One-dimensional brownian-motion model for transport measurements in high-temperature superconductors

Abstract

Using a one-dimensional model of Brownian motion of vortices over pinning wells, we derive a current-voltage equation assuming a distribution of the effective pinning length. The model describes linear and nonlinear regimes of the E(J) curves in a single-particle description. Thermally activated flux flow and flux flow define the two limits of the dissipative process, respectively, at very low and high current. The pinning relief is described by pinning well depth and pinning well gradient, respectively, which can be checked by resistive and current-voltage measurements. The model is then applied to a YBa2Cu3O7−δ thin film. It provides a phenomenological model of the dissipation induced by transport current