The upper critical field of layered superconductors

The results of a theoretical study of the upper critical fields of layered superconducting compounds are presented. It is found that for sufficiently decoupled layers the parallel critical fieldsH_c2,‖ can be quite large compared to those expected with ordinary type II superconductors and essentially determined by the destruction of the superconductivity in the individual superconducting layers. It is found thatH_c2,‖ can be calculated from standard pair breaking theory in terms of a pair breaking parameter appropriate for layered compounds. The pair breaking parameter includes both orbital effects and the effects of Pauli paramagnetism and spin-orbit scattering.