Tuning exchange bias effects in Co₃C/CoFe₂O₄ magnetic nanocomposites.

Co₃C/CoFe₂O₄ nanocomposite were successfully synthesized via polyol reduction and glycolate precursor decomposition, followed by hydrothermal-assisted nanocomposite formation. The morphology and structure of the nanocomposite were characterized by Scanning electron microscopy (SEM) and X-ray powder diffraction. The hysteresis loop was recorded by varying applied magnetic fields from -3T to 3T for 50K-300K temperature values. The temperature-dependence of the field-cooled and the zero-field-cooling magnetization were investigated from room temperature to 50 K for H = 200 Oe. The saturation magnetization was found 53.14 emu/g and Coercivity 654.7Oe at 300K temperature. Moreover, The coercivity was found to be enhanced to about 7899.36 Oe at 50 K while shifting in the hysteresis loops due to the exchange-bias effect were also observed reaching 169 Oe. The blocking temperature for this nanocomposite system was also found to be 92.8K. Analysis of data shows the exchange bias increasing at low temperature. The maximum energy density (BH)max of the nanocomposite is 2.085MGOe at 300K and magnetic anisotropy constant ranges from 0.1005-1.3879×10^5 J/m3 for 300K-50K temperatures.