Field percolation and high current density in 80/20 DyBa2Cu3O7-x/Dy2BaCuO5 bulk magnetically textured composite ceramics

We measured the AC susceptibility of magnetically textured (123) 80%/211(20%) DyBaCuO composite in a special set-up in order to enhance the intergrain contribution. The synthesis process led to very clean ''weak links'' at grain boundaries. At the percolation threshold bulk shielding paths were such that the intergrain critical current density J(c) was above 10(5) A/cm(2). The field dependence of J(c) was understood through an analytical form indicating a distribution of currents similar to the law of clusters at fracture/percolation thresholds.