• Title/Summary/Keyword: Josephson junctions

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Simulation Results of the 4 stage Single Flux Quantum Voltage Multiplier (4 stage 단자속 양자 Voltage Multiplier의 Simulation 결과)

  • Chu, Hyung-Gon;Jung, Ku-Rak;Kang, Joon-Hee
    • 한국초전도학회:학술대회논문집
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    • v.9
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    • pp.238-241
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    • 1999

  • Analog-to-digital converter has attracted a lot of interests as one of the most prospective area of an application of Josephson Junction technology. Recently, the development of a digital-to-analog converter has been pursued to achieved the high performance. One of the main advantage in using single flux quantum logic in a digital-to-analog converter is the low voltage drop in a single Josephson Junction and hence the resolution of the output voltage of this digital-to-analog converter can be very high. In this work, we have used a software, called WRspice, to study a voltage multiplier circuit which is the basic block in building a digital-to-analog circuit. In simulation, we operated a voltage multiplier with .4 Josephson Junctions per stage and studied the dependence on the circuit bias currents and the circuit inductors of the voltage multiplier. Our simulation results showed a fast operation and reasonable circuit margins.

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Determination of Penetration Depth of Nb Electrodes in $Nb/A1O_x/Nb$ Josephson Junction by Resistive Method ($Nb/A1O_x/Nb$ 조셉슨 접합에서 저항측정을 이용한 Nb 전극의 침투깊이 측정)

  • 김동호;김규태;박종원;황준석;홍현권
    • Progress in Superconductivity and Cryogenics
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    • v.4 no.1
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    • pp.50-54
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    • 2002

  • Penetration depth of Nb electrodes in $Nb/A1O_x/Nb$ Josephson junctions has been measured by resistive method. For a given applied field, the total flux through the junction is temperature dependent because the penetration depth of Nb electrode varies with temperature. If the total flux equals an integral multiple of the flux quantum at certain temperatures, resistive peaks appear at those temperatures. The penetration depth of Nb can be determined by applying the above condition, The temperature dependence of penetration depth was found to be well described by the two-fluid model.

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Operation of a Single Flux Quantum 4-stage Shift Register Fabricated with High $T_c$ Ramp-edge Junction Technology (고온 초전도 경사형 모서리 접합을 이용한 4단 쉬프트 레지스터의 동작)

  • Kim, J. H.;Park, J. H.;Kim, S. H.;Jung, K. R.;Kang, J. H.;Sung, G. Y.;Hahn, T. S.
    • Progress in Superconductivity
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    • v.3 no.1
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    • pp.83-86
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    • 2001

  • We have fabricated a single flux quantum 4-stage shift register with interface-controlled $Y_1$$Ba_2$$Cu_3$$O_{7-x}$(YBCO) Josephson junction. The YBCO Josephson junctions showed RSJ-like current-voltage(I-V) curves at temperatures 45~80K. We tested load and shift operation of shift register with binary data sequences “1000”, “1010”, “1011”, and “1111” at 58K. For all the binary data sequences, the shift register operated successfully. By operating the circuit with proper current pulses, we observed no errors during at least 12 hours operation for all the data sequences.s.

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