Fluctuation diamagnetism around the superconducting transition in a cuprate crystal with a reduced Meissner fraction

TL;DR

This study investigates fluctuation diamagnetism near the superconducting transition in a cuprate crystal with reduced Meissner fraction, showing that inhomogeneities can be accounted for within the Ginzburg-Landau framework.

Contribution

It demonstrates that structural inhomogeneities and reduced Meissner fraction can be incorporated into the Ginzburg-Landau model to explain diamagnetic behavior in cuprate superconductors.

Findings

Diamagnetism explained by Ginzburg-Landau theory with inhomogeneities

Reduced Meissner fraction does not preclude conventional fluctuation analysis

Structural inhomogeneities influence the superconducting transition behavior

Abstract

The magnetization around the superconducting transition was measured in a Tl$_{0.5}$Pb$_{0.5}$Sr$_2$CaCu$_2$O$_7$ crystal affected by a considerable reduction ($\sim$55%) of its effective superconducting volume fraction but still with a relatively sharp low-field Meissner transition, a behaviour that may be attributed to the presence of structural inhomogeneities. By taking into account these inhomogeneities just through the Meissner fraction, the observed diamagnetism may still be explained, consistently above and below the superconducting transition, in terms of the conventional Ginzburg-Landau approach with fluctuations of Cooper pairs and vortices.