Bryan, M. T.García-Torres, J.Martin, E. L.Hamilton, J. K.Calero Borrallo, CarlesPetrov, P. G.Winlove, C. P.Pagonabarraga Mora, IgnacioTierno, PietroSagués i Mestre, FrancescOgrin, F. Y.2020-01-132020-01-132019-04-082331-7019https://hdl.handle.net/2445/147684Self-propulsion of magneto-elastic composite microswimmers is demonstrated under a uniaxial field at both the air-water and the water-substrate interfaces. The microswimmers are made of elastically linked magnetically hard Co-Ni-P and soft Co ferromagnets, fabricated using standard photolithography and electrodeposition. Swimming speed and direction are dependent on the field frequency and amplitude, reaching a maximum of 95.1 μm/s on the substrate surface. Fastest motion occurs at low frequencies via a spinning (air-water interface) or tumbling (water-substrate interface) mode that induces transient inertial motion. Higher frequencies result in low Reynolds number propagation at both interfaces via a rocking mode. Therefore, the same microswimmer can be operated as either a high or a low Reynolds number swimmer. Swimmer pairs agglomerate to form a faster superstructure that propels via spinning and rocking modes analogous to those seen in isolated swimmers. Microswimmer propulsion is driven by a combination of dipolar interactions between the Co and Co-Ni-P magnets and rotational torque due to the applied field, combined with elastic deformation and hydrodynamic interactions between different parts of the swimmer, in agreement with previous models.application/pdfeng(c) American Physical Society, 2019MagnetismeFerromagnetismeFotolitografiaMagnetismFerromagnetismPhotolithographyinfo:eu-repo/semantics/article6905292020-01-13info:eu-repo/semantics/openAccess