Origin of multiplexing capabilities of multifrequency magnetic ratchets.
Through a combination of theory, numerical simulation, and experiment, we investigate the motion of magnetic beads on the surface of a magnetic ratchet driven by multifrequency fields. Here, we focus on the influence of static forcing terms, which were not included in previous models, and we derive analytical models that show why the static forcing terms are responsible for inducing beads of two different sizes to move in opposite directions on the same ratchet potential. We begin our analysis with the simplest possible forcing model, and we show that the main effect of the static forcing terms is to delay the phase of flux reversal. From there, we move onto the full analysis and theoretically derive the phase range for which opposite motion among two different bead types is achieved. Based on these theoretical results, we conduct experimental investigations that explore the effects of bead size and static forcing coefficient on the direction of bead motion, which confirm most of the expected trends. These results shed light both on past experimental work both by ourselves and others, as well as elucidate the more general multiplexing capabilities of ratchets.
University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai, People's Republic of China. ouyangyuyu@gmail.com
Yuyu
Y
Ouyang
Mukarram A
MA
Tahir
Daniel J
DJ
Lichtenwalner
Benjamin B
BB
Yellen
D003198:Computer Simulation; D060526:Magnetic Fields; D008956:Models, Chemical; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000528:radiation effects*; D009038:Motion; D013314:Stress, Mechanical
D020409:Molecular Motor Proteins