Interlayer critical current in the vortex state of Bi2Sr2CaCu2O8+delta intrinsic junctions

We measure the current-voltage (I-V) characteristics of the Bi2Sr2CaCu2O8+d elta intrinsic Josephson junctions in the magnetic field parallel to the c- axis. In the liquid phase of vortices, the I-V curve reveals three stages: ohmic relation at low currents, rapid resistive transition and a quasiparti cle branch. If the maximum Josephson current I-c is defined at the transiti on, its field dependence is in quantitative agreement with the recent measu rements on the Josephson plasma frequency omega(P). This leads to the concl usion that both Ic and omega(P) equivalently give the information for the i nterlayer phase coherence. In spite of the finite Josephson current, there appears Lorentz-force-independent dissipation at small currents, indicating that the interlayer critical current is zero in the liquid phase. We discu ss the applicability of the phase-slip mechanism associated with the in-pla ne motion of the vortex pancakes. (C) 1999 Elsevier Science Ltd. All rights reserved.