Field-responsive colloidal assemblies defined by magnetic anisotropy

Author(s)
Gabi Steinbach, Michael Schreiber, Dennis Nissen, Manfred Albrecht, Ekaterina Novak, Pedro A. Sanchez, Sofia S. Kantorovich, Sibylle Gemming, Artur Erbe
Abstract

Particle dispersions provide a promising tool for the engineering of functional materials that exploit self-assembly of complex structures. Dispersion made from magnetic colloidal particles is a great choice; they are biocompatible and remotely controllable among many other advantages. However, their dominating dipolar interaction typically limits structural complexity to linear arrangements. This paper shows how a magnetostatic equilibrium state with noncollinear arrangement of the magnetic moments, as reported for ferromagnetic Janus particles, enables the controlled self-organization of diverse structures in two dimensions via constant and low-frequency external magnetic fields. Branched clusters of staggered chains, compact clusters, linear chains, and dispersed single particles can be formed and interconverted reversibly in a controlled way. The structural diversity is a consequence of both the inhomogeneity and the spatial extension of the magnetization distribution inside the particles. We draw this conclusion from calculations based on a model of spheres with multiple shifted dipoles. The results demonstrate that fundamentally new possibilities for responsive magnetic materials can arise from interactions between particles with a spatially extended, anisotropic magnetization distribution.

Organisation(s)
Computational and Soft Matter Physics
External organisation(s)
Helmholtz-Zentrum Dresden-Rossendorf, Universität Augsburg, Ural Federal University, Technische Universität Chemnitz
Journal
Physical Review E
Volume
100
No. of pages
10
ISSN
2470-0045
DOI
https://doi.org/10.1103/PhysRevE.100.012608
Publication date
07-2019
Peer reviewed
Yes
Austrian Fields of Science 2012
103015 Condensed matter
Keywords
ASJC Scopus subject areas
Condensed Matter Physics, Statistical and Nonlinear Physics, Statistics and Probability
Portal url
https://ucrisportal.univie.ac.at/en/publications/0bb1e8b5-b14b-4509-9aad-69ad251bdb67