Thermally Driven Untethered Swimmer Using a Convection Flow with the Eddy Current Loss Due to AC Magnetic Fields

Untethered microswimmers are essential for various applications. Here, we propose a thermally driven untethered swimmer using a convection flow with the eddy current loss due to AC magnetic fields and examine the performance of the swimmer. Specifically, we demonstrate that a floating object with a Cu oblique beam can be moved at a velocity of up to 1.8 mm/s by applying an AC magnetic field of 10.2 mT with a frequency of 11.7 kHz. Furthermore, by measuring the temperature of the Cu plate under the magnetic field, we clarify the role of the eddy current. In addition, we clarify the design concept of the convective swimmer from measurements at various angles of the oblique beam and applied magnetic fields. Our findings should contribute to the development of innovative untethered thermally driven microrobots and microswimmers.