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DY: Fachverband Dynamik und Statistische Physik

DY 48: Granular Matter and Contact Dynamics

DY 48.8: Talk

Thursday, March 21, 2024, 16:45–17:00, BH-N 128

Exploring the impact of concentration and applied magnetic field on the diffusion coefficient of ferrogranulate: insights from computer simulations — •Oksana Bilous¹, Pedro Sánchez¹, Ali Lakkis², Reinhard Richter², and Sofia Kantorovich¹ — ¹Computational and Soft Matter Physics, University of Vienna, Vienna, Austria — ²Experimental Physik, University of Bayreuth, Bayreuth, Germany

We study how an applied magnetic field affects the self-diffusion of magnetic particles in a ferrogranulate layer*a composite of glass and steel millimetre-sized particles on a shaken substrate. Initially, the system is maintained in a non-aggregated state through high shaking amplitude, followed by a step-like quench that induces particle aggregation and a slowdown. When an external magnetic field is applied perpendicular to the layer, aggregation is inhibited, prompting an investigation into its impact on particle diffusion. Molecular dynamics simulations model the ferrogranulate as a mixture of Stockmayer and repulsive spheres, with shaking amplitude mimicked by a thermostat. We find that at low applied field values, the system exhibits a bistable gas-liquid regime at high concentrations, while for stronger fields, the system shows no signs of a phase transition, significantly influencing the system dynamics.

Keywords: ferrogranulate system; structural transformation; magnetically driven particle-based systems