Flux-flow behavior in high Tc superconductors

We have been exploring flux-flow behavior in high temperature superconductor material by numerically solving Ginzburg-Landau (GL) equation and comparing it to experimental results. Surprisingly, without incorporating phenomenological activation energy and pinning force models and despite the approximate nature of GL equation, the power law IV curves with different exponents are obtained based on the relative magnitudes of normal conductivity sigma and kappa, the ratio between the London penetration depth (lambda) and the coherence length (zeta). Simulations demonstrate that, for typical sigma and kappa values, vortices of opposite magnetic field polarity are created at two boundaries of the high T-c material and when they reach the center, they pass through and are injected into opposite polarity sides. Injection and what it entails shed light on unexplained high T-c behavior, open ways for practical applications, eliminate the need for phenomenological models, help us to understand and predict high T-c flux-flow properties. (C) 2014 AIP Publishing LLC.