Influence of Van der Waals bonds on crystallographic and physical properties of reduced-graphene-oxide/BiFeO₃ nanocomposites

We examined the influence of interfacial Van der Waals vis-a-vis covalent bonds on the crystallographic and physical properties of reduced-graphene-oxide/BiFeO3 nanocomposites. The crystallographic, magnetic, and ferroelectric properties have been measured and it was found that the presence of Van der Waals bonds have rather moderate influence on the structural properties such as distortion, bond lengths and angles, and structural noncentrosymmetry. However, in sharp contrast to the observation made in the case of the nanocomposites containing covalent bonds, presence of Van der Waals bonds results in dramatic decrease in the remanent ferroelectric polarization determined from direct electrical measurements. Van der Waals bonds appear to have changed the characteristics of the BiFeO3-graphene layer interfaces due to either large carrier mobility of the graphene layer and/or generation of strong dead layer. Enhanced functionalities, therefore, could be possible only for covalent bonded oxide-graphene interfaces. (c) 2023 Elsevier B.V. All rights reserved.