Generalized Ginzburg-Landau functional for highT c-superconductors in magnetic field in the critical region

Abstract

Using a generalized Ginzburg-Landau functional, which phenomenologically describes the critical region of a phase transition, we discuss some thermodynamic properties of high T c superconductors for which the critical region is experimentally accessible. For instance, the Little-Parks experiment could indicate entry in the critical region. Some advantages of this approach for superconductors in magnetic field w.r.t. simple scaling theory is discussed also.