Theoretical study of alignment dynamics of magnetic oblate spheroids in rotating magnetic fields

This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by AIP Publishing. The published article can be found at: http://scitation.aip.org/content/aip/journal/pof2/28/6/10.1063/1.4953009Access to this item has been restricted by repository administrators at the request of the publisher until June 30, 2017.Magnetic composites containing anisotropic magnetic particles can achieve properties not possible in corresponding bulk or thin films of the magnetic material. In this work, we discuss how planar magnetic anisotropy may be achieved in a composite by aligning disk-shaped particles in an in-plane rotating magnetic field. Previous efforts have reported a simple model of aligning particles in a high-frequency rotating magnetic field. However, no complete analytic solution was proposed. Here, we provide a full analytic solution that describes the alignment dynamics of microdisks in a rotating field that covers the entire frequency range. We also provide simplified solutions at both high-frequency and low-frequency limits through asymptotic expansions for easy implementation into industrial settings. The analytic solution is confirmed by numerical simulation and shows agreement with experiments