Characterization of the rotational dynamics of magnetic microdiscs in suspension

Abstract

We present the fabrication and dynamic characterization of magnetic microdiscs suspended in liquid. The free-floating discs function like synchronized micro-shutters when actuated by an external magnetic field. Their motion is monitored via light transmission in response to a rotating magnetic field. We demonstrate that their dynamic rotation depends on the amplitude and the rotation frequency of the applied magnetic field. Consequently, the discs can function as local microsensors of their environment to optically study fluid viscosity change or particles/biological environment interactions.