Electric and magnetic properties of a composite consisting of silicone rubber and ferrofluid

Abstract

Electric and magnetic properties in the frequency range (500 Hz − 2 MHz) of a composite consisting of silicone rubber and ferrofluid with magnetite particles, in a mass ratio 1/20, were investigated. Structural analysis of nanoparticles within the ferrofluid (FM sample) was performed by XRD diffraction and morphology of composite (SR-FM sample), was investigated by SEM analysis. The frequency dependence of the imaginary component, μ″, of complex magnetic permeability of composite sample exhibits two maxima. These have been associated with the Brownian relaxation process within the ferrofluid drops remained in vesicles of silicone rubber. At the same time, a dielectric relaxation process attributed to the Schwarz relaxation was also highlighted. The mechanical mobility, u, of the charge carriers, u = 1.5∙108 m/sN, from the composite sample, was computed. Based on the complex impedance measurements, the frequency dependence of the conductivity, σ(f), was determined, which respects the Jonscher universal law. The static conductivity, σdc = 2.38∙10-7 S/m, of composite sample, was determined. The results allowed the evaluation of the energy barrier of electrical conduction process, Wm = 0.353 eV and the crossover frequency, ωc = 3.39∙105 rad/s, for composite sample. The performed study is useful in manufacturing magnetic elastomeric composite materials with predetermined properties and for possible technological and biomedical applications.