Abstract :
Manganese ferrite nanoparticles with dysprosium (Dy) ions substituted for iron ions have been prepared by using a sol–gel method. Substitution of a small fraction Dy for Fe results in the larger magnetocrystallite anisotropy of MnFe2−xDyxO4 (x=0.2, 0.4) nanoparticles than that of MnFe2O4 nanoparticles. The magnetosrystallite anisotropy was enhanced with the increase in the substituted dysprosium content. Combining the result of Mössbauer spectra with ZFC and FC curves, we know clearly that the Dy substitution can modify the anisotropy of MnFe2O4 nanoparticles for its strong spin–orbital coupling. Through this simple substitution, we can control the magnetosrystallite anisotropy of the magnetic nanoparticles and make good use of the products according as we need.