Synthesis Condition and Treatment Assisted Tuning of Structural, Magnetic Properties and Bandgap of Ni Nano Ferrite

Abstract

We report synthesis condition, and thermal treatment assisted tuning of structural, magnetic properties, and bandgap of Ni nano ferrite. Experimental techniques of x-ray diffraction ‘XRD,’ vibration sample magnetometry, Ultraviolet-visible (UV-Vis) diffuse reflectance measurements, Scanning Electron Microscopy ‘SEM,’ Energy Dispersive spectroscopy ‘EDS’ measurements, were used to study the synthesized samples. XRD verify the formation of nano spinel ferrite phase (grain diameter: 38.3-39.2nm), and incorporation of Ni, Fe in spinel lattice, with lattice parameter (0.8345-0.8352nm), which also shows the presence of α -Fe 2 O 3 phase. Results reveal that synthesis condition, and thermal treatment show: a) SEM images with non-homogeneous particle size dispersion, particle agglomeration, while EDS confirms the presence of all elements in studied NiFe 2 O 4 samples, b) non-equilibrium cation distribution, modification of inversion parameter, oxygen parameter, c) strengthening of A-O-B, A-O-A and weakening of B-O-B interaction super-exchange interactions, d) fine-tuning of bandgap (1.39 eV-1.68 eV), and depends on structural properties, e) observed magnetic properties are a collective effect of non-equilibrium cationic distribution; modification of A-O-B, A-O-A, B-O-B super-exchange interactions, and surface spin-canting. Prospective applications based on synthesized nano ferrites are also discussed. Thus, in this work we report, sol-gel auto-combustion synthesis of NiFe 2 O 4 : by varying synthesis conditions (via microwave-assisted sol-gel synthesis, conventional sol-gel synthesis in dry gel form), and post-preparation thermal annealing, to tune structural, magnetic properties and bandgap energy. Prepared samples are studied by x-ray diffraction ‘XRD,’ vibration sample magnetometry, Ultraviolet-visible (UV-Vis) diffuse reflectance measurements, Scanning Electron Microscopy SEM,’ Energy Dispersive spectroscopy ‘EDS’ measurements.