Magnetoelectric coupling in Fe3O4/P(VDF-TrFE) nanocomposites

Nanocomposite films composed of nanoparticles Fe3O4 embedded in copolymers of vinylidene fluoride and trifluoroethylene P(VDF-TrFE) (70/30) have been elaborated. The effect of Fe3O4 content on the cristallinity ratio, dielectric and magnetoelectric properties of the nano-piezo-composites was studied and discussed. Dielectric characterization showed an increase of the permittivity and a decrease of the resistivity with the increasing ratio of nanofillers. Thermal analysis revealed a decrease of the cristallinity of the composite. Poling process was found to be difficult for Fe3O4 contents higher than 1%, because of the low breakdown fields and diminished resistivity with increasing Fe3O4 content. As a consequence, magnetoelectric measurements were conducted only on nanocomposites with Fe3O4 contents lower than 0.5% in the case of poled samples. The optimal value of the first order magnetoelectric (ME) coefficient αp was obtained for a nanoparticles content of 0.3% wt.