Optimizing piezoelectric and magnetoelectric responses on CoFe2O4/P(VDF-TrFE) nanocomposites

Magnetoelectric (ME) nanocomposite films composed of magnetostrictive CoFe2O4 nanoparticles with sizes between 35 and 55 nm embedded in P(VDF-TrFE) have been successfully prepared by a solvent casting method. The ferroelectric, piezoelectric, magnetic and ME properties of the nanocomposite and their variation with the wt% of the ferrite filler, thickness of the composite and direction of the applied magnetic field have been investigated. Ferroelectric and piezoelectric properties were improved when a small amount of ferrite nanoparticles was added to the polymeric matrix. Magnetic properties vary linearity with ferrite content. The highest ME response of 41.3 mV cm-1 Oe-1 was found in the composite with 72 wt% when a 2.5 kOe DC field was transversely applied to the sample surface. This value is among the highest reported in two phase particulate polymer nanocomposites. Thickness of the composite has no influence in the ME response, allowing tailoring sensor thickness for specific applications. The good value of the ME coefficient and the flexibility of the films make these composites suitable for applications in ME smart devices. (paper)