Fluctuation spectroscopy of granularity in superconducting structures

TL;DR

This paper proposes fluctuation spectroscopy as a novel method to detect granularity in disordered metals near superconducting transition, revealing temperature-dependent resistance behavior and magnetic field sensitivity.

Contribution

It introduces a new spectroscopic approach to identify granularity in superconducting structures through resistance and magnetic field analysis.

Findings

Resistance peaks at certain temperatures due to fluctuation effects

Resistance behavior changes with temperature due to Cooper pair coherence

Magnetic fields influence resistance maximum via a Maki-Thompson mechanism

Abstract

We suggest to use `fluctuation spectroscopy' as a method to detect granularity in a disordered metal close to a superconducting transition. We show that with lowering temperature $T$ the resistance $R(T)$ of a system of relatively large grains initially grows due to the fluctuation suppression of the one-electron tunneling but decreases with further lowering $T$ due to the coherent charge transfer of the fluctuation Cooper pairs. Under certain conditions, such a maximum in $R(T)$ turns out to be sensitive to weak magnetic fields due to a novel Maki -- Thompson type mechanism.