Trajectory of a Non-Magnetic Particle Transported by a Rotating Magnetic Particle Chain

Transportation of microscale subject is important in the MEMS application. In this paper, movement of a non-magnetic particle driven by a chain consisted of several magnetic particles in a rotational field is experimentally manipulated and observed. The results reveal two distinct motion behaviors of the non-magnetic particle depending on its initial position. For an “outer” particle, whose initial position is at the edge of gyration region, the angular movement is most significant at the timing when contacting with the chain. The net rotating angle of an outer particle per contact remains nearly constant regardless of the length of the rotating chain. Nevertheless, interaction with an “inner” particle, whose initial position is well covered by the gyration, would cause the chain drifting, so that its radial distance to the rotational origin varies continuously. As a result, the overall movement of an inner particle follows a spiral-like trajectory with varying radius in each cycle. Based on the experimental measures, a kinematic model is developed, which enables to numerically predict the trajectory of a non-magnetic particle.