Anisotropic Critical Current Density in Superconducting Bi sub 2 Sr sub 2 Ca Cu sub 2 O sub 8 Crystals.

Critical current densities and resistivities were measured in a single crystal of the high-T sub c superconductor Bi sub 2 Sr sub 2 Ca Cu sub 2 O sub 8 within the ab basal plane (||) and along the c direction (ppd). A large anisotropy in critical current density found, J sub (c ||) /J sub (c ppd) ~ 10 sup 3, in quantitative agreement with the large normal- state resistivity anisotropy near T sub c. The data provide strong evidence for a 2D layered structure of metallic planes separated by semi-insulating barriers.