The exchange bias effect in CoFe2O4/NiO nanocomposites prepared by chemical co-precipitation method

In this work, we report the synthesis of CoFe 2 O 4 /NiO nanocomposite systems via soft chemical co-precipitation method. Four samples (RM-1, RM-2, RM-3 and RM-4) were prepared with different weight percentage of NiO varying from 10% to 40%. Room temperature x-ray diffraction patterns of all the samples showed the presence of cubic spinel phase of cobalt ferrite with NiO phase without trace of any kind impurities. The magnetization M-H loops were recorded under field cool regime at 5 K and room temperature for all samples. Enhanced coercivity and exchange bias were observed with decrease of NiO weight percentage in the systems. Magnetic measurements showed that nanocomposite system RM-1 has high coercivity H C = 13.12 kOe and exchange bias H EB = 555 Oe at 5 K. Small amount of exchange bias was found in all nano composite system due to presence of weak interfacial spins coupling at room temperature.