Abstract: The dynamics of aggregated chains in magnetorh- elogical suspensions subject to rotating magnetic fields are experimentally studied combining scattering dichroism and video microscopy experiments. When a rotating field is imposed the chainlike aggregates rotate synchronously with the magnetic field. The total number of aggregated particles shows two different behaviors depending on Mason number. For low Mason numbers, it remains almost constant, and above the critical Mason number, the rotation of the field prevents the particle aggregation process from taking place, so the number of aggregated particles decreases with Mason number. A molecular dynamics simulation showing good agreement with the experiments results is also reported.

Key words: Aggregation chain, Magnetorhelogical suspensions, Mason number, Molecular-dynamics, Rotating magnetic fields