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Magnetically Induced Rotating Rayleigh-Taylor Instability
Published on: March 3, 2017
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Excluded volume causes integer and fractional plateaus in colloidal ratchet currents
Pietro Tierno1, Thomas M Fischer2
1Estructura i Constituents de la Matèria, Universitat de Barcelona, Avenida Diagonal 647, 08028 Barcelona, Spain and Institut de Nanociència i Nanotecnologia IN2UB, Universitat de Barcelona, 08028 Barcelona, Spain.
Physical Review Letters
|March 4, 2014
Summary
We observed direct ratchet currents in paramagnetic colloids moving over magnetic bubbles. Particle interactions cause stepwise current increases, enabling controlled colloidal transport.
Area of Science:
- Soft matter physics
- Colloidal science
- Magnetohydrodynamics
Background:
- Paramagnetic colloids are utilized in various applications, including microfluidics and targeted drug delivery.
- Understanding their collective behavior under external fields is crucial for designing advanced materials and devices.
Purpose of the Study:
- To investigate the collective transport of paramagnetic colloids driven by a rotating magnetic field above a magnetic bubble lattice.
- To analyze the emergence of ratchet currents and their dependence on field amplitude and particle interactions.
Main Methods:
- Experimental setup involving paramagnetic colloids and a magnetic bubble lattice.
- Application of an external rotating magnetic field to drive particle motion.
- Measurement of colloidal current and its dependence on field amplitude.
Main Results:
- A direct ratchet current was measured, exhibiting a stepwise increase with increasing field amplitude.
- Excluded volume interactions lead to the formation of composite clusters with distinct occupation sites.
- Transient energy minima facilitate particle hopping between clusters, resulting in synchronous and period-doubled transport modes.
Conclusions:
- The study demonstrates a controllable method for collective colloidal transport using magnetic fields and bubble lattices.
- Particle interactions play a key role in dictating the stepwise current response and transport dynamics.
- The findings offer potential for precise manipulation of colloidal systems for technological applications.
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