Magnetic characteristics of magnetic compound fluid (MCF) under DC and AC magnetic fields

Abstract We experimentally investigated the magnetic permeability of three intelligent fluids—magnetic fluid (MF), magneto-rheological fluid (MRF), and magnetic compound fluid (MCF)—under an AC magnetic field and their magnetization under a DC magnetic field. MCF is a magnetically responsive fluid composed of MF and MRF, as developed by Shimada in 2001. With the increase in the number of nm-sized magnetite or μm-sized iron particles, the magnetic permeability of the fluids under an AC magnetic field and magnetization under a DC magnetic field increases. These results can be considered to depend on the particle cluster in a solvent. Therefore, we observed the formation of the clusters extracted from the fluids by using the technique proposed by Shimada. When the magnetic permeability under an AC magnetic field and magnetization under a DC magnetic field increase, the size of the clusters becomes smaller and the density of the clusters in the solvent becomes larger.