A finite element program was used to calculate current distributions in superconductors,
assuming a nonlinear (power-law or percolation-type) local dependence of the electrical
field on current density. A bicrystal geometry, which forms the basic building block of (Bi, Pb)
2 Sr 2 Ca 2 Cu 3 O x powder-in-tube tapes and other polycrystalline conductors, was
studied. Current–voltage curves and critical currents were calculated for different
geometrical and electromagnetic parameters. Bicrystals of “brick-wall” and “railway-switch” …