Magnetic properties of nanocomposites containing Fe-Ni or Fe dispersed in a Mn-Zn ferrite matrix

Composites have been prepared from Mn-Zn and Fe or Fe/sub 25/Ni/sub 75/ nanostructured powders, by melting in a planetary mill, compaction, and subsequent annealing. A solid state oxido-reduction reaction between iron and ferrite degrades the magnetic properties. On the other hand, Permalloy, which is more resistant to this reaction, results in soft magnetic nanocomposites which possess a magnetization higher than those of good ferrites.