Observation of structures of chain vortices inside anisotropic high- Tc superconductors.

In order to elucidate the formation mechanism of unconventional arrangements of vortices in high- Tc superconducting thin films at an inclined magnetic field to the layer plane, we investigated the structures of vortex lines inside the films by Lorentz microscopy using our 1-MV field-emission electron microscope. Our observation results concluded that vortex lines are tilted to form linear chains in YBaCu3O(7,8). Vortex lines in the chain-lattice state in Bi2Sr2CaCu2O(8+delta), on the other hand, are all perpendicular to the layer plane, and therefore only vortices lined up along Josephson vortices form chains.