title: Dynamics of the field-induced formation of hexagonal zipped-chain superstructures in magnetic colloids.
abstract: Combining nuclear magnetic resonance and molecular dynamics simulations, we unravel the long-time dynamics of a paradigmatic colloid with strong dipole-dipole interactions. In a homogeneous magnetic field, ionic ferrofluids exhibit a stepwise association process from ensembles of monomers over stringlike chains to bundles of hexagonal zipped-chain patches. We demonstrate that attractive van der Waals interactions due to charge-density fluctuations in the magnetic particles play the key role for the dynamical stabilization of the hexagonal superstructures against thermal dissociation. Our results give insight into the dynamics of self-organization in systems dominated by dipolar interactions.
authors.affiliation: Institut für Festkörperphysik, EW 5-4, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Heinrich
authors.forename: A R
authors.initials: AR
authors.lastname: Goñi
authors.forename: A
authors.initials: A
authors.lastname: Smessaert
authors.forename: S H L
authors.initials: SH
authors.lastname: Klapp
authors.forename: L M C
authors.initials: LM
authors.lastname: Cerioni
authors.forename: T M
authors.initials: TM
authors.lastname: Osán
authors.forename: D J
authors.initials: DJ
authors.lastname: Pusiol
authors.forename: C
authors.initials: C
authors.lastname: Thomsen