Voltage relaxation and its influence on critical current measurements

Based on the collective creep model, we numerically studied evolution of el ectric field and current density in superconductors and its influence on tr ansport measurements of critical current. It is shown that many experimenta l facts, such as the dependence of V-I curves on sweeping rate of applied c urrent and voltage relaxation are the results of this evolution. The simula tion results are confirmed by electric transport measurements on Ag-sheathe d Bi2-xPbxSr2Ca2Cu3Oy tapes. Discussions on influences of the voltage relax ation on electric transport measurements including superconducting critical current are made.