ORDER-PARAMETER RELAXATION EFFECTS ON THE I-V CHARACTERISTICS OF HIGH-T-C JOSEPHSON-JUNCTIONS

To probe the origin of excess currents observed in the I-V characteristics of high-T-c Josephson junctions, we studied the time-dependent Ginzburg-Landau (TDGL) model for the high-T-c Josephson junction. In high-T-c superconductors, due to their extremely short coherence length xi(T) and high transition temperature T-c, the order parameter fluctuations as well as relaxation effects are expected to play an important role near the voltage-onset of the Josephson junctions. We performed numerical calculations on the TDGL equations coupled with Maxwell equations with the rigid boundary conditions. The obtained results suggest that excess currents observed in high-T-c single Josephson junctions are related with the relaxation mechanism of the order parameter.