% IMPORTANT: The following is UTF-8 encoded. This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.
@ARTICLE{Mller:173113,
author = {Müller, Kathrin and Osterman, Natan and Babic, Dusan and
Likos, C. N. and Dobnikar, Jure and Nikoubashman, A.},
title = {{P}attern {F}ormation and {C}oarse-{G}raining in
{T}wo-{D}imensional {C}olloids {D}riven by {M}ultiaxial
{M}agnetic {F}ields},
journal = {Langmuir},
volume = {30(18)},
issn = {0743-7463},
address = {Washington, DC},
publisher = {ACS Publ.},
reportid = {FZJ-2014-06526},
pages = {5088-5096},
year = {2014},
abstract = {We study the pattern formation in a two-dimensional system
of superparamagnetic colloids interacting via spatially
coherent induced interactions driven by an external
precessing magnetic field. On the pair level, upon changing
the opening angle of the external field, the interactions
smoothly vary from purely repulsive (opening angle equal to
zero) to purely attractive (time-averaged pair interactions
at an opening angle of 90°). In the experiments, we
observed ordered hexagonal crystals at the repulsive end and
coarsening frothlike structures for purely attractive
interactions. In both of these limiting cases, the dense
colloidal systems can be sufficiently accurately described
by assuming pairwise additivity of the interaction
potentials. However, for a range of intermediate angles,
pronounced many-body depolarization effects compete with the
direct induced interactions, resulting in inherently
anisotropic effective interactions. Under such conditions,
we observed the decay of hexagonal order with the
concomitant formation of short chains and percolated
networks of chains coexisting with free colloids. In order
to describe and investigate these systems theoretically, we
developed a coarse-grained model of a binary mixture of
patchy and nonpatchy particles with the ratio of patchy and
nonpatchy colloids as the order parameter. Combining genetic
algorithms with Monte Carlo simulations, we optimized the
model parameters and quantitatively reproduced the
experimentally observed sequence of colloidal structures.
The results offer new insight into the anisotropy induced by
the many-body effects. At the same time, they allow for a
very efficient description of the system by means of a
pairwise-additive Hamiltonian, whereupon the original,
one-component system features a two-component mixture of
isotropic and patchy colloids.},
cin = {IAS-2 / ICS-2},
ddc = {670},
cid = {I:(DE-Juel1)IAS-2-20090406 / I:(DE-Juel1)ICS-2-20110106},
pnm = {451 - Soft Matter Composites (POF2-451)},
pid = {G:(DE-HGF)POF2-451},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000336020800007},
pubmed = {pmid:24742096},
doi = {10.1021/la500896e},
url = {https://juser.fz-juelich.de/record/173113},
}