(572i) Dynamics of Superparamagnetic Particles Under Rotating Magnetic Fields

Magnetic fields have become a useful tool in directing the assembly of magnetic colloids into hierarchical structures. There is great potential for promising magnetically tunable systems if fundamental knowledge of the collective interactions of these particles under various fields can be obtained. Superparamagnetic particles in particular have gained traction in this pursuit because they behave non-magnetically in the absence of a field and almost instantaneously change their behavior in the presence of a field. However, the exploration of this ability in time-varying magnetic fields, e.g. rotating magnetic fields (RMFs), has yet to be fully elucidated. The dynamics of these types of systems display unique rotational dynamics and properties that give clues to existing magnetic interactions previously neglected in these systems, e.g. magnetic relaxation time. In this work, we elucidate dynamics of superparamagnetic particles under rotating magnetic fields and show there is a large parameter space in magnetic colloidal systems yet to be unveiled. Ultimately, understanding the dynamics of these magnetically assembled systems aids in the expansion of their applications in tunable materials and devices.