Influence of Co/Fe ratios on the structures and the magnetic properties of FexCo1−x/CoyFe1−yFe2O4

The metal–ferrite composites FexCo1−x/CoyFe1−yFe2O4 are synthesized by using disproportion of Fe(α) and reduction of Co(α) by Fe0 in a concentrated and boiling KOH solution. The structures and magnetic properties are investigated by XRD and VSM. XRD shows that the samples without calcinations contain b.c.c, f.c.c and spinel structures; the samples with 300 °C calcinations contain b.c.c and spinel structures; and the samples with 500 °C calcinations contain f.c.c and spinel structures. Magnetic measurement shows that the sample with Co/Fe=0.9 and without calcinations has the maximal coercive field of 2504.44 Oe and the sample with Co/Fe=0.3 and without calcinations has the maximal saturation magnetization of 94.69 emu/g corresponding to the maximal remnant magnetization of 28.47 emu/g.