Flux Lattice Melting and the onset of H_c2 fluctuations

TL;DR

This paper presents a hydrodynamic theory explaining why flux lattice melting in superconductors occurs near the onset of H_c2 fluctuations, suggesting increased fluctuation strength pushes the melting transition away.

Contribution

It introduces a hydrodynamic argument based on the Hansen-Verlet criterion to explain the relationship between flux lattice melting and H_c2 fluctuations, generalizable beyond high-temperature superconductors.

Findings

Flux lattice melting temperature is close to the onset of H_{c2} fluctuations.

Increased fluctuation strength can push the melting transition away.

The argument is based on hydrodynamic considerations, not specific to high-Tc superconductors.

Abstract

The flux lattice melting temperature in optimally doped YBCO has been shown to be very close to that of the onset of fluctuations around H_{c2}(T). Here, we present a theoretical argument in support of the idea that this occurs because the increased strength of the fluctuations as a function of magnetic field pushes away the first order flux lattice melting transition. The argument is based on hydrodynamic considerations (the Hansen-Verlet freezing criterion). It is not specific to high-temperature superconductors and can be generalized to other systems.