Dielectric dispersion in CoFe2O4/PVDF nanocomposites influenced by ceramic contents and thermal mediation

Abstract

Characteristics like high dielectric constants, ferroelectric and coupled magnetic behaviour when combined in multiferroic materials become quite essential for use in numerous applications including multi-functional devices and also as multi-layer ceramic capacitors. In this context, ceramic polymer nanocomposites of CoFe2O4/polyvilylidene difluoride (CFO/PVDF) are prepared in this work. Energy dispersive X-ray spectra of the samples confirmed the presence of elements in the exact stoichiometric ratio. A field emission scanning electron microscope revealed the minute details of the morphological features of the composite films. In the frequency range of 20 Hz to 20 MHz, as frequency is increased, the dielectric constant (real and imaginary) and tangent loss show a decrease but with the increase in temperature and CFO concentration, the dielectric features show an increase. Electro active regions, resistance and relaxation frequencies of the samples have been explained using complex impedance spectroscopy. As frequency and temperature is increased, the conductivity increases as a result, due to an increase in concentration of CFO nanoparticles. The electric field induced polarization studied by precision ferroelectric tester shows a decreasing trend from a maximum value as some of the samples can show conductivity because polarization versus electric field (P–E) loop is elliptical shaped and these properties are of tremendous value for industrial and commercial applications.