Multiple Ordering and the Low-Temperature Phase Transition inFe3O4

Abstract

The multiple-ordering theory of the low-temperature transition in ${\mathrm{Fe}}_3$ ${\mathrm{O}}_4$ is established by observation of two peaks in the heat capacity and by changes in the shapes of the Mössbauer lines, both occurring between 113 and 123 K. The two transitions are believed to arise from different mechanisms and the shapes of the heat-capacity peaks respond differently to impurities. Concern about the predictions of the theory regarding the low-temperature phase is occasioned by the paucity of structural data.