REDISTRIBUTION OF LOCAL CURRENT DENSITIES IN HIGH-T(C) CERAMICS IN EXTERNAL MAGNETIC-FIELDS

Using a model with Lorentz force induced fluxon motion to describe tra nsport current properties in high-T(c) ceramics, a locally varying cri tical current density j(c)(r) has been predicted. An external magnetic field B(a) applied perpendicular to the transport current shifts the maximum of j(c)(r) from the center position of the sample to that side of the cross section where the self-field B(s) and the external field B(a) have opposite directions. The calculated redistribution of the c ritical current density obtained with the force model is verified expe rimentally by measuring the asymmetric change of the magnetic self-fie ld close to the sample boundaries. A nearly quantitative agreement bet ween model calculation and experiment is found by adjusting a single p arameter.