Filamentary Superconducting-Normal-Metal Composites

Abstract
We describe the properties of a composite material consisting of superconducting filaments separated by normal metal barriers. The coupling between superconducting elements, and hence the diamagnetic response, is by proximity effect diffusion through the normal material and increases as the temperature is lowered. This behavior is contrasted with that of Josephson tunnelling in anisotropic structures which has been shown to lead to a decoupling transition. The diamagnetism and critical field behavior of (SN)X, TaSe3, and NbSe3 are compared with the predictions of the model.