Motion synchronicity of a micro-magnetic-particle chain in a rotating field

Abstract

A magnetic chain consisted of micro-sized beads in a rotating magnetic field is experimented to observe its motion synchronicity with the external field. If the field frequency is sufficiently high, reverse motion occurs to slow down the average angular speed, so that the chain rotates much slower than the external field. A square field configuration, in which the instantaneous strength and angular speed vary with time within every rotating period, is proposed to improve the chaining stability and the motion synchronicity while a same overall frequency with the conventionally used circular field configuration is preserved.