Mossbauer spectroscopy of NiFe2O4 nanoparticles: The effect of Ni2+ in the Fe3+ local microenvironment in both tetrahedral and octahedral sites

Two samples of combustion synthesized nickel ferrite nanoparticles were characterized using X-ray diffraction, scanning and transmission electron microscopy, magnetization measurements and MOssbauer spectroscopy with a high velocity resolution. It was shown that MOssbauer spectra of nickel ferrite can be well fitted by using ten magnetic sextets related to the different numbers of Ni2+ cations in the Fe3+ local microenvironments in both tetrahedral and octahedral sites supported by calculations of such probabilities. it was shown that increase of the number of Ni2+ cations in the Fe-57 local microenvironment around both sites leads to decrease of the hyperfine field. (C) 2017 Elsevier B.V. All rights reserved.