CO-DOPED FERRITE SINGLE DOMAINS AND THE EFFECT OF METALLIC NANOINCLUSIONS

Magnetic properties measurements were performed on metal-ferrite compo sites prepared by coprecipitation of Co and Fe chlorides at various Co /Fe ratios. The microstructure can be described as octahedrally shaped ferrite particles with nanometric CoFe alloy inclusions, Upon elimina tion of the metallic fraction, and increase in coercive field H-c and a decrease in saturation magnetization M(s) were observed. Scanning el ectron microscopy observations revealed that ferrite particles were in micron range, with a narrow size distribution. The composite magnetic properties can be interpreted in terms of a nanostructured exchanged- coupled system, while the ferrite-only magnetic behavior is close to a single-domain, Stoner-Wohlfarth system. (C) 1996 American Institute o f Physics.