Title :
YBCO SQUIDs fabricated by field-emission electron beam source
Author :
Kim, S.-J. ; Chen, J. ; Mizugaki, Y. ; Nakajima, K. ; Yamashita, T.
Author_Institution :
Res. Inst. of Electr. Commun., Tohoku Univ., Sendai, Japan
fDate :
6/1/1999 12:00:00 AM
Abstract :
We report the applicability of YBa/sub 2/Cu/sub 3/O/sub 7-y/ (YBCO) SQUIDs fabricated by field-emission electron beam source. The junctions show hysteresis and self-resonance steps related to a high frequency resonance in the dc SQUID loop at a voltage V/sub res/=/spl Phi//sub 0//2/spl pi/(LC/2)/sup 1/2/ around 0.3 T/sub c/. The noise spectrum of the SQUIDs was measured with dc-bias schemes at different temperatures and showed values around 10/sup -4/ /spl Phi//sub 0//Hz/sup 1/2/ down to frequencies of 10 Hz at 40 K. The influence of magnetic flux, operating temperatures and flux-voltage transfer factor (|dV/d/spl Phi/|) were investigated. We also tested inverter operation of a dc-biased Josephson logic gate composed of an rf SQUID and a dc SQUID to realize logic circuit performance. Operation of the inverter has been successfully demonstrated although the operating temperature is low, around 10 K.
Keywords :
Josephson effect; SQUIDs; barium compounds; high-temperature superconductors; logic gates; superconducting device noise; superconducting logic circuits; yttrium compounds; 40 to 10 K; YBa/sub 2/Cu/sub 3/O/sub 7/; dc SQUID; dc SQUID loop; dc-bias schemes; dc-biased Josephson logic gate; field-emission electron beam source; flux-voltage transfer factor; high frequency resonance; hysteresis; inverter operation; logic circuit performance; magnetic flux; noise spectrum; operating temperatures; rf SQUID; self-resonance steps; Circuit testing; Electron beams; Inverters; Magnetic hysteresis; Resonance; Resonant frequency; SQUIDs; Temperature; Voltage; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
