Effect of microstrain on the magnetic properties of reduced graphene oxide by Fe3O4 nanoparticles: insight from experimental and density functional theory

In this report, we studied the impact of particle size-lattice strain on the magnetic properties of reduced graphene oxide functionalized with iron oxide (rGO: Fe3O4) nanocomposite. The microstrain analysis from X ray diffraction data analysis showed increased microstrain at low atomic concentration of Fe3O4 in rGO. While the effect of rGO functionalization with Fe3O4 leads to overall enhancement of the magnetization (rGO:(17 imes {10}^-6 o) rGO: Fe3O4 (I): (24 imes {10}^-2 o) rGO: Fe3O4 (II): (5.5 imes {10}^-2) emu/g), the microstrain also plays a crucial role. The microstrain-based magnetic enhancement can be attributed to increased defects emanating from Fe atoms. Density function theory calculations showed increased density of state above the Fermi energy, suggesting formation of unoccupied states, which explains the enhanced magnetization. The partial density of state showed C 2p, O 2p and Fe 3d orbital states as the major contributors of the observed magnetic properties.