Combustion Synthesis and Magnetic Studies of Hausmannite,

Abstract:- Hausmannite, Mn3O4, nanoparticles were synthesized successfully via combustion synthesis route with MnCl2.4H2O as manganese source. The samples were characterized to find the structural, functional and magnetic properties by XRD, FT-IR, FT-Raman and VSM respectively. An attempt is made to summarize the detailed field dependent magnetization study of the synthesized material is presented. Structural studies by XRD indicate that the synthesized material as tetragonal crystal structure with size 35nm. FT-IR and FT-Raman analysis revealed stretching vibrations of metal ions in tetrahedral and octahedral co-ordination confirming the crystal structure. Magnetic studies of the as synthesized sample depict paramagnetic behaviour at room temperature. The superparamagnetic behaviour was observed at room temperature with no saturation magnetization and hysteresis in the region of measured field strength. These measurements as a function of temperature and field strength showed a reduction in ferrimagnetic temperature Tc = 41K as compared to those reported for the bulk Tc = 43K