Structure and phase transition of Josephson vortices in anisotropic high-Tc superconductors

Monte Carlo simulation is performed on high-T-c superconductors in a magnetic field ie. By monitoring the temperature dependence of the helicity modulus and the specific heat, we have demonstrated a second-order phase transition, in the universality class of the 3D XY model, between phases of finite resistivity and of zero ah-plane resistivity. Josephson-vortex lattice, glass, and chains waving along the c axis are obtained at lower temperatures depending on the anisotropy and the magnetic field. These results are discussed in consistency with experimental observations.