PERCOLATION TRANSITION OF THE VORTEX LATTICE AND C-AXIS RESISTIVITY IN HIGH-TEMPERATURE SUPERCONDUCTORS

We use the three-dimensional Josephson-junction array system as a mode l for studying the temperature dependence of the c-axis resistivity of high-temperature superconductors, in the presence of an external magn etic field H applied in the c direction. We show that the temperature at which the dissipation becomes different from zero corresponds to a percolation transition of the vortex lattice. In addition, the qualita tive features of the resistivity versus temperature curves close to th e transition are obtained starting from the geometrical configurations of the vortices. The results apply to the cases H not equal 0 and H=0 .