The structure of nanoparticle manganese zinc ferrites synthesized by a reverse micellar method is determined by analysis of the extended x-ray-absorption fine structure in combination with other techniques. Both empirical and theoretical standards are employed; manganese, zinc, and iron edges are refined simultaneously. It is determined that samples synthesized under similar conditions sometimes exhibit a markedly different distribution of cations between the available sites in the spinel structure; this in turn causes significant differences in the magnetic properties of the samples. In addition, it is found that the mean-square displacements for manganese-oxygen bonds are consistently higher than for zinc-oxygen bonds, perhaps due to the presence of manganese ions of more than one valence.

• Received 12 July 2002

DOI:https://doi.org/10.1103/PhysRevB.66.224405