Title :
Nonlinear AC response of YBCO weak link bridges and quantum circuit theory
Author :
Jiang, H. ; Widom, A. ; How, H. ; Yuan, T. ; Vittoria, C.
Author_Institution :
Northeastern Univ., Boston, MA, USA
fDate :
11/1/1993 12:00:00 AM
Abstract :
Microbridge weak links fabricated on YBCO films with artificial single grain boundary are discussed. The weak link bridges show typical Shapiro step behaviour upon application of microwave radiation at 20 GHz. However, application of signals at 0.1-4 MHz induced nonlinear responses at temperatures below Tc of the weak link bridges. The AC nonlinearity was independent of external magnetic fields and microwave radiation up to 20 GHz. The authors propose a circuit theory model based upon a quantum macroscopic Hamiltonian of the Josephson junction to explain the experimental results. The theoretical predictions are in good agreement with the experimental results
Keywords :
Josephson effect; barium compounds; high-temperature superconductors; superconducting junction devices; superconducting thin films; yttrium compounds; 0.1 to 4 MHz; 20 GHz; AC nonlinearity; Josephson junction; Shapiro step behaviour; YBCO weak link bridges; YBa2Cu3O7; artificial single grain boundary; microbridge weak links; microwave radiation; nonlinear AC response; quantum circuit theory; quantum macroscopic Hamiltonian; Bridge circuits; Circuit theory; Electric variables measurement; Equivalent circuits; Grain boundaries; Quantum mechanics; Resistors; Temperature; Voltage; Yttrium barium copper oxide;
Journal_Title :
Magnetics, IEEE Transactions on
