Electrical, magnetic, and magneto-electric properties of PVDF/ZnFe2O4 polymer nanocomposites

Abstract

In this study, (1–x) Polyvinylidene fluoride (PVDF)/(x) ZnFe₂O₄ (ZF), x = 0, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, & 1.0 polymer nanocomposites (PNC) were prepared. The idea of preparing nanocomposites employing the synthesis method is novel as the thermal treatment is used to control the agglomeration and further cold-pressed method to preserve the spherulites helpful in improved multiferroic properties. A detailed and systematic study on percolation, electrical, magnetic, and magneto-electric properties were performed. Electrical measurements indicate a substantial enhancement in the dielectric constant from 32 to 70 (100 Hz) at the percolation threshold of 0.39 \(\pm\) 0.001 during the insulator-to-metal transition. The percolation exponents [s, s’] were assessed utilizing scaling laws, lying in the universal percolation region. Modulus spectra demonstrated relaxation behavior at the percolation threshold, and the relaxation was fitted with the modified Kohlrausch–Williams–Watts function, yielding a stretching coefficient within the range of [0–1], confirming non-Debye-type relaxation. Notably, percolated samples exhibited improved conductivity, obeying Jonscher’s power law. Additionally, the Arrott plot confirms the ferromagnetic behavior through positive intercepts on the M² axis, and the magnetization is retained in the PNC by the sum property of the composite. The highest magneto-electric coupling coefficient value is about 0.6 mV/cm. Oe is achieved in 0.6PVDF- 0.4ZF nanocomposites at the low frequency of 23-Hz AC field superimposed with 0.5 Tesla DC field due to the higher magnetostriction generated in ferrite at this fraction, resulting in large change in the magneto-electric coupling coefficient.