Effect of molar concentration of coprecipitating agent on the microstructural and optical properties of manganese ferrite nanoparticles
Cubic spinel ferrite nanoparticles manganese ferrite (MnFe2O4) are synthesized using the co-precipitation method. The structural parameters of all the samples have been studied through X-ray diffraction (XRD) patterns. Field effect scanning electron microscopy micrographs (FESEM) show the formation of highly dense forms of nanoparticles along with spherical morphology. But, at molarities of 1.3 M and 1.6 M, elongated particles were seen. The variation in bond distances with an increase in the molar concentration of NaOH could be attributed to more diffusion of Mn2+ ions and a deviation in the number of oxygen atoms in MnFe2O4. Raman spectra show that A1g band wavenumber shifts towards a higher wavenumber up to 1.3 M. This suggests an increase in bond length and lattice distortion, which is consistent with XRD results. Fourier transform infrared (FTIR) studies indicate that Mn2+ shifts from tetrahedral to octahedral site with an increase in molar concentration. FTIR results demonstrate that the molar concentration of NaOH significantly affects shape of nanoparticles, bond lengths, and amount of Mn2+ ions on the tetrahedral sites of MnFe2O4 nanoparticles.