Measurements and analyses of hysteretic field dependences of critical currents in bicrystalline Nd1Ba2Cu3O7 films

Abstract

We measured the critical current densities (J(cb)) of grain boundaries (GB) in the bicrystalline Nd1Ba2Cu3O7 films Of several misorientation angles under various applied fields. J(cb)'s showed hysteresis curves as functions of fields. The main features of the data were qualitatively consistent with the calculation results. In the calculations, J(cb)'s were expressed as functions of the densities of Josephson vortices, which were estimated from the field distributions around GB. We calculated the field distributions using the Brandt's formula and expressed J(cb) by the modified Kim's model. (C) 2003 Elsevier B.V. All rights reserved.