Viscoelastic ferrogel: Dynamic magnetic susceptibilities

Theoretical model to describe magnetodynamics of a ferrogel, i.e., an assem bly of ferromagnetic nanoparticles embedded in a gel, is proposed. The reor ientations of the particles are determined by the influence of the elastic matrix and the rotational Brownian motion. The set of essential parameters, on which the components of the dynamic magnetic susceptibility tenser depe nd, is discussed. In the framework of the model, absorption of the energy o f an ac field is studied. With allowance for the interaction of elastic and Brownian forces, the effective relaxation times and eigenfrequencies for t he longitudinal and transverse components of the ferrogel magnetization are evaluated.