Observation of viscous flux flow in YBa2Cu3O7-δ low-angle grain boundaries

The dynamics of vortices within an YBa2Cu3O7-delta low-angle grain boundary have been investigated by means of current-voltage measurements with a magnetic field applied in the plane of the boundary. The high electric field regime can be explored without significant heating of the sample because the gauge length for the flux flow is of order the intervortex spacing, enabling the accurate determination of the flux flow resistivity rho(f). It is observed that the well-known phenomenological expression rho(f)/rho(n)approximate to B/B-c2 remains valid. The effect of the anisotropy of the superconductor on flux Row is also experimentally investigated.