Dynamic magnetic behaviour and Mössbauer effect measurements of magnetite nanoparticles prepared by a new technique in the co-precipitation method

Nanoparticles of magnetite (Fe3O4) were prepared by a simple co-precipitation method where a new technique has been employed in this method. Anhydrous ferric chloride (FeCl3) and ferrous chloride tetrahydrate (FeCl2 ⋅4H2O) were used as precursor materials for the preparation of Fe3O4. An X-ray diffraction (XRD) pattern and high resolution transmission electron microscopy (HRTEM) of the as dried sample clearly indicate the formation of the magnetite phase of the sample. ac hysteresis loops in the frequency range of 10-400 Hz and a Mössbauer spectrum of the as prepared sample were observed at room temperature and at ∼∼20 K. Various magnetic properties viz., coercive field, ac magnetisation, hysteresis loss etc. were also extracted from the observed loops. Results of ac magnetic and room temperature Mössbauer effect measurements indicate the presence of superparamagnetic relaxation of the nanoparticles.