Structural and Electrical properties of (PVDF TrFE)/CoFe2O4 nano-composites

Abstract

In present work, P(VDF-TrFE)/CoFe2O4 nanocomposite free-standing films are prepared, and their structural, electrical and magnetic properties are discussed in detail. CoFe2O4 nanoparticles are synthesized by a low-cost sol-gel method. While, free-standing P(VDF-TrFE)/CoFe2O4 nanocomposite films with varying CoFe2O4 (CFO) concentrations have been prepared using solvent casting (The drying casting method). XRD and FTIR techniques were used for structural analysis. The crystallinity of the films is affected by the addition of cobalt ferrite nanoparticles to P(VDF-TrFE). Fourier transform infrared spectroscopy reveals the presence of the beta-phase in all composite films. Reflectance is measured against energy, reveals the presence of the d-d transition associated with the CFO particles. Ferroelectric response at room temperature is measured by measuring polarization against electric field loops at frequency 10 Hz. P(VDF-TrFE) films show saturated ferroelectric hysteresis loops, indicating that the addition of TrFE monomers caused a high content β-phase. Good ferroelectric response has been achieved for low CFO concentration, while P(VDF-TrFE)/CFO films show non-saturated ferroelectric hysteresis loops at higher concentrations, confirming lossy capacitive behavior. Change in saturation and remanent polarization is observed and discussed in detail as a function of CFO concentration. A detailed analysis of the dielectric properties of P(VDF-TrFE) and P(VDF-TrFE)/CFO are done and their corresponding activation energies has been calculated. Both P(VDF-TrFE) and P(VDF TrFE/CFO) nanocomposite films exhibit significant variations in the magnitude of the dielectric constant. Magnetic moment vs magnetic field loops is measured to observed the magnetic response of P(VDF-TrFE)/CFO nanocomposite films, which show ferromagnetic behavior. Additionally, the variation of magnetic moment due to the inhomogeneous distribution of CFO nanoparticles within the film from the center to the edge of the film is observed.