Effects of the sweep rate of the applied field on the agglomeration of magnetic particles in magnetic fluid film

In this work, the influence of the sweep rates of applied magnetic fields on the agglomeration of magnetic particles in the magnetic fluid film are reported. It was observed that a smaller column agglomerated by magnetic particles results at a higher sweep rate as compared with that at a lower sweep rate. Besides, the magnetic moment per volume inside a column decreases rapidly when the sweep rate is raised from 0 to 15 Oe/s, and almost remains constant as the sweep rate exceeds 20 Oe/s. This variation implies that the packing of magnetic particles inside a column depends on the sweep rate. Thus, the sweep rate is a crucial variable determining the internal structure of columns.