D. Reefman et Hb. Brom, LANGEVIN DYNAMICS SIMULATION OF VORTICES IN A LAYERED SUPERCONDUCTOR, Physica. C, Superconductivity, 213(1-2), 1993, pp. 229-245
We study the dynamics of the vortex lattice with a Langevin dynamics m
ethod in a layered superconductor, for systems of up to 4180 vortices,
subject to periodic boundary conditions. The interaction between the
pancake vortices in each layer is of magnetic origin, and the accompan
ying long-range interaction is dealt with exactly. Temperature is take
n into account by means of a gaussian noise source. Depending on the v
alue of the magnetic field (applied perpendicular to the layers) we ob
serve layer decoupling prior to lattice melting. We calculate the temp
erature dependence of the positional and angular correlation functions
, and several time dependent correlation functions. The obtained resul
ts are compared to simulations for a single layer. Some effects of pin
ning are addressed briefly. In the simulations, we also obtain the NMR
spin-relaxation rates due to thermal motion of the vortices. The rele
vance of this relaxation mechanism for existing systems is discussed,
and the effects of weak pinning on the melting are addressed briefly.