Tricritical Points of Thin Superconducting Films

Abstract

A similarity between the phase diagrams of systems which are believed to exhibit tricritical points and the phase diagram of the transition to the superconducting state of a thin film in a uniform magnetic field suggests the existence of a tricritical point in the latter system. The superconducting case is of interest because the field thermodynamically conjugate to the order parameter can be realized physically. The conjugate field plays an important role in models of the tricritical point but has been believed to be unphysical in systems studied thus far.