Dynamic Susceptibility of Ensembles of Immobilized Magnetic Nanoparticles

The article is devoted to theoretical studying the dynamic response of ensembles of nanosized ferromagnetic particles immobilized in a nonmagnetic medium to an external field. The main attention of the work is paid to analyzing the effect of interparticle magnetic interactions on the complex magnetic susceptibility of a composite and the intensity of heat generation in it under the action of the alternating magnetic field. The analysis has shown that the dependence of the magnitude of the thermal effect on the parameter of the interparticle magnetodipole interaction is nonmonotonic and passes through a maximum. We hope that this result will help to understand the physical reason for the qualitative contradictions between the conclusions inferred in different studies devoted to the influence of the interparticle interactions on the components of the complex magnetic susceptibility of magnetic composites and the intensity of the heat generation under the action of alternating fields.