Patent GB-924170-A (GB)
Title: Superconductive circuit component
IPC: H01L39/10
Filed: 1960-07-21
Abstract: 924,170. Superconductive circuits. INTER. NATIONAL BUSINESS MACHINES COR. PORATION. July 21, 1960 [Nov. 3, 1959], No. 25409/60. Class 40 (9). [Also in Group XXXVI] A superconducting element comprises a piezo-electric body having a pair of electrodes on different faces of the bodies, at least one of the electrodes being of superconducting material. When a potential of one polarity is applied between the electrodes the deformation of the superconducting electrode by the piezo-electric body raises its critical temperature while polarity of opposite potential lowers it. In the arrangement shown in Fig. 3, with switch 27 in its upper position and switch 17 open, no potential is applied across the piezo-electric body between electrodes 12A, 11A. Electrode 11A is superconducting and introduces no resistance in series with source 30 and resistor 31. Voltmeter 33 reads zero. When switch 26 is closed the piezo-electric body deforms electrode 11A becomes resistive and the voltage drop across it is indicated by meter 33. With switch 27 in its lower position the temperature may be so adjusted that electrode 11A is normally resistive, closure of switch 26 (which may be electronic or electromechanical) making it superconductive. Fig. 4 shows a bi-stable circuit, each side of which consists of the superconducting electrode applied to the piezoelectric device 11B, 11C, the gate conductor of one of cryotrons K38, K39, the control conductors of the corresponding cryotron in the other path and the control winding of one of read-out cryotrons K41, K40., Consider that initially the circuit in the state where current flow is through superconducting electrode 11C, gate K39, control K38 and read-out control winding K41. A switch 42 is moved to position X from its centre position N, gate 8C is deformed and becomes resistive so that the current from source 35 is shared with gate 8B. The current in gate conductor K38 rises increasing the control current in K39 while that in gate conductor K39 falls and control K38 falls consequently the circuit changes over gate 8B becomes superconducting and 8C wholly resistive. This state of affairs is indicated by the fact that gate K41 is resistive and K40 superconducting. When switch 42 returns to terminal N, gate 8C is again superconducting, but the current remains in the path through 8B until restored to the other path by putting switch 42 to position Y. In the arrangement of Fig. 5, centre-tapped source 61 applies opposite potentials to gate 8D, 8E to make one superconducting and the other resistive according to the position of switch 62, this state of affairs being indicated by read-out cryotrons K58, K59. The circuit is operated just. below the critical temperature but may be operated well above with magnetic biasing to adjust it to just above. In the oscillator of Fig. 6 the potential developed when superconductive element 11F is resistive is amplified in D.C. amplifier 73 and applied to terminal 12F, making the device deform so that 11F becomes superconductive. The voltage applied to amplifier 73 ceases and the cycle is repeated, the voltage pulses being derived at terminals 74, 75.