Structure and Phase Transition of Josephson Vortices in Anisotropic High-TcSuperconductors

Monte Carlo simulation is performed on high- $T_c$ superconductors in a magnetic field $\perp \hat{\mathbf{c}}$. 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 $\mathrm{XY}$ model, between phases of finite resistivity and of zero $\mathrm{ab}$-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.