Magnetodielectric effect of Graphene-PVA Nanocomposites

TL;DR

This study reports on graphene-PVA nanocomposites exhibiting a magnetodielectric effect, with potential applications in nanogenerators, by analyzing their electrical and dielectric properties under magnetic fields.

Contribution

It introduces a novel graphene-PVA nanocomposite with measurable magnetodielectric effects and explains the underlying mechanisms involving Maxwell-Wagner polarization.

Findings

Dielectric constant changed by 1.8% at 1 Tesla magnetic field.

Dielectric behavior follows Debye-type relaxation.

Electrical conduction occurs via hopping between localized states.

Abstract

Graphene-Polyvinyl alcohol (PVA) nanocomposite films with thickness $120 \mu m$ were synthesized by solidification of PVA in a solution with dispersed graphene nanosheets. Electrical conductivity data were explained as arising due to hopping of carriers between localized states formed at the graphene-PVA interface. Dielectric permittivity data as a function of frequency indicated the occurrence of Debye-type relaxation mechanism. The nanocomposites showed a magnetodielectric effect with the dielectric constant changing by 1.8% as the magnetic field was increased to 1 Tesla. The effect was explained as arising due to Maxwell-Wagner polarization as applied to an inhomogeneous two-dimensional,two-component composite model. This type of nanocomposite may be suitable for applications involving nanogenerators.