Study of CoFe2O4/NiFe2O4 nanocomposite ferrite film

Electroless nanostructured films of hard ferrite (CoFe2O4), soft ferrite (NiFe2O4) and composite ferrite CoFe2O4/NiFe2O4 (hard/soft ferrite) were deposited on soda lime glass. The structures and magnetic properties of samples were characterised by X-ray powder diffraction, field emission scanning electron microscopy and superconducting quantum interference device (SQUID, MPMSXL). The results of magnetic properties revealed that the saturation magnetisation (M-s), remanent magnetisation (M-r), coercivity (H-c) and M-r/M-s ratio of composite ferrite film (CoFe2O4/NiFe2O4) were higher than those of a single hard ferrite film (CoFe2O4) and soft ferrite film (NiFe2O4). The enhancement in magnetic properties of composite ferrite film (CoFe2O4/NiFe2O4) may be attributed to the exchange coupling interaction between hard magnetic and soft magnetic materials. The mean crystallite size of soft ferrite (NiFe2O4), hard ferrite (CoFe2O4) and composite ferrite films (CoFe2O4/NiFe2O4) was found to be in the range of 20-40nm. The exchange-spring interaction mechanism was discussed.