Structural, dielectric, and magnetic properties of reduced graphene oxide-wrapped MnFe2O4 composites synthesized by in-situ sol-gel autocombustion method

Abstract Herein, the reduced graphene oxide (rGO) wrapped MnFe2O4 (MFO@rGO) composites with different rGO content of 10, 20, 30, and 40 wt% have been synthesized by a one-step in-situ sol-gel autocombustion method. The synthesized composites have been tested for their structural, electrical, dielectric, and magnetic characteristics. The composites are characterized by using standard techniques (XRD, HR-TEM, FTIR, and Raman spectroscopy). The composite having 20 wt% of rGO exhibits the highest value of dielectric constant (e'∼1.32 × 104 at 100 Hz, e'∼143 at 1 MHz) and dc conductivity (σdc = 4.31 × 10−6 Ω−1-cm−1) among the investigated composites. The dipole polarization contribution to the dielectric relaxation behavior of MFO@rGO composites is observed, which arises from the increased vacancy defect dipoles in rGO sheets. The impedance studies show the existence of two different time relaxation phenomena in MFO@rGO composites. The magnetic measurements reveal the superparamagnetic behavior of composites. The saturation magnetization of composites decreases first with the increase in rGO content up to 20 wt% and then increases with a further increase in rGO content. The findings of this research make these composites a potential candidate for various applications such as EMI shielding and energy storage devices.