  Langevin dynamics is used to study equilibrium properties of the suspension
of magnetic filaments (chains of nanoparticles permanently crosslinked with
polymers). It is shown that the filament suspension generally has a larger
magnetic susceptibility than the system of unlinked nanoparticles with the same
average particle concentration. However, actual susceptibility gain strongly
depends on length and flexibility of filaments. It is also shown that in a
strong gravitational (centrifugal) field sedimentation profiles of filaments
are less homogeneous than that of unlinked particles. The spatial distribution
of filaments weakly depends on the intensity of interparticle dipole-dipole
interactions.
