High-temperature x-ray study of the system Fe3O4-Mn3O4

A series of compositions in the system Fea04-Mna04 was prepared and examin ed at high temperatures by X-ray diffraction methods. Although Fea04 and Mna0 4 form a continuous series of substitutional solid solutions stable at room temperatures, t hose compositions co ntaining less than 60 percent of Mna04 are cubic, of the spinel type, and the rest are t etragonal. Those compositions t hat are teg ragonal at room temperature pass through a two-phase region when heated and acquire the cubic spinel-type structure at high temperatures. The temperature range of t he t wo-phase (exsei~n ) region varies with composition.