Abstract: The various embodiments described herein include methods, devices, and systems for fabricating and operating transistors. In one aspect, a transistor includes: (1) a semiconducting component configured to operate in an on state at temperatures above a semiconducting threshold temperature; and (2) a superconducting component configured to operate in a superconducting state while: (a) a temperature of the superconducting component is below a superconducting threshold temperature; and (b) a first current supplied to the superconducting component is below a current threshold; where: (i) the semiconducting component is located adjacent to the superconducting component; and (ii) in response to a first input voltage, the semiconducting component is configured to generate an electromagnetic field sufficient to lower the current threshold such that the first current exceeds the lowered current threshold, thereby transitioning the superconducting component to a non-superconducting state.

Abstract: A superconducting switch is provided in which the structural strength of the superconducting switch is kept, and thermal efficiency between a superconducting film and a heater is high when an ON state (superconducting state) and an OFF state (normal conducting state) of the superconducting switch are switched. The superconducting switch includes a substrate, a heater for generating heat by energization, a conductive film, and a MgB2 film evaporated on the conductive film. The heater, the conductive film and the MgB2 film are laminated in this order on one surface of the substrate.

Abstract: The present invention is directed, inter alia, to a switch comprising: (A) a superconducting material whose field cooled and zero field cooled ac permittivities differ from each other, and whose field cooled and zero field cooled ac susceptibilities differ from each other, in a range of temperature below the superconducting transition temperature of the material; (B) means for applying a static magnetic field to said material; (C) means for controllably applying to said material an oscillating magnetic field of a magnitude effective to convert said material from a state exhibiting filed cooled permittivity to a state exhibiting zero field cooled permittivity; and (D) means for applying to said material a heat pulse effective to convert said material from a state exhibiting zero field cooled permittivity to a state exhibiting field cooled permittivity, said switch operating between a superconducting zero field cooled state and a superconducting field cooled state.

Abstract: A hybrid superconducting-semiconducting field effect transistor-like circuit element comprised of a superconducting field effect transistor and a closely associated cryogenic semiconductor inverter for providing signal gain is described. The hybrid circuit functions nearly as an ideal pass gate in cryogenic cross-bar applications.

Abstract: A superconducting switch is composed of anisotropic magnetic material. The switch has a first superconducting section, a variable resistive section and a second superconducting section. An external magnetic field is applied so that the first and second superconducting sections remain superconducting and the resistive section changes resistance when the magnetic field applied exceeds the critical field of the variable resistance section. The different critical field regions are achieved by exploiting the natural critical field anisotropy of the ceramic superconductors (a previously unobserved phenomena in metal superconductors). By making the different sections with different orientations they will exhibit different critical field valves for a given direction of applied fields. The state of the switch is changed by either increasing or decreasing the external magnetic field about the critical field value of the resistive section of the switch.

Abstract: A HTS switch includes a HTS conductor for providing a superconducting path for an electrical signal and an serpentine wire actuator for controllably heating a portion of the conductor sufficiently to cause that portion to have normal, and not superconducting, resistivity. Mass of the portion is reduced to decrease switching time.

Abstract: A logic circuit device includes a superconductive body formed of a ceramic superconductive material. The ceramic superconductive material has random grain boundaries which act as weak couplings. The ceramic superconductive material also has a magneto-resistive property. There is at least one conductor arranged near the ceramic superconductive body in order to exert a magnetic field on the ceramic superconductive body. The ceramic superconductive body changes its resistance in response to the magnetic field generated by the conductor. The ceramic superconductive body can be used as part of a logic circuit.

Abstract: A device having superconductive and resistive states including an element comprising a high temperature superconductive material having a first (high) state with a first (high) critical current density and having a second (low) state with a second (low) critical current density, wherein the second (low) critical current density is less than the first (high) critical current density. A transient pulse generator applies a transient pulse to the element. The transient pulse changes the state of the element between the first (high) and second (low) states, the element being superconductive in the first (high) state, and the element being resistive in the second (low) state. A YBa.sub.2 Cu.sub.3 O.sub.7-x or YBa.sub.2 Cu.sub.3 O.sub.7-x -Ag compound exhibiting bifurcation of its critical current density versus temperature curve. A process for the production of a YBa.sub.2 Cu.sub.3 O.sub.7-x or YBa.sub.2 Cu.sub.3 O.sub.

Abstract: A superconducting non-linear device comprising a superconducting conductor, a current source associated with the conductor for applying to the conductor a bias current, and a control device associated with the current source for selectably varying the bias current between a first value below the critical current for the conductor means and a second value above the critical current. The non-linear device is a switching device comprising a switching element in the form of a superconducting film, a terminal for inputting a signal to the switching element, a terminal for outputting a signal from the switching element, and a circuit for applying a DC bias current to the switching element and for causing the DC bias current to vary between a first value below the critical current for the superconducting film and a second value above the critical current.

Abstract: A superconductive switching device includes an elongated gate which is circumferentially spirally overwound by a trigger. Both the gate and the trigger are superconductive, but the resistance of the trigger is much smaller than the normal resistance of the gate. Only a relatively small current is needed to cause the device to switch from a closed configuration where current flows through the switching device to a closed configuration where current flows to a load. Operation of the switching device is suitable for use with high frequencies and, with such frequencies, the switching device operates in a cyclical manner.

Abstract: A combination of optical interconnect technology with superconducting matal to form a superconducting neural network array. Superconducting material in a matrix has the superconducting current decreased in one filament of the matrix by interaction of the Cooper pairs with radiation controlled by a spatial light modulator. This decrease in current results in a switch of current, in a relative sense, to another filament in the matrix. This "switching" mechanism can be used in a digital or analog fashion in a superconducting computer application.

Abstract: A load is selectively supplied with current from an energy storing inductor shunted by a superconducting device. In the normal and superconducting states, the superconducting device respectively has an impedance greater than and much less than that of the load. Circulating current from the inductor flows through the device while it is in a superconducting state. The load is connected to the inductor and superconducting device so that when the device is in the normal state circulating current in the inductor is swtiched to flow from the device through the load. A solenoid wound on the superconducting structure responds to a current source to induce an axial magnetic field in the structure. The axial magnetic field induces in the structure an azimuthal current having sufficient density to change the device from the superconducting to the normal state.