Self-assembly of magnetic microparticles in AC magnetic fields. Excitation of the system by an AC magnetic field provides a variety of patterns that can be controlled by adjusting the frequency and the amplitude of the field. At low particle densities the low-frequency magnetic excitation favors cluster phase formation, while high frequency excitation favors chains and netlike structures. For denser configurations, an abrupt transition to the network phase was obtained.
The United States Government has certain rights in this invention pursuant to Grant No. W-31-109-ENG-38 between the United States Department of Energy and The University of Chicago representing Argonne National Laboratories.