Berlin 2008 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 20: POSTERS Driven Soft Matter

CPP 20.24: Poster

Wednesday, February 27, 2008, 16:00–18:30, Poster A

Active components at interfaces — •Thomas Fischer¹ and Pietro Tierno² — ¹Experimentalphysik V, Bayreuth, Germany — ²Physics, Barcelona, Spain

We study the motion of paramagnetic colloidal particles placed above magnetic bubble domains of a uniaxial garnet film and driven through the lattice by external magnetic field modulation. An external tunable precessing field propels the particles either in localized orbits around the bubbles or in superdiffusive or ballistic motion through the bubble array. This motion results from the interplay between the driving rotating signal, the viscous drag force and the periodic magnetic energy landscape. We explain the transition in terms of the incommensurability between the transit frequency of the particle through a unit cell and the modulation frequency. Ballistic motion dynamically breaks the symmetry of the array and the phase locked particles follow one of the six crystal directions.