Flux Lattice Melting and the onset of H_c2 fluctuations

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.