Mossbauer studies of nanosize CuFe2O4 particles

Nanocrystalline CuFe2O4 particles are prepared by wet chemical method. The particles of various sizes are obtained by heat treatment in the temperature range 773-1073 K. The room temperature Mossbauer spectrum for all samples shows the presence of both sextet and doublet indicating the presence of superparamagnetic fractions. The isomer shift, quadrupole splitting and hyperfine field values are found to change with particle size. However, these changes in Mossbauer parameters may also be due to the Jahn-Teller effect that essentially arises due to the migration of Cu2+ from tetrahedral sites to octahedral sites resulting in crystal structure change from cubic to tetragonal system. These aspects are studied by using Mossbauer spectroscopy and are correlated to the X-ray diffraction data.