Breakdown by a magnetic field of the superconducting fluctuations in the normal state: A simple phenomenological explanation

TL;DR

This paper presents a phenomenological explanation for the sharp disappearance of superconducting fluctuations in the normal state under magnetic fields near Hc2(0), based on magnetization measurements and quantum limits.

Contribution

It introduces a simple phenomenological model incorporating quantum uncertainty limits into the Gaussian-Ginzburg-Landau framework to explain experimental observations.

Findings

Superconducting fluctuations sharply vanish near Hc2(0) in low-Tc superconductors.

Quantum limits can phenomenologically explain the disappearance of fluctuations.

Magnetization measurements support the proposed model.

Abstract

We first summarize our recent observations, through magnetization measurements in different low-Tc superconductors, of a rather sharp disappearance of the superconducting fluctuations in the normal state when the magnetic field approaches Hc2(0), the upper critical field extrapolated to T=0K. We propose that a crude phenomenological description of the observed effects may be obtained if the quantum limits associated with the uncertainty principle are introduced in the Gaussian-Ginzburg-Landau description of the fluctuation-induced magnetization.