Janus microdimer swimming in oscillating magnetic field

Artificial microswimmers powered by magnetic fields have numerous
applications, such as drug delivery, biosensing for minimally invasive
medicine and environmental remediation. Recently, a Janus microdimer
surface walker that can be propelled by an oscillating magnetic field near
a surface was reported by Li et al.[2018]. To clarify the mechanism for
the surface walker, we numerically studied in detail a Janus microdimer
swimming near a wall actuated by an oscillating magnetic field. The
results showed that a Janus microdimer in an oscillating magnetic field
can produce magnetic torque in the y-direction, which eventually propels
the Janus microdimer along the x-direction near a wall. Furthermore, we
found that the Janus microdimer can also move along a special direction in
an oscillating magnetic field with two orientations without a wall. The
knowledge obtained in this study is fundamental for understanding the
interactions between a Janus microdimer and surfaces in an oscillating
magnetic field and is useful for controlling Janus microdimer motion with
or without a wall.