In-situ observation of behavior of magnetic particle clusters during torque transfer between textured magnetic poles

The viscosity of Magneto Rheological Fluid (MRF) is changed by magnetic field. Thus the MRF is used for the devices which control the amount of transfer of force or torque electrically, such as brakes and dumpers[1][2]. In magnetic field, magnetic particles in MRF form clusters are formed along lines of magnetic force and transfer force or torque between the magnetic poles. In other research, the binding force of a single chain is measured by optical tweezers under microscopy[3]. However, behavior such as magnetic particles forming clusters and breaking under stress has not been clarified experimentally or analytically. To date, our group has designed and demonstrated microscopic observation of behavior of magnetic particles[4]. In this study, in-situ observation is performed with textured poles. The morphology of textures such as depth and shape of edges are varied with the aim of enhancement of the torque transfer due to the concentration of magnetic field.