Order parameter of inhomogeneous superconductors

The configuration-averaged thermodynamic free-energy 〈f〉 of an inhomogeneous superconductor is calculated within a Gaussian approximation of the Ginzburg-Landau formalism. The equilibrium order parameter $\text{gy}$ (T) shows a systematic depression below the predicted BCS values, whereas the critical exponent β remains unchanged. These predictions are supported by recent tunneling measurements in A?—A?₂O₃)—Pb junctions done by Gray and Schuller. The small tails observed in these experiments are explained by the existing Josephson coupling between A? and Pb order parameters.