  We investigate the properties of magnetic supracolliodal polymers -- magnetic
filaments (MFs) -- with super-paramagnetic monomers, with and without Van der
Waals (VdW) attraction between them. We employ molecular dynamics (MD)
simulations to elucidate the impact of crosslinking mechanism on the structural
and magnetic response of MFs to an applied external homogeneous magnetic field.
We consider two models: plain crosslinking, which results in a flexible
backbone; and constrained crosslinking, which provides significant stiffens
against bending. We find that for plain crosslinking, even a slight increase of
the central attraction leads to collapsed MF conformations. Structures that
initially exhibit spherical symmetry evolve into cylindrically symmetric ones,
with growing magnetic field strength. Plain crosslinking also allows for
conformational bistability. MFs with constrained crosslinking tend to, instead,
unravel in field. In both crosslinking scenarios, central attraction is able to
hinder low-field magnetic response of MFs, albeit the bistability of plainly
crosslinked MFs manifests itself also in the high-field region.
