Regensburg 2022 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
DY: Fachverband Dynamik und Statistische Physik
DY 11: Granular Matter and Contact Dynamics
DY 11.1: Vortrag
Montag, 5. September 2022, 15:30–15:45, H19
Measuring the coarsening dynamics of ferromagnetic granular networks under impact of a vertical magnetic field — Matthias Biersack1, Oksana Bilous2, Pedro Sanchez2, Sofia Kantorovich2, and •Reinhard Richter1 — 1University of Bayreuth, Experimental Physics V, 95447 Bayreuth, Germany — 2Computational Physics, University of Vienna, 1090 Vienna, Austria
We are exploring in experiments the aggregation process in a shaken granular mixture of glass and magnetized steel beads, occuring in a horizontal vessel after the shaking amplitude is suddenly decreased. Then the magnetized beads form a transient network that coarsens in time into compact clusters, following a viscoelastic phase separation [1]. A homogeneous magnetic field oriented parallel to the system plane has been observed to "unknot" network structures orthogonal to the field [2]. Here we focus on the impact of a homogeneous magnetic field oriented in vertical direction. For certain field amplitudes we observe a three-phase state, namely mobile glass beads, a grid of isolated steel beads and the coarsening network. Our results demonstrate that via dipole-dipole repulsion the field reduces the mobility of isolated steel beads, thus hindering the growth of the networks. The experimental results are compared with those of numerical simulations.
[1] A. Kögel, et al. Soft Matter, 14 (2018) 1001.
[2] P. A. Sánchez, J. Miller, S. S. Kantorovich, R. Richter, J. Magn. Magn. Mater, 499 (2019) 166182.