Tumbling Motion Yielding Fast Displacements Of Synthetic Antiferromagnetic Nanoparticles For Biological Applications

Synthetic antiferromagnetic micro/nanoparticles usable for biological applications were recently developed using a top-down approach, made of alternating NiFe layers and non magnetic Ru spacers. We describe here different types of motions of magnetic particles chains, controlled either by field gradients or alternating magnetic fields and combination of both. Of particular interest is a displacement named "tumbling motion" consisting in a combination of rotation and translation, with friction on the bottom surface of the container, as a bicycle wheel on a horizontal surface. This motion yields a translation speed 10-30 times faster than by using conventional gradient of magnetic field. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3633121]