Nucleation of the electroactive β-phase, dielectric and magnetic response of poly(vinylidene fluoride) composites with Fe2O3 nanoparticles

► Multiferroics provide large potential applications. ► Iron oxide magnetic nanoparticles of ~ 15 nm were synthesized. ► Nanoparticle/PVDF multiferroic nanocomposites were prepared. ► Nanoparticles nucleate the piezoelectric β-phase of PVDF. ► Magnetic and dielectric response depends on nanoparticles content.