NONHOMOGENOUS TRANSPORT CURRENT-DENSITY AND VOLTAGE DISTRIBUTION IN ISOTROPIC HIGH T-C SUPERCONDUCTORS

Transport mentally for boundary conditions imposing a nonhomogeneous c ut-rent flow. Numerical simulations for the voltage distribution were based on a local nonlinear constitutive relation for the current densi ty and the electric field, predicted by the vortex glass model extende d to a nonhomogeneous current flow, in experiments the voltage drops a t different sample locations were measured as a function of applied cu rrent, in a wide temperature range at low magnetic fields, and both th e linear and the nonlinear regimes were examined. Our results support a local description, where long-range correlations in the millimeter s cale are absent. (C) 1998 Elsevier Science B.V.