Programmable magnetoelastic energy landscapes for autonomous microscopic machines

The function of microscopic machines is determined by the dynamic changes in their conformations. While the past few years have seen unprecedented advances in our ability to create intricate microscopic structures via nanofabrication, folding of biomolecules, or self-assembly, our ability to design dynamic changes in these structures to enhance their function remains highly limited. To uncover design paradigms that enable function in such microscopic structures, it is useful to develop simplified experimental platforms where operating principles can be easily designed and explored. Here, we introduce such a platform based on panels covered with programmable nanomagnetic domains, connected by flexible elastic hinges. We show that the combination of magnetic and elastic parameters gives rise to tunable energy minima that can be accessed by applying an external magnetic field. With this platform, we demonstrate basic paradigms for generating work cycles at the microscale. We first show how multidirectional control of an external magnetic field can be used to guide a device through a three-state work cycle. Alternatively, we demonstrate how gradients in an energy landscape can be used to generate work cycles using an applied magnetic field oscillating along a single degree-of-freedom. This single degree-of-freedom actuation allows us to pump energy in a neutral direction relative to the device motion, such that the physics and machine design dictate how this energy is channeled into locomotion.