Mechanically induced cation redistribution and spin canting in nickel ferrite

The structural and magnetic evolution in nickel ferrite (NiFe2O4) caused by high-energy milling are investigated by Mossbauer spectroscopy. It is found that the nanostructural state of the milled NiFe2O4 is characterized by a reduced concentration of iron ions on tetrahedral sites. The degree of inversion in NiFe2O4 is calculated from the subspectral area ratio of both high- and zero-field Mossbauer spectra. Several interesting features are involved in the work, e.g., superparamagnetic relaxation, mechanically induced cation redistribution, and spin-canting effect.