Motion of Magnetic Chains in a Vibrating Field

This article outlines and illustrates the manipulations and mechanisms of micro magnetic chain by both experiment and simulations. A reversible microchain consisting of superparamagnetic particles whose diameters are about 4.5 micro-meters is formed under a static directional field and manipulated by an additional perpendicular field. We demonstrate the chains appear different behaviors, from rigid body oscillations and bending distortions to rupture failures. The ruptures can be divided into two categories which depend on the breakup position either at center or on two sides. By calculating the induced drag which dominates the distortions and ruptures of the chains, we find that the distortions and ruptures occur at the position between the two particles which sustain significant drag variation.