Numerical simulations of elastic properties of flux-line lattices in high-T/sub c/ superconductors

We propose a quantitative model of the effective interaction between the magnetic flux-lines in a layered superconductor. It is derived from the Lawrence-Doniach model with all of its parameters derivable from experiments. Numerical simulations are performed using the Langevin dynamics technique for parameters suitable for Bi-2212. We studied the elastic properties of flux line lattices with various values of interlayer coupling strength and pinning strengths. We show that the "softening" of the flux-line lattices with increasing temperature is mainly due to the increase of configurational entropy of the lattice. The calculated results show good agreement with experimental observations and provide a unique way to study the properties of flux-line lattices with random pinning.