Structural, magnetic and electrical properties of electroactive-superparamagnetic PVDF-Sn0.2Fe2.8O4 nanocomposite films

PVDF films embedded with magnetic Sn0.2Fe2.8O4 nanoparticles at selected volume percentages (<20%) were prepared by using a quick and cost-efficient method of solution casting. Using a facile technique of alternate stirring and ultrasonication of the dispersion, the less investigated electroactive gamma-PVDF phase was predominantly obtained in the pure polymer as well as loaded films. X-ray diffraction with Rietveld analysis and TEM imaging established the pure spinel phase and size of nanoparticles, respectively. Additionally, FTIR spectroscopy evidenced the gamma-phase crystallinity of all the nanocomposite films with traces of alpha-PVDF in >= 5 vol% films. The films exhibited superparamagnetic character; the saturation magnetization increased with Sn0.2Fe2.8O4 content (from approximate to 0.1 to 7 emu/g) with nearly constant coercivity (approximate to 16 Oe). The dielectric constant varied between 1 and 8 with low tangent loss (<0.11) in the 100 Hz-1 MHz frequency range. These nanocomposite films hold promise in areas like micro-electronics, interlayer applications, magnetic sensors, actuators and microwave devices.