Dynamic magnetic behaviour of interacting /spl gamma/-Fe/sub 2/O/sub 3/ nanoparticles dispersed in epoxy resin

摘要

The dynamical behaviour of /spl gamma/-Fe/sub 2/O/sub 3/ particles synthesized by a microemulsion route, with an average diameter of 7 nm and dispersed in an epoxy-resin at different concentrations, has been investigated by a.c. magnetic susceptibility measurements (8>f (Hz)>1000). For the most diluted sample, the frequency dependence of the temperatures of the maximum of the in-phase susceptibility follow an Arrhenius law with physical /spl tau//sub 0/ value (10/sup -10/ s). Unphysical, much lower values are found for samples consisting of interacting particles. The results are explained by accounting for the change of interparticle distance and number of particle neighbours.