Thermal Fluctuation Effects in Magnetophoresis of Superparamagnetic Microbeads.

Thermal fluctuation effects in magnetophoresis of commercial superparamagnetic beads are analyzed. By tracking the trajectories of the beads the distribution functions of their displacements in two perpendicular directions are determined. This allows us to determine simultaneously the mean velocity of the beads and their diffusion coefficient. Magnetic moment of a single bead is found by applying the Einstein relation. Distribution of the magnetic moment values are analyzed for two commercial samples of the superparamagnetic beads. [ABSTRACT FROM AUTHOR]