Title :
Focused electron beam damaged YBCO Josephson junctions for THz device applications
Author :
Kim, S.-J. ; Yamashita, T.
Author_Institution :
RIEC, Tohoku Univ., Sendai, Japan
fDate :
6/1/1999 12:00:00 AM
Abstract :
We investigate the high-frequency properties of focused electron beam (FEB) damaged Josephson junctions for THz device applications. The FEB damaged YBCO junctions exhibit the resistively shunted junction (RSJ)-like current-voltage (I-V) curve and the microwave-induced Shapiro steps for all operation temperatures. At 4.2 K, the junctions exhibited the microwave-induced Shapiro steps up to 3 mV in dV/dI-V curves suggesting that the junctions can respond up to about 1.5 THz. To estimate the high frequency performance of the junctions, direct irradiation by a far infrared (FIR) laser at 0.76 THz is carried out and the clear first Shapiro step is observed for the junctions with I/sub C/R/sub N/ product of about 2 mV and at the operation temperature of 6 K.
Keywords :
Josephson effect; barium compounds; electron beam effects; high-temperature superconductors; superconducting microwave devices; yttrium compounds; 0.76 to 1.5 THz; 4.2 to 6 K; YBCO Josephson junction; YBaCuO; current-voltage characteristics; far infrared laser irradiation; focused electron beam damage; high frequency properties; microwave-induced Shapiro steps; resistively shunted junction; terahertz device; Electron beams; Finite impulse response filter; Frequency estimation; Grain boundaries; Josephson junctions; Nonhomogeneous media; Substrates; Superconducting microwave devices; Temperature; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
