Field synchronized bidirectional current in confined driven colloids

We investigate the collective colloidal current that emerges when strongly confined magnetic microspheres are subjected to a biased, but spatially uniform, precessing magnetic field. We observe a net bidirectional current composed of colloidal particles which periodically meet assembling into rotati...

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Detalles Bibliográficos
Autores: Meng, Fanlong, Ortiz-Ambriz, Antonio, Massana-Cid, Helena, Vilfan, Andrej, Golestanian, Ramin, Tierno, Pietro
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2020
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/149287
Acceso en línea:https://hdl.handle.net/2445/149287
Access Level:acceso abierto
Palabra clave:Col·loides
Camps magnètics
Moviment brownià
Colloids
Magnetic fields
Brownian movements
Descripción
Sumario:We investigate the collective colloidal current that emerges when strongly confined magnetic microspheres are subjected to a biased, but spatially uniform, precessing magnetic field. We observe a net bidirectional current composed of colloidal particles which periodically meet assembling into rotating dimers, and exchange their positions in a characteristic, 'ceilidh'-like dance. We develop a theoretical model which explains the physics of the observed phenomena as dimer rupture and onset of current, showing agreement with Brownian dynamic simulations. By varying the tilt angle and the frequency of the applied field, we discover two separate transport mechanisms based on different ways the dimers break up during particle transport. Our results demonstrate an effective technique to drive microscale matter by using a combination of confinement and homogeneous field modulations, not based on any gradient of the applied field.