Magnetorheology and magnetostriction of isolated chains of nonlinear magnetizable spheres

The magnetic, magnetorheological, and magnetostrictive behavior of nonlinea r magnetizable particles in a nonmagnetic continuum is considered. The magn etization of isolated spheres in a uniform magnetic field is solved exactly for the case where the field-dependent, sphere permeability is given by th e Frohlich-Kennelly equation. This solution is incorporated into a point-di pole model for suspensions composed of aligned, isolated chains of spheres. The suspension magnetization and shear storage modulus reflect the nonline ar magnetization, saturating at large field strengths, consistent with some experimental observations and in agreement with previous calculations. Ana lysis of the magnetostrictive behavior reveals that additional magnetostric tion parameters are required compared to materials whose magnetization is l inear in the applied field. (C) 2001 The Society of Rheology.