Vortex decoupling line and its anisotropy in BiSrCaCuO single crystals observed by J(H, T, θ) transport current measurements

Transport critical current densities in single crystals of the strongly anisotropic high-T superconductor BiSrCaCuO were measured in a wide range of temperature, applied field and angles between field direction and c-axis of the crystals, above and below the decoupling line. In the low-field region, below the decoupling line, an analysis of the field and angle dependences of the J allows us to assume a dominance of the collective pinning mechanism, which is similar to that found in moderately anisotropic YBaCuO single crystals. We provide scaling analysis of the J(H, T, θ) dependences to probe the vortex topology and to locate the decoupling line on the H-T-θ diagram.