Co-doped ferrite single domains and the effect of metallic nanoinclusions

Magnetic properties measurements were performed on metal–ferrite composites 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 elimination of the metallic fraction, and increase in coercive field Hc and a decrease in saturation magnetization Ms were observed. Scanning electron 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.