One-step processing of spinel ferrites via the high-energy ball milling of binary oxides

MnZn ferrites have been produced via the high-energy ball milling of binary oxide precursors. The milled ferrites have a nonequilibrium cation site distribution, with an unusually high population of Zn cations on the octahedral sites. The particle size distribution drops precipitously with milling time from 60+/-1 to similar to14+/-1 nm at 10 h, but increases to 18.5+/-1 nm after long durations (20-40 h) concurrent with the formation of nearly pure ferrite. A 1 h anneal at 673 K facilitates a redistribution of cations to their near equilibrium sites. This processing approach circumvents the need for deleterious high-temperature heat treatments that often lead to nonstoichiometries in the resulting ferrites. (C) 2003 American Institute of Physics.