Magnetotaxis is a well known phenomenon in swimming microorganisms which sense magnetic fields e.g. by incorporating crystalline magnetosomes. In designing artificial active matter with tunable dynamics, external magnetic fields can provide a versatile method for guidance. Here, it is the question what material properties are necessary to elicit a significant response. In this working paper, we document in experiments on self-propelling nematic microdroplets that the weak diamagnetic torques exerted by a sub-Tesla magnetic field are already sufficient to significantly affect the dynamics of these swimmers. We find a rich and nontrivial variety of dynamic modes by varying droplet size, state of confinement and magnetic field strength.
@article{arxiv.2409.14558,
title = {Magnetotaxis in droplet microswimmers},
author = {Martin W. Wagner and Freek Domburg and Carsten Krüger and Jens Meyer and Jiaqi Zhang and Prashanth Ramesh and Corinna C. Maass},
journal= {arXiv preprint arXiv:2409.14558},
year = {2024}
}