RESISTIVITY OF HIGH-TEMPERATURE SUPERCONDUCTORS - IS THE VORTEX STATE A LIQUID

We discuss thermally activated resistivity of strongly layered high-temperature superconductors such as Bi2Sr2CaCu2O8 in the limit in which the dominant pinning mechanism is the intrinsic pinning due to the layered structure. From a comparison of our theory with the experimental data we conclude that the vortex state of such superconductors must be disordered over a substantial range of parametersa melted liquid. The magnetic field, the temperature, and the current dependence of the calculated activation energy are consistent with experiments. © 1990 The American Physical Society.