Driving Paramagnetic Colloidal Assemblies with Magnetic Fields

Controlled and directed colloidal transport is observed when placing paramagnetic colloids in an AC magnetic field.   To achieve controlled swimming at the microscale, the swimmer must be able to make a sequence of deformations that are cyclic but not time reversible.  Two paramagnetic bodies in a circular eccentric rotating magnetic field will move together in a directed manner.  We will describe this method and show how Brownian motion enhances this propulsion.