CATION DISTRIBUTION OF MnFe2O4 NANOPARTICLES SYNTHESIZED UNDER AN INDUCED MAGNETIC FIELD

Nanoparticles of MnFe 2 O 4 have been synthesized under an induced magnetic field by a hydrothermal process. A strong correlation between the cation distribution and the magnetic properties of MnFe 2 O 4 nanoparticles has been identified. From the results of Mössbauer spectroscopy it has been found that the nanoparticles synthesized under zero magnetic fields have 21% inversion occupancy in the tetrahedral sites by Fe 3+ cations, while this value decreases to 10% in the sample formed under a 0.25 T magnetic field. The results explain well the decrease in saturation magnetization from 62.2 emu/g to 52.8 emu/g for the sample formed under a magnetic field. This provides an understanding on how to control the inner structure in order to control the magnetic properties of these spinel ferrite nanoparticles.