Fig. 4 depicts the changes of shear viscosities for bare CI based
MRF and CI/OA, CI/DA suspensions differing in surfactant contents
as a function of shear rate in the absence of magnetic field. The
investigated MRFs exhibited non-Newtonian behavior because of
the high particle concentration and tiny remnant magnetization of
the magnetic iron particles despite their soft magnetic characteristics. It is possible to observe that these suspensions show two different shear thinning regions distinguished by a critical
shear rate 0.1s. This shear thinning behavior was attributed to
changes in the internal structure under shear deformation.The
shear viscosity shown in Fig. 4 follows power law behavior