Abstract: In a superconducting random access memory according to this invention, drive lines such as a word line and a bit line, and a sense line for accessing a memory cell array are each divided into a plurality of blocks and an in-block signal propagation circuit having a level-logic drive circuit and sense circuit each with high load drive capability is used for signal propagation in each of the blocks. Further, for long-distance signal propagation between the blocks, superconducting passive transmission lines formed by single flux quantum (SFQ) devices and capable of high-speed operation are used. As a result, the high-speed operation as a whole is enabled. It is possible to additionally use splitters or confluence buffers and latch circuits and, further, a binary tree structure may be adopted.

Abstract: A superconducting circuit includes a first transformer to produce a first alternating-current output at a secondary-side inductor, a second transformer to produce a second alternating-current output at a secondary-side inductor, a first pulse generating circuit to produce a single flux quantum pulse responsive to the first alternating-current output, a second pulse generating circuit to produce a single flux quantum pulse responsive to the second alternating-current output, and a confluence buffer circuit to merge the single flux quantum pulses from the pulse generating circuits, wherein each of the pulse generating circuits includes a superconducting loop including the secondary-side inductor, a first Josephson junction situated in the superconducting loop to generate the single flux quantum pulse, and a second Josephson junction situated in the superconducting loop, a threshold value of the second Josephson junction for an electric current flowing through the secondary-side inductor being different from tha

Abstract: A Josephson device includes a first superconducting electrode layer, a barrier layer and a second superconducting electrode layer that are successively stacked. The first and second superconducting electrode layers are made of an oxide superconductor material having (RE)1(AE)2Cu3Oy as a main component, where an element RE is at least one element selected from a group consisting of Y, La, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu, and an element AE is at least one element selected from a group consisting of Ba, Sr and Ca. The barrier layer is made of a material that includes the element RE, the element AE, Cu and oxygen, where in cations within the material forming the barrier layer, a Cu content is in a range of 35 At. % to 55 At. % and an RE content is in a range of 12 At. % to 30 At. %, and the barrier layer has a composition different from compositions of the first and second superconducting electrode layers.

Abstract: A high-temperature superconductive device is disclosed, including a ramp-edge junction. The ramp-edge junction includes a first electrode layer (5) that defines the size of the ramp-edge junction and a second electrode layer (6). The width of the second electrode layer (6) is greater than the width of the first electrode layer (5). The first electrode layer (5) and the second electrode layer (6) touch in part, and are separated via a first insulation layer (7) in remaining part. Because the ramp-edge junction includes the first electrode layer (5) and the second electrode layer (6), the inductance of the ramp-edge junction can be reduced with the critical current density Jc being kept at a high level.

Abstract: The present invention provides a superconducting device including a substrate, a first superconducting pattern formed on the substrate, an insulating pattern formed on the first superconducting pattern, and a second superconducting pattern formed at the uppermost level in the multilayered superconducting pattern. A barrier layer of a Josephson junction is formed on the lower side of, or within the second superconducting pattern. The second superconducting pattern constitutes a circuit element on the insulating pattern.

Abstract: A first Josephson junction in a Single Flux Quantum circuit (SFQ circuit) and a second Josephson junction in an interface circuit (latch driver circuit) are formed with junction materials different from each other, and the junction materials are selected so that the hysteresis of the first Josephson junction in a current-voltage characteristic is smaller than the hysteresis of the second Josephson junction in a current-voltage characteristic.

Abstract: A circuit includes a latch circuit including a Josephson junction and configured to perform a latch operation based on a hysteresis characteristic in response to a single flux quantum, a load circuit including load inductance and load resistance and coupled to an output of the latch circuit, and a reset circuit provided between the output of the latch circuit and the load circuit and configured to reset the latch circuit a predetermined time after the latch operation by the latch circuit, wherein the Josephson junction is driven by a direct current.

Abstract: A superconducting junction element has a lower electrode formed by a superconductor layer, a barrier layer provided on a portion of a surface of the lower electrode, an upper electrode formed by a superconductor and covering the barrier layer, and a superconducting junction formed by the lower electrode, the barrier layer and the upper electrode. A critical current density of the superconducting junction is controlled based on an area of the lower electrode.

Abstract: A superconducting circuit includes a first transformer to produce a first alternating-current output at a secondary-side inductor, a second transformer to produce a second alternating-current output at a secondary-side inductor, a first pulse generating circuit to produce a single flux quantum pulse responsive to the first alternating-current output, a second pulse generating circuit to produce a single flux quantum pulse responsive to the second alternating-current output, and a confluence buffer circuit to merge the single flux quantum pulses from the pulse generating circuits, wherein each of the pulse generating circuits includes a superconducting loop including the secondary-side inductor, a first Josephson junction situated in the superconducting loop to generate the single flux quantum pulse, and a second Josephson junction situated in the superconducting loop, a threshold value of the second Josephson junction for an electric current flowing through the secondary-side inductor being different from tha

Abstract: A circuit includes a latch circuit including a Josephson junction and configured to perform a latch operation based on a hysteresis characteristic in response to a single flux quantum, a load circuit including load inductance and load resistance and coupled to an output of the latch circuit, and a reset circuit provided between the output of the latch circuit and the load circuit and configured to reset the latch circuit a predetermined time after the latch operation by the latch circuit, wherein the Josephson junction is driven by a direct current.

Abstract: In a superconducting random access memory according to this invention, drive lines such as a word line and a bit line, and a sense line for accessing a memory cell array are each divided into a plurality of blocks and an in-block signal propagation circuit having a level-logic drive circuit and sense circuit each with high load drive capability is used for signal propagation in each of the blocks. Further, for long-distance signal propagation between the blocks, superconducting passive transmission lines formed by single flux quantum (SFQ) devices and capable of high-speed operation are used. As a result, the high-speed operation as a whole is enabled. It is possible to additionally use splitters or confluence buffers and latch circuits and, further, a binary tree structure may be adopted.

Abstract: At least two ramp-edge-structure Josephson junctions having different critical current densities to one another are provided on a substrate.

Abstract: A circuit includes a latch circuit including a Josephson junction and configured to perform a latch operation based on a hysteresis characteristic in response to a single flux quantum, a load circuit including load inductance and load resistance and coupled to an output of the latch circuit, and a reset circuit provided between the output of the latch circuit and the load circuit and configured to reset the latch circuit a predetermined time after the latch operation by the latch circuit, wherein the Josephson junction is driven by a direct current.

Abstract: To obtain a superconducting driver circuit which can obtain an output voltage of several millvolts or above, can use a DC power source as a driving power source, can form no capacitance between it and a ground plane, and has a small occupation area, the superconducting driver circuit is constructed by superconducting flux quantum interference devices (SQUIDs) each constructing a closed loop having as components two superconducting junctions and an inductor. The SQUIDs share the inductors and are connected in series in three or more stages.

Abstract: At least two ramp-edge-structure Josephson junctions having different critical current densities to one another are provided on a substrate.

Abstract: To provide a planarization method which does not depend upon the size and the density of a wiring pattern and in which a reliable wiring system and a Josephson device can be formed and wiring structure, an insulation layer is planarized by forming a reversal pattern mask of wiring and selectively removing the insulation layer on the wiring.

Abstract: There is provided a superconducting multi-stage sigma-delta modulator including a first superconducting sigma-delta modulator having a first integrator and a first comparator and outputting a sigma-delta modulated signal and a second superconducting sigma-delta modulator having a second integrator and a second comparator and outputting a sigma-delta modulated signal. The first integrator and the second integrator are magnetically coupled.

Abstract: A Josephson junction having a barrier layer sandwiched by two superconductors wherein the superconductors include one or more elements selected from the group of Y, La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu, one or more elements selected from the group of Ba, Sr and Ca, and Cu and oxygen, wherein the two superconductors each include at least five elements with compositions different from each other, or the barrier layer (5) includes one or more elements selected from the group of La, Nd, Sm and Eu, and one or more elements selected from the group of Y, Gd, Dy, Ho, Er, Tm, Yb and Lu.

Abstract: There is provided a superconducting multi-stage sigma-delta modulator including a first superconducting sigma-delta modulator having a first integrator and a first comparator and outputting a sigma-delta modulated signal and a second superconducting sigma-delta modulator having a second integrator and a second comparator and outputting a sigma-delta modulated signal. The first integrator and the second integrator are magnetically coupled.

Abstract: To obtain a superconducting driver circuit which can obtain an output voltage of several millvolts or above, can use a DC power source as a driving power source, can form no capacitance between it and a ground plane, and has a small occupation area, the superconducting driver circuit is constructed by superconducting flux quantum interference devices (SQUIDs) each constructing a closed loop having as components two superconducting junctions and an inductor. The SQUIDs share the inductors and are connected in series in three or more stages.