Critical current of Josephson-coupled systems in perpendicular fields

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