Correlation between structure and magnetic transport mechanisms in YBCO films

This paper studies the striking correlation between nanosized structural pa tterns in YBCO films and macroscopic transport current. A nanosized network of parallel Josephson junctions laced by insulating dislocations is almost mimicking the grain boundary structural network. It contributes to the mac roscopic properties and accounts for the strong intergranular pinning acros s the film in the intermediate temperature range. The correlation between t he two networks enables to find out an outstanding scaling law in the (J(c) ,B) plane and to determine meaningful parameters concerning the matching be tween the vortex lattice and the intergranular defect lattice. Two asymptot ic behaviors of the pinning force below the flux flow regime are checked: t he corresponding vortex phases are clearly individuated.