Weak Link Superconducting Switching Apparatus and Method.
DEPARTMENT OF THE NAVY WASHINGTON D C
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The present switch is based upon the use of thermal hysteresis to establish stable voltage and no-voltage states. It is a thin-film proximity effect weak link superconductor having a pair of separated strong superconductor regions linked by a short length of a thin-film weak superconductor, i.e. a material having a critical current and a transition temperature less than the material of the strong regions. Raising of a control current above the critical current current switching produces a voltage across the weak link. Power dissipation then produces a thermal instability causing the voltage to quickly rise and establish a stable voltage state. Temperature rising with power dissipation lowers the critical current of weak link. Magnetic switching can achieve the same results. Subsequent reduction in control current to the lowered critical current produces a second thermal instability and a voltage drop to a stable zero voltage state. The voltage rise and drop are sufficiently fast for use in lieu of solid state devices in high speed digital circuits. Achievable voltage rise time is estimated to be as low as 100 psec. Author
- Electrical and Electronic Equipment