Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 55: Networks: From Topology to Dynamics II (joint DY/BP/SOE)

BP 55.8: Talk

Friday, March 20, 2015, 11:30–11:45, BH-N 128

Coarsening dynamics of transient networks in an experiment with dipolar hard spheres — •Armin Koegel and Reinhard Richter — Experimentalphysik 5, Universität Bayreuth, D-95440 Bayreuth, Germany

Permanent magnetic dipoles may self-assemble to linear chains and rings, even without an externally applied magnetic field. This has been investigated for nano-sized particles in ferrofluids; see e.g. [1,2] However, in this system the emerging structures and their dynamics are difficult to observe. Similar aggregates have also been observed in a mixture of glass beads and magnetized steel spheres, which are shaken in a vessel [3]. In the present contribution we focus on the formation of transient networks in this system, when quenching the amplitude of the vibrations [4]. We analyze the evolving networks by the number of spheres in a network cluster, its gyration radius, and its average shortest path length.

1. P.G. De Gennes and A. Pincus, Phys. Kondens. Mater. 1, 189 (1970).
2. T. A. Prokopieva, V. A. Danilov, S. S. Kantorovich, Ch. Holm, Phys. Rev. E 80, 031404 (2009).
3. D. L. Blair, A. Kudrolli, Phys. Rev. E 67, 021302 (2003).
4. http://www.ep5.uni-bayreuth.de/de/research/Magnetic-Soft-Matter/video/ferronetwork.html