Dynamic susceptibility of soft ferrogels. Effect of interparticle interaction.

We present the results of theoretical analysis of the dynamic susceptibility of soft elastic-viscous ferrogels with embedded single-domain ferromagnetic particles chaotically distributed in the host medium. The magnetic anisotropy of the particle is supposed to be strong. The effect of magnetic interparticle interaction is a focus of our attention. A differential equation for the statistically averaged (measured) magnetic moment of the particle is derived. Our analysis shows that in the case of a weak applied field, the interparticle interaction increases the composite magnetization and decreases the rate of its remagnetization.