Title :
Capacitively shunted, hysteretic YBa/sub 2/Cu/sub 3/O/sub 7/ step-edge junctions
Author :
Daly, K.P. ; Burch, J.F. ; Hu, R. ; Lee, A.E. ; Luine, J. ; Pettiette-Hall, C.
Author_Institution :
TRW Space & Technology Group, Redondo Beach, CA, USA
fDate :
3/1/1993 12:00:00 AM
Abstract :
Hysteretic YBa/sub 2/Cu/sub 3/O/sub 7/ step-edge junctions on LaAlO/sub 3/ substrates have been fabricated by shunting intrinsically overdamped junctions with a monolithic capacitor. By comparing the I-V curves of junctions fabricated on the same substrate with and without capacitor counterelectrodes, the authors are confident that the observed hysteresis is due to the shunting capacitor. The capacitor consists of a dielectric layer (SrTiO/sub 3/ or LaAlO/sub 3/), deposited on the YBa/sub 2/Cu/sub 3/O/sub 7/ directly over the step-edge junction and an Ag counterelectrode. Capacitor counterelectrodes ranging in area from 10 mu m*30 mu m to 200 mu m*220 mu m have been investigated. Dielectric layers several tens of nanometers thick have been used. The inferred beta /sub c/ values are as large as 10 at 4 K and decrease with increasing temperature. At 65 K, beta /sub c/ of 1.3 was observed. The measured beta /sub c/ values are smaller than one would naively calculate. These differences are attributed to the usual limitations of lumped-element circuit analysis and resistive losses.<>
Keywords :
barium compounds; critical currents; high-temperature superconductors; hysteresis; superconducting junction devices; yttrium compounds; 4 K; 65 K; Ag counterelectrode; I-V curves; LaAlO/sub 3/ substrate; SrTiO/sub 3/ dielectric layer; capacitively shunted junction; hysteretic YBa/sub 2/Cu/sub 3/O/sub 7/ step edge junction; lumped-element circuit analysis; monolithic capacitor; resistive losses; Bandwidth; Capacitors; Critical current; Dielectrics; High temperature superconductors; Logic; Magnetic hysteresis; Pulsed laser deposition; Testing; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
