Dresden 2009 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 22: Brownian motion and transport II

DY 22.2: Vortrag

Donnerstag, 26. März 2009, 10:30–10:45, ZEU 118

Computer simulation of ratchet transport of colloids on magnetically striped substrates — •Andrea Fortini and Matthias Schmidt — Theoretische Physik II, Universität Bayreuth, Universitätsstraße 30, D-95440 Bayreuth, Germany

We consider a two-dimensional model of paramagnetic colloidal particles on a magnetically patterned substrate. The pattern consists of stripe-like domains with opposite magnetization and wavelengths of the order of several particle diameters. The influence of an external oscillating magnetic field induces directed particle transport via a ratchet mechanism. Using computer simulations we investigate which of the collective transport phenomena observed in experiments with super-paramagnetic particles sedimented on top of a garnet film [P. Tierno et al, Phys. Rev. Lett 100, 148304 (2008)] can be realized with simple model dynamics. In particular the importance of the roles of topology and of curvature of the magnetic domains is addressed.