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 γ-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 γ-phase crystallinity of all the nanocomposite films with traces of α-PVDF in ≥5 vol% films. The films exhibited superparamagnetic character; the saturation magnetization increased with Sn0.2Fe2.8O4 content (from ≈0.1 to 7 emu/g) with nearly constant coercivity (≈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.