We have imaged interacting crossing pancake vortex (PV) and Josephson vortex (JV) lattices in highly anisotropic ${\mathrm{B}\mathrm{i}}_2{\mathrm{S}\mathrm{r}}_2{\mathrm{C}\mathrm{a}\mathrm{C}\mathrm{u}}_2{\mathrm{O}}_{8+\delta }$ single crystals under tilted magnetic fields. The dependence of vortex structures on in-plane field is in good quantitative agreement with theoretical predictions, yielding an almost temperature-independent anisotropy parameter of $\gamma =640\pm 25$. We directly confirm that the PV/JV attraction arises from small PV displacements in the presence of JV supercurrents and demonstrate how the existence of quenched disorder leads to indirect JV pinning and dynamic vortex fragmentation.

• Received 12 March 2002

DOI:https://doi.org/10.1103/PhysRevLett.89.217003