Temperature and frequency dependence of the dielectric and piezoelectric response of P(VDF–TrFE)/CoFe2O4 magnetoelectric composites

Abstract

CoFe₂O₄ nanoparticles embedded in polyvinylidene fluoride–trifluoroethylene (P(VDF–TrFE)) matrix show suit­able properties for practical applications as piezoelectric and magnetoelectric transducers. The knowledge about the dielectric and electromechanical responses of the multiferroic films in a broad frequency and temperature range is essential for applicability. The purpose of this work is to investigate the dielectric, ferroelectric and piezoelectric properties of multiferroic composites based on P(VDF–TrFE) as a host matrix and CoFe₂O₄ as a magnetic filler. Free-standing films with a different concentration of the filler were investigated. The polarization switching was demonstrated for all the compositions. The polarization displacement hysteresis was achieved at different temperatures. The piezoelectric coefficient d₃₃ is not affected by different concentration of ferrite. On the other hand, the composition with the largest weight % of CoFe₂O₄ shows higher coercive fields which is not favourable for applications. This indicates that the optimal content of the filler must be determined and taken into account when optimizing both ferroelectric and magnetoelectric properties.