free of overlying oxide layers, and a second electrical conductor contacts the overlying superconductive layer and extends laterally over the adjacent laterally abutting nonsuperconductive layer portion.

Abstract: An oxide superconductor thin film is formed on a substrate by emitting molecular beams of constituent elements of the oxide superconductor to the substrate under high vacuum, wherein at first a molecular beam of one of the constituent elements of the oxide superconductor, of which an oxide thin film can be deposited so as to have a smooth surface, is emitted so as to form the oxide thin film of one or two unit cells. And then, all the molecular beams of constituent elements of the oxide superconductor are emitted to the oxide thin film so as to form the oxide superconductor thin film.

Abstract: The edge-defined, film-fed growth technique process is modified to produce a thin ribbon of bi-crystalline sapphire wherein the grain boundary is an essentially straight boundary and the angle is predetermined by selective cutting of the two seeds which are placed closely together during growth. The angle selection is optimized based on the superconducting material to be deposited and the application intended. After the ribbon is pulled, the ribbon is processed by cutting an appropriate section therefrom with the grain boundary. The substrate is polished and the high Tc superconducting material is deposited thereon to produce devices which rely on weak link Josephson junctions.

Abstract: A Josephson junction device comprising a single crystalline substrate including a principal surface, a layer of the same material as the substrate formed on the principal surface of the substrate so as to form a step on the principal surface, and an oxide superconductor thin film formed on the principal surface of the substrate. The oxide superconductor thin film includes a first and a second superconducting portions respectively positioned above and below the step, which are constituted of single crystals of the oxide superconductor, a junction portion between the first and the second superconducting portions, which is constituted of a single crystal of the oxide superconductor of which crystal orientation is different from those of the first and second superconducting portions, and grain boundaries between the first superconducting portion and the junction portion and between the second superconducting portion and the junction portion, which constitute one weak link of the Josephson junction.

Abstract: A lanthanum aluminate ( LaAlO.sub.3) substrate on which thin films of layered perovskite copper oxide superconductors are formed. Lanthanum aluminate, with a pseudo-cubic perovskite crystal structure, has a crystal structure and lattice constant that closely match the crystal structures and lattice constants of the layered perovskite superconductors. Therefore, it promotes epitaxial film growth of the superconductors, with the crystals being oriented in the proper direction for good superconductive electrical properties, such as a high critical current density. In addition, LaAlO.sub.3 has good high frequency properties, such as a low loss tangent and low dielectric constant at superconductive temperatures. Finally, lanthanum aluminate does not significantly interact with the superconductors. Lanthanum aluminate can also used to form thin insulating films between the superconductor layers, which allows for the fabrication of a wide variety of superconductor circuit elements.

Abstract: A superconducting device or a super-FET has a pair of superconducting electrode regions (20b,20c) consisting of a thin film (20)oxide superconductor being deposited on a substrate (5) and a weak link region (20a), the superconducting electrode regions (20b, 20c) being positioned at opposite sides of the weak link region (20a) these superconducting electrode regions (20b, 20c) and the weak link region (20a) being formed on a common plane surface of the substrate (5). The weak link region (20a) is produced by local diffusion of constituent element(s) of the substrate (5) into the thin film (20) of the oxide superconductor in such a manner that a substantial wall thickness of the thin film (20) of the oxide superconductor is reduced at the weak link region (20a) so as to leave a weak link or superconducting channel (10) in the thin film (20) of oxide superconductor over a non-superconducting region (50) which is produced by the diffusion.

Abstract: In a method of manufacturing a superconducting device which has a first thin film of oxide superconductor material formed on a substrate and a second thin film formed on the first thin film of oxide superconductor material, after the second thin film is deposited on the first thin film of oxide superconductor material, a multi-layer structure formed of the first and second thin films is patterned so that a side surface of the first thin film is exposed. In this condition, the whole of the substrate is heated in an O.sub.2 atmosphere or in an O.sub.3 atmosphere so that oxygen is entrapped into the first thin film of oxide superconductor material. Thereafter, the patterned multi-layer structure is preferably covered with a protection coating.

Abstract: A superconducting device has a substrate and a superconducting film formed on the substrate. A surface of the substrate has a first surface portion of which a curvature is constant or changes continuously, a second surface portion of which a curvature is constant or changes continuously, and a third surface portion at which the first and second surface portions meet and at which the curvatures of the first and second surface portions become discontinuous. The superconducting film formed on the surface of said substrate has a grain boundary serving as a junction only in a portion corresponding to the third surface portion of the substrate.

Abstract: There is disclosed a superconductor junction structure comprising: a first superconducting layer of an oxide superconductor formed in a desired pattern on a substrate; a non-superconducting layer of a non-superconductor formed on at least a part of the side faces of the first superconducting layer, a portion of the surface of the substrate near the part, and a top face of the first superconducting layer; and a second superconducting layer of the oxide superconductor formed on the non-superconducting layer, the non-superconducting layer being formed thin at the part, and forming a tunnel barrier.

Abstract: A superconducting element includes a superconducting thin film bridge extending along the surface of a substrate, and a control electrode member for injecting quasi particles into a portion of an intersection region of the superconducting thin film bridge. The intersection region extends across the superconducting thin film bridge in a direction which is perpendicular to the current flow direction of the superconducting thin film bridge. A remaining portion of the intersection region, which is not injected with quasi particles by the control electrode member, operates as a weak-coupling bridge to thereby control the current flow within the superconducting thin film bridge.

Abstract: A superconductor device is provided including a base, a base electrode formed on the base which is made of a Bi-system oxide superconductive material containing an alkaline earth metal, a barrier layer formed on the base electrode which is made of Bi--Sr--Cu--O, a counter electrode formed on the barrier layer which is made of a Bi-system oxide superconductive material containing an alkaline earth metal, a contact electrode formed so as contact with the counter electrode, and a separation layer for separating said contact electrode from said base electrode.

Abstract: An anisotropic superconductor junction device consisting of a lower superconducting layer and an upper superconducting layer separated by a barrier layer, in which the upper and lower superconducting layers and the barrier layer each have a (103) crystal orientation in which the c axis is arranged in the same direction at an angle of 45 degrees relative to the plane of the junction.

Abstract: A stacked Josephson junction device includes a pair of copper oxide superconductor layers and a non-superconductor layer formed between the pair of oxide superconductor layers. The copper oxide superconductor layers are composed of a compound copper oxide having the composition expressed by the general formula:LnBa.sub.2 Cu.sub.3 O.sub.v(where Ln is Y or rare earth element and 6<v.ltoreq.7).The non-superconductor layer is composed of a chemical compound having the composition expressed by the general formula:Bi.sub.2 Y.sub.x Sr.sub.y Cu.sub.z O.sub.w(where x, y, z and w indicate ratio of components0.ltoreq.x.ltoreq.2,1.ltoreq.y.ltoreq.3,1.ltoreq.z.ltoreq.3,6.ltoreq.w.ltoreq.13.

Abstract: Superconducting transition metal oxide films are provided which exhibit very high onsets of superconductivity and superconductivity at temperatures in excess of 40.degree. K. These films are produced by vapor deposition processes using pure metal sources for the metals in the superconducting compositions, where the metals include multi-valent nonmagnetic transition metals, rare earth elements and/or rare earth-like elements and alkaline earth elements. The substrate is exposed to oxygen during vapor deposition, and, after formation of the film, there is at least one annealing step in an oxygen ambient and slow cooling over several hours to room temperature. The substrates chosen are not critical as long as they are not adversely reactive with the superconducting oxide film. Transition metals include Cu, Ni, Ti and V, while the rare earth-like elements include Y, Sc and La. The alkaline earth elements include Ca, Ba and Sr.

Abstract: A SQUID comprises a substrate, a washer of an oxide superconductor thin film formed on a principal surface of the substrate, a hole shaped a similar figure to the washer at the center of the washer, a slit formed between one side of the washer and the hole, and a Josephson junction which connects portions of the washer at the both sides of the slit across the slit. In the SQUID, the ratio of similarity of the washer to the hole ranges 100 to 2500.

Abstract: A thin-film superconductor includes a substrate, a ferroelectric film, and a superconducting oxide film. The ferroelectric film extends on the substrate. The ferroelectric film is made of a crystal contains Bi and O. The superconducting oxide film extends on the ferroelectric film, and containing Bi, Cu, and an alkaline-earth metal element. The superconducting oxide film may contain at least two different alkaline-earth metal elements.

Abstract: c-axis oriented YBa.sub.2 Cu.sub.3 O.sub.7 layers are grown with intervening SrTiO.sub.3 layers bridged over steps at which there is a transformation to a-axis crystal-oriented growth. The multilayer superconductor has YBa.sub.2 Cu.sub.3 O.sub.7 layers which are not thicker than 500 nm while the intervening layers of SrTiO.sub.3 have thicknesses of 20 to 30 nm.

Abstract: An oxide-superconducting device comprises first and second electrodes of oxide-superconductor which are connected through a tunnel barrier layer. The oxide-superconductor is formed on a substrate having a recess, and it includes grain boundaries along the recess. The tunnel barrier layer is formed along the grain boundaries, and it is made of any material of an element F, Cl, Br, I, C, O, S, P or N, a mixture consisting of such elements, and a compound containing such an element, the material being introduced into the grain boundaries and/or lattice interstices near the grain boundaries.

Abstract: A thin film device comprising a substrate and an oxide superconductor film formed thereon, wherein said oxide superconductor film comprises atomic monolayers each composed of at least one kind of element of the oxide superconductor, which are deposited substantially in a vertical direction to the substrate so that the pereodicy of the lattice structure of the oxide superconductor is substantially maintained, and at an intermediate portion of the oxide superconductor film, at least a part of the atoms of the oxide superconductor is substituted by other element in the lattice structure of the oxide superconductor to form a non-superconductor interlayer, and the pereodicy of the lattice structure of the oxide superconductor film is substantially maintained across the interface between the oxide superconductor and said non-superconductor interlayer.

Abstract: A superconducting device includes a first thin film of oxide superconductor material formed on a substrate, a second thin film of insulator material stacked on the first thin film of oxide superconductor material, and a third thin film of oxide superconductor material formed on the second thin film of insulator material. The second thin film of insulator material is formed of an amorphous oxide including the same constituent elements as those of the oxide superconductor material of the first thin film. The second thin film of insulator material is formed by heat-treating the first thin film of oxide superconductor material in a gaseous atmosphere bringing a surface of the oxide superconductor material into an amorphous condition, after the first thin film of oxide superconductor material has been formed on the substrate.

Abstract: A Josephson junction device comprising a single crystalline substrate including a principal surface having two horizontal planes and a smooth slope between the two horizontal planes, and an oxide superconductor thin film formed on the principal surface of the substrate. The oxide superconductor thin film includes a first and a second superconducting portions of a single crystalline oxide superconductor respectively positioned on the two horizontal planes of the substrate, a junction portion of a single crystalline oxide superconductor having a different crystal orientation from the two superconducting portions positioned on the slope of the substrate and two grain boundaries between each of the two superconducting portions and the junction portion. The grain boundaries constitutes one weak link of the Josephson junction.

Abstract: The invention relates to a structured superconductive track and a process for making it from epitaxial high temperature superconductor (HTSC) layers using lift off technique, in which a HTSC track deposited on an elevated substrate region is surrounded by an insulating layer of doped HTSC lying on a lower substrate region, and the substrate region with the superconductive track formed thereon is elevated such that the superconductive track is isolated from the insulating layer.

Abstract: A hysteretic high-T.sub.c trilayer Josephson junction, and a method of forming the same are disclosed. The junction includes lower and upper high T.sub.c superconducting cuprate films separated by a barrier layer, where the thin films each include a molecular junction layer adjacent the barrier layer which is characterized by a high-T.sub.c cuprate stoichiometry and crystal structure, and a flat two-dimensional surface, as evidenced by its electron diffraction pattern using reflected high-energy electron diffraction. The junction and barrier layers in the junction are formed by atomic layer-by-layer deposition.

Abstract: The disclosure relates to a Josephson junction formed by a non-superconducting barrier between two superconducting films of the (R) BaCuO (R=rare earth) group. In order to take advantage of the greater coherence length of superconductors along the CuO planes, i.e. perpendicularly to the long axis "c" of the crystal unit cell, the superconducting film is oriented so that the axis "c" is parallel to the plane of the junction. The device can be applied to Josephson junctions and to SQUIDs.

Abstract: A Josephson break junction device suitable for highly sensitive electronic detecting systems. A superconductor film such as YBa.sub.2 Al.sub.3 O.sub.7 is deposited on a substrate such as a single-crystal MgO. The film is fractured across a narrow strip by at least one indentation in the substrate juxtaposed from the strip to form a break junction. A transducer is affixed to the substrate for applying a bending movement to the substrate to regulate the distance across the gap formed at the fracture to produce a Josephson turned junction effect. Alternatively, or in addition to the transducer, a bridge of a nobel metal is applied across the gap to produce a weak-link junction.

Abstract: A novel method of producing weak-link grain boundary Josephson junctions in high temperature superconducting thin films is disclosed. These junctions are reliably and reproducibly formed on uniform planar substrates (10) by the action of a seed layer (40) placed intermediate the substrate (10) and the superconductor film (20). The superconductor film (22) grown atop the seed (42) is misoriented from the rest of the film (24) by an angle between 5.degree. and 90.degree.. The grain boundary (30) so formed acts as a high quality weak-link junction for superconductor devices. The performance of these junctions can be improved by the addition of buffer layers (50, 60) between the substrate (10) and the superconductor film (20).

Abstract: A microbridge superconductor device includes a substrate, made of a material such as LaAlO.sub.3, having a lower planar substrate surface, an inclined surface having an overall upward inclination of from about 20 to about 80 degrees from the plane of the lower planar substrate surface, and an upper planar substrate surface parallel to the lower planar substrate surface and separated from the lower planar substrate surface by the inclined surface. A layer of a c-axis oriented superconductor material, made of a material such as YBa.sub.2 Cu.sub.3 O.sub.7-x, is epitaxially deposited on the lower planar substrate surface, and has an exposed a-axis edge adjacent the intersection of the lower planar substrate surface with the inclined surface. The a-axis exposed edge is beveled away from the intersection. A layer of a c-axis oriented superconductor material is epitaxially deposited on the upper planar substrate surface, and has an exposed a-axis edge adjacent the inclined surface.

Abstract: Disclosed is an article that comprises a superconductor-insulator (s-i) layer structure. The superconductor material has nominal composition Ba.sub.1-x M.sub.x BiO.sub.3-y (M is K, Rb, or K and Rb, 0.35<x.ltorsim.0.5, 0<y.ltorsim.0.25). In some preferred embodiments the insulator is a Ba- and Bi containing oxide, exemplarily BaBi.sub.2 O.sub.4, Ba.sub.1-x M.sub.x BiO.sub.3 (0.ltoreq.x<0.35), or Ba.sub.1-x Bi.sub.1+x O.sub.3 (0.ltoreq.x.ltorsim.0.5). In other embodiments the insulator is an insulating oxide with the NaCl structure (e.g., Mg.sub.1-x Ca.sub.x O), an insulating perovskite (e.g., BaZrO.sub.3 ), an insulator with the K.sub.2 NiF.sub.4 structure (e.g., Ba.sub.2 PbO.sub.4), an insulating fluoride with the BaF.sub.2 structure (e.g., Ba.sub.1-x Sr.sub.x F.sub.2), or an insulating fluoride with the NaCl structure (e.g., LiF). Disclosed are also advantageous methods of making an article according to the invention.

Abstract: A superconducting tunnel junction is disclosed herein. The superconducting tunnel junction is characterized in that a pair of oxide superconducting layers thereof and a tunnel barrier layer located between the oxide superconducting layers have the same or almost the same crystal structure and the same or almost the same lattice constant in a direction of a, b, or c axis. The layers have good crystallization.

Abstract: Josephson contacts are fabricated in ceramic compounds from classes of high temperature superconductors. The succession of layers in the single-crystal determines the properties of the Josephson contacts. The supercurrent flows in the direction of the crystallographic c-axis. In a category of substances of high temperature superconductors the Josephson contacts are located in the space between each of two copper oxide planes. In a different class of high temperature superconductors the Josephson contacts are located between each of two single copper oxide planes. The electrical properties such as critical supercurrent density, capacitance and shunt resistance or the Josephson contacts are adjusted by controlled addition or controlled withdrawal of oxygen. Using stacks of such intrinsic Josephson contacts within a single-crystal, current-controllable high frequency generators, Josephson voltage normals and SQUIDS can be realized.

Abstract: A method, and the resulting structure, of growing a superconducting perovskite thin film of, for example, YBa.sub.2 Cu.sub.3 O.sub.7-x. A buffer layer of, for example, the perovskite PrBa.sub.2 Cu.sub.3 O.sub.7-y, is grown on a crystalline (001) substrate under conditions which favor growth of a,b-axis oriented material. Then the YBa.sub.2 Cu.sub.3 O.sub.7-x layer is deposited on the buffer layer under changed growth conditions that favor growth of c-axis oriented material on the substrate, for example, the substrate temperature is raised by 110.degree. C. However, the buffer layer acts as a template that forces the growth of a,b-axis YBa.sub.2 Cu.sub.3 O.sub.7-x, which nonetheless shows a superconducting transition temperature near that of c-axis oriented films.

Abstract: Epitaxial heterojunctions formed between high temperature superconductors and metallic or semiconducting oxide barrier layers are provided. Metallic perovskites such as LaTiO.sub.3, CaVO.sub.3, and SrVO.sub.3 are grown on electron-type high temperature superconductors such as Nd.sub.1.85 Ce.sub.0.15 CuO.sub.4-x. Alternatively, transition metal bronzes of the form A.sub.x MO.sub.3 are epitaxially grown on electron-type high temperature superconductors. Also, semiconducting oxides of perovskite-related crystal structures such as WO.sub.3 are grown on either hole-type or electron-type high temperature superconductors.