2002/09/30 by A. Engel, Andreas Engel, Hanns Walter Mueller +3 · 2 citations
Computer Science · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Nonlinear Dynamics and Pattern Formation #cond-mat.mtrl-sci #cond-mat.soft #stochastic dynamics and bifurcation
paper · pdf · doi:10.1103/physrevlett.91.060602
4 pages, 3 figures, corrected version, improved figures, to be published in Phys. Rev. Lett
arxiv created 2003/06/23 · openalex publication_date 2003/08/07 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Colloidal suspensions of ferromagnetic nanoparticles, so-called ferrofluids, are shown to be suitable systems to demonstrate and investigate thermal ratchet behavior: By rectifying thermal fluctuations, angular momentum is transferred to a resting ferrofluid from an oscillating magnetic field without net rotating component. Via viscous coupling the noise driven rotation of the microscopic ferromagnetic grains is transmitted to the carrier liquid to yield a macroscopic torque. For a simple setup we analyze the rotation of the ferrofluid theoretically and show that the results are compatible with the outcome of a simple demonstration experiment.