Magneto-dielectric behaviour of concentrated magnetic fluid

Strong magnetodielectric effects in magnetorheological elastomers

“…It should be noted that a long-chain model of the magnetodielectric effect developed by Xu Pei-Ying et al 35 has been applied by Kopcansky and coworkers to describe the effect observed in magnetite-based ferrouids. 27,28 This model seems to work well for ferrouids with small concentrations of magnetic particles, so that distances between the magnetic particles are much higher than the particles' size and their interactions can be described in terms of point-like dipoles. In our case the magnetic ller concentration within elastomers is close to percolation and the model of point-like dipoles cannot be applied.…”

“…In particular, a magnetodielectric effect was reported for magnetic uids based on iron nanoparticles in elastomer Isopar-M 25 and in PDMS ferromagnetic gels; 26 however, the change of permittivity did not exceed 15%. Permittivity and magnetodielectric effects in the ferrouids based on the dielectric liquid were studied in a number of publications; [27][28][29][30] the value of permittivity relative change was found to be about 20% in the mineral-oil-based ferrouids with magnetic magnetite nanoparticles. 27 A magnetodielectric effect in Co 3 O 4 nanoparticles within a silica glass has been recently observed 31 to reach only 2% in the magnetic eld of 12 kOe.…”