Theory of magnetoconductivity induced by superconducting fluctuations in anisotropic bulk and fibrous samples

We present a calculation of the fluctuation-induced magnetoconductivity σᶠ(T,H,θ) for an anisotropic bulk and an anisotropic single fiber superconductor in the dirty limit. The purpose of the exercise is to show that, by measuring the variation of σᶠ(T,H,θ) with angle θ and field H, one can easily differentiate between an anisotropic bulk sample and one with fibrous morphology. To illustrate our point we analyze the available experimental data on (SN)ₓ. Our analysis favors a model according to which this metal consists of thin ({~}150 {}) anisotropic fibers.