Voltage-current characteristics and critical current in Y-doped Bi-2212

Abstract

The characteristic current-voltage (I-V) profiles and critical current I_c of Y-doped Bi-2212 thin film of various concentrations were investigated at different temperatures and applied magnetic fields. The current dependence of voltage shows a nonlinear behavior. This nonlinearity becomes apparent as the applied magnetic field is increased. I_c on the other hand, lowers as the temperature and magnetic field becomes higher. Thermal activation and increase in the number of vortices contributing to vortex motion caused the reduction of I_c. However, Y addition delays the dropping of Ic with applied field (dI_c/dB). Y-doping creates possible defects in the sample which act as pinning centers thereby maintaining a resistanceless flux flow at high transport current.