TUNING OF CRYSTALLITE SIZE, ENERGY GAP, AND MAGNETIC PROPERTY OF Mn-DOPED CoFe2O4 NANOPARTICLES

Abstract

This paper focuses on the synthesis and structural, optical, and magnetic characterization of Mn-doped CoFe2O4 nanoparticles synthesized by a simple chemical co-precipitation method. Synthesized magnetic nanoparticles were characterized by XRD, FTIR, UV-Vis, PL, TEM, VSM, and EPR spectroscopy. XRD analysis confirmed the significant reduction in the crystallite size from [Formula: see text][Formula: see text]nm to 10[Formula: see text]nm as the Mn content is increased from 0 to 1. UV-Vis spectra confirmed that the Co–Mn ferrite is a direct bandgap magnetic material that possesses an energy gap from 3.92[Formula: see text]eV to 4.33[Formula: see text]eV. FTIR vibrational frequency observed between 468 and 548 [Formula: see text]confirmed the existence of metal–oxygen bond at tetrahedral and octahedral sites. Photoluminescence spectra confirmed the red emission of the samples from the peak at 680[Formula: see text]nm. TEM analysis suggests that the single domain of CoFe2O4 nanoparticles may vary between 38 and 72[Formula: see text]nm. Composition analysis confirmed the homogeneous mixing of Co, Mn Fe, and O atoms in the synthesized samples. The VSM study confirmed that Mn substitution favors transition from ferromagnetic to superparamagnetic. VSM analysis also confirmed the lessening in saturation magnetization and coercivity on Mn doping. The X-band electron paramagnetic resonance spectrum recorded at room temperature conveys that the superexchange interaction is increased with the increase in Mn concentration.