Critical current of Josephson-coupled systems in perpendicular fields

We calculate the magnetic field and temperature dependence of the critical current density jc along the c axis in Josephson-coupled layered systems when the applied magnetic field is parallel to the c axis. jc decreases with field and temperature because of the thermal fluctuations of the vortices which induce a phase difference across the junctions. The anisotropy ratio 1/ jc acquires a field and temperature dependence. The decoupling phase transition line above which the superconducting current along the c axis vanishes is determined.