Graphene nanoplatelets/Ni-Co-Nd spinel ferrite composites with improving dielectric properties

Due to their low cost, easy preparation, and outstanding electrical, dielectric, and magnetic properties, spinel ferrites are of enormous scientific and technological importance. Moreover, graphene nanoplatelets (GNPs) are an excellent supporting material for the construction of a wide range of composites. The sol-gel auto combustion (SGAC) route was used to prepare Ni0.5Co0.5Fe1.97Nd0.03O4 (NCNF) ferrite and their composites with GNPs. Single-phase structures were found by X-ray diffraction (XRD) analysis and the crystallite size increased with the insertion of GNPs into the NCNF sample. Raman spectra also confirmed the spinel structure of the ferrites and supported the existence of graphene in the composite. Micrographs indicate that agglomeration decreased in all the samples. It was found for the NCNF/2.5 wt%GNPs composite, the energy bandgap was 1.90 eV, while the temperature coefficient of resistance (TCR) had a value of -4.27 K-1 and the values of the dielectric constant and quality (Q) factor were a maximum. Moreover, the dielectric tangent loss was minimum, and magnetic tangent loss was maximum for the NCNF/2.5 wt%GNPs composite. A saturation magnetization of 108.83 emu/g and 24.06 GHz microwave frequency were observed for NCNF/2.5 wt%GNPs composite. Therefore, the composite NCNF/2.5 wt%GNPs had improved dielectric characteristics making them a promising material for a variety of applications, including microwave frequency operating devices, bolometric devices, and microwave absorbing materials.