Title :
YBa/sub 2/Cu/sub 3/O/sub 7-x/ Josephson junctions on bicrystal Al/sub 2/O/sub 3/ and SrTiO/sub 3/ substrates
Author :
Vale, L.R. ; Ono, R.H. ; Rudman, D.A.
Author_Institution :
Nat. Inst. of Stand. & Technol., Boulder, CO, USA
fDate :
6/1/1997 12:00:00 AM
Abstract :
Bicrystal grain-boundary junctions (bi-GBJs) have been reproducibly fabricated on SrTiO/sub 3/ (STO) and r-plane Al/sub 2/O/sub 3/ (sapphire) bicrystal substrates. Sapphire bicrystals are candidates for high-frequency applications due to their low dielectric constant and loss tangent. The sapphire bi-GBJs demonstrated resistively shunted junction (RSJ)-like current voltage characteristics, with junction parameters comparable to the STO bi-GBJs and critical current densities Jc/spl sim/10/sup 5/ A/cm/sup 2/. Independent control of junction resistance (R/sub N/) was demonstrated with the use of Au shunt layers. In addition, overlayers such as Au or STO may act to passivate the GBJs and improve long term stability.
Keywords :
Josephson effect; barium compounds; bicrystals; critical current density (superconductivity); grain boundaries; high-temperature superconductors; sapphire; strontium compounds; yttrium compounds; Al/sub 2/O/sub 3/; Au; Au shunt layer; STO substrate; SrTiO/sub 3/; YBa/sub 2/Cu/sub 3/O/sub 7-x/ Josephson junction; YBa/sub 2/Cu/sub 3/O/sub 7/; bicrystal grain boundary junction; critical current density; current voltage characteristics; dielectric constant; dielectric loss tangent; high-frequency applications; normal resistance; passivation; resistively shunted junction; sapphire substrate; stability; Annealing; Critical current; Dielectric substrates; Frequency; Grain boundaries; Josephson junctions; Mixers; Pulsed laser deposition; Voltage; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
