A Low Temperature Synthesis and Optical Characterization of Mn-Ni Mixed Nanoferrites

Objectives: The presented work investigates the optical properties of Mn-Ni mixed nanoferrites prepared by a low temperature synthesis method. Methods: A series of manganese nickel (Mn-Ni) mixed spinel nanoferrites having chemical formula Mn_1-xNi_xFe₂O₄ (x = 0.1, 0.2, 0.3, 0.4, 0.5) have been synthesized by a simple chemical co-precipitation method. The spinel phase formation of the prepared nanoferrites was confirmed using x-ray diffraction (XRD). Optical properties were investigated using UV-visible absorption spectroscopy recorded in the range 200 to 900 nm. Using the absorption spectra and Tauc's relation, the band gap was estimated. Findings: The prepared nanoferrites possess narrow band gap. It was observed that concentration of nickel has profound effect on the optical band gap. A remarkable decrease in the optical band gap was observed with increasing nickel concentration revealing the tunability of the optical band gap by compositional variation of the nanoferrites. Application: The prepared magnetic nanoparticles owing to its large surface to volume ratio with tunable narrow band gap may find applications in photocatalysis, dye degradation, waste water treatment technology etc.