Fe/Fe3O4 nanocomposite powders with giant high magnetization values by high energy ball milling.

The present work reports on the relatively higher saturation magnetization values of Fe/Fe₃O₄ nanocomposites. For example, the nanocomposites of Fe obtained after milling for 10 h with 5, 10 and 15 wt% of Fe₃O₄ had displayed saturation magnetization values of 210, 238 and 216 Am² kg^–1, respectively, in contrast to 218 Am² kg^–1 of bulk Fe. Similarly, the maximum magnetization values for the nanocomposites after 20 and 30 h of milling were 215 and 190 Am² kg^–1 for the sample containing 5 and 15 wt% of Fe₃O₄, respectively. The values of H_C and M_r suggest that nanocomposites exhibit soft ferromagnetic behaviour. The ball milling also reduced the crystallite and particle size of Fe from microndimension to nanometres. This was confirmed from X-ray diffraction, transmission electron microscopy and scanning electron microscopy analyses. The crystallite size of pure Fe decreased to 35, 20 and 19 nm, respectively, for the samples having 5, 10 and 15 wt% of Fe₃O₄ after 10 h of milling. The crystallite size decreased further with increased milling time. [ABSTRACT FROM AUTHOR]