DEFECTS IN FLUX LATTICES AND FLUX CREEP IN HIGH-T(C) SUPERCONDUCTORS

We have estimated the energy of a dislocation loop and found that it exhibits a strong temperature dependence and extrapolates to zero slightly above a temperature which we have previously identified as the melting temperature of the pure lattice. The magnitude of this energy and its dependence on the temperature, the magnetic field and the Landau-Ginzburg parameter all agree reasonably well with experimental estimates for the activation energy in thermally assisted flux flow at low currents. Estimates of the prefactor of the resistivity due to hopping of the flux loop also agree with experimental results. Our result is the first quantitative estimate of the activation energy.