ABSTRACT
The underlying subject of this introductory chapter is the mutual relationship between experimentally observed heat capacity and magnetic susceptibility for superconductors, and the thermodynamic consequences of dissipative or nondissipative conduction of electricity by metals. Normal metals are dissipative conductors of electric current. Superconductors are nondissipative conductors of similar currents. The transition from normal conductor to superconductor involves an explicit change in entropy for the conductor. The recent experimental demonstration of Landauer’s principle, which links thermodynamics and information, by Lutz et al. [1] con-rms the need for a change in system conduction free energy at the phase transition between normal metal and superconductor. We submit that this is one of the central questions that must be addressed in superconductivity. The three subjects introduced here are thus: free energy differences between dissipative and nondissipative conductors; the increased heat capacity of superconductors at the critical temperature, Tc, as compared to the precursor normal metal; and the extreme value of superconductor magnetic susceptibility, –1.0 (no units).
