Flux lattice melting in high-Tc superconductors

Abstract

We derive the wave-vector-dependent elastic moduli for a flux line lattice in compounds with underlying tetragonal crystalline symmetry. We find that it is essential to retain wave-vector dependence of the moduli when dealing with compounds where κ is large, as it is in the high-Tc materials. We use our results to establish a Lindemann criterion for flux lattice melting, which we then compare with experimental data on two materials, and find excellent agreement. The melting curves are suppressed well below the mean-field superconducting-normal transition line and are linear in temperature over a wide range of magnetic fields. The point H=0, T=Tc is approached as 1-T/Tc∼H1/2. The degree of suppression of the melting curves among the different compounds is accounted for in the main by differences in mass anisotropy.

Source-reported materials — not catalogue approval

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