Critical behavior of layered superconductors

The authors investigate the properties of layered superconductors with Josephson interactions between the layers as the transition temperature is approached, assuming that the coupling between layers is so weak that the transition from two-dimensional to three-dimensional fluctuations comes about in the strong-fluctuation regime. Precisely this situation is realized in high-temperature superconductors made with Bi, Tl, and Pb. They obtain the temperature dependences of the penetration depths and critical currents in various crystallographic directions