Investigation of structural and magnetic properties of La doped Co–Mn ferrite nanoparticles in the presence of α-Fe2O3 phase

Abstract

Co0.5Mn0.5LaxFe2-xO4 nano ferrites with x = 0.0, 0.02, 0.04, 0.06, 0.08 and 1.0 have been synthesized by using sol-gel method. The crystalline structure of nano ferrites was examined using the X-ray diffraction and showed the presence of α-Fe2O3 phase along with the spinel phase in all compositions as hematite which it also confirmed from Mössbaur spectra. The crystallite size D and lattice strain have been estimated using the Williamson Hall plot. It is found that the crystallite size decreases with increasing of La content except at x = 0.08 while the strain has fluctuated in sign between plus and minus. Room temperature Mössbaur spectra have been recorded for all compositions. The value of isomer shift for both sites is found between 0.18 and 0.39 mm/s, indicating that Fe ions have a high spin state with Fe3+. It is also noticed that relative area (RA) of sextet B decreases with La3+ substitution, making the Fe3+ ions replaced by La3+ ions leads to decreasing of the average magnetization.