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

Abstract

CoFe2O4 nanoparticles embedded on polyvinylidene fluoride (PVDF) matrix shows suitable propertied for practical application as piezoelectric and magnetoelectric transducers. Essential for these applications is the knowledge about the dielectric, ferroelectric and piezoelectric responses of the multiferroic films at high frequencies and low temperatures. This work reports on the effect of ferrite content, temperature and frequency on the dielectric, ferroelectric and piezoelectric responses of magnetoelectric CoFe2O4 nanocomposites. It was observed that for frequencies lower than 100 kHz, no substantial differences are detected on the ɛ’ and ɛ’’ values from composites with CoFe2O4 contents ranging from 5 to 11 wt.%. For higher frequencies (100 kHz - 250 MHz) and at temperatures ranging from 150 K to 400 K the same trend is observed, the ɛ’ and ɛ’’ values are being higher for the composite with 5 wt.% of ferrite content and lower in the composites with 11 wt.%, indicating that after a critical filler loading, the e CoFe2O4 nanoparticles lead to a decrease the dielectric response of the composites at higher frequencies. For all composite compositions increasing temperature leads to lower coercive fields and higher piezoelectric and polarization values.