Theory of the Diamagnetism Above the Critical Temperature for Cuprates

TL;DR

This paper models the diamagnetic response above the critical temperature in cuprates by considering local superconducting regions that develop at the pseudogap temperature, explaining the large diamagnetic signals observed experimentally.

Contribution

It introduces a critical-state model for local superconducting domains above $T_c$, providing a theoretical explanation for the observed diamagnetic signals in high-$T_c$ cuprates.

Findings

The model reproduces the magnitude of the observed diamagnetic signals.

Local superconducting regions develop at the pseudogap temperature.

Diamagnetism above $T_c$ can be explained by the critical-state behavior of domains.

Abstract

Recently experiments on high critical temperature superconductors has shown that the doping levels and the superconducting gap are usually not uniform properties but strongly dependent on their positions inside a given sample. Local superconducting regions develop at the pseudogap temperature ($T^*$) and upon cooling, grow continuously. As one of the consequences a large diamagnetic signal above the critical temperature ($T_c$) has been measured by different groups. Here we apply a critical-state model for the magnetic response to the local superconducting domains between $T^*$ and $T_c$ and show that the resulting diamagnetic signal is in agreement with the experimental results.