Josephson junction character along the c-axis in Bi2Sr2CaCu2O8+δ

Critical currents along the c-axis have been studied in single crystalline Bi2Sr2CaCu2O8+δ in magnetic fields. It is observed that the current-voltage relation has a sudden jump with a characteristic hysteresis, reminiscent of the typical Josephson junction character. The maximum critical current density obtained is approximately 230 A/cm2 at 0 K and it seems to follow the characteristic temperature dependence of the Josephson current. In addition, the angular dependence of the junction resistance as a function of angle between magnetic field and c-axis shows a peculiar sharp peak with a width less than 0.5 , which strongly depends upon the current density and the magnetic field. This new phenomenon very close to the ab-plane is temporarily attributed to the effect of motion of the Josephson vortex. (orig.)