Magnetic phase evolution and particle size estimation study on nanocrystalline Mg–Mn ferrites

Abstract

The nanocrystalline spinel ferrite compositions of MgxMn1−xFe2O4 (x = 0.0, 0.2, 0.4 and 0.5) system have been synthesized by the chemical co-precipitation route. The structural and magnetic properties have been studied by means of X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and Mossbauer spectroscopic measurements. 57Fe Mossbauer spectra of three specimens, as prepared, annealed at 200 °C and sintered at 1,100 °C, of the studied compositions are recorded and analyzed to study the magnetic phase evolution. The Mossbauer spectra of as-prepared samples show a paramagnetic doublet, annealed samples exhibit simultaneous presence of a central paramagnetic doublet superimposed on two broad magnetic sextets while spectra for sintered samples show two well-resolved Zeeman split sextets corresponding to the Fe3+ ions at the tetrahedral sites and the other due to the Fe3+ ions at the octahedral sites of the spinel lattice along with presence of central doublet. The particle size estimated from the probability versus hyperfine magnetic field distribution curve is in agreement with those determine from XRD and TEM analysis, validates the method employed.