Title :
High T/sub c/ superconducting step-edge junctions and their properties in millimeter-wave band
Author :
Feng, Y.J. ; Kang, L. ; Wang, X.B. ; Yang, S.Z. ; Zuo, J.P. ; Wang, H.B. ; Xu, W.W. ; Cheng, Q.H. ; Wu, P.H. ; Yan, S.L. ; Zhou, L.
Author_Institution :
Dept. of Electron. Sci. & Eng., Nanjing Univ., China
fDate :
6/1/1995 12:00:00 AM
Abstract :
Superconducting step-edge junctions were fabricated on step-edges in (100) LaAlO/sub 3/ substrates by sputter-deposited epitaxial YBaCuO and TlBaCaCuO thin films. The substrate steps were patterned by ion beam etching using metal film as a mask. The transport properties of the junctions were characterized by four-probe electrical measurements. The critical current-normal resistance product (I/sub c/R/sub N/) was larger than 0.2 mV (77 K) for most of the junctions. Clear Shapiro steps were observed in the current-voltage characteristics of the junctions with 36 GHz or 95 GHz millimeter-wave irradiation. The high frequency properties of these high T/sub c/ Josephson junctions showed that they were quite suitable for the Josephson harmonic mixer used in the digital phase locked millimeter and sub-millimeter wave sources.<>
Keywords :
Josephson effect; barium compounds; calcium compounds; critical currents; high-temperature superconductors; millimetre wave mixers; sputter etching; superconducting device testing; superconducting epitaxial layers; superconducting junction devices; superconducting microwave devices; thallium compounds; yttrium compounds; 36 GHz; 77 K; 95 GHz; Josephson harmonic mixer; LaAlO/sub 3/; LaAlO/sub 3/ substrates; Shapiro steps; TlBaCaCuO; TlBaCaCuO thin films; YBaCuO; YBaCuO thin films; critical current-normal resistance product; current-voltage characteristics; digital phase locked millimeter wave source; four-probe electrical measurements; high T/sub c/ Josephson junctions; high T/sub c/ superconducting step-edge junctions; high frequency properties; ion beam etching; metal film mask; millimeter-wave band properties; millimeter-wave irradiation; sputter-deposited epitaxial films; transport properties; Electrical resistance measurement; Ion beams; Josephson junctions; Sputter etching; Sputtering; Substrates; Superconducting epitaxial layers; Superconducting films; Superconducting thin films; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
