Study of CoFe₂O₄/NiFe₂O₄ nanocomposite ferrite film

Abstract

Electroless nanostructured films of hard ferrite (CoFe 2 O 4 ), soft ferrite (NiFe 2 O 4 ) and composite ferrite CoFe 2 O 4 /NiFe 2 O 4 (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 (CoFe 2 O 4 /NiFe 2 O 4 ) were higher than those of a single hard ferrite film (CoFe 2 O 4 ) and soft ferrite film (NiFe 2 O 4 ). The enhancement in magnetic properties of composite ferrite film (CoFe 2 O 4 /NiFe 2 O 4 ) may be attributed to the exchange coupling interaction between hard magnetic and soft magnetic materials. The mean crystallite size of soft ferrite (NiFe 2 O 4 ), hard ferrite (CoFe 2 O 4 ) and composite ferrite films (CoFe 2 O 4 /NiFe 2 O 4 ) was found to be in the range of 20–40 nm. The exchange-spring interaction mechanism was discussed.