The development of motility mechanisms controllable on the sub-micron length scale is crucial for both nanorobotics and shapeable magnetoelectronics. We showcase that the nanoscale shape deformation of a flexible magnet can be controlled by its magnetic attributes. Namely, we consider a problem of coupling the geometrical and magnetic degrees of freedom of an elastic loop-shaped nanowire. The minimum energy states of the system essentially depend on its geometric, magnetic, and elastic parameters. Depending on the parameters, one can distinguish two different states: a sufficiently small magnetic ring is magnetized almost uniformly, forming an `onion state’ with two magnetic domain walls. An opposite case of large, rigid magnetic rings is characterized by a flux free vortex state. These findings open new avenues of investigation with deformable, multiply connected magnetic rings for applications in multifunctional nanorobotics.
Yuri Gaididei, Kostiantyn V. Yershov, Denis D. Sheka, Volodymyr P. Kravchuk, Avadh Saxena,
Magnetization-induced shape transformations in flexible ferromagnetic rings,
Phys. Rev. B 99, 014404 (2019),
doi: 10.1103/PhysRevB.99.014404 (pdf)